bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of alcohol consumption in patients with alcoholic liver cirrhosis during the evaluation process for liver transplantation
Authors: Hempel Johann-Martin , Greif-Higer Gertrud , Kaufmann Thomas , Beutel Manfred E.
Published: May 2012

Alcoholic liver cirrhosis (ALC) is a commonly accepted indication for liver transplantation (LT). Any alcohol consumption is considered a contraindication for LT. However, the assessment of abstinence in everyday practice mostly relies on patient self-reporting, which must be considered highly unreliable. After consumption, ethanol is eliminated by alcohol dehydrogenase, with methanol accumulating in the blood. Methanol, which is known to be a sensitive and specific indicator for recent alcohol consumption, has not been used for verifying alcohol consumption in LT assessments yet. Therefore, the purpose of this study was to test the feasibility of using methanol testing to identify recent alcohol consumption in LT candidates during routine and short-notice appointments. We compared methanol and ethanol measurements with self-reported alcohol consumption for 41 patients with ALC during the evaluation process before they were accepted onto the waiting list. In 32 of the 92 blood samples drawn from these 41 patients during the study, a relapse was detected by the methanol test. Both the ethanol test results and the self-reported data were positive in only 3 cases. Thus, the methanol test identified 29 additional cases of alcohol consumption. Furthermore, the methanol test discovered recent alcohol consumption in 5 of 10 transplant patients when both self-reported data and ethanol test results were negative. As a part of blood alcohol analysis, the methanol test is more sensitive than self-reporting and ethanol testing for the detection of recent alcohol consumption. Also, short-notice appointments for blood alcohol analysis reveal more cases of alcohol relapse than routine, long-term appointments. The measurement of methanol as a sensitive screening test for recent alcohol consumption should be implemented both in law and in daily, routine practice. Liver Transpl 18:1310–1315, 2012. © 2012 AASLD.
Reinforcement of Polymeric Submicrometer‐sized Fibers by Microfibrillated Cellulose
Authors: Fortunato Giuseppino , Zimmermann Tanja , Lübben Jörn , Bordeanu Nico , Hufenus Rudolf
Published: May 2012

To 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.

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ΔR2* gadolinium‐diethylenetriaminepentacetic acid relaxivity in venous blood
Authors: Patil Vishal , Johnson Glyn
Published: May 2012

The accuracy of perfusion measurements using dynamic, susceptibility‐weighted, contrast‐enhanced MRI depends on estimating contrast agent concentration in an artery, i.e., the arterial input function. One of the difficulties associated with obtaining an arterial input function are partial volume effects when both blood and brain parenchyma occupy the same pixel. Previous studies have attempted to correct arterial input functions which suffer from partial volume effects using contrast concentration in venous blood. However, the relationship between relaxation and concentration (C) in venous blood has not been determined in vivo. In this note, a previously employed fitting approach is used to determine venous relaxivity in vivo. In vivo relaxivity is compared with venous relaxivity measured in vitro in bulk blood. The results show that the fitting approach produces relaxivity calibration curves which give excellent agreement with arterial measurements. Magn Reson Med 69:1104–1108, 2013. © 2012 Wiley Periodicals, Inc.
Manganese‐enhanced MRI optic nerve tracking: effect of intravitreal manganese dose on retinal toxicity
Authors: Luo Lisha , Xu Hui , Li Ying , Du Zhaodong , Sun Xiaodong , Ma Zhizhong , Hu Yuntao
Published: May 2012

The aim of this study was to provide data on the dose dependence of manganese‐enhanced MRI (MEMRI) in the visual pathway of experimental rats and to study the toxicity of MnCl2 to the retina. Sprague–Dawley rats were intravitreally injected with 2 μL of 0, 10, 25, 50, 75, 100, 150 and 300 mm MnCl2, respectively. The contrast‐to‐noise ratio (CNR) of MEMRI for optic nerve enhancement was measured at different concentrations of MnCl2. Simultaneously, the toxicity of manganese was evaluated by counting retinal ganglion cells and by retinal histological examination using light microscopy and transmission electron microscopy. The CNR increased with increasing concentration of MnCl2 up to 75 mm. Retinal ganglion cell densities were reduced significantly when the concentration of MnCl2 in the intravitreal injection was equal to or greater than 75 mm. Increasing numbers of ribosomes in retinal ganglion cells were first detected at 25 mm of MnCl2. The retinal toxicity of MnCl2 at higher concentration also included mitochondrial pathology and cell disruption of retinal ganglion cells, as well as abnormalities of photoreceptor and retinal pigment epithelium cells. It can be concluded that intravitreal injection of MnCl2 induces retinal cell damage that appears to start from 25 mm. The concentration of MnCl2 should not exceed 25 mm through intravitreal injection for visual pathway MEMRI in the rat. Copyright © 2012 John Wiley & Sons, Ltd.
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

