bluuebunny/crossref_metadata_2025 huggingface dataset:
Die Licht(r)evolution. Weiße LEDs für die Allgemeinbeleuchtung
Authors: Kölper Christopher , Bergbauer Werner , Straßburg Martin , Linder Norbert
Published: March 2011

Leuchtdioden (LEDs) glänzen durch lange Lebensdauer, gute Farbwiedergabe, schnelle Einschaltzeit und Dimmbarkeit. Das macht sie zunehmend attraktiv für die Allgemeinbeleuchtung. Vor allem benötigen sie weniger Energie als konventionelle Leuchtmittel. Als Materialsysteme haben sich AlInGaN und AlInGaP etabliert, die Lichtfarben in einem breiten Spektralbereich ermöglichen. Nur für grünes Licht gibt es noch kein effizientes LED‐Material. Der dafür nötige hohe Indiumgehalt im geeigneteren AlInGaN sorgt für fehlerhafte Kristallgitter, was die Effizienz senkt. Nanostrukturen könnten das Problem lösen. Für weiße Leuchtdioden haben sich verschiedene Verfahren etabliert. Gängig ist die Kombination einer blauen LED mit einem Leuchtstoff, der einen Teil ihres Lichts ins Gelbe konvertiert. LEDs haben ein großes Potenzial zur weiteren Steigerung ihrer Effizienz und Helligkeit. Sie werden schon bald in vielen Bereichen konventionelle Technologien ablösen.
Bose‐Einstein‐Kondensat aus Licht
Authors: Klaers Jan , Schmitt Julian , Vewinger Frank , Weitz Martin
Published: March 2011

Bose‐Einstein‐Kondensate (BEC) stellen einen Zustand von Quantengasen dar, den Satyendra Nath Bose und Albert Einstein in den 1920er Jahren für ein Gas von idealen Bosonen vorausgesagt haben. In einem BEC verhalten sich die Teilchen im Grundzustand wie ein einzelnes “Superteilchen.” Dies wurde erstmals 1995 mit atomaren Gasen realisiert, die auf Temperaturen im Nanokelvinbereich gekühlt wurden (Phys. Unserer Zeit 1996, 27 (5), 200 und 2003, 34 (4), 168). Seitdem gab es viele weitere Experimente mit verschiedenen bosonischen Teilchen, lediglich mit dem wohl bekanntesten Vertreter, dem Photon, ließ sich bislang kein BEC herstellen. Dies gelang kürzlich unserer Gruppe an der Universität Bonn.
Synthesis, characterization, and electrochemical studies of new 5‐ and 6‐nitro N‐acyl‐1H‐indazoles
Authors: Recabarren‐Gajardo G. , Gacitúa M. , Murueva I. , Romero J. , Espinosa‐Bustos C. , Mella‐Raipán J. , del Valle M. A. , Pessoa‐Mahana C. D. , Tapia R.
Published: March 2011

Two series of new N‐1 acylindazoles containing 5‐ or 6‐nitro groups were synthesized with moderate to good yields and characterized by IR and NMR spectroscopy. Cyclic voltammetry in aprotic media was utilized for the electrochemical characterization of the compounds. The calculated reduction potentials in physiological conditions are similar to those of known commercial antichagasic drugs. Therefore, the novel series reported herein are prospective candidates for antichagasic biological evaluation. Theoretical calculation results indicate that the studied dinitro derivatives undergo a single step reduction process because of the energy proximity of their radical and anionic state. Copyright © 2011 John Wiley & Sons, Ltd.
Conformational analysis of 4,4‐dimethyl‐4‐silathiane and its S‐oxides
Authors: Shainyan Bagrat A. , Suslova Elena N. , Kleinpeter Erich
Published: March 2011

4,4‐Dimethyl‐4‐silathiane and its S‐oxides [n = 0 (1), 1 (2), 2 (3)] were studied experimentally by variable temperature dynamic NMR spectroscopy down to 103 K and the frozen ring inversion was revealed for all three compounds. The barriers for the degenerate ring inversion in 1 and 3 were measured to be 4.8 and 5.0 kcal/mol at the coalescence temperatures of 111 and 116 K, respectively, and practically coincide with the calculated barriers of 4.60 kcal/mol in 1 and 4.46 kcal/mol in 3. The frozen equilibrium mixture 2‐ax/2‐eq contains 37% of the 2‐ax and 63% of the 2‐eq conformer. The ring inversion barrier proved to be ca. 4.8 kcal/mol. Calculations at the B3LYP/6‐311+G(d,p) level of theory showed the 2‐ax conformer to be 0.90 kcal/mol more stable than the 2‐eq conformer in the gas phase whereas in solution the relative stability of the conformers calculated using the PCM model at the same level of theory is inverted to become 0.19 (in CHCl3) or 0.36 kcal/mol (in DMSO) in favor of the 2‐eq conformer. The chair–chair interconversion mechanism of sulfoxide 2 includes two intermediate energetically equivalent 1,4‐twist forms and the 2,5‐boat transition state: 2‐ax (chair) ⇆ 2 (1,4‐twist) ⇆ [2 (2,5‐boat)]≠ ⇆ 2 (1,4‐twist) ⇆ 2‐eq (chair). The calculated ring inversion barriers are 5.1 (2‐ax → 2‐eq) and 4.2 kcal/mol (2‐eq → 2‐ax) in the gas phase, and 4.03 and 4.22 kcal/mol, respectively, in chloroform. Copyright © 2011 John Wiley & Sons, Ltd.
Thiol‐ene clickable hyperscaffolds bearing peripheral allyl groups
Authors: Roy Raj Kumar , Ramakrishnan S.
Published: March 2011

