bluuebunny/crossref_metadata_2025 huggingface dataset:
WWAN ceramic chip antenna for mobile phone application
Authors: Hsu Ming‐Ren , Wong Kin‐Lu
Published: November 2008

A promising compact ceramic chip antenna capable of generating two wide operating bands at about 900 and 2000 MHz for covering GSM850/900/1800/1900/UMTS WWAN (wireless wide area network) operation is presented. The antenna comprises a ceramic chip base of high relative permittivity 40 and small volume 2.5 × 5 × 40 mm3 (0.5 cm3) and a simple metal pattern embedded therein. The metal pattern is of an asymmetric T‐shape with two different simple radiating arms; no meandering in the metal pattern is used, which is different from the meandered‐type metal pattern used in conventional chip antennas. Without meandering in the metal pattern, the possible large coupling between the adjacent portions in the metal pattern can be avoided. Large operating bandwidths are hence promising to be achieved. Also, without meandering in the metal pattern, the proposed chip antenna can still occupy a small volume for WWAN operation. The small volume allows it easy for the proposed antenna to incorporate the possible electronic elements such as the speaker and the lens of the embedded camera at the top portion of the system circuit board of the mobile phone to achieve a compact integration. Details of the proposed ceramic chip antenna are presented and studied. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 103–110, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24020
Compact broadband planar antenna for DVB‐H applications
Authors: Hanqing Ma , Chu Qing‐Xin
Published: November 2008

A novel compact broadband planar antenna for digital television signal reception is presented. The antenna consists of a folded radiating patch and a parasitic arm, which are easily printed on an FR4 substrate. The antenna occupies an area of only 70 × 42 mm2, while it covers a bandwidth (3:1 VSWR) of 360 MHz (460–820 MHz). Moreover, it has dipole‐like radiation patterns within its operation band with gain values larger than 0 dBi. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 239–242, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24024
Rectangular microstrips with variable air gap and varying aspect ratio: Improved formulations and experiments
Authors: Chattopadhyay Sudipta , Biswas Manotosh , Siddiqui Jawad Y. , Guha Debatosh
Published: November 2008

The resonant modes and characteristics of a rectangular microstrip with a variable air gap are theoretically and experimentally examined. Effect of varying width to length ratio is another important aspect addressed and a computer aided design is presented. Thorough experiments are presented, a few of which are reported for the first time. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 169–173, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24025
Monitoring of gliomas in vivo by diffusion MRI and 1H MRS during gene therapy‐induced apoptosis: interrelationships between water diffusion and mobile lipids
Authors: Liimatainen Timo , Hakumäki Juhana M. , Kauppinen Risto A. , Ala‐Korpela Mika
Published: November 2008

The measurement of water diffusion by diffusion‐weighted MRI (DWI) in vivo offers a non‐invasive method for assessing tissue responses to anti‐cancer therapies. The pathway of cell death after anti‐cancer treatment is often apoptosis, which leads to accumulation of mobile lipids detectable by 1H MRS in vivo. However, it is not known how these discrete MR markers of cell death relate to each other. In a rodent tumour model [i.e. ganciclovir‐treated herpes simplex thymidine kinase (HSV‐tk) gene‐transfected BT4C gliomas], we studied the interrelationships between water diffusion (Trace{D}) and mobile lipids during apoptosis. Water diffusion and water‐referenced concentrations of mobile lipids showed clearly increasing and interconnected trends during treatment. Of the accumulating 1H MRS‐visible lipids, the fatty acid CHCH groups and cholesterol compounds showed the strongest associations with water diffusion (r2 = 0.30; P < 0.05 and r2 = 0.48; P < 0.01, respectively). These results indicate that the tumour histopathology and apoptotic processes during tumour shrinkage can be interrelated in vivo by DWI of tissue water and 1H MRS of mobile lipids, respectively. However, there is considerable individual variation in the associations, particularly at the end of the treatment period, and in the relative compositions of the accumulating NMR‐visible lipids. The findings suggest that the assessment of individual treatment response in vivo may benefit from combining DWI and 1H MRS. Absolute and relative changes in mobile lipids may indicate initiation of tumour shrinkage even when changes in tissue water diffusion are still small. Conversely, greatly increased water diffusion probably indicates that substantial cell decomposition has taken place in the tumour tissue when the 1H MRS resonances of mobile lipids alone can no longer give a reliable estimate of tissue conditions. Copyright © 2008 John Wiley & Sons, Ltd.
Diffusion‐weighted imaging of the prostate and rectal wall: comparison of biexponential and monoexponential modelled diffusion and associated perfusion coefficients
Authors: Riches S. F. , Hawtin K. , Charles‐Edwards E. M. , de Souza N. M.
Published: November 2008

