bluuebunny/crossref_metadata_2025_split huggingface dataset:
Compression hysteresis of fibrous systems
Authors: Stankovic Snezana B. 
Published: February 2008

AbstractThis investigation deals with the compression of fibrous systems with oriented distribution of fibers into yarns, which are incorporated in a particular way into fabrics (by weft knitting technology). The compression phenomenon was investigated from both experimental and theoretical aspects. The knitted fabrics were subjected to successive compression–release cycles. According to the compression–release curves obtained, the viscoelastic response of the fibrous materials was determined. In such a way, the mechanical model based on van Wyk's compression theory was applied successfully to determine the compression hysteresis, although it is considered that the theory does not explain mechanical hysteresis of fiber assembly. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Foam formation from fluorinated polyphosphazenes by liquid CO2 processing
Authors: Steely Lee B. , Li Qixiu , Badding John V. , Allcock Harry R. 
Published: February 2008

AbstractThree dimensional foams of fluorinated polyphosphazenes were prepared using liquid CO2 to solvate polymer films, which were then expanded by volatilization of liquid CO2 within the polymer matrix. The polymers dissolved in CO2 at 1.5 × 107 Pa (2200 psi) and room temperature. Materials were examined using Raman spectroscopy before and during high pressure CO2 exposure. The solubility in liquid CO2 is attributed to interactions between the solvent and the fluorine atoms in the polymer side groups. Fluoroalkoxy polyphosphazenes are known for their hydrophobicity and fire retardant properties, and these characteristics are retained in the foams. Scanning electron microscopy, water swelling, and preliminary fire retardance tests were conducted to determine the morphology and properties of the foams. These materials are possible candidates for a number of different engineering applications. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Effects of welding procedures on mechanical and morphological properties of hot gas butt welded PE, PP, and PVC sheets
Authors: Balkan Onur , Demirer Halil , Ezdeşir Ayhan , Yıldırım Hüseyin 
Published: February 2008

AbstractMechanical and morphological properties of hot gas butt welds on polyethylene (PE), polypropylene (PP), and polyvinyl chloride (PVC) sheets for four different procedures, which are single and double V‐welds with and without a welding shoe, were investigated. Besides, weldabilities of base materials were evaluated by rheological measurements. These revealed that weldabilities of PE and PP sheets were better than that of PVC. Welding energy (Ew), which is transferred onto weld surfaces, was calculated to evaluate weld quality. The results of tensile, impact, and bending tests indicated that the weld strengths of PVC sheets were lower than those of PE and PP sheets. When the welding shoe was used, weld strength increased significantly for each material because of the presence of sufficient welding pressure and the effective heating on surfaces. The best results were attained for the double V‐welds with the welding shoe. Morphology of welded regions was evaluated by polarized light, stereo, and scanning electron microscopy. Polarized light microscopy studies indicated that the heat‐affected zone (HAZ) consisted of welding rod core, molten zone, and deformed spherulitic zone, and the welding interface was indistinguishable from the base material when the welding pressure was enough. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Electrical performance evaluation of low‐concentrating non‐imaging photovoltaic concentrator
Authors: Mallick Tapas K , Eames Philip C 
Published: February 2008

AbstractSecond generation prototype photovoltaic facades of reduced costs incorporating devices with optically concentrating elements (PRIDE) incorporate 6 mm wide ‘Saturn’ solar cells at the absorber of the dielectric concentrator. The concentrators were made using injection moulding technique with potential to manufacture in large‐scale applications. Four different concentrator panels have been experimentally verified at outdoors to identify the non‐identical current–voltage (I–V) curves. The I–V curve, fill factor and solar to electrical conversion efficiency of four PRIDE concentrator modules have been evaluated from the 24 manufactured in the ‘IDEOCONTE’ project. The maximum solar to electrical conversion efficiency and the fill factor of the PRIDE concentrator were 9·1 and 70%, respectively. The mismatch loss of the ‘unit concentrators’ has been identified that occurred due to the lack of bonding between the concentrator unit and the solar cell and the rear glass. The average power concentration ratio of PRIDE concentrators manufactured by the improved method was 2·10 compared to a similar non‐concentrating panel and the optical efficiency of the PRIDE system was 83%. Copyright © 2008 John Wiley & Sons, Ltd.
A decremental PEEP trial for determining open‐lung PEEP in a rabbit model of acute lung injury
Authors: Hua Yi‐Ming , Lien Shao‐Hung , Liu Tao‐Yuan , Lee Chuen‐Ming , Yuh Yeong‐Seng 
Published: February 2008