Radical catalyzed thiol‐ene reaction has become a useful alternative to the Huisgen‐type click reaction as it helps to expand the variability in reaction conditions as well as the range of clickable entities. Thus, direct generation of hyperbranched polymers bearing peripheral allyl groups that could be clicked using a variety of functional thiols would be of immense value. A specifically designed AB2 type monomer, that carries two allyl benzyl ethers groups and one alcohol functionality, was shown to undergo self‐condensation under acid‐catalyzed melt‐transetherification to yield a hyperbranched polyether that carries numerous allyl end‐groups. Importantly, it was shown that the kinetics of polymerization is not dramatically affected by the change of the ether unit from previously studied methyl benzyl ether to an allyl benzyl ether. The peripheral allyl groups were readily clicked quantitatively, using a variety of thiols, to generate an hydrocarbon‐soluble octadecyl‐derivative, amphiphilic systems using 2‐mercaptoethanol and chiral amino acid (N‐benzoyl cystine) derivatized hyperbranched structures; thus demonstrating the versatility of this novel class of clickable hyperscaffolds. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Syntheses of terminally functionalized polyisobutylene derivatives using diazonium salts
Authors: Bergbreiter David E. , Priyadarshani Nilusha
Published: March 2011

A new strategy for the synthesis of end‐functionalized polyisobutylene (PIB) oligomers is detailed. Commercially available vinyl‐terminated PIB oligomers were modified to form aniline‐terminated PIB via an aromatic electrophilic substitution reaction. The PIB‐bound aryl amines so formed were then converted into diazonium salts using isopentyl nitrite and an acid in methylene chloride. These salts served as versatile intermediates in synthetic reactions affording azo dye‐containing PIB derivatives and other terminally‐functionalized PIB derivatives not readily available by other reactions. The advantages and limitations of various name reactions including diazo couplings, Sandmeyer reactions, dediazoniations, and Heck reactions are discussed. The kinetics of polar substitution reactions at the termini of these nonpolar oligomers and the effects of solvent on these reactions were also examined. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis and nonlinear optical properties of novel Y‐type polyester containing tricyanovinylthiazolylazoresorcinoxy group with enhanced thermal stability of dipole alignment
Authors: Cho You Jin , No Hyo Jin , Kim Mi Sung , Lee Ju‐Yeon
Published: March 2011

Novel Y‐type polyester 4 containing 5‐methyl‐4‐{5‐(1,2,2‐tricyanovinyl)‐2‐thiazolylazo}resorcinoxy groups as nonlinear optical (NLO) chromophores, which are parts of the polymer backbone, was prepared, and its NLO properties were investigated. Polyester 4 is soluble in common organic solvents such as N,N‐dimethylformamide and dimethylsulfoxide. Polymer 4 shows a thermal stability up to 250 °C from thermogravimetric analysis with glass‐transition temperature obtained from differential scanning calorimetry of approximately 94 °C. The second harmonic generation (SHG) coefficient (d33) of poled polymer film at 1560‐nm fundamental wavelength is 8.12 × 10−9 esu. The dipole alignment exhibits a thermal stability even at 6 °C higher than glass‐transition temperature (Tg), and no significant SHG decay is observed below 100 °C due to the partial main‐chain character of polymer structure, which is acceptable for NLO device applications. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis, characterization, and ethylene (Co)polymerization behavior of trichlorotitanium 2‐(1‐(arylimino)propyl)quinolin‐8‐olates
Authors: Huang Wei , Zhang Wenjuan , Liu Shaofeng , Liang Tongling , Sun Wen‐Hua
Published: March 2011

A series of trichlorotitanium complexes containing 2‐(1‐(arylimino)propyl)quinolin‐8‐olates was synthesized by stoichiometric reaction of titanium tetrachloride with the corresponding potassium 2‐(1‐(arylimino)propyl)quinolin‐8‐olates and was fully characterized by elemental analysis, nuclear magnetic resonance spectroscopy, and by single‐crystal X‐ray diffraction study of representative complexes. All titanium complexes, when activated with methylaluminoxane, exhibited high catalytic activity toward ethylene polymerization [up to 1.15 × 106 g mol−1(Ti) h−1] and ethylene/α‐olefin copolymerization [up to 1.54 × 106 g mol−1 (Ti) h−1]. The incorporation of comonomer was confirmed to amount up to 2.82 mol % of 1‐hexene or 1.94 mol % of 1‐octene, respectively. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Chiral crystal of a C2v‐symmetric 1,3‐diazaaulene derivative showing efficient optical second harmonic generation
Authors: Ma Xiao‐Hua , Fu Li‐Min , Zhao Yunfeng , Ai Xi‐Cheng , Zhang Jian‐Ping , Han Yu , Guo Zhi‐Xin
Published: March 2011