This study compares parameters from monoexponential and biexponential modelling of diffusion‐weighted imaging of normal and malignant prostate tissue and normal rectal wall tissues. Fifty men with Stage Ic prostate cancer were studied using endorectal T2‐weighted imaging and diffusion‐weighted imaging with 11 diffusion‐sensitive values (b‐values = 0, 1, 2, 4, 10, 20, 50, 100, 200, 400, 800 s/mm2). Regions of interest were drawn within non‐malignant central gland and peripheral zone, malignant prostate tissue and normal rectal wall tissue. Both a monoexponential and biexponential model was fitted over various b‐value ranges, giving an apparent diffusion coefficient (ADC) from the monoexponential model and a diffusion coefficient, perfusion coefficient and perfusion fraction from the biexponential model. In all tissues, over the full range of b‐values, the ADC from the monoexponential model was significantly higher than the corresponding diffusion coefficient from the biexponential model. As the minimum b‐value increased, the ADC decreased and was equal to the diffusion coefficient for some b‐value ranges. The biexponential model best described the data when low b‐values were included, suggesting that there is a fast perfusion component. Neither model could distinguish between benign prostate tissues on the basis of diffusion coefficients, but the rectal wall tissue and malignant prostate tissue had significantly lower diffusion coefficients than normal prostate tissues. Perfusion coefficients and fractions were highly variable within the population, so their clinical utility may be limited, but removal of this variable perfusion component from reported diffusion coefficients is important when attributing clinical differences to diffusion within tissues. Copyright © 2008 John Wiley & Sons, Ltd.
The skulls of Chief Nonosabasut and his wife Demasduit – Beothuk of Newfoundland
Authors: Black S. M. , Marshall I. C. L. , Kitchener A. C.
Published: November 2008

In March 1819 a young woman was abducted by white settlers and her husband was killed. They were among the few remaining members of the Beothuk of Newfoundland. Eight years later their skulls were removed from their burial hut and transferred to the University of Edinburgh. This paper describes these two important skulls and details injuries and pathologies not previously recorded in detail. Chief Nonosabasut displayed evidence of extensive trauma to the region of his chin which is most likely to be evidence of previous, but well‐healed, combat injuries. His wife, Demasduit, presented with an intriguing perimortem fracture to the left parietal bone which extended onto the base of the skull. This is discussed in the light of evidence available at the time of her death. Copyright © 2008 John Wiley & Sons, Ltd.
Natural gradient‐projection algorithm for distribution control
Authors: Zhang Zhenning , Sun Huafei , Zhong Fengwei
Published: November 2008

In this paper, we use an information geometric algorithm to solve the distribution control problem. Here, we consider the distribution of the output determined by the control input only. We set up two manifolds that are formed by the B‐spline functions and the system output probability density functions, and we call them the B‐spline manifold(B) and the system output manifold(M), respectively. Moreover, we call the new designed algorithm natural gradient‐projection algorithm. In the natural gradient step, we use natural gradient algorithm to obtain an optimal trajectory of the weight vector on the B‐spline manifold from the viewpoint of information geometry. In the projection step, we project the selected points on B onto M. The coordinates of the projections on M give the trajectory of the control input u. Copyright © 2008 John Wiley & Sons, Ltd.
The insulin‐like growth factor system and sarcomas
Authors: Rikhof Bart , de Jong Steven , Suurmeijer Albert JH , Meijer Coby , van der Graaf Winette TA
Published: November 2008

Sarcomas are a diverse group of malignant mesenchymal tumours arising from bone and soft tissues. The identification of critical cellular signalling pathways in sarcomas is an important issue for the development of new targeted therapies. This review highlights the experimental and clinical evidence supporting the role of the insulin‐like growth factor (IGF) signalling system in the cellular transformation and progression of several types of sarcoma, including rhabdomyosarcoma, synovial sarcoma, leiomyosarcoma, Ewing's sarcoma and osteosarcoma. Preclinical data suggest that the IGF system could be a promising target for therapy in these sarcomas. Currently, therapies interrupting IGF signalling have been or are being developed. In recent phase 1 clinical studies with humanized monoclonal antibodies directed against IGF receptor type 1 (IGF‐1R), objective tumour responses were observed in several patients with Ewing's sarcoma, encouraging further clinical testing in Ewing's sarcoma and other sarcoma (sub)types. Moreover, the occasional occurrence of paraneoplastic hypoglycaemia as a result of the secretion of incompletely processed forms of pro‐IGF‐II by sarcomas is discussed. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Telomere‐associated proteins: cross‐talk between telomere maintenance and telomere‐lengthening mechanisms
Authors: De Boeck Gitte , Forsyth Ramses G , Praet Marleen , Hogendoorn Pancras CW
Published: November 2008

Telomeres, the ends of eukaryotic chromosomes, have been the subject of intense investigation over the last decade. As telomere dysfunction has been associated with ageing and developing cancer, understanding the exact mechanisms regulating telomere structure and function is essential for the prevention and treatment of human cancers and age‐related diseases. The mechanisms by which cells maintain telomere lengthening involve either telomerase or the alternative lengthening of the telomere pathway, although specific mechanisms of the latter and the relationship between the two are as yet unknown. Many cellular factors directly (TRF1/TRF2) and indirectly (shelterin‐complex, PinX, Apollo and tankyrase) interact with telomeres, and their interplay influences telomere structure and function. One challenge comes from the observation that many DNA damage response proteins are stably associated with telomeres and contribute to several other aspects of telomere function. This review focuses on the different components involved in telomere maintenance and their role in telomere length homeostasis. Special attention is paid to understanding how these telomere‐associated factors, and mainly those involved in double‐strand break repair, perform their activities at the telomere ends. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Prenatal screening for serious congenital heart defects using nuchal translucency: a meta‐analysis
Authors: Wald Nicholas J. , Morris Joan K. , Walker Kate , Simpson John M.
Published: November 2008

Objectives

To assess the performance of nuchal translucency (NT) measurements in screening for congenital heart defects (CHD) which would benefit from prenatal detection.

