bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reinforcement of Polymeric Submicrometer‐sized Fibers by Microfibrillated Cellulose
Authors: Fortunato Giuseppino , Zimmermann Tanja , Lübben Jörn , Bordeanu Nico , Hufenus Rudolf 
Published: May 2012

AbstractTo improve their mechanical properties, biodegradable network‐forming microfibrillated cellulose (MFC) is introduced into PEO fibers by an electrospinning (e‐spinning) procedure. The influence of MFC is investigated with respect to e‐spinning process parameters as well as morphological and mechanical properties of the fibers. The determination of the Young's modulus is established using both macro‐tensile testing procedures of aligned fiber patches and AFM on single fibers. Highly filled fiber systems are obtained, showing an enhancement of Young's modulus by a factor of up to ten compared to pure PEO fibers. The morphological investigations reveal fibers with circular cross‐sections incorporating homogeneously dispersed MFC within the polymer matrix. The introduction of MFC has no relevant effect on processing and the appearance of the fiber.magnified image
The population impact of screening for Down syndrome: audit of 19 326 invasive diagnostic tests in England and Wales in 2008
Authors: Morris Joan K. , Waters Jonathan J. , de Souza E. 
Published: May 2012

ABSTRACTObjectivePregnant women who receive a high screening risk result for Down, Edwards or Patau syndrome are offered diagnostic tests that carry a risk of miscarriage. This study determined how many women had such tests per syndrome diagnosis.MethodThe number of tests per Down, Edwards or Patau syndrome diagnosis adjusted for maternal and gestational age at diagnosis was calculated using routine data from 18 (95%) cytogenetic laboratories in England and Wales in 2008.ResultsThere were 19 326 tests that identified 1118 diagnoses of Down syndrome and 615 of Edwards and Patau syndromes. There were eight chorionic villus samplings (CVS) per syndrome diagnosis compared with 16 amniocenteses (gestational age adjusted). The lowest number of tests per diagnosis (three for CVSs and for amniocentesis) resulted from an abnormal ultrasound scan. Among pregnant women, 2.9% had an invasive diagnostic test. If a CVS and an amniocentesis increase the risk of a miscarriage by 1% and 0.5%, respectively, approximately one miscarriage for every 14 Down, Edwards or Patau syndrome diagnosis would have occurred.ConclusionA simple measurement of the population impact of screening for Down syndrome can be calculated using data already collected. Annual estimates should be produced to monitor the national fetal anomaly screening programme. © 2012 John Wiley & Sons, Ltd.
Effect of interrupting prenatal Down syndrome screening due to a large nuchal translucency
Authors: Wald Nicholas J. , Bestwick Jonathan P. , Huttly Wayne J. 
Published: May 2012

ABSTRACTObjectiveThe aim of this study is to determine the effect of interrupting prenatal Down syndrome screening for women with large nuchal translucency (NT) measurements on the performance of combined and integrated tests.DesignDistribution of large NT at 11–13 weeks of gestation was determined from a screening programme (204 982 pregnancies, 509 with Down syndrome). Monte Carlo simulation was used to estimate the effects of interrupting screening on the detection rate (DR) and false‐positive rate (FPR) in (i) the remaining women and (ii) all women.ResultsAt 12 weeks of gestation, 28% of affected (76/275) and 0.4% of unaffected (389/107 386) pregnancies had an NT of ≥3.5 mm. Among the remaining women, for an 85% DR, combined test FPR was 7.2% with interpretation of screening but 4.1% without interruption (1.8% and 0.9% respectively for integrated test). Among all women (women who interrupted screening with an NT of ≥3.5 mm and a 1/150 risk cut‐off for others), the FPR was 0.1 and 0.2 percentage points higher for the same DR at 12–13 weeks compared with no interruption using the combined and integrated tests, respectively, and 0.3 and 0.7 percentage points higher at 11 weeks.ConclusionInterrupting combined or integrated screening is acceptable using an NT of ≥3.5 mm, but screening performance in screened women will seem less than expected. This should be taken into account when performing audits. © 2012 John Wiley & Sons, Ltd.
Fetal sex determination using cell‐free fetal DNA: service users' experiences of and preferences for service delivery
Authors: Lewis Celine , Hill Melissa , Skirton Heather , Chitty Lyn S. 
Published: May 2012