Achiral nonlinear optical (NLO) chromophores 1,3‐diazaazulene derivatives, 2‐(4′‐aminophenyl)‐6‐nitro‐1,3‐diazaazulene (APNA) and 2‐(4′‐N,N‐diphenylaminophenyl)‐6‐nitro‐1,3‐diazaazulene (DPAPNA), were synthesized with high yield. Despite the moderate static first hyperpolarizabilities (β0) for both APNA [(136 ± 5) × 10−30 esu] and DPAPNA [(263 ± 20) × 10−30 esu], only APNA crystal shows a powder efficiency of second harmonic generation (SHG) of 23 times that of urea. It is shown that the APNA crystallization driven cooperatively by the strong H‐bonding network and the dipolar electrostatic interactions falls into the noncentrosymmetric P212121 space group, and that the helical supramolecular assembly is solely responsible for the efficient SHG response. To the contrary, the DPAPNA crystal with centrosymmetric P‐1 space group is packed with antiparalleling dimmers, and is therefore completely SHG‐inactive. 1,3‐Diazaazulene derivatives are suggested to be potent building blocks for SHG‐active chiral crystals, which are advantageous in high thermal stability, excellent near‐infrared transparency and high degree of designing flexibility. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
Cloud point suppression in dilute solutions of model gradient copolymers with prespecified composition profiles
Authors: Gallow Keith C. , Jhon Young K. , Tang Wei , Genzer Jan , Loo Yueh‐Lin
Published: March 2011

Gradient copolymers of 2‐hydroxyethyl methacrylate (HEMA) and 2‐(dimethylamino)ethyl methacrylate (DMAEMA) having prescribed linear, parabolic, and hyperbolic composition profiles were synthesized with the guidance of a numerical model that determines the instantaneous comonomer feed rate. These materials exhibit low polydispersity indices (<1.1); the evolution of the overall DMAEMA content and the absolute molecular weight of the copolymers are all in good agreement with the quantities predicted by our model. Compared to random copolymers of HEMA and DMAEMA, the cloud points of dilute buffered aqueous solutions of gradient copolymers decrease with increasing gradient strength; where the gradient strength is defined as the largest difference in the instantaneous composition along the copolymer. The temperature range over which the solutions transition from transparent to turbid also broadens significantly with increasing gradient strength. Both observations suggest the onset of transition to be dictated by the least soluble ends of the polymer chains. These correlations point to the importance of monomer sequence distribution in determining the macroscopic physical properties of copolymers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
Multiaxial deformation of polyethylene and polyethylene/clay nanocomposites: in situ synchrotron small angle and wide angle X‐ray scattering study
Authors: Gurun Bilge , Bucknall David G. , Thio Yonathan S. , Teoh Chin Ching , Harkin‐Jones Eileen
Published: March 2011

A unique in situ multiaxial deformation device has been designed and built specifically for simultaneous synchrotron small angle X‐ray scattering (SAXS) and wide angle X‐ray scattering (WAXS) measurements. SAXS and WAXS patterns of high‐density polyethylene (HDPE) and HDPE/clay nanocomposites were measured in real time during in situ multiaxial deformation at room temperature and at 55 °C. It was observed that the morphological evolution of polyethylene is affected by the existence of clay platelets as well as the deformation temperature and strain rate. Martensitic transformation of orthorhombic into monoclinic crystal phases was observed under strain in HDPE, which is delayed and hindered in the presence of clay nanoplatelets. From the SAXS measurements, it was observed that the thickness of the interlamellar amorphous region increased with increasing strain, which is due to elongation of the amorphous chains. The increase in amorphous layer thickness is slightly higher for the nanocomposites compared to the neat polymer. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
The impact of breast cancer on mother–child relationships in Korea
Authors: Kim Sue , Ko Yun Hee , Jun Eun Young
Published: March 2011

Objective

For families with dependent children, the situational crisis of a cancer diagnosis may compound the developmental task of parenting. This study aimed to explore the impact of breast cancer on Korean mothers and their children following diagnosis.

Methods

Korean women diagnosed with breast cancer at 50 years or younger more than a year ago were recruited by posting announcements at a breast cancer clinic and through referrals and snowball sampling. A one‐time in‐depth interview ranging from 60 to 90 min was conducted and data were transcribed verbatim for content analysis.

Results

Five themes emerged from the data: (1) The delicate balance of being able to focus on self, which also was a conflicting factor in their relationship with children; (2) The continuing challenge of taking care of children, which was closely linked to supports, health condition, and cultural notions of parenting and lingering stigma; (3) The importance of informing children in a timely manner; (4) An overall shift in attitudes towards raising children as independent beings; and (5) Relinquishing and re‐envisioning the future for their children and themselves.

Conclusions

Breast cancer brings new challenges in mother–child relationships with culturally framed issues. Findings can guide healthcare providers in giving relevant anticipatory guidance for women diagnosed with breast cancer and in considering family‐focused psychosocial and behavioral interventions for families with breast cancer.

Copyright © 2011 John Wiley & Sons, Ltd.
Hydrodynamics of holographic flavored plasmas
Authors: Bigazzi F. , Cotrone A.L. , Tarrío J.
Published: March 2011

We provide a short review of the hydrodynamical properties of a class of strongly coupled thermal gauge theories, coupled to massless fundamental flavor fields, having a dual supergravity description. The analysis is valid for more general classes of nearly conformal holographic plasmas, where the breaking of conformality is driven by marginally (ir)relevant deformations.
Composition and toxic, repellent and feeding deterrent activity of essential oils against the stored‐grain pests Tribolium castaneum (Coleoptera: Tenebrionidae) and Sitophilus oryzae (Coleoptera: Curculionidae)
Authors: Stefanazzi Natalia , Stadler Teodoro , Ferrero Adriana
Published: March 2011

BACKGROUND: The composition and bioactivity of essential oils from Tagetes terniflora Kunth, Cymbopogon citratus Stapf. and Elyonurus muticus (Spreng) Kuntz were evaluated against stored‐grain pests.