Methods

A literature search was conducted of studies published prior to August 2007 of CHD and NT measurements in fetuses without chromosome defects. From this, data on 159 pregnancies were obtained. Fetuses with CHD that would benefit from prenatal detection were identified and their NT measurements were compared with NT measurements in 29 776 unaffected fetuses without Down syndrome from the Serum Urine and Ultrasound Screening Study (SURUSS) trial to determine the screening performance of NT measurements.

Results

In all 67 fetuses with CHD were identified as potentially likely to benefit from prenatal detection. Using NT measurements, the estimated detection rate (DR) for a 5% false‐positive rate (FPR) was 52% (95% CI: 42–71).

Conclusion

Prenatal screening for CHD using NT measurements is likely to be effective, and given that NT measurement is already in place as part of prenatal screening for Down syndrome; this is an ideal time to set up demonstration projects to validate these results. Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis of bis(2,3‐epoxycyclohexyl) and its cationic photopolymerization in the presence of different diols
Authors: Wang Zhonggang , Lin Xiaobo , Liu Wanshuang
Published: November 2008

BACKGROUND: An ester‐free cycloaliphatic di‐epoxide, bis(2,3‐epoxycyclohexyl), with epoxycyclohexyl moieties linked via carbon–carbon bonds was synthesized and characterized. The photopolymerization of the di‐epoxide was systemically investigated in the presence of different diols, 1,2‐ethanediol, 1,4‐butanediol, 1,2‐propanediol and pinacol, using real‐time Fourier transform infrared spectroscopy to follow the reaction process.

RESULTS: Among the four diols, the presence of pinacol resulted in the fastest photopolymerization rate and highest degree of conversion of di‐epoxy groups, but a relatively low gel content, while the addition of 1,2‐ethanediol led to an inhibiting effect on the di‐epoxide reaction rate, but the product showed the highest gel content. The influences of the diols on the cationic photopolymerization behavior of the di‐epoxide were explained according to the steric hindrance, proton‐trapping ability and electronic effect of the diols.

CONCLUSION: The study results provide the possibility to conveniently manipulate the photopolymerization rate and modify the properties of an epoxy resin by simply adjusting the structure and amount of added diol in the polymerization system to meet the demands for potential microelectronic and optoelectronic packaging applications. Copyright © 2008 Society of Chemical Industry
Synthesis of carbazole‐based light‐emitting polymers incorporating 2,5‐bis(phenylethenyl)‐4‐decyloxyanisole as collateral fluorophore
Authors: Takagi Koji , Nakagawa Tsuyoshi , Takao Hidenobu
Published: November 2008

The Suzuki coupling polymerization between bis(carbazole) monomer (CzDB) and 9,9‐dihexylfluorene‐2,7‐diboronic acid was carried out to obtain PFCz‐PEDA0 having the number‐averaged molecular weight of 7000. The absorption and emission maximum wavelengths were observed at 344 and 408 nm, respectively. The quantum yield (QY) was relatively low (0.12) because of the photo‐induced electron transfer. Subsequently, CzPEDA‐bearing 2,5‐bis(phenylethenyl)‐4‐decyloxyanisole (PEDA) segment sandwiched with 3‐bromocarbazole units was copolymerized to give PFCz‐PEDAn (n = 05, 10, 20, 35, and 50). The content of PEDA segment in polymer could be controlled by the monomer feed ratio. In CHCl3 solution, the absorbance at around 400 nm became larger with one isosbestic point at 370 nm, and the emission peak at 448 nm became prominent with increasing the PEDA content. The QY of polymer was increased as the PEDA content, which was a consequence of the fluorescence resonance energy transfer from carbazole‐containing chromophore (energy donor) to PEDA fluorophore (energy acceptor). In spin‐coated film, the maximum QY was obtained in PFCz‐PEDA05 having the most appropriate molar balance of energy donor and acceptor units. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 8141–8148, 2008
Synthesis of UV‐cured acrylic–silica hybrid nanocomposites from dendritic acrylic oligomer and acrylic‐functionalized silica
Authors: Chiang Hau‐Chun , Liu Chia‐Hong , Tsiang Raymond Chien‐Chao
Published: November 2008

An acrylic–silica hybrid polymeric nanocomposite, comprising well‐distributed silica nanoparticles in acrylic matrix, has been synthesized at a markedly rapid rate from a dendritic acrylic oligomer (DAO) and an acrylic‐functionalized silica (A‐silica) via UV‐curing. A‐silica was made by functioning colloidal silica nanoparticles with 3‐methacryloxypropyltrimethoxysilane (MATMS) and DAO was formed by reacting 1,5‐diamino‐2‐methylpentane (MPMDA) with trimethylopropane triacrylate (TMPTA). The MATMS has been found either doubly or singly bonded to silica nanoparticles but not triply bonded, and the inclusion of MATMS into the siloxane network structure increases the size of silica nanoparticles. The well distribution of A‐silica and its good compatibility with DAO cause an increase in Td of the acrylic–silica hybrid material. Silica nanoparticles are too small to cause any significant light scattering, and do not have deleterious effects on transparency. The “hybrid‐on‐polyethylene terephathalate” films exhibited satisfactory hardness and surface roughness because of silica nanoparticles. The preparation as well as the characterization of the constituting species and the final hybrid material are described in detail. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 8149–8158, 2008
Fluorenyl cardo copolyimides containing poly(ethylene oxide) segments: Synthesis, characterization, and evaluation of properties
Authors: Maya Eva M. , Muñoz Dulce M. , Lozano Angel E. , de Abajo Javier , de la Campa Jose G.
Published: November 2008