AbstractA positive end‐expiratory pressure (PEEP) above the lower inflection point (LIP) of the pressure–volume curve has been thought necessary to maintain recruited lung volume in acute lung injury (ALI). We used a strategy to identify the level of open‐lung PEEP (OLP) by detecting the maximum tidal compliance during a decremental PEEP trial (DPT). We performed a randomized controlled study to compare the effect of the OLP to PEEP above LIP and zero PEEP on pulmonary mechanics, gas exchange, hemodynamic change, and lung injury in 26 rabbits with ALI. After recruitment maneuver, the lavage‐injured rabbits received DPTs to identify the OLP. Animals were randomized to receive volume controlled ventilation with either: (a) PEEP = 0 cm H2O (ZEEP); (b) PEEP = 2 cm H2O above OLP (OLP + 2); or (c) PEEP = 2 cm H2O above LIP (LIP + 2). Peak inspiratory pressure and mean airway pressure were recorded and arterial blood gases were analyzed every 30 min. Mean blood pressure and heart rate were monitored continuously. Lung injury severity was assessed by lung wet/dry weight ratio. Animals in OLP + 2 group had less lung injury as well as relatively better compliance, more stable pH, and less hypercapnia compared to the LIP + 2 and ZEEP groups. We concluded that setting PEEP according to the OLP identified by DPTs is an effective method to attenuate lung injury. This strategy could be used as an indicator for optimal PEEP. The approach is simple and noninvasive and may be of clinical interest. Pediatr Pulmonol. 2008; 43:371–380. © 2008 Wiley‐Liss, Inc.
Glyphosate applied at low doses can stimulate plant growth
Authors: Velini Edivaldo D , Alves Elza , Godoy Maria C , Meschede Dana K , Souza Reginaldo T , Duke Stephen O 
Published: February 2008

AbstractBACKGROUND:Glyphosate blocks the shikimic acid pathway, inhibiting the production of aromatic amino acids and several secondary compounds derived from these amino acids. Non‐target plants can be exposed to low doses of glyphosate by herbicide drift of spray droplets and contact with treated weeds. Previous studies have reported that low doses of glyphosate stimulate growth, although these data are very limited. The objective of this study was to determine the effects of low glyphosate doses on growth of a range of plant species.RESULTS:Growth of maize, conventional soybean, Eucalyptus grandis Hill ex Maiden, Pinus caribea L. and Commelia benghalensis L. was enhanced by 1.8–36 g glyphosate ha−1. Growth of glyphosate‐resistant soybean was unaffected by any glyphosate dose from 1.8 to 720 g AE ha−1. The optimum doses for growth stimulation were distinct for plant species and tissue evaluated. The greatest stimulation of growth was observed for C. benghalensis and P. caribea. Shikimic acid levels in tissues of glyphosate‐treated soybean and maize were measured and found to be elevated at growth‐stimulating doses.CONCLUSION:Subtoxic doses of glyphosate stimulate the growth of a range of plant species, as measured in several plant organs. This hormesis effect is likely to be related to the molecular target of glyphosate, since the effect was not seen in glyphosate‐resistant plants, and shikimate levels were enhanced in plants with stimulated growth. Copyright © 2008 Society of Chemical Industry
Pentacene devices: Molecular structure, charge transport and photo response
Authors: Nickel Bert , Fiebig Matthias , Schiefer Stefan , Göllner Martin , Huth Martin , Erlen Christoph , Lugli Paolo 
Published: February 2008

AbstractIn this feature article, we will discuss to which extend the peculiar growth properties of pentacene on metallic contacts and on gate dielectrics contribute to the device performance of organic thin film transistors. The early growth state of pentacene monolayers is reviewed, as well as the molecular structure of the so called thin film phase. Then, the relation of structural defect densities to trap densities is discussed. The spatially resolved photo response of a pentacene transistor will be presented in the context of injection barriers and contact homogeneity. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characteristics and mechanisms of hysteresis in polymer field‐effect transistors
Authors: Paasch G. , Scheinert S. , Herasimovich A. , Hörselmann I. , Lindner Th. 
Published: February 2008