RESULTS: Fumigant and contact toxicities were observed with T. terniflora on adults of both pests. In contact toxicity, this oil was less toxic to Tribolium castaneum (Herbst). Essential oils from C. citratus and E. muticus showed contact toxicity on S. oryzae. All essential oils produced: (a) repellency on larvae and adults of T. castaneum and adults of Sitophilus oryzae (L.); (b) post‐ingestive toxicity on T. castaneum larvae and S. oryzae adults and alteration of nutritional index on T. castaneum and S. oryzae adults. Cymbopogon citratus reduced the relative growth rate and the efficiency of conversion of ingested food in T. castaneum larvae. Tagetes terniflora produced a feeding stimulant effect in T. castaneum adults. In addition, they had a feeding deterrent action against S. oryzae adults. The composition of essential oils from C. citratus and E. muticus varied only in one component.

CONCLUSION: These results showed that the essential oils from T. terniflora, C. citratus and E. muticus should be studied further for their use in integrated pest management programmes for T. castaneum and S. oryzae control. Copyright © 2011 Society of Chemical Industry
Spray drift as influenced by meteorological and technical factors
Authors: Arvidsson Tommy , Bergström Lars , Kreuger Jenny
Published: March 2011

BACKGROUND: The objective of this study was to investigate spray drift from a conventional field sprayer as influenced by meteorological and technical factors, and to provide spray operators with data on which to base sound judgements when applying pesticides. The study was conducted in grazing fields and cereal crops.

RESULTS: Interpreting the results from 15 field trials under varying meteorological conditions using different boom heights and driving speeds indicates that, during normal spraying conditions, the most decisive factors influencing the total spray drift (TSD) will be boom height and wind speed, followed by air temperature, driving speed and vapour pressure deficit. One important finding was that TSD (within the encompassed range of meteorological conditions and a boom height of 0.4 m) could be expressed as a simple function of the fraction of droplets ≤ 100 µm. In cereal crops: TSD = 0.36 + 0.11× [fr. (d ≤ 100 µm)] and in grazing fields, TSD = 1.02 + 0.10× [fr. (d ≤ 100 µm)]. In most cases a fraction of the airborne drift passed over the 6 m sampling mast located 5 m downwind of the spray swath.

CONCLUSIONS: Under specified conditions, the present results indicate a simple relation between the total spray drift and volume fractions of droplets ≤ 100 µm. Given the nozzle type, it was concluded that the most decisive factors determining TSD are wind speed and boom height. Evaluating the relative importance of the meteorological and technical factors contributes to increasing knowledge in this field of research. Copyright © 2011 Society of Chemical Industry
Febuxostat: new xanthine oxidase inhibitor for gout
Authors: Chaplin Steve , Doherty Michael
Published: March 2011

Febuxostat (Adenuric) is a xanthine oxidase inhibitor licensed for the treatment of chronic hyperuricaemia when urate deposition has already occurred. In our New products review Steve Chaplin presents the clinical data relating to its efficacy and adverse effects and Professor Michael Doherty discusses its place in the treatment of gout. Copyright © 2011 Wiley Interface Ltd
Compatibility of cancer cells with nanostructured oxidized porous silicon substrates
Authors: Zeidman Tal , Parush Ran , Massad Na'ama , Segal Ester
Published: March 2011

The attachment and long‐term viability of three types of human cancer cell lines (glioma U87, breast cancer MDA‐MB‐231, and cervical cancer HeLa) onto nanostructured oxidized porous Si substrates is investigated. The porous layers are fabricated to give cylindrically‐shaped structures with pore diameters in the tunable range of 10 to 150 nm by anodizing a heavily‐doped p‐type Si. The Alamar Blue viability assay and optical microscopy are employed to assess the attachment, viability and the morphology of the cells. The results show that cells remain viable and proliferate on all surfaces. The nano‐architecture of the studied scaffolds does not exert a deleterious effect on cancer cells. Cell coverage levels comparable to standard culture preparations on tissue culture polystyrene are observed (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of thick ordered mesoporous silica membranes
Authors: Vanga Kumar , Cheam Dawdon , Middlebrook Christopher , Bergstrom Paul
Published: March 2011

Mesoporous silicon membranes with very uniform and vertical pores are fabricated by electrochemical anodization resulting in pore diameters between 15‐30 nm and pore depths of 550 μm. The influence of applied current density on the pore morphology is characterized for the formation of mesoporous silicon membranes. These porous silicon membranes are thermally oxidized to form transparent silica membranes. The current study involved ellipsometric measurements of the optical properties of porous silica material spectroscopically from 300 nm to 1000 nm. Normal transmittance through the membrane was measured and found to be attenuated significantly at short wavelengths but approached the transmittance of bulk silicon for the near infrared. Angularly resolved transmission and reflection study is performed extending into the infrared regime. Refractive index and extinction coefficients are modeled based on the optical measurements. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Secondary electron imaging of titania thin film for surface potential analysis
Authors: Kumagai Kazuhiro , Sekiguchi Takashi
Published: March 2011

We demonstrate the surface potential sensitivity of secondary electron (SE) imaging of titania thin film by scanning electron microscopy (SEM), and discuss the image formation mechanism. The 1‐nm titania film on Si substrate was imaged as bright region against the substrate. The SE image of the film varied with SE detector, but did not with primary electron energy. The contrast of the film was reversed by only 1‐nm carbon deposition. This result suggests that a slight change of surface potential altered the efficiency of secondary electron emission. This high sensitivity of secondary electrons to the surface potential is promising for improvement of thin‐film observation by SEM. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Monitoring of the growth of microcrystalline silicon by plasma‐enhanced chemical vapor deposition using in‐situ Raman spectroscopy
Authors: Muthmann S. , Köhler F. , Meier M. , Hülsbeck M. , Carius R. , Gordijn A.
Published: March 2011