A set of new block copolyimides containing fluorenyl cardo moieties (FR) in the polyimide blocks and poly(ethylene oxide) (PEO) sequences has been prepared using the two‐step method of polyimide synthesis. The combination of both moieties led to novel copolyimides with good solubility in a variety of solvents, which could easily be processed into films. Copolyimides with PEO content from 30 to 56 wt % were amorphous, showed good mechanical properties, and absorbed less water than other PEO‐containing polyimides previously reported. Copolyimides with higher PEO content (60 and 65%) showed crystallinity and yielded soft films. All of the copolymers showed two glass transition temperatures, the first one around −25 °C attributed to the PEO segments, and the second one at much higher temperature, which corresponded to the polyimide domains. The thermal degradation occurred in two steps, the first one being associated with the degradation of the PEO segments and the second one with the generalized aromatic polyimide decomposition. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 8170–8178, 2008
Functionalizable biodegradable photocrosslinked elastomers based on 2‐oxepane‐1,5‐dione
Authors: Timbart Laurianne , Amsden Brian G.
Published: November 2008

The use of aliphatic polyesters for biomedical applications is limited by the lack of functionality of their backbones. The aim of the following study was to develop a novel elastic scaffold material containing functional groups to be used for future derivatization to tether peptide ligands to support cell adhesion, migration, and differentiation. The elastomer was based on three‐arm star copolymers composed of ε‐caprolactone and a functionalized ε‐caprolactone, 2‐oxepane‐1,5‐dione, and end‐terminated with acrylate groups. The elastomer thus contains a ketone and two approaches were examined for obtaining a photocrosslinkable elastomer containing functional groups: crosslinking followed by ketone reduction using sodium borohydride to generate pendant hydroxyl groups, and reaction of the ketone with hydrazines. Reduction of the ketone lead to degradation of the elastomer through transesterification and ethanolate mediated cleavage of the polymer backbone. Reaction with hydrazines did not degrade the polymer and resulted in efficient functionalization of the elastomer. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 8191–8199, 2008
Alveolar and bronchial nitric oxide output in healthy children
Authors: Sepponen Anna , Lehtimäki Lauri , Huhtala Heini , Kaila Minna , Kankaanranta Hannu , Moilanen Eeva
Published: November 2008

Exhaled nitric oxide (NO) concentration is a marker of pulmonary inflammation. It is usually measured at a single exhalation flow rate. However, measuring exhaled NO at multiple flow rates allows assessment of the flow‐independent NO parameters: alveolar NO concentration, bronchial NO flux, bronchial wall NO concentration, and bronchial diffusing capacity of NO. Our aim was to determine the flow‐independent NO parameters in healthy schoolchildren and to compare two different mathematical approaches. Exhaled NO was measured at four flow rates (10, 50, 100, and 200 ml/sec) in 253 schoolchildren (7–13 years old). Flow‐independent NO parameters were calculated with linear method (flows ≥50 ml/sec) and non‐linear method (all flows). Sixty‐six children (32 boys and 34 girls) with normal spirometry and no history or present symptoms of asthma, allergy, atopy or other diseases were included in the analysis. Median bronchial NO flux was 0.4 nl/sec (mean ± SD: 0.5 ± 0.3 nl/sec) and median alveolar NO concentration was 1.9 ppb (2.0 ± 0.8 ppb) with the linear method. Bronchial NO flux correlated positively with height (r = 0.423; P < 0.001), FEV1 (r = 0.358; P = 0.003), and FVC (r = 0.359; P = 0.003). With the non‐linear method, median bronchial wall NO concentration was 49.6 ppb (68.0 ± 53.3 ppb) and bronchial diffusing capacity of NO was 10.0 pl/sec/ppb (11.8 ± 7.5 pl/sec/ppb). The non‐linear method gave lower alveolar NO concentration (1.4 [1.5 ± 0.7] ppb, P < 0.001) and higher bronchial NO flux (0.5 [0.6 ± 0.3] nl/sec, P < 0.001) than the linear method, but the results were highly correlated between the two methods (r = 0.854 and r = 0.971, P < 0.001). In conclusion, the multiple flow rate method is feasible in children but different mathematical methods give slightly different results. Reference values in healthy children are of value when applying bronchial and alveolar NO parameters in the diagnostics and follow‐up of inflammatory lung diseases. Pediatr. Pulmonol. 2008; 43:1242–1248. © 2008 Wiley‐Liss, Inc.
Language and the pain experience
Authors: Wilson Dianne , Williams Marie , Butler David
Published: November 2008