Objective

Pregnant 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.

Method

The 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.

Results

There 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.

Conclusion

A 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

Objective

The 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.

Design

Distribution 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.

Results

At 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.

Conclusion

Interrupting 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

Objective

The 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.

Methods

We used a qualitative approach using semistructured interviews. Thirty‐eight women and six of their partners were recruited.

Results

NIPD 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.

Conclusion

Women 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

The 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

A 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

Nylon 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

Electrospinning 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

Assessing 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

Objective

The 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.

Methods

Seventy‐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.

Results

Significant 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.

Conclusion

Email‐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

BACKGROUND

Evidence 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.

METHODS

Non‐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.

RESULTS

All 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.

CONCLUSION

Normal 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

In 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

We 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

The 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.
Multiple testing for a combination drug with two study endpoints
Authors: Shao Jun , Zhang Sheng , Zhao Jiwei , Chiang Alan
Published: May 2012

A combination drug product with two or more active compounds may be superior to each of its components with higher dose levels and, therefore, is preferred in terms of efficacy, cost, and safety. To study a combination drug, researchers often conduct trials by using a factorial design with combinations of dose levels of each drug component. By applying some bootstrap methods, we construct multiple testing procedures to simultaneously identify combinations superior to each drug component with any dose level. These multiple testing procedures are more powerful than Holm's step‐down procedure that is known to be very conservative. When there is only one study endpoint, applying the bootstrap is straightforward. In many studies, however, there are two or more study endpoints and it is not simple to apply the bootstrap. We apply one version of the bootstrap and then use an upper bound to control the familywise error defined as the probability of rejecting at least one true null hypothesis. Properties of the bootstrap multiple testing procedures are discussed and examined in some simulation studies. Copyright © 2012 John Wiley & Sons, Ltd.
Die Tragfähigkeit versteifter Blech‐ und Kastenträger in einfacher Näherung
Authors: Herzog Max
Published: May 2012

Nach 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

Der 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

Der 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.
English as a Transcultural Language in Swedish Policy and Practice
Authors: Hult Francis M.
Published: May 2012

The globalization of English in Sweden is examined as it takes shape in educational policy and practice. Following in the tradition of a “new wave” of language policy and planning research that emphasizes connections between policy and how it is interpreted by local stakeholders, this investigation focuses on textual data from Swedish national curricular documents and observational data of preservice English language educators during teacher training. Discourse analysis was conducted in order to illuminate underlying policy discourses, on the one hand, and facilitate tracing intertextual connections to the voices of educators, on the other hand. Drawing upon current perspectives on linguistic globalization, major discursive tensions engendered in the processes of transculturation through which English as a global language is locally situated in Sweden are brought to light. The study illustrates how educational language policy serves as a discursive space for ongoing negotiation about the status of English in Sweden.
Developing Academic Language in English Language Learners Through Sheltered Instruction
Authors: Short Deborah J. , Fidelman Carolyn G. , Louguit Mohammed
Published: May 2012

This article describes a study examining the effects of Sheltered Instruction Observation Protocol (SIOP) model instruction on the academic language performance of middle and high school English language learners. The SIOP model is an approach for teaching content curriculum to students learning through a new language. Teachers employ techniques that make the content concepts accessible and also develop students' skills in the new language. Using a quasi‐experimental design, the research was conducted in content area and English as a second language classes in two districts in northern New Jersey over 2 years. The analysis presents student achievement data from state‐mandated language proficiency tests in the final year of the intervention, after most of the treatment teachers had completed their professional development in the SIOP model. There were statistically significant differences in the average mean scores in favor of the treatment student group on Writing, Oral Language, and Total English scores of the IDEA Language Proficiency Tests with small to medium effect sizes. The results from this study show that the SIOP model offers a promising approach to professional development that can improve the quality of instruction to English language learners and increase their English language achievement.
Advantages and Disadvantages of Native‐ and Nonnative‐English‐speaking Teachers: Student Perceptions in Hong Kong
Authors: Florence Ma Lai Ping
Published: May 2012