Raman spectra of microcrystalline silicon layers have been recorded in‐situ during growth. The spectra have been collected under realistic conditions for solar cell deposition. To enable these measurements an electrode with an optical feed through has been developed. By using a metallic grid to shield the feed through it is possible to achieve homogeneous deposition of µc‐Si:H at a sufficient optical transmission. In‐situ Raman measurements were carried out during the deposition of a layer with an intentionally introduced gradient in crystallinity that was seen in‐situ as well in reference measurements performed on the same layer ex‐situ. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
19.4%‐efficient large‐area fully screen‐printed silicon solar cells
Authors: Gatz Sebastian , Hannebauer Helge , Hesse Rene , Werner Florian , Schmidt Arne , Dullweber Thorsten , Schmidt Jan , Bothe Karsten , Brendel Rolf
Published: March 2011

We demonstrate industrially feasible large‐area solar cells with passivated homogeneous emitter and rear achieving energy conversion efficiencies of up to 19.4% on 125 × 125 mm2 p‐type 2–3 Ω cm boron‐doped Czochralski silicon wafers. Front and rear metal contacts are fabricated by screen‐printing of silver and aluminum paste and firing in a conventional belt furnace. We implement two different dielectric rear surface passivation stacks: (i) a thermally grown silicon dioxide/silicon nitride stack and (ii) an atomic‐layer‐deposited aluminum oxide/silicon nitride stack. The dielectrics at the rear result in a decreased surface recombination velocity of Srear = 70 cm/s and 80 cm/s, and an increased internal IR reflectance of up to 91% corresponding to an improved Jsc of up to 38.9 mA/cm2 and Voc of up to 664 mV. We observe an increase in cell efficiency of 0.8% absolute for the cells compared to 18.6% efficient reference solar cells featuring a full‐area aluminum back surface field. To our knowledge, the energy conversion efficiency of 19.4% is the best value reported so far for large area screen‐printed solar cells. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Lag‐time effects on a naturally ventilated large thermometer screen
Authors: Harrison R. G.
Published: March 2011

Systematic natural ventilation effects on measured temperatures within a standard large wooden thermometer screen are investigated under summer conditions, using well‐calibrated platinum resistance thermometers. Under low ventilation (2 m wind speed u2 < 1.1 m s−1), the screen slightly underestimates daytime air temperature but overestimates air temperature nocturnally by 0.2°C. The screen's lag time L lengthens with decreasing wind speed, following an inverse power law relationship between L and u2. For u2 > 2 m s−1, L ∼ 2.5 min, increasing, when calm, to at least 15 min. Spectral response properties of the screen to air temperature fluctuations vary with wind speed because of the lag changes. Ventilation effects are particularly apparent at the higher (>25°C) temperatures, both through the lag effect and from solar heating. For sites where wind speed decreases with increasing daytime temperature, thermometer screen temperatures may consequently show larger uncertainties at the higher temperatures. Under strong direct beam solar radiation (>850 W m−2) the radiation effect is likely to be <0.4°C. Copyright © 2011 Royal Meteorological Society
Background‐error covariances for a convective‐scale data‐assimilation system: AROME–France 3D‐Var
Authors: Brousseau Pierre , Berre Loïk , Bouttier François , Desroziers Gérald
Published: March 2011

AROME–France is a convective‐scale numerical weather prediction system running operationally at Météo‐France since the end of 2008. It uses a 3D‐Var assimilation scheme to determine its initial conditions. Climatological background‐error covariances of such a system are calculated using differences between forecasts from an AROME ensemble assimilation. These statistics are compared with the lower‐resolution ALADIN–France system ones: they provide 3D‐Var analysis increments that are more intense and more localized, in accordance with the actual AROME model resolution.

AROME ensemble‐assimilation (ENS_DA) covariances have also been compared with covariances calculated with an AROME ensemble of forecasts run in spin‐up mode (ENS_SU). On the one hand, ENS_SU appears to be a reasonable approximation of ENS_DA compared with ALADIN–France covariances, by representing a large part of the small‐scale variance increase. On the other hand, ENS_DA allows for a fully cycled development of small‐scale forecast perturbations, which leads to a further enhancement of small‐scale covariances. This aspect is shown to be beneficial in terms of assimilation diagnostics and forecast performance and in a case study. Copyright © 2011 Royal Meteorological Society
Estimating background‐error variances with the ECMWF Ensemble of Data Assimilations system: some effects of ensemble size and day‐to‐day variability
Authors: Bonavita Massimo , Raynaud Laure , Isaksen Lars
Published: March 2011

Ensemble of data assimilations (EDA) methods have been shown to be able to provide flow‐dependent estimates of analysis and background error statistics. For this reason, they potentially present a way to overcome one of the main limitations of current variational data assimilation systems. However, the limited number of ensemble members which can be realistically run in an operational context and the stochastic nature of the EDA approach lead to high levels of sampling noise in the relevant ensemble statistics. To answer this problem, an ‘objective filtering’ technique of the sample ensemble variances proposed by Raynaud et al. in 2009 has been implemented at ECMWF. In this article we present a comparison of the ability of ensemble data assimilation systems of different sizes (10 to 50 members) to represent flow‐dependent background‐error variances. In particular, the ensemble‐based variances are examined in the cases of the severe storm Klaus (24 January 2009) over France and the Atlantic tropical hurricane Ike (1–14 September 2008). Our results show that, while a relatively small ensemble (10 members) can be sufficient to resolve the larger‐scale error structures connected to an extratropical cyclogenesis, a larger ensemble is beneficial to resolve more localised anomalies like those connected with a hurricane. In this sense, the objective filtering technique provides a useful indication of the spatial scales the ensemble is able to resolve in a statistically robust way.