ABSTRACTObjectiveThe aim of this study was to determine service users' experiences of and preferences for service delivery of fetal sex determination by noninvasive prenatal diagnosis (NIPD) using cell‐free fetal DNA.MethodsWe used a qualitative approach using semistructured interviews. Thirty‐eight women and six of their partners were recruited.ResultsNIPD was viewed as a positive development, which facilitated reproductive autonomy as it expanded reproductive choice. The majority of women heard about NIPD during pregnancy and had received information about the test at a specialist centre. Features of NIPD women considered most important were that it could be performed early in pregnancy and was safe. Participants had a preference for being given information about NIPD and test results by a healthcare professional experienced in genetic testing and with specialist knowledge about their condition, rather than a general practitioner or midwife who may not have the same level of knowledge. Women also valued receiving their test results by telephone.ConclusionWomen were overwhelmingly positive about their experience of NIPD, which suggests that current delivery of this service in England is acceptable to these patients who are at high risk of sex‐linked genetic disorders. They particularly valued expert counselling both before and after testing, emphasising that it should be offered through specialist services. © 2012 John Wiley & Sons, Ltd.
Enhanced mechanical and thermal properties of rigid polyurethane foam composites containing graphene nanosheets and carbon nanotubes
Authors: Yan Dingxiang , Xu Ling , Chen Chen , Tang Jianhua , Ji Xu , Li Zhongming 
Published: May 2012

AbstractThe comparative study of rigid polyurethane foam (RPUF) nanocomposites based on graphene nanosheets (GNSs) and carbon nanotubes (CNTs) has been reported. A GNS content of 0.3 wt% in polyol turns to be optimal for its foamability with the isocyanate component, as verified by rheology measurements. Scanning electron microscopy and transmission electron microscopy observations reveal a homogeneous dispersion of GNSs and CNTs in the RPUF nanocomposites. Only 0.3 wt% loading of GNSs and CNTs led to 36% and 25% improvement respectively in the compressive modulus of the RPUF nanocomposites. Meanwhile, 16 °C and 14 °C improvements in the glass transition temperature confirm the important role of both the nanofillers in the heat resistance of RPUF nanocomposites. These results additionally indicate that GNSs work more effectively than CNTs in mechanical property and heat resistance enhancement of the RPUF nanocomposites. The superiority of GNSs over CNTs can be attributed to their wrinkled surface structure, unique two‐dimensional geometrical morphology and higher specific surface area, which results in stronger interaction and restriction of segmental motion at the interface between the GNSs and the RPUF matrix. In addition, changes in the thermal conductivity of the nanocomposites are negligible, indicating that incorporation of GNSs and CNTs will not hinder the application of RPUF nanocomposites as thermal insulators. On the contrary, the enhancement in mechanical properties and heat resistance will undoubtedly expand the application range of polyurethane foam materials. Copyright © 2012 Society of Chemical Industry
Synthesis of polylactide‐based thermoset resin and its curing kinetics
Authors: Chang ShaoKun , Zeng Chao , Li Jianbo , Ren Jie 
Published: May 2012

AbstractA new class of biobased thermoset resins, methacrylated four‐armed star‐shaped polylactides (M4sPLAs), was prepared. The effect of star architecture, e.g. varying arm length, on the properties of the cured products was examined. Based on differential scanning calorimetry, the non‐isothermal and isothermal curing behaviors of these M4sPLAs were investigated. Various curing kinetic parameters were obtained and elucidated using autocatalytic reaction models. Experimental results indicate that the oligomers can be crosslinked into a rigid network within a curing time varying from several minutes to more than an hour upon thermal initiation. The curing processes of M4sPLAs with varying arm length are different and complex, as indicated by the change of various kinetic parameters, reaction orders and evolutions of activation energy under the test reaction conditions. High crosslinking density is especially effective for improving the thermal stability of polylactide, but also leads to slower degradation rate and deterioration of its impact properties. Copyright © 2012 Society of Chemical Industry
Antimicrobial activity of organic photosensitizers embedded in electrospun nylon 6 nanofibers
Authors: Lim Ki Sub , Oh Kyung Wha , Kim Seong Hun 
Published: May 2012