The Native English Teachers (NETs) Scheme has been in place for over 20 years in secondary schools in Hong Kong and yet how students perceive these teachers is under‐researched. This article reports a study which analyses student perceptions of the advantage and disadvantages of learning English from NETs and their non‐native counterparts, local English teachers (LETs). Data were collected through semi‐structured group interviews with 30 secondary students studying in three different schools in Hong Kong. Content data analysis was conducted, and main themes that emerged from interview transcripts were categorised. Results show that the perceived advantages of LETs include their proficiency in students' L1, their knowledge of students' learning difficulties, the ease students experience in understanding their teaching, and in communication. The perceived advantages of NETs are their good English proficiency and ability to facilitate student learning. The disadvantages of one category of teachers appear to be the reverse of the advantages of another. Data also show that some students experience anxiety when encountering NETs and tend to prefer certain teaching styles. This study has significant implications for classroom teaching practice and teacher professional development.

Video Abstract
Participation in Peer Response as Activity: An Examination of Peer Response Stances From an Activity Theory Perspective
Authors: Zhu Wei , Mitchell Deborah A.
Published: May 2012

This article reports a case study that examined English as a Second Language students' peer response stances from an activity theory perspective. More specifically, the study was guided by the constructs of activity and motive/object in Leont'ev's theory. Multiple sources of data were collected from two native Spanish‐speaking students enrolled in a low‐advanced EAP writing class, including recordings of their peer response sessions and individual interviews. An inductive and recursive qualitative analysis approach was adopted to analyze the data. Transcripts of student participation in peer response sessions were analyzed to identify the two participants' stances during peer response, and interviews were analyzed to understand the students' motives/objects for participation in peer response. Data analyses indicate that each participant had a distinct motive/object for participating in peer response, and that these motives/objects motivated the students' peer response stances. Implications of the study for instructional practices and research are discussed.
An investigation of variable power collective pitch control for load mitigation of floating offshore wind turbines
Authors: Lackner Matthew A.
Published: May 2012

This paper investigates the loads on offshore floating wind turbines and a new control method that can be used to reduce these loads. In this variable power collective pitch control method, the rated generator speed, which is the set point that the collective pitch control attempts to drive the actual generator speed towards, is no longer a constant value but instead a variable that depends on the platform pitch velocity. At a basic physical level, this controller achieves the following: as the rotor of a floating turbine pitches upwind, the controller adjusts so as to extract more energy from the wind by increasing the rated generator speed and thus damps the motion; as the rotor pitches downwind, less energy is extracted because the controller reduces the rated generator speed and again damps the motion. This method is applied to the NREL 5 MW wind turbine model, in above‐rated conditions where the platform motion is most problematic. The results indicate significant load reductions on key structural components, at the expense of minor increases in power and speed variability. The loads on the blades and tower are investigated more generally, and simple dynamic models are used to gain insight into the behavior of floating wind turbine systems. It is clear that for this particular design, aerodynamic methods for reducing platform motion and tower loads are likely inadequate to allow for a viable design, and so new designs or possibly new control degrees of freedom are needed. Copyright © 2012 John Wiley & Sons, Ltd.
Computational investigations of blunt trailing‐edge and twist modifications to the inboard region of the NREL 5 MW rotor
Authors: Chow Raymond , van Dam C.P.
Published: May 2012