Background and Purpose. People in persistent pain have been reported to pay increased attention to specific words or descriptors of pain. The amount of attention paid to pain or cues for pain (such as pain descriptors), has been shown to be a major factor in the modulation of persistent pain. This relationship suggests the possibility that language may have a role both in understanding and managing the persistent pain experience. The aim of this paper is to describe current models of neuromatrices for pain and language, consider the role of attention in persistent pain states and highlight discrepancies, in previous studies based on the McGill Pain Questionnaire (MPQ), of the role of attention on pain descriptors. The existence of a pain neuromatrix originally proposed by Melzack (1990) has been supported by emerging technologies. Similar technologies have recently allowed identification of multiple areas of involvement for the processing of auditory input and the construction of language. As with the construction of pain, this neuromatrix for speech and language may intersect with neural systems for broader cognitive functions such as attention, memory and emotion. Method. A systematic search was undertaken to identify experimental or review studies, which specifically investigated the role of attention on pain descriptors (as cues for pain) in persistent pain patients. A total of 99 articles were retrieved from six databases, with 66 articles meeting the inclusion criteria. After duplicated articles were eliminated, the remaining 41 articles were reviewed in order to support a link between persistent pain, pain descriptors and attention. Results. This review revealed a diverse range of specific pain descriptors, the majority of which were derived from the MPQ. Increased attention to pain descriptors was consistently reported to be associated with emotional state as well as being a significant factor in maintaining persistent pain. However, attempts to investigate the attentional bias of specific pain descriptors highlighted discrepancies between the studies. As well as the diversity of pain descriptors used in studies, they were inconsistently categorized into domains of pain. A lack of consistent bias towards certain pain descriptors was observed, and may be explained simply by the fact that the words provided are not those which subjects themselves would use. Conclusion. These findings suggest that the multidimensional and individual nature of the persistent pain experience may not be adequately explained by pain questionnaires such as the MPQ. Personalized pain descriptors may communicate the pain experience more appropriately, but may also contribute to an increased sensitivity of cortical pain processing areas by capturing increased attention for that individual. The language used as part of communication between therapists and people with persistent pain may provide an, as yet, unexplored adjunct strategy in management. Copyright © 2008 John Wiley & Sons, Ltd.
On the use of localized plasmon polaritons in solar cells
Authors: Hallermann Florian , Rockstuhl Carsten , Fahr Stephan , Seifert Gerhard , Wackerow Stefan , Graener Heinrich , Plessen Gero v. , Lederer Falk
Published: November 2008

We describe some fundamental properties of localized plasmon polaritons in metallic nanoparticles, and discuss their use for enhancing solar cells efficiency by photon management. Two scenarios are detailed. The first is an example of spectral photon management utilizing localized plasmon polaritons to increase the up‐conversion efficiency of ions embedded in a glass matrix comprising metallic nanoparticles. The second example details quantitatively how the strong field enhancement and the large scattering cross‐section of plasmons at the resonance wavelength can be employed directly to enhance light absorption in thin‐film solar cells. Preliminary experimental results on tailoring appropriate materials are also shown. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Neodymium‐doped fluorochlorozirconate glasses as an upconversion model system for high efficiency solar cells
Authors: Ahrens Bernd , Löper Philipp , Goldschmidt Jan Christoph , Glunz Stefan , Henke Bastian , Miclea Paul‐Tiberiu , Schweizer Stefan
Published: November 2008

Thermal processing of as‐made fluorozirconate glasses which were additionally doped with neodymium and chlorine ions leads to enhanced upconversion fluorescence intensities. The samples were annealed between 240 °C and 290 °C and the optimum value of upconversion intensity was found for the 270 °C sample. The development of glasses doped with Er, whose luminescence characteristics make it a better choice for application as an upconversion layer on silicon solar cells, is in progress. In addition, we present external quantum efficiency measurements of a silicon solar cell with a NaYF4:Er3+ upconverter. We also show a theoretical analysis where erbium transitions can be enhanced selectively to increase upconversion efficiency. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical and experimental analysis of photonic structures for fluorescent concentrators with increased efficiencies
Authors: Goldschmidt Jan Christoph , Peters Marius , Prönneke Liv , Steidl Lorenz , Zentel Rudolf , Bläsi Benedikt , Gombert Andreas , Glunz Stefan , Willeke Gerhard , Rau Uwe
Published: November 2008

In this study we present a theoretical and experimental analysis of the application of photonic band stop filters on top of photovoltaic fluorescent concentrators in order to increase the photon collection efficiency. The light guiding effect of the fluorescent concentrator relies on total internal reflection. The escape cone of total internal reflection is their major loss mechanism. Our ray tracing simulation allows to calculate the beneficial effect of photonic band stop reflection filters, which reduce these losses, and to simulate the angular distribution of the light trapped in the concentrator. We present simulations of the optical properties of 1D and 3D photonic structures and how 3D structures are realized with colloidal opals. We also show that the application of a 1D photonic structure increases the efficiency of a real system by 20% relative. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Solar cell as a heat engine: energy–entropy analysis of photovoltaic conversion
Authors: Markvart Tom
Published: November 2008