AbstractHysteresis effects do occur usually in polymer field‐effect devices. It has been suggested that trap recharging or mobile ions, or formation/dissociation of bipolarons (BP) in the accumulation layer can cause this effect. Here, at first a literature survey on the hysteresis in field‐effect transistors is given. Then examples of measured hysteresis in field‐effect transistors and in metal‐insulator‐semiconductor (MIS) capacitors are presented. The typical peculiarity is the dependency of the flat band voltage on the sweep direction of the gate voltage. Our recent numerical simulations on the trap recharging mechanism in MIS capacitors are continued and extended to transistors. Energetically distributed traps can lead to hysteresis. But the form of the hysteresis deviates from the observed one and extreme parameter values are needed. Thus it is more likely that trap recharging can modify a hysteresis caused by another mechanism. For discussing the bipolaron mechanism the equilibrium between polarons and doubly charged states of the polymer chains was analyzed anew. With a rate constant for the bipolaron formation determined recently by Salleo and Street relaxation times for formation/dissociation are determined. They indicate that these processes can cause the hysteresis. A further possible mechanism influencing the hysteresis is connected with complexes between polarons, bipolarons and mobile counter ions. The estimated rate constants indicate processes on the time scale of the measurements. Numerical simulations of these processes as well as of the role of mobile ions and their reactions are required for a full description of the hysteresis. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Novel organic semiconductors and processing techniques for organic field‐effect transistors
Authors: Tsao H. N. , Räder H. J. , Pisula W. , Rouhanipour A. , Müllen K. 
Published: February 2008

AbstractThe performance of organic field‐effect transistors (FETs) is dictated by the active material employed in such devices. The tendency of the molecules to self‐assemble into highly ordered structures greatly influences charge carrier transport. Also, with the ultimate goal to realize easily produced, cheap and large area electronics, solution processing is crucial. In this aspect, we synthesized dodecyl substituted hexa‐peri ‐hexabenzocoronene HBC‐C12 which is a soluble disk‐shaped molecule with the tendency to pack into columnar stacks. We devised a zone‐casting technique that uniaxially aligned these molecules, enabling the solution processing of macroscopically ordered semiconducting layers, resulting in an improvement of the charge carrier mobility of up to two orders of magnitude compared to non‐oriented films. Furthermore, a donor‐acceptor copolymer was deposited from solution, giving a charge carrier mobility of µsat = 0.17 cm2/Vs even though no macroscopic order could be observed. This is surprising since any disorder acts as trapping sites and inhibits charge carrier transport. We explain this phenomenon by a close π‐stacking distance of the backbones. Finally, giant graphene molecules were successfully deposited via a novel soft‐landing technique, allowing the processing of insoluble molecules into highly oriented and pure thin films. This is a promising way for achieving high performance FETs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Molecular beam deposition and characterization of thin organic films on metals for applications in organic electronics
Authors: Witte G. , Wöll Ch. 
Published: February 2008

AbstractThe deposition of organic thin films on metal substrates using molecular beam deposition will be reviewed with a special emphasis on molecules which exhibit high charge carrier mobilities and are thus suited to be used as organic semiconductors (OSCs), namely pentacene, rubrene and perylene. Special emphasis will be on aspects of organic molecular beam deposition (OMBD) relevant for the device performance in organic field effect transistors (OFETs), in particular with regard to avoiding or minimizing structural defects at support/OSC interfaces. In addition, another aspect governing – and often limiting – charge injection at electrodes into an OSC, electronic level alignment at molecule/metal interfaces, will be discussed in the context of recent accurate ab‐initio electronic structure calculations. Finally, we will present a novel experimental approach to determine charge transport properties of defect‐free, nm‐sized OSCs where extrinsic contributions to e.g. charge carrier mobilities can be strictly excluded, thus opening the way towards the determination of true intrinsic OSC properties. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Percolation on dual lattices with k‐fold symmetry
Authors: Bollobás Béla , Riordan Oliver 
Published: February 2008

