bluuebunny/crossref_metadata_2025 huggingface dataset:
Properties of supercritical fluid extrusion‐based crosslinked starch extrudates
Authors: Ayoub Ali , Rizvi Syed S. H.
Published: December 2007

Starch microcellular foam was produced by supercritical fluid extrusion (SCFX) using native and pregelatinized starch mixtures. The starch solution was reacted with epichlorohydrin (EPI) under alkaline conditions in a continuous twin‐screw extruder in the presence of supercritical carbon dioxide. The relationship between crosslinking density and cell size and their distribution in the foamed extrudates was studied. An increase in the EPI concentration from 0 to 0.5% was accompanied by an increase in the degree of crosslinking as measured by differential scanning calorimetry and confirmed by diffusion coefficient measured by nuclear magnetic resonance. The diffusion coefficient of crosslinked sample was observed to be 12.5 times lower than that of non crosslinked control. The average cell size of the microporous structure, observed by scanning electron microscopy, showed a decrease from 147 to 61 μm as the concentration of EPI was increased. The cell size distribution of the crosslinked samples was significantly improved but the total expansion was lowered. The results obtained to date indicate, for the first time, that reactive extrusion of starch with EPI with supercritical carbon dioxide as a blowing agent offers a promising new technique to generate microporous foams for use in various applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Simultaneous determination of monomeric and oligomeric alkannins and shikonins by high‐performance liquid chromatography–diode array detection–mass spectrometry
Authors: Assimopoulou A. N. , Ganzera M. , Stuppner H. , Papageorgiou V. P.
Published: December 2007

Alkannin and shikonin (A/S) derivatives have been found in the roots of several Boraginaceous species and are produced through plant tissue cultures. The chiral compounds alkannins and shikonins are potent pharmaceutical substances with a wide spectrum of pharmacological activities such as wound healing, antimicrobial, anti‐inflammatory, anticancer and antioxidant. Although oligomeric A/S derivatives have been detected in root extracts and commercial samples their detection and determination through high‐performance liquid chromatography has not been reported. Therefore, in the present study a rapid, simple high‐performance liquid chromatography–diode array detection–mass spectrometry (HPLC‐DAD‐MS) method was developed to detect, separate and determine monomeric and oligomeric/polymeric derivatives of alkannin/shikonin simultaneously for the first time. An optimization of HPLC‐DAD parameters was performed. Both atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI) modes were applied, in order to compare detection of monomeric and oligomeric A/S. Additionally, oligomeric A/S constituents in several samples were identified and the mode of A/S polymerization was proposed. Copyright © 2007 John Wiley & Sons, Ltd.
Mental health teaching to UK psychology undergraduates: report of a survey
Authors: Cromby John , Harper David , Reavey Paula
Published: December 2007

One of the limitations on developing more progressive applied psychology training is the teaching received by students at undergraduate level. In this study, we focus on the provision of teaching about mental health or its equivalents (e.g. abnormal psychology and clinical psychology) on UK undergraduate psychology programmes. Most students who go on to train as clinical psychologists will have received teaching on modules like these. A survey questionnaire was sent to 109 university departments which might offer a module in mental health mental health module and 348 individuals who might be involved in such modules. The majority of programmes responding offered a mental health module, which was available each year as an optional subject. A number of findings on the content and delivery of the modules are reported and a number of recommendations are made including more involvement from practitioners and service users. Copyright © 2007 John Wiley & Sons, Ltd.
Integrierte flexible Datenverarbeitung in einem webbasierten LIMS – Idee und Praxis eines Excel‐Prozessors in Serverapplikationen
Authors: Göde B. , Holzmüller‐Laue S. , Rimane K. , Thurow K.
Published: December 2007

Durch zunehmende Laborautomatisierung fallen immer größere Datenmengen an, deren zentrales Management für Qualitätssicherung und Informationsverfügbarkeit von entscheidender Bedeutung ist, wodurch ein leistungsfähiges und zugleich bedarfsgerechtes Laborinformationsmanagementsystem (LIMS) eine zwingende Voraussetzung für die Effizienz eines modernen Labors darstellt. Für ein branchenübergreifendes, insbesondere F&E‐orientiertes LIMS ist ein freier Umgang mit integrierten Berechnungsvorschriften wünschenswert, da so u. a. notwendige applikationsspezifische Informationsverdichtungen oder erweiterungsfähige Parameterberechnungen möglich sind. Vor diesem Hintergrund wurde eine Datenverarbeitungsmöglichkeit entwickelt, die in LIMS serverseitig integrierbar ist und für den Nutzer den Charakter eines offenen Werkzeugs annimmt. Diese Offenheit bezieht sich auf den operativen Einsatz mathematischer und logischer Algorithmen zwischen Workflowparametern bzw. Prozessgrößen im LIMS sowie auf die Möglichkeit zur einfachen dateibasierten Informationsübernahme von Gerätesystemen auf Prozessgrößen des LIMS. Konzept und Einsatz des so genannten Excel‐Prozessors sind Bestandteil strategischer F&E‐Arbeiten eines möglichst offenen und flexiblen LIMS für die Life Science Automation, die unter dem Begriff openLIMS gebündelt werden. Die vorgestellte Lösung eines Excel‐Prozessors wurde in das webbasierte openLIMS integriert und an zahlreichen analytischen Messsystemen erprobt.
Bestimmung der Widerstandskraft und des Transportverhaltens kugelförmiger Partikel in Strömungen mit Hilfe moderner CFD‐Werkzeuge
Authors: Schütz S. , Schilling M. , Piesche M.
Published: December 2007