AbstractNylon 6 nanofibers containing organic photosensitizers were investigated to demonstrate the antimicrobial properties in the application of the material to protective clothing and home appliances. Benzophenone (BP), 4, 4′‐bis(dimethylamino)benzophenone (MK) and thioxanthen‐9‐one (TX) were used as photosensitizers and the nylon 6 nanofibers were prepared using electrospinning. Field emission scanning electron microscopy morphology of the nanofibers showed that even and continuous nylon 6 nanofibers were well prepared through electrospinning and that the organic photosensitizers were evenly distributed in the nanofibers. There was no significant reduction of crystallinity in the nylon 6 nanofibers through the insertion of the organic photosensitizers. After UV (365 nm) irradiation of the photosensitizers, the intensity of peak photon excitation in the electron spin resonance spectra was increased. Antimicrobial properties of the prepared nanofibers were tested against Staphylococcus aureus and Escherichia coli according to JIS Z 2801. It was found that antimicrobial properties of nylon 6 nanofibers containing MK and TX were superior to those of nylon 6 nanofibers containing conventionally used BP. The antimicrobial effects of the nanofibers for S. aureus were superior to those for E. coli. The antimicrobial activity gradually increased as the UV irradiation time increased. Copyright © 2012 Society of Chemical Industry
Electrospinning pure protein solutions in core–shell fibers
Authors: Tiwari Sandeep Kumar , Venkatraman Subbu 
Published: May 2012

AbstractElectrospinning of protein‐loaded fibers faces many challenges, e.g. burst release owing to segregation of the protein on the fiber surface, loss of activity due to electrospinning conditions, limitation of loading capacity etc. Core–shell electrospinning provides an effective way to electrospin fibers wherein the core can be loaded with bioactive molecules in friendly conditions of a compatible polymer solution, thereby protecting the molecules from the electrostatic field and organic solvent of shell solutions. The shell polymer, after the electrospinning, acts as a barrier to control the release of the loaded molecules. However, the limitation of loading capacity still remains due the prerequisite of using an additional polymer as additive to achieve the minimum viscosity of the core solution required for viscous drag by the shell solution being drawn by the electrostatic force. The work reported here aims to alleviate the need of a polymer additive by using aqueous protein solutions of very high concentration. High concentrations of protein solutions were successfully electrospun as the core of the protein–poly(lactide‐co‐glycolic acid) core–shell fibers. A partitioning effect was seen in the controlled release of hydrophilic proteins as they were retained in the aqueous core for longer times. Using lysozyme as a model protein, it was shown that the activity is significantly retained after electrospinning, compared with electrospinning in monolithic fibers. Moreover, the lysozyme activity was also comparable with the lysozyme released from core–shell fibers spun using poly(vinyl acetate) as additive in the core. Copyright © 2012 Society of Chemical Industry
Silent reading fluency using underlining: Evidence for an alternative method of assessment
Authors: Price Katherine W. , Meisinger Elizabeth B. , Louwerse Max M. , D'Mello Sidney K. 
Published: May 2012

AbstractAssessing silent reading fluency in classroom environments is challenging. This article reports on a method of assessing silent reading using underlining, an approach that solves many problems other silent reading fluency assessment measures face. This method computationally monitors readers' silent reading fluency by the speed they underline words in a text. Traditional silent reading fluency measures were compared with the new underlining methodology. Fourth‐ and sixth‐grade students completed silent reading fluency measures (i.e., moving windows, underlining, and paper‐and‐pencil reading tasks), along with measures of their oral reading fluency, reading comprehension, and vocabulary knowledge. Strong alternate‐form reliability coefficients were found for underlining, which significantly correlated with other measures of silent reading fluency and reading comprehension. Underlining methodology also correlated with common language factors, such as word length and word frequency. Together, these results provide support for the psychometric properties of underlining and suggest that it is a promising alternative method of assessing silent reading fluency. © 2012 Wiley Periodicals, Inc.
Evaluation of a social cognitive theory‐based email intervention designed to influence the physical activity of survivors of breast cancer
Authors: Hatchett Andrew , Hallam Jeffrey S. , Ford M. Allison 
Published: May 2012

AbstractObjectiveThe aim of this study is to evaluate a 12‐week social cognitive theory (SCT)‐based email intervention designed to influence the physical activity of survivors of breast cancer.MethodsSeventy‐four volunteers (intervention group, n = 36; control group, n = 38) were recruited by mass email and written letter solicitation. Participants completed a series of online questionnaires measuring demographic characteristics, physical activity readiness, level of physical activity and selected SCT variables at baseline, 6 and 12 weeks. The intervention group received email messages based on SCT designed specifically for breast cancer survivors and targeting physical activity. For the first 6 weeks of the intervention, participants assigned to the intervention group received messages weekly, from weeks 7 to 12, participants received messages every other week and had access to an e‐counselor. The control group did not receive email messages, nor did they have access to an e‐counselor.ResultsSignificant differences in levels of self‐reported vigorous physical activity were found between groups at 6 and 12 weeks. Significant differences were also found for self‐reported moderate physical activity at 12 weeks.ConclusionEmail‐based interventions based on SCT can significantly influence levels of self‐reported physical activity of breast cancer survivors.Copyright © 2012 John Wiley & Sons, Ltd.
Uptake and antitumoral effects of iodine and 6‐iodolactone in differentiated and undifferentiated human prostate cancer cell lines
Authors: Aranda Nuri , Sosa Susana , Delgado Guadalupe , Aceves Carmen , Anguiano Brenda 
Published: May 2012