AbstractZhang found a simple, elegant argument deducing the nonexistence of an infinite open cluster in certain lattice percolation models (for example, p = 1/2 bond percolation on the square lattice) from general results on the uniqueness of an infinite open cluster when it exists; this argument requires some symmetry. Here we show that a simple modification of Zhang's argument requires only two‐fold (or three‐fold) symmetry, proving that the critical probabilities for percolation on dual planar lattices with such symmetry sum to 1. Like Zhang's argument, our extension applies in many contexts; in particular, it enables us to answer a question of Grimmett concerning the anisotropic random cluster model on the triangular lattice. © 2008 Wiley Periodicals, Inc. Random Struct. Alg., 2008
Seasonal Growth Rate of the Sponge Haliclona oculata (Demospongiae: Haplosclerida)
Authors: Koopmans Marieke , Wijffels René H. 
Published: February 2008

AbstractThe interest in sponges has increased rapidly since the discovery of potential new pharmaceutical compounds produced by many sponges. A good method to produce these compounds by using aquaculture of sponges is not yet available, because there is insufficient knowledge about the nutritional needs of sponges. To gain more insight in the nutritional needs for growth, we studied the growth rate of Haliclona oculata in its natural environment and monitored environmental parameters in parallel. A stereo photogrammetry approach was used for measuring growth rates. Stereo pictures were taken and used to measure volumetric changes monthly during 1 year. Volumetric growth rate of Haliclona oculata showed a seasonal trend with the highest average specific growth rate measured in May: 0.012 ± 0.004 day−1. In our study a strong positive correlation (p < 0.01) was found for growth rate with temperature, algal biomass (measured as chlorophyll a), and carbon and nitrogen content in suspended particulate matter. A negative correlation (p < 0.05) was found for growth rate with salinity, ammonium, nitrate, nitrite, and phosphate. No correlation was found with dissolved organic carbon, suggesting that Haliclona oculata is more dependent on particulate organic carbon.
Building Capacity of State Adolescent Pregnancy Prevention Coalitions to Implement Science‐Based Approaches
Authors: Rolleri Lori A. , Wilson Mary Martha , Paluzzi Patricia A. , Sedivy Valerie J. 
Published: February 2008

AbstractA central question in adolescent reproductive health circles is how to effectively disseminate research to practitioners in a way that supports them in using the most scientifically sound and effective programming. In 2002, the Division of Reproductive Health at the Centers for Disease Control and Prevention (CDC) tackled this question by funding three national‐level and five state‐level organizations focused on adolescent pregnancy prevention to promote the use of science‐based programs and approaches. Healthy Teen Network (HTN) and Education, Training and Research Associates (ETR), two national organizations, have partnered under this CDC funding to implement an effective model for capacity building. This paper provides an overview of the approaches used by HTN and ETR in capacity building using a seven‐step process. We describe how we modified the Interactive Systems Framework for Dissemination and Implementation (ISF) for science‐based innovations to apply to capacity‐building for adolescent reproductive health (ARH) programs, and how we developed relevant, sustainable training and technical support. We conclude by reviewing some of the results of this training, and discuss the future work that will likely continue to advance the science behind effective dissemination of ARH research to practice.
EuroGentest
Authors: Cassiman J.-J. 
Published: February 2008

Zusammenfassung
Dank der begeisterten Hilfe Tausender europäischer Humangenetiker, die sich direkt und indirekt an der Umsetzung der Ziele des Exzellenznetzwerks (NoE) EuroGentest beteiligt haben und mit der Unterstützung der European Society of Human Genetics (ESHG) hat EuroGentest in den ersten drei Jahren eine Reihe von Produkten geliefert, die der „Genetics Community“ helfen können, ihre Dienstleistungen zu verbessern und zu harmonisieren. EuroGentest wurde dadurch zu einem Markenzeichen für die Qualität europäischer Genetikeinrichtungen und hat eine in Europa beispiellose Bewegung zur Verbesserung der Qualität der Einrichtungen und zur Harmonisierung der entsprechenden Dienstleistungen angestoßen. Viele der hier genannten Aktivitäten und Ergebnisse tragen dazu bei, dass Forschungsergebnisse rasch in die Diagnostik übernommen werden können und schaffen die Voraussetzung dafür, dass dies auch in Zukunft gewährleistet ist, so daß die Bürger schnell und effizient von den täglichen Fortschritten in der genetischer Forschung profitieren können.
Modelling the reproductive efficiency in a beef cow herd: effect of calving date, bull exposure and body condition at calving on the calving–conception interval and calving distribution
Authors: BLANC F. , AGABRIEL J. 
Published: February 2008