The day‐to‐day variability of the ensemble statistics and how this affects the objective spatial filtering procedure are also examined. Our conclusion is that a time‐independent implementation of the filter based on a climatology of truncation wave numbers results in more robust ensemble statistics estimates, and ultimately in improved forecast skill scores. Copyright © 2011 Royal Meteorological Society
PRET, the Probability of RETurn: a new probabilistic product based on generalized extreme‐value theory
Authors: Prates Fernando , Buizza Roberto
Published: March 2011

A new probabilistic forecast product, the Probability of RETurn (PRET), is introduced. PRET, the probability of occurrence of an event that corresponds to a specific return period, is computed from forecasts given by the ECMWF Ensemble Prediction System. It has been designed to provide easy‐to‐interpret and valuable information on the intensity and rarity of the expected severe weather, especially when the ensemble‐based forecast distribution falls outside the model climate distribution. PRET definition relies on the Generalized Extreme Value family of distributions, which has been applied to study the statistics of the extremes in the model forecasts and observed datasets, and to estimate the levels corresponding to return periods not included in the datasets.

PRET forecasts for the 2‐metre maximum and minimum temperatures over Europe have been generated for six summer and six winter seasons (2003 to 2009). Case‐studies have been used to illustrate that the new product is easier to interpret than products that are now commonly used, such as probability forecasts and maps of Extreme Forecast Indices. Average diagnostics of PRET forecasts indicate that the skill in predicting extremely hot temperatures in the warm season is higher than the skill in predicting extremely cold temperatures in the cold season. Copyright © 2011 Royal Meteorological Society
Stability and robust stability of positive Volterra systems
Authors: Ilchmann Achim , Ngoc Pham Huu Anh
Published: March 2011

We study positive linear Volterra integro‐differential systems with infinitely many delays. Positivity is characterized in terms of the system entries. A generalized version of the Perron–Frobenius theorem is shown; this may be interesting in its own right but is exploited here for stability results: explicit spectral criteria for L1‐stability and exponential asymptotic stability. Also, the concept of stability radii, determining the maximal robustness with respect to additive perturbations to L1‐stable system, is introduced and it is shown that the complex, real and positive stability radii coincide and can be computed by an explicit formula. Copyright © 2011 John Wiley & Sons, Ltd.
The delimitation of the workspace accuracy in coordinate measuring technique
Authors: Swornowski Pawel
Published: March 2011

Dimensional measurements based on coordinate metrology are widely used for product verification, process control and dimensional faults root causes diagnostics of various manufacturing processes. In this study, the results of the measuring surface scanning of coordinate measuring machine with the prototype of optoelectronic device have been presented. The presented device is able to determine actual (real) inaccuracy of the CMM in two axes (X, Y). The prototype scanning device is installed in the measuring probe place. The method makes possible scanning with the established accuracy (max. 0.1 µm). A short description of the new method and the device is added, and some initial results are discussed. The results concern the inaccuracy of the CMMs example measuring area. SCANNING 33: 45–52, 2011. © 2011 Wiley Periodicals, Inc.
A zero‐ and K‐inflated mixture model for health questionnaire data
Authors: Finkelman Matthew D. , Green, Jennifer Greif , Gruber Michael J. , Zaslavsky Alan M.
Published: March 2011

In psychiatric assessment, Item Response Theory (IRT) is a popular tool to formalize the relation between the severity of a disorder and the associated responses to questionnaire items. Practitioners of IRT sometimes make the assumption of normally distributed severities within a population; while convenient, this assumption is often violated when measuring psychiatric disorders. Specifically, there may be a sizable group of respondents whose answers place them at an extreme of the latent trait spectrum. In this article, a zero‐ and K‐inflated mixture model is developed to account for the presence of such respondents. The model is fitted using an expectation–maximization (E‐M) algorithm to estimate the percentage of the population at each end of the continuum, concurrently analyzing the remaining ‘graded component’ via IRT. A method to perform factor analysis for only the graded component is introduced. In assessments of oppositional defiant disorder and conduct disorder, the zero‐ and K‐inflated model exhibited better fit than the standard IRT model. Copyright © 2011 John Wiley & Sons, Ltd.
The value of relational learning in global buyer‐supplier exchanges: a dyadic perspective and test of the pie‐sharing premise
Authors: Cheung Mee‐Shew , Myers Matthew B. , Mentzer John T.
Published: March 2011

Research in collaborative interorganizational relationships has typically focused on the value of these relationships to a specific supply chain partner. Furthermore, the phenomenon has rarely been explored in a global setting. Using primary data from 126 cross‐border dyads, we investigate the influence of relational learning on the relationship performance of both the buyer and the supplier, testing the contention that both members (1) benefit from relational learning efforts and (2) enjoy equal pieces of the benefits pie. We find that three specific types of relational learning (information sharing, joint sensemaking, and knowledge integration) influence relationship performance, and that these dimensions of relational learning affect supply chain partners in different ways. We draw conclusions regarding the relative value of relational learning for both buyers and suppliers. Copyright © 2011 John Wiley & Sons, Ltd.
Fetal heart ventricular mass obtained by STIC acquisition combined with inversion mode and VOCAL
Authors: Messing B. , Cohen S. M. , Valsky D. V. , Shen O. , Rosenak D. , Lipschuetz M. , Yagel S.
Published: March 2011

Objective

Estimation of fetal heart ventricular mass is important for fetal cardiac evaluation in cases of structural or functional cardiac disorders or extracardiac factors. It may be used with other cardiac parameters to ascertain the severity and prognosis of such disorders, or the nature and timing of intervention. We applied a novel technique combining spatiotemporal image correlation (STIC) with three‐dimensional inversion mode and Virtual Organ Computer‐aided AnaLysis (VOCAL™) for fetal cardiac mass assessment in healthy fetuses in the second and third trimesters.