A thermodynamic theory for the voltage or free energy generated by a quantum solar energy converter which has recently been proposed, is developed here in a more direct and simpler way. We consider separately the luminescence and conversion of a single photon of the incident radiation. The energy/entropy balance for the conversion process yields an expression for the voltage in a form familiar from the classical thermodynamics of the work carried out by the heat engine. A similar balance for the absorption and emission of light gives an expression for the irreversible entropy generation which reduces the open circuit voltage generated by the solar cell. Detailed expressions for losses due to individual mechanisms, including non‐radiative recombination, are obtained with the use of an approximation where photons in the incident and emitted beams are modelled as an ideal two‐dimensional gas. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A systematic study on the stability of UV ink photoinitiators in food simulants using GC
Authors: Wang Zhi‐Wei , Huang Xiu‐Ling , Hu Chang‐Ying
Published: November 2008

Several studies have been published on the stability of plastic monomers and additives in food simulants. However, there are practically no published results about the stability of ink components in food simulants. In this work, the stability of two ultraviolet (UV) ink photoinitiators (PIs) in one aqueous and in two substitute fat food simulants was studied under various time–temperature conditions. Furthermore, the addition of the stabilizing agent hydroquinone monomethyl ester (HQMME) in the same conditions was considered as a comparative experiment. The PIs tested were 1‐hydroxycyclohexyl‐1‐phenyl ketone (Irgacure‐184) and benzyldimethyl ketal (Irgacure‐651). The various test conditions included exposure of 10 days to temperatures of 20, 40 and 60°C for 10% ethanol and 95% ethanol simulants, and exposure of 2 days to temperatures of 20, 40 and 60°C for isooctane. Following exposure to these conditions, the additive samples were analysed. The extracts of samples exposed to various temperature conditions as well as unexposed spiked controls and blanks were analysed by gas chromatography (GC) on a non‐polar (5%‐phenyl)‐methylpolysiloxane capillary column. The results showed that the protective effect of HQMME was not obvious in all test conditions under dark conditions. The Irgacure‐184 was quite stable under all test conditions whether the stabilizing agent was added or not. Irgacure‐651 was stable almost under all test conditions, except in 10% ethanol at 60°C. The mass spectrum of decomposed product of Irgacure‐651 was detected by GC‐MS (Mass Spectrum), and the structure of the decomposed product was obtained by mass spectrographic analysis. The method of detection and disposal is also applicable for UV ink PI migration testing from several different paper or paperboard‐plastic coating layer materials into the food simulants used in the study. Copyright © 2008 John Wiley & Sons, Ltd. 2008
Comparison of a 250 kV single‐stage accelerator mass spectrometer with a 5 MV tandem accelerator mass spectrometer – fitness for purpose in bioanalysis
Authors: Young G. C. , Corless S. , Felgate C. C. , Colthup P. V.
Published: November 2008

The introduction of ‘compact’ accelerator mass spectrometers into biomedical science, including use in drug metabolism and bioanalytical applications, is an exciting recent development. Comparisons are presented here between a more established and relatively large tandem accelerator which operates at up to 5 MV and a conventional laboratory‐sized 250 kV single‐stage accelerator mass spectrometer. Biological samples were enriched with low levels of radiocarbon, then converted into graphite prior to analysis on each of the two instruments. The data obtained showed the single‐stage instrument to be capable of delivering comparable results, and thus able to provide similar study support, with that provided by the 5 MV instrument, without the significant overheads and complexities which are inherent to the operation of the larger instrument. We believe that the advent of these laboratory‐sized accelerator mass spectrometry (AMS) instruments represents a real turning point in the potential for application of AMS by a wider user group. Copyright © 2008 John Wiley & Sons, Ltd.
Short cycle distribution in random regular graphs recursively generated by pegging
Authors: Gao Pu , Wormald Nicholas
Published: November 2008

We introduce a new method of generating random d‐regular graphs by repeatedly applying an operation called pegging. The pegging operation is abstracted from a type of basic operation applied in a type of peer‐to‐peer network called the SWAN network. We prove that for the resulting graphs, the limiting joint distribution of the numbers of short cycles is independent Poisson. We also use coupling to bound the rate at which the distribution approaches its limit. The coupling involves two different, though quite similar, Markov chains that are not time‐homogeneous. © 2008 Wiley Periodicals, Inc. Random Struct. Alg., 2009
Translations of scientific practice to “students' images of science”
Authors: van Eijck Michiel , Hsu Pei‐Ling , Roth Wolff‐Michael
Published: November 2008

In the science education research literature, it often appears to be assumed that students “possess” more or less stable “images of science” that directly correspond to their experiences with scientific practice in science curricula. From cultural‐historical and sociocultural perspectives, this assumption is problematic because scientific practices are collective human activities and are therefore neither identical with students' experiences nor with the accounts of these experiences that students make available to researchers. “Students' images of science” are therefore translated from (rather than directly correspond to) scientific practices. Drawing on data collected during and after preuniversity biology students' internships in a scientific laboratory, we exemplify the role of these translations in the production of “students' images of science.” A coarse‐grained analysis based on existing research showed our data to be comparable with earlier studies on “students' images of science.” A fine‐grained analysis shows how “students' images of science” were coproduced along a trajectory of translations that was determined by the use of particular actions and tools, and a particular division of labor in scientific practice. We propose to reconceptualize “students' images of science” as particular coproductions at a given point in time. The methodological and educational implications of this proposal are discussed. © 2008 Wiley Periodicals, Inc. Sci Ed 93:611–634, 2009
Knowledge sharing and trust in collaborative requirements analysis
Authors: Luna‐Reyes Luis F. , Black Laura J. , Cresswell Anthony M. , Pardo Theresa A.
Published: November 2008