The effects of twist and section shape modifications in the inboard region on the aerodynamic characteristics of the NREL 5 MW rotor have been examined using a Reynolds‐averaged Navier–Stokes method OVERFLOW2. The baseline rotor blade was modified by increasing the trailing‐edge thickness over the inboard region by modifying the sections’ thickness distribution aft of the maximum thickness location. Results when compared with the baseline rotor show that a modest increase of trailing‐edge thickness to 10–20%c increased power capture by 1%. Further increases in trailing‐edge thickness decrease in effectiveness to the point of reducing power capture when thicknesses reach 40%c. Increasing trailing‐edge thicknesses also leads to an increase in thrust, but this load is concentrated in the inboard region, resulting in a small increase in root bending moments. The blunt trailing‐edge concept greatly reduces the spanwise extent of inboard flow separation evident in the baseline NREL 5 MW rotor. The low‐pressure region aft of the trailing edge, created by the geometry, acts to reduce the spanwise spreading of the inboard separation. Rotors with modified twist distributions over the inboard 35%R of span are also compared. Inboard twist angles are varied from + 6° to − 6° from the baseline twist schedule. Increasing inboard blade twist reduces overall rotor power capture but reduces thrust at a faster rate. Power capture remains constant with decreasing inboard geometry twist, whereas thrust increases approximately linearly by 0.75% for a decrease in thrust of 6°. Copyright © 2012 John Wiley & Sons, Ltd.
Bayesian estimation for target tracking, Part III: Monte Carlo filters
Authors: Haug A.J.
Published: May 2012

This is the third part of a three part article series examining methods for Bayesian estimation and tracking. In the first part we presented the general theory of Bayesian estimation where we showed that Bayesian estimation methods can be divided into two very general classes: a class where the observation‐conditioned posteriordensitiesare propagated in time through a predictor/corrector method and a second class where the first twomomentsare propagated in time, with state and observation moment prediction steps followed by state moment update steps that use the latest observations. In the second part, we make the assumption that all densities are Gaussian and, after applying an affine transformation and approximating all nonlinear functions by interpolating polynomials, we recover the sigma point class of Kalman filters. In this third part, we show that approximating a non‐Gaussian density by a set of Monte Carlo samples drawn from an importance density leads to particle filter methods, where the posterior density is propagated in time and moment integrals are approximated by sample moments. These methods include the sequential importance sampling bootstrap, optimal, and auxiliary particle filters and more general Monte Carlo particle filters.WIREs Comput Stat2012 doi: 10.1002/wics.1210

This article is categorized under:

Statistical and Graphical Methods of Data Analysis > Bayesian Methods and Theory
Growth of Dunaliella tertiolecta and associated bacteria in photobioreactors
Authors: Lakaniemi Aino-Maija , Intihar Veera M , Tuovinen Olli H , Puhakka Jaakko A
Published: May 2012

The aim of this study was to test three flat-plate photobioreactor configurations for cultivation of marine green alga Dunaliella tertiolecta under non-axenic growth conditions and to characterize and quantify the associated bacteria. The photobioreactor cultivations were conducted using tap water-based media. Static mixers intended to enhance mixing and light utilization did not generally increase algal growth at the low light intensities used. The maximum biomass concentration (measured as volatile suspended solids) and maximum specific growth rate achieved in the flat plate with no mixer were 2.9 g l−1 and 1.3 day−1, respectively. Based on quantitative polymerase chain reaction, bacterial growth followed the growth of D. tertiolecta. Based on 16S rDNA amplification and denaturing gradient gel electrophoresis profiling, heterotrophic bacteria in the D. tertiolecta cultures mainly originated from the non-axenic algal inocula, and tap water heterotrophs were not enriched in high chloride media (3 % salinity). Bacterial communities were relatively stable and reproducible in all flat-plate cultivations and were dominated by Gammaproteobacteria, Flavobacteria, and Alphaproteobacteria.
Measurement of plasma B6 vitamer profiles in children with inborn errors of vitamin B6 metabolism using an LC‐MS/MS method
Authors: Footitt Emma J. , Clayton Peter T. , Mills Kevin , Heales Simon J. , Neergheen Viruna , Oppenheim Marcus , Mills Philippa B.
Published: May 2012