AbstractBACKGROUNDEvidence indicates that iodine per se could be implicated in the physiology of several organs that can internalize it. In thyroid and breast cancer, iodine treatments inhibit cell proliferation and induce apoptosis through a direct (mitochondria) and/or indirect effect (iodolipid generation). Here, we determined the uptake of iodide (I−) and iodine (I2), as well as the antiproliferative and apoptotic effects of 6‐iodolactone (6‐IL) and both forms of iodine in human prostate cells lines.METHODSNon‐cancerous (RWPE‐1) and cancerous (LNCaP, DU‐145) cells, as well as nude mice xenotransplanted with DU‐145 cells were used as cancer models. Iodine uptake was analyzed with radioactive tracers, transporter expression by qRT‐PCR, cell proliferation by blue trypan, apoptosis by enzyme immunoassay or fluorescence, BAX and BCL‐2 by western‐blot, and caspsase 3 by enzymatic assay.RESULTSAll three cell lines take up both forms of iodine. In RWPE‐1 cells, I− uptake depends on the Na+/I− symporter (NIS), whereas it was independent of NIS in LNCaP and DU‐145 cells. Antiproliferative effects of iodine and 6‐IL were dose and time dependent; RWPE‐1 was most sensitive to I− and 6‐IL, whereas LNCaP was more sensitive to I2. In the three cell lines both forms of iodine activated the intrinsic apoptotic pathway (increasing the BAX/BCL‐2 index and caspases). Iodine supplementation impaired growth of the DU‐145 tumor in nude mice.CONCLUSIONNormal and cancerous prostate cells can take up iodine, and depending on the chemical form, it exerts antiproliferative and apoptotic effects both in vitro and in vivo. Prostate 73: 31–41, 2013. © 2012 Wiley Periodicals, Inc.
Analysis of the temperature‐dependent current–voltage characteristics and the barrier‐height inhomogeneities of Au/GaN Schottky diodes
Authors: Roul Basanta , Bhat Thirumaleshwara N. , Kumar Mahesh , Rajpalke Mohana K. , Kalghatgi A. T. , Krupanidhi S. B. 
Published: May 2012

AbstractIn this report, the current–voltage (I–V) characteristics of Au/GaN Schottky diodes have been carried out in the temperature range of 300–510 K. The estimated values of the Schottky‐barrier height (SBH) and the ideality factor of the diodes based on the thermionic emission (TE) mechanism were found to be temperature dependent. The barrier height was found to increase and the ideality factor to decrease with increasing temperature. The conventional Richardson plot of ln(Is/T2) versus 1/kT gives the SBH of 0.51 eV and Richardson constant value of 3.23 × 10−5 A cm−2 K−2 which is much lower than the known value of 26.4 A cm−2 K−2 for GaN. Such discrepancies of the SBH and Richardson constant value were attributed to the existence of barrier‐height inhomogeneities at the Au/GaN interface. The modified Richardson plot of ln(Is/T2)–q2σ/2k2T2 versus q/kT, by assuming a Gaussian distribution of barrier heights at the Au/GaN interface, provided the SBH of 1.47 eV and Richardson constant value of 38.8 A cm−2 K−2. The temperature dependence of the barrier height is interpreted on the basis of existence of the Gaussian distribution of the barrier heights due to the barrier‐height inhomogeneities at the Au/GaN interface.
Exponential stability of slowly varying discrete systems with multiple state delays
Authors: Medina Rigoberto 
Published: May 2012

SUMMARYWe give sufficient conditions for the exponential stability of a class of perturbed time‐varying difference equations with multiple delays and slowly varying coefficients. Under appropriate growth conditions on the perturbations, combined with the ‘freezing’ technique, we establish explicit conditions for global exponential stability. Copyright © 2012 John Wiley & Sons, Ltd.
A scalable NAT‐based solution to Internet access denial by higher‐tier ISPs
Authors: Abu‐Amara Marwan , Al‐Baiz Abdulaziz , Mahmoud Ashraf S. , Sqalli Mohammed H. , Azzedin Farag 
Published: May 2012