Many information technology projects fail due to problems in requirements definition. Possible leverage points in improving requirements analysis lie in collaborative processes crossing functional and organizational boundaries, in which stakeholders learn about the problem and together identify possible solution requirements. Establishing trust among parties is critical to collaborative work, particularly in the early stages of information systems projects. However, there are few guidelines on how to establish trust among project participants. This paper draws on empirical work from the Center for Technology in Government facilitating interagency groups and system dynamics to generate a simple model of the role of knowledge sharing in building trust during the requirements analysis phase of a complex information systems project. Analysis of the model suggests that trust can depend on the pace of knowledge sharing among participants. More broadly, this examination offers a closer look at some of the “soft” variable dynamics that play critical roles in project progress. Copyright © 2008 John Wiley & Sons, Ltd.
Simple virtual reality display of fetal volume ultrasound
Authors: Tutschek B.
Published: November 2008

Three‐dimensional (3D) ultrasound volume acquisition, analysis and display of fetal structures have enhanced their visualization and greatly improved the general understanding of their anatomy and pathology. The dynamic display of volume data generally depends on proprietary software, usually supplied with the ultrasound system, and on the operator's ability to maneuver the dataset digitally. We have used relatively simple tools and an established storage, display and manipulation format to generate non‐linear virtual reality object movies of prenatal images (including moving sequences and 3D‐rendered views) that can be navigated easily and interactively on any current computer. This approach permits a viewing or learning experience that is superior to watching a linear movie passively. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
The second von Willebrand type A domain of cochlin has high affinity for type I, type II and type IV collagens
Authors: Nagy Ildikó , Trexler Mária , Patthy László
Published: November 2008

MINT‐6796048:

type I collagen (uniprotkb:P02452) binds (MI:0407) to cochlin‐vWA2 uniprotkb:O43405) by surface plasmon resonance (MI:0107)

MINT‐6796166:

type III collagen (uniprotkb:P02462) binds (MI:0407) to cochlin‐vWA2 (uniprotkb:O43405) by surface plasmon resonance (MI:0107)

MINT‐6796062:

type II collagen (uniprotkb:P02458) binds (MI:0407) to cochlin‐vWA2 (uniprotkb:O43405) by surface plasmon resonance (MI:0107)
White matter integrity linked to functional impairments in aging and early Alzheimer's disease
Authors: Kavcic Voyko , Ni Hongyan , Zhu Tong , Zhong Jianhui , Duffy Charles J.
Published: November 2008

Background

Alzheimer's disease (AD) is associated with changes in cerebral white matter (WM), but the functional significance of such findings is not yet established. We hypothesized that diffusion tensor imaging (DTI) might reveal links between regional WM changes and specific neuropsychologically and psychophysically defined impairments in early AD.

Methods

Older adult control subjects (OA, n = 18) and mildly impaired AD patients (n = 14) underwent neuropsychological and visual perceptual testing along with DTI of cerebral WM. DTI yielded factional anisotropy (FA) and mean diffusivity (〈D〉) maps for nine regions of interest in three brain regions that were then compared with the performance measures.

Results

AD patients exhibited nonsignificant trends toward lower FAs in the posterior region's callosal and subcortical regions of interest. However, posterior callosal FA was significantly correlated with verbal fluency and figural memory impairments, whereas posterior subcortical FA was correlated with delayed verbal memory, figural memory, and optic flow perceptual impairments.

Conclusions

WM changes in early AD are concentrated in posterior cerebral areas, with distributions that correspond to specific functional impairments. DTI can be used to assess regional pathology related to individual's deficits in early AD.
Status of computerized cognitive testing in aging: A systematic review
Authors: Wild Katherine , Howieson Diane , Webbe Frank , Seelye Adriana , Kaye Jeffrey
Published: November 2008

Background

Early detection of cognitive decline in the elderly has become of heightened importance in parallel with the recent advances in therapeutics. Computerized assessment might be uniquely suited to early detection of changes in cognition in the elderly. We present here a systematic review of the status of computer‐based cognitive testing, focusing on detection of cognitive decline in the aging population.

Methods

All studies purporting to assess or detect age‐related changes in cognition or early dementia/mild cognitive impairment by means of computerized testing were included. Each test battery was rated on availability of normative data, level of evidence for test validity and reliability, comprehensiveness, and usability. All published studies relevant to a particular computerized test were read by a minimum of two reviewers, who completed rating forms containing the abovementioned criteria.

Results

Of the 18 test batteries identified from the initial search, 11 were appropriate to cognitive testing in the elderly and were subjected to systematic review. Of those 11, five were either developed specifically for application with the elderly or have been used extensively with that population. Even within the computerized testing genre, great variability existed in manner of administration, ranging from fully examiner‐administered to fully self‐administered. All tests had at least minimal reliability and validity data, commonly reported in peer‐reviewed articles. However, level of rigor of validity testing varied widely.