Methods

STIC acquisition was performed during fetal quiescence with the abdomen uppermost, at an angle of 30–50°, without color Doppler mapping. Myocardial volume measurements were performed in postprocessing using VOCAL mode, set to 15°. Beginning with the heart in four‐chamber view at end diastole, a trace was drawn manually including the myocardium and interventricular septum. Inversion mode colors the intraventricular (anechoic, fluid‐filled) voxels; this intraventricular volume was subtracted automatically from the total. Mass was determined by multiplying the result by the estimated fetal myocardial density (1.050 g/cm3). The process was repeated for right and left ventricles.

Results

Data from 106 fetuses at 21–38 weeks' gestation were obtained and scatterplots of fetal cardiac ventricular mass distribution were created. Several cases of fetuses with disordered cardiac ventricle (supraventricular tachycardia, hypoplastic left heart syndrome, dilated cardiomyopathy, twin‐to‐twin transfusion syndrome, Ebstein anomaly, non‐immune hydrops fetalis, septate right atrium and diaphragmatic hernia) were examined. Ventricular mass parameters were markedly affected as compared with normal cases of similar gestational age.

Conclusions

STIC acquisition combined with inversion mode and VOCAL is a feasible method of cardiac ventricular mass quantification. This methodology may have added value in fetal cardiac evaluation in cases of anatomic malformation or cardiac dysfunction, or in cases of maternal diabetes. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Performance analysis of uplink spatial multiplexing MIMO MT‐CDMA over multipath fading channels
Authors: Yang Wei , Gong Yi , Xu Changlong
Published: March 2011

In this paper, we consider multiple‐input multiple‐output (MIMO) multi‐tone code division multiple access (MT‐CDMA) uplink transmission over multipath fading channels. The zero‐forcing vertical Bell Laboratories layered space‐time architecture (ZF V‐BLAST) algorithm and maximum ratio combining scheme are applied at the receiver. The average bit error rate (BER) expression is derived provided that the number of receive antennas is not less than that of transmit antennas. The BER expression is verified by simulations. Numerical results show that the numbers of transmit and receive antennas have significant effects on the BER performance of the considered system. Spatial and path diversity show different capabilities to improve the BER performance. The MIMO MT‐CDMA system based on the ZF V‐BLAST algorithm is capable of achieving a better BER performance and a higher capacity than the conventional MT‐CDMA system. Copyright © 2011 John Wiley & Sons, Ltd.
ATPase activity of a yeast secretory glycoprotein allows ER exit during inactivation of COPII components Sec24p and Sec13p
Authors: Suntio Taina , Shiryaev Sergey A. , Makarow Marja
Published: March 2011

Proteins exit the endoplasmic reticulum (ER) in vesicles pinching off from the membrane at sites covered by the COPII coat, which consists of Sec23/24p and Sec13/31p. We have shown that the glycoprotein Hsp150 exits the ER in the absence of Sec13p or any member of the Sec24p family. The determinant responsible for this resides in the C‐terminal domain of Hsp150 (CTD). Here, A‐ and B‐type Walker motifs were identified in the CTD. Authentic Hsp150 from the yeast culture medium, as well as Hsp150 and the CTD fragment produced in Escherichia coli, exhibited ATPase activity nearly three times higher than the published activity of the ER chaperone Kar2p/BiP. Deletion of the Walker motif, and a K335A mutation in it, abolished the ATPase activity. Hsp150 homologues Pir3p and Pir4p, differing in critical amino acids of the Walker motif, also lacked ATPase activity. Unexpectedly, inactivation of the ATPase activity blocked ER exit of Hsp150 in the absence of Sec24p or Sec13p function, whereas secretion in normal cells was not compromised. To our knowledge this is the first documentation of the ATPase activity of a protein serving an intracellular transport function. Copyright © 2011 John Wiley & Sons, Ltd.
Resection of a Transplantable Single‐Nodule Hepatocellular Carcinoma in Child‐Pugh Class A Cirrhosis: Factors Affecting Survival and Recurrence
Authors: Muscari Fabrice , Foppa Bertrand , Carrere Nicolas , Kamar Nassim , Peron Jean‐Marie , Suc Bertrand
Published: March 2011

Background

The aim of this study was to estimate the survival rates and define risk factors for tumor recurrence after resection surgery for single hepatocellular carcinomas (HCCs) ≤5 cm (on preoperative imaging) that developed on compensated cirrhosis.

Methods

A retrospective review studied patients treated by surgical resection. Overall survival (OS), disease‐free survival (DFS), recurrence rates, and risk factors were studied for all patients.