SUMMARYA model of reproductive performance was developed to study the influences of breeding management decisions and animal characteristics on the reproductive performance and the calving distribution in a beef herd. In the model, reproductive performance is formalized as a sequence of events (parturition, ovulation, conception), each of which modifies the reproductive status of the simulated cow. With respect to reproduction, a cow can be in one of three possible states: open-not-cycling, open-cycling or pregnant. The length of the different intervals that are included between two successive reproductive events (calving to first cycle interval, length of oestrous cycles, calving–conception and calving intervals) is formalized using stochastic or empirical laws that may be influenced by numerous animal or environmental factors or by management decisions (feeding strategy, breeding season and length of the breeding period). Within the herd, cows are considered to differ from each other by their parity, calving date, body condition at calving and their bull exposure.Calving to first oestrous interval (postpartum anoestrous interval (PPAI)) is expressed as the sum of three equations which formalize the respective effects of calving date, body condition score at calving (BCScalving) and the response to early bull exposure in interaction with BCScalving. The influences of these variables on reproductive performance were quantified by analysing data sets (three bibliographical and two experimental) or by expertise. Special attention was paid to the influence of calving date on PPAI and a biological interpretation of this effect is proposed. Probabilities of natural insemination success were estimated according to the number of oestrus and the number of matings.The model was fitted to data from primiparous Charolais cows (n=139) bred at the experimental station Laqueuille (French National Institute for Agricultural Research (INRA)). Its ability to simulate PPAI was tested using an independent data set of primiparous Charolais cows (n=188) from the experimental farm Le Pin. The model only accounts for 39% of the observed inter-individual variability. However, the analysis of the mean square deviation components led to validation of the structure of the model. In particular, the assumption that the influence of calving date on PPAI can be attributed to a sensitivity of the reproductive function to the variation of the photoperiod during the month preceding parturition was confirmed. Simulations also revealed that fat cows could have similar anoestrus to thin cows when they are exposed early to a bull. Such a result emphasized the necessity to investigate further and better calibrate the combined effects of BCS at calving and bull exposure on PPAI.
Botulinum toxin A for quality of life improvement in post-parotidectomy gustatory sweating (Frey's syndrome)
Authors: Hartl D M , Julieron M , LeRidant A-M , Janot F , Marandas P , Travagli J-P 
Published: February 2008

AbstractObjective:To measure patient-reported quality of life before and after botulinum toxin A treatment of post-parotidectomy Frey's syndrome (gustatory sweating).Patients and methods:A questionnaire concerning functional, social and emotional aspects of Frey's syndrome (14 questions, with responses on a zero to three point scale) was administered to 17 patients (13 women and four men) before and one month after intradermal injection of botulinum toxin A. Parotidectomy had been performed one to 19 years previously, for benign (n = 10) or malignant (n = 7) tumours, with gustatory sweating occurring a median of 15 months after surgery (range: one month to 14 years). Pre- and post-treatment quality of life scores were compared using Wilcoxon's test (p < 0.05).Results:Patients' reported functional quality of life improved significantly (p = 0.0004). Their social and emotional scores were not significantly modified (p = 0.155 and 0.142, respectively). Seven patients (41 per cent) found the injections painful, but all patients said that the effects were beneficial, that they would undergo new injections if necessary and that they would recommend this treatment to other patients. The benefit lasted over 1.5 years for 60 per cent of patients. No correlation was found between duration of the effect and the extent of parotidectomy (p = 0.067).Conclusions:Botulinum toxin A significantly improved patients' functional quality of life, without significant improvement in their social or emotional quality of life, according to our questionnaire results. The duration of the effect was longer than the reported physiological effect of botulinum toxin A on acetylcholine receptors.