ABSTRACTThe Internet is an interconnection of autonomous systems (ASes) that are mostly controlled by Internet service providers (ISPs). ASes use Border Gateway Protocol (BGP) to communicate routing information in the form of reachability paths. However, BGP does not guarantee that the advertised reachability paths will be exactly followed. As a result, traffic belonging to a specific network can be intentionally dropped as it is routed by BGP through a malicious ISP; a behavior we define as Internet access denial. The impact of Internet access denial, especially when performed by higher‐tier ISPs, is significant. In this work, network address translation (NAT) is used as a solution to overcome the Internet access denial problem by hiding the traffic identity. The proposed solution is scalable to fit large networks, by using pools of IP addresses across several NAT routers. Moreover, the proposed solution addresses the server reachability problem that is associated with NAT routers by introducing a novel approach. The performance degradation of introducing NAT is significantly small as shown by our experiments' results. Copyright © 2012 John Wiley & Sons, Ltd.
Die Tragfähigkeit versteifter Blech‐ und Kastenträger in einfacher Näherung
Authors: Herzog Max 
Published: May 2012

AbstractNach einem kurzen Rückblick auf die geschichtliche Entwicklung der Bemessung von Blech‐ und Kastenträgern wird die Aussage verschiedener normengemäßer (DIN 4114 sowie DIN 18800) und nichtnormengemäßer (des Verfassers) Berechnungsverfahren mit dem gemessenen Verhalten großer Blech‐ und Kastenträger verglichen. Dabei wird festgestellt, dass die geltenden Stahlbaunormen mit der Wirklichkeit schlechter übereinstimmen als andere Berechnungsverfahren. Dieser Umstand ist beim Entwurf wichtiger Tragwerke zu beachten, wenn Schadensfälle (z. B. vierte Donaubrücke in Wien) vermieden werden sollen.Ultimate load capacity of stiffened plate and box girders in simple approximation. After a short review of the historical development of dimensioning plate and box girders the statement of different standardized (DIN 4114 and DIN 18800) as well as non‐standardized (author) methods are compared with the measured behavior of full‐size plate and box girders. It shows that the valid standards are in less good agreement with reality than other known methods of dimensioning. This fact must be considered in the design of important structures if damages (e.g. fourth Danube bridge Vienna) are to be prevented.
Membranversteifter Träger
Authors: Alpermann Holger , Gengnagel Christoph 
Published: May 2012

AbstractDer membranversteifte Träger ist ein neues hybrides Tragelement, bei dem die Membran eine unverzichtbare Rolle im Tragverhalten spielt. Der hier vorgestellte Träger hat die Geometrie eines Dreigurtbinders, bei dem drei Membranflächen die Profile kraftschlüssig verbinden und gegeneinander versteifen. Die Membranfläche im Obergurt erhöht die Knicklast des Obergurtes ausschlaggebend, die seitlichen Membranflächen dienen zur Aussteifung der Felder unter asymmetrischen Lasten. Die kontinuierliche Verbindung der Membran zu den Profilen verhindert Spannungsspitzen und erhöht die Knicklast der Profile. Das Tragverhalten des Trägers wird numerisch analysiert. Der Einfluss wichtiger Entwurfsparameter wird hinsichtlich des Tragverhaltens untersucht.Membrane restrained girder. The membrane restrained girder is a new hybrid, structural element, where the membrane is an indispensable part of the structural behaviour. The presented girder has the geometry of a three‐chord truss. A flat membrane connects the chords with each other and restrains them. The membrane between the upper chords rises the buckling load decisive, the membranes on the side brace the fields between the struts against deformation under asymmetrical loads. The continuous connection of the membrane to the chords avoids stress‐peaks and increases the buckling load of the chords. The structural behaviour of the girder is analysed numerical and the influence of important design‐parameters examined.
Flughafen Berlin Brandenburg BER: Stahlkonstruktion mit Korrosions‐ und Brandschutz
Authors: Brux Gunther 
Published: May 2012

AbstractDer neue Hauptstadt‐Airport Berlin Brandenburg (BER) erhält ein ansprechendes Fluggastterminal, dessen Dach und Fassade aus Verbundglas und Stahl besteht – einer Konstruktion die nach Anbringen des Korrosionsschutzes mit Dämmschichtbildnern für den vorbeugenden Brandschutz beschichtet ist, ohne die Architektur zu beeinträchtigen. Vorteilhaft war hier das Zusammenwirken von Brand‐ und Korrosionsschutz.