Results

A total of 49 patients were treated by resection. The 5‐year OS and DFS rates were 52 and 41%, respectively, after 2000. Three independent risk factors were found for OS and DFS: macroscopic vascular invasion, satellite nodules, R1 resection. In the absence of these three factors, the 5‐year OS was 59%. Recurrence rates were 63%. Delayed recurrence was significantly related to the 5‐year OS. One factor was correlated with early recurrence: the presence of satellite nodules; and one factor was correlated with late recurrence: hepatitis C virus infection.

Conclusions

R0 resection for HCC on compensated cirrhosis may offer good long‐term survival in the absence of satellites nodules and macrovascular invasion. Thus, a “first approach” resection is proposed with the possibility of “salvage transplantation.” In other cases, resection may be a bridge to transplantation (“transplantation de principe”).
A non‐smooth tumor margin in the hepatobiliary phase of gadoxetic acid disodium (Gd‐EOB‐DTPA)‐enhanced magnetic resonance imaging predicts microscopic portal vein invasion, intrahepatic metastasis, and early recurrence after hepatectomy in patients with hepatocellular carcinoma
Authors: Ariizumi Shun‐ichi , Kitagawa Koichi , Kotera Yoshihito , Takahashi Yutaka , Katagiri Satoshi , Kuwatsuru Ryohei , Yamamoto Masakazu
Published: March 2011

Background

The value of the hepatobiliary phase of gadoxetic acid disodium (Gd‐EOB‐DTPA)‐enhanced magnetic resonance imaging (MRI) in patients with hepatocellular carcinoma (HCC) has not been evaluated in detail.

Methods

Between 2008 and 2009, 61 patients with HCC within the Milan criteria underwent Gd‐EOB‐DTPA‐enhanced MRI and hepatectomy. The tumor margin was determined preoperatively based on hepatobiliary phase images. Microscopic portal vein invasion (MPVI), intrahepatic metastasis (IM), and recurrence of HCC within 1 year after hepatectomy were evaluated in 24 patients with non‐smooth margins at the periphery of the tumor and 37 patients with smooth margins.

Results

The number of patients with MPVI and IM of HCC was significantly higher among those with non‐smooth margins (42 and 38%, respectively) than among those with smooth margins (3%;p = 0.0002 and 5%;p = 0.0042, respectively). A non‐smooth margin was identified as a significant predictor of MPVI (odds ratio 18.814,p = 0.024) and IM (odds ratio 6.498,p = 0.036) of HCC on multivariate analysis. Furthermore, a non‐smooth margin was identified as a significant predictor of recurrence within 1 year after hepatectomy (odds ratio 4.306,p = 0.04) on multivariate analysis.

Conclusions

A non‐smooth tumor margin in the hepatobiliary phase of Gd‐EOB‐DTPA‐enhanced MRI is useful to predict MPVI, IM, and early recurrence of HCC after hepatectomy.
A Systematic Review of Outcomes of Fasciotomy, Aponeurotomy, and Collagenase Treatments for Dupuytren's Contracture
Authors: Chen Neal C. , Srinivasan Ramesh C. , Shauver Melissa J. , Chung Kevin C.
Published: March 2011

Background

Needle aponeurotomy and collagenase injection are alternative treatments of Dupuytren's contracture to open partial fasciectomy; however, reported data are difficult to interpret without a formal systematic review.

Methods

A Medline, EMBASE, and Cochrane database search was performed, and 277 articles were identified. Articles were stratified by level of evidence, and those of the highest level for each technique were included. Evidence available for needle aponeurotomy was of low quality so only cohorts larger than 100 patients were included.

Results

The sample size of patients for open partial fasciectomy ranged from 37-261. The recurrence rate ranged from 12-39%, with mean follow-up time of 1.5-7.3 years. The complication rate ranged from 14-67%. Complications included nerve division (2-5%), infection (4-12%), neurapraxia (0.4-52%), and regional pain syndrome (2-13%). For needle aponeurotomy the sample size ranged from 117-211. The recurrence rate ranged from 50-58%, with mean follow-up time of 3-5 years. With regard to collagenase injection, the sample size ranged from 13-204. The recurrence rate ranged from 10-31%, with mean follow-up time of 120 days to 4 years. For the two latter procedures, adverse effects consisted primarily of skin tears (9-25%). Kruskal-Wallis testing demonstrated that the recurrence rate was significantly higher for needle aponeurotomy than for open partial fasciectomy ( p=0.001), and the recurrence rate was significantly higher for open partial fasciectomy than for collagenase injection ( p=0.001).

Conclusions

The recurrence rates and types of complications differ between open partial fasciectomy and needle aponeurotomy or collagenase injection. Long-term outcomes have not been well reported.
Role of MeCP2, DNA methylation, and HDACs in regulating synapse function
Authors: Kavalali Ege T. , Nelson Erika D. , Monteggia Lisa M.
Published: March 2011

Over the past several years there has been intense effort to delineate the role of epigenetic factors, including methyl-CpG-binding protein 2, histone deacetylases, and DNA methyltransferases, in synaptic function. Studies from our group as well as others have shown that these key epigenetic mechanisms are critical regulators of synapse formation, maturation, as well as function. Although most studies have identified selective deficits in excitatory neurotransmission, the latest work has also uncovered deficits in inhibitory neurotransmission as well. Despite the rapid pace of advances, the exact synaptic mechanisms and gene targets that mediate these effects on neurotransmission remain unclear. Nevertheless, these findings not only open new avenues for understanding neuronal circuit abnormalities associated with neurodevelopmental disorders but also elucidate potential targets for addressing the pathophysiology of several intractable neuropsychiatric disorders.