Vitamin B6 dependent seizure disorders are an important and treatable cause of childhood epilepsy. The molecular and biochemical basis for some of these disorders has only recently been elucidated and it is likely that inborn errors affecting other parts of this complex metabolic pathway are yet to be described. In man vitamin B6 ingested from the diet exists as six different vitamers, pyridoxal (PL), pyridoxamine (PM), pyridoxine (PN), pyridoxal 5’‐phosphate (PLP), pyridoxamine 5’‐ phosphate (PMP) and pyridoxine 5’‐phosphate (PNP). Its breakdown product, 4‐pyridoxic acid (PA), is excreted in urine. Here we describe an analytical LC‐MS/MS method to measure all vitameric B6 forms in plasma and have subsequently applied this methodology to investigate children with vitamin B6 responsive seizure disorders. We show that patients with inborn errors of B6 metabolism such as pyridox(am)ine 5’‐phosphate oxidase (PNPO) deficiency have characteristic B6 profiles which allow them to be differentiated from each other and control populations, even when on treatment with B6. Regardless of diagnosis, patients on treatment doses of pyridoxine hydrochloride and pyridoxal phosphate have markedly elevated levels of some vitameric forms (PLP, PL and PA). Such mega doses of B6 treatment are known to be associated with neurotoxicity. This LC‐MS/MS method will be a useful tool for treatment monitoring and may help further our understanding of mechanisms of neurotoxicity in patient groups.
“What is inside This Right Lower Quadrant Sac?” Spectrum of Computed Tomography Abnormalities that Affect the Cecum
Authors: Virmani Vivek , Sethi Vineeta , Fasih Najla , Kielar Ania
Published: May 2012

The current pictorial is a comprehensive review of the various cecal pathologies, including both those that solely involve the cecum and those in which the cecum may be secondarily involved. The various cecal abnormalities will be categorized as inflammatory, infectious, vascular, neoplastic, congenital, and foreign bodies. Emphasis will be placed on the imaging features that, when coupled with the clinical history, help to reach a diagnosis or to narrow the differential diagnosis.
Engineering and control of biological systems: A new way to tackle complex diseases
Authors: Menolascina Filippo , Siciliano Velia , di Bernardo Diego
Published: May 2012

In this work, we will review the latest progress in synthetic biology and the most significant developments achieved so far, both in unicellular and multicellular organisms, with emphasis on human health.
Shock propagation in liquids containing bubbly clusters: a continuum approach
Authors: Grandjean H. , Jacques N. , Zaleski S.
Published: May 2012

The present work investigates the influence of bubble clustering on the propagation of shock waves in bubbly liquids. A continuum model is developed to describe the macroscopic response of a bubbly liquid with a cluster structure, using a two-step homogenization technique. The proposed methodology allows us to simulate shock wave propagation over long distances with a small computation time and to study the effect of bubble clustering on the shock structure. It is shown that the typical length of the shock profile is related to the global response of the clusters instead of the single-bubble dynamics, as in homogeneous bubbly flows. The accuracy of the proposed modelling is assessed through comparisons with axisymmetric simulations, in which clusters are directly specified, with given positions and sizes, and with experimental data.
On the flow field induced by a hovering rotor or a static jet
Authors: Spalart Philippe R.
Published: May 2012

The flow in the far field of an isolated static momentum source is considered, taking into account the entrainment of fluid by the turbulent jet which develops far downstream irrespective of the type of device. The result is a simple analytical model for the irrotational region, which depends only on the thrust applied. This equation is implied by Stewart (J. Fluid Mech., vol. 1, 1956, pp. 593–606) for a jet. For a rotor, the model is radically different from the classical one derived from an actuator disk without turbulence or mixing in the wake, which led to a sink flow in the far field. The velocities decay like $1/ r$ rather than $1/ {r}^{2} $, where $r$ is the radius, and are everywhere directed in the direction opposite to the thrust, rather than pointing towards the origin. The momentum source drives a co-flow which converges towards the turbulent region, thus supplying the entrained fluid. This flow pattern supports the assumption that the fluid surrounding the turbulent region is irrotational, better than the sink-flow model would. The model depends only on one empirical constant, a measure of the entrainment in a fully developed jet, for which a range of values is determined from the experimental literature. If the rotor is climbing, the sink flow is recovered; however, the limit of that equation as the climb velocity tends to zero, leading to hover, is singular. For both jets and rotors, this model used in a boundary condition should eliminate extraneous parameters and reduce the computational cost of numerical simulations, and may guide the design of chambers used for experiments, following Ricou & Spalding (J. Fluid Mech., vol. 11, 1960, pp. 21–32).