Conclusion

All test batteries exhibited some of the strengths of computerized cognitive testing: standardization of administration and stimulus presentation, accurate measures of response latencies, automated comparison in real time with an individual's prior performance as well as with age‐related norms, and efficiencies of staffing and cost. Some, such as the Mild Cognitive Impairment Screen, adapted complicated scoring algorithms to enhance the information gathered from already existing tests. Others, such as CogState, used unique interfaces and subtests. We found that although basic indices of psychometric properties were typically addressed, sufficient variability exists that currently available computerized test batteries must be judged on a case‐by‐case basis.
Progranulin mutation causes frontotemporal dementia in the Swedish Karolinska family
Authors: Chiang Huei‐Hsin , Rosvall Lina , Brohede Jesper , Axelman Karin , Björk Behnosh F. , Nennesmo Inger , Robins Tiina , Graff Caroline
Published: November 2008

Background

Frontotemporal dementia (FTD) is a neurodegenerative disease characterized by cognitive impairment, language dysfunction, and/or changes in personality. Recently it has been shown that progranulin (GRN) mutations can cause FTD as well as other neurodegenerative phenotypes.

Methods

DNA from 30 family members, of whom seven were diagnosed with FTD, in the Karolinska family was available for GRN sequencing. Fibroblast cell mRNA from one affected family member and six control individuals was available for relative quantitative real‐time polymerase chain reaction to investigate the effect of the mutation. Furthermore, the cDNA of an affected individual was sequenced.

Results

Clinical and neuropathologic findings of a previously undescribed family branch are presented. A frameshift mutation in GRN (g.102delC) was detected in all affected family members and absent in four unaffected family members older than 70 years. Real‐time polymerase chain reaction data showed an ∼50% reduction of GRN fibroblast mRNA in an affected individual. The mutated mRNA transcripts were undetectable by cDNA sequencing.

Conclusions

Segregation and RNA analyses showed that the g.102delC mutation, previously reported, causes FTD in the Karolinska family. Our findings add further support to the significance of GRN in FTD etiology and the presence of modifying genes, which emphasize the need for further studies into the mechanisms of clinical heterogeneity. However, the results already call for attention to the complexity of predictive genetic testing of GRN mutations.
Successful Management of Perforated Duodenal Diverticulitis With Intra‐abdominal Drainage and Feeding Jejunostomy: A Case Report and Literature Review
Authors: Chen Chin‐Fan , Wu Deng‐Chyang , Chen Chao‐Wen , Hsieh Jan‐Sing , Chen Chiao‐Yun , Wang Jaw‐Yuan
Published: November 2008

We report the clinical experience of one patient with perforated duodenal diverticulitis who was successfully treated by intra‐abdominal drainage and feeding jejunostomy. A 53‐year‐old male patient visited our hospital due to acute onset of abdominal pain and distension. Physical examination revealed tenderness over the epigastric area and right‐lower quadrant of the abdomen without obvious rebound tenderness or muscle guarding. Duodenal diverticulitis with a retroperitoneal abscess was identified by abdominal computed tomography scan. Surgical intervention was performed after the failure of conservative treatment. The operative findings were compatible with perforated duodenal diverticulitis, and intra‐abdominal drainage of retroperitoneal abscess with simultaneous feeding jejunostomy was undertaken. The patient was doing well at the 4‐month postoperative follow‐up visit. We suggest the use of a conservative operative method, as opposed to conventional diverticulectomy and duodenorrhaphy, as an alternative approach for the management of this disorder, especially when conservative treatment has failed.
Homonymous Central Quadrantanopia Caused by an Extrastriate (V2/V3) Infarction: A Case Report
Authors: Lin Shu‐Fang , Kuo Yu‐Ting , Chang Fang‐Ling , Tsai Rong‐Kung
Published: November 2008

A 66‐year‐old Taiwanese aboriginal male had complained of right‐side blurred vision for 2 months, especially when reading. He had a 10‐year history of hypertension and cardiovascular disease. His best‐corrected visual acuity was 20/25 in each eye. Ophthalmoscopy revealed asymmetrical cupping, but a normal disc. Humphrey perimetry showed an upper homonymous para‐central quadrantanopic defect. Brain magnetic resonance imaging showed an infarction in the left lower calcarine area over the extrastriate (V2/V3) cortical area and a narrowing of the left middle and posterior cerebral arteries due to severe arteriosclerosis.
q-SERIES IN MARKOV CHAINS WITH BINOMIAL TRANSITIONS
Authors: Economou Antonis , Kapodistria Stella
Published: November 2008

We consider a single-server Markovian queue with synchronized services and setup times. The customers arrive according to a Poisson process and are served simultaneously. The service times are independent and exponentially distributed. At a service completion epoch, every customer remains satisfied with probability p (independently of the others) and departs from the system; otherwise, he stays for a new service. Moreover, the server takes multiple vacations whenever the system is empty.

Some of the transition rates of the underlying two-dimensional Markov chain involve binomial coefficients dependent on the number of customers. Indeed, at each service completion epoch, the number of customers n is reduced according to a binomial (n, p) distribution. We show that the model can be efficiently studied using the framework of q-hypergeometric series and we carry out an extensive analysis including the stationary, the busy period, and the sojourn time distributions. Exact formulas and numerical results show the effect of the level of synchronization to the performance of such systems.