Das klassische Euler‐Lagrange‐Modell zur Berechnung der Bewegung einzelner Partikel in Mehrphasenströmungen beruht auf der Annahme der Partikel als Massenpunkte. Bewegen sich jedoch die Partikel in engen Strömungsquerschnitten, kann der Einfluss der realen Partikelausdehnung nicht mehr vernachlässigt werden, da in diesem Fall das Größenverhältnis von Partikel‐ und Strömungsgeometrie das Transport‐ und Widerstandsverhalten signifikant beeinflusst. Es wird ein Rechenmodell entwickelt und vorgestellt, in dem Partikel bei der Simulation von Mehrphasenströmungen volumetrisch aufgelöst betrachtet werden. Die Partikelbewegung wird über Kräfte‐ und Momentenbilanzen direkt aus den an der Partikeloberfläche angreifenden Strömungskräften berechnet und mit Hilfe eines Dynamic‐Mesh‐Verfahrens abgebildet.
FDA PAT Initiative – Eine Anwendersicht zu technischen Möglichkeiten und aktueller industrieller Umsetzung
Authors: Dünnebier G. , Tups H.
Published: December 2007

Die in der Pharmazeutischen Industrie etablierten Good Manufacturing Practices (GMP) sind empirische Standards, die bewährte Vorgehensweisen in der Produktion beschreiben. Die FDA erkannte die Notwendigkeit, die Effizienz in der Pharmaproduktion durch Einsatz von in anderen Industrien bewährten Technologien zu erhöhen und zugleich weiterhin die Qualität der produzierten Pharmazeutika sicherzustellen. Wie man diesen Paradigmenwechsel in der Praxis angeht und welche Erfahrungen in der pharmazeutischen Produktion damit bis heute vorliegen, wird in diesem Beitrag detailliert geschildert. Dabei werden sowohl die einsetzbaren Technologien als auch erste ausgewählte Anwendungen vorgestellt. Die Beispiele zeigen, dass die Industrie die Herausforderungen aus der FDA Initiative angenommen hat.
Relative tumor burden predicts metastasis‐free survival in pediatric osteosarcoma
Authors: Lee Jun Ah , Kim Min Suk , Kim Dong Ho , Lim Jung Sub , Yoo Ji Young , Koh Jae Soo , Lee Soo‐Yong , Jeon Dae‐Geun , Park Kyung Duk
Published: December 2007

Background

To analyze the significance of relative tumor burden in pediatric osteosarcoma.

Methods

We retrospectively reviewed 241 patients with localized pediatric osteosarcoma and measured tumor size on MR images at presentation. Absolute tumor size parameters measured on MR images were converted to relative values by dividing body surface area. Both absolute and relative size parameters were analyzed for their correlation with metastasis‐free survival (MFS).

Results

The 5‐year MFS was 67.5 ± 3.1%, with median follow‐up of 72 months (range, 8–205 months). In addition to poor histologic response (RR 3.24; 95% CI: 1.99–5.28; P < 0.001), large relative tumor plane (RTP; RR 3.28; 95% CI: 1.72–6.25; P < 0.001), large relative tumor area (RTA; RR 4.14; 95% CI: 1.53–11.22; P = 0.005), and large absolute tumor width (ATW; RR; 3.10; 95% CI: 1.23–7.79; P = 0.02) shortened the MFS. When survival was analyzed by combining RTP and histologic response, patients with small RTP and a good response showed the best survival (5‐year MFS of 90.2 ± 3.6%), while those with large RTP and a poor response showed the worst survival (5‐year MFS of 45.1 ± 6.6%).

Conclusion

Relative two‐dimensional tumor size parameters (RTP and RTA) rather than absolute values are useful prognostic factors in pediatric osteosarcoma patients. © 2007 Wiley‐Liss, Inc.
Demarcation of the cortical division zone in dividing plant cells
Authors: Van Damme Daniel , Geelen Danny
Published: December 2007

Somatic cytokinesis in higher plants involves, besides the actual construction of a new cell wall, also the determination of a division zone. Several proteins have been shown to play a part in the mechanism that somatic plant cells use to control the positioning of the new cell wall. Plant cells determine the division zone at an early stage of cell division and use a transient microtubular structure, the preprophase band (PPB), during this process. The PPB is formed at the division zone, leaving behind a mark that during cytokinesis is utilized by the phragmoplast to guide the expanding cell plate toward the correct cortical insertion site. This review discusses old and new observations with regard to mechanisms implicated in the orientation of cell division and determination of a cortical division zone.
Inflammation and insulin resistance
Authors: de Luca Carl , Olefsky Jerrold M.
Published: December 2007

Obesity‐induced chronic inflammation is a key component in the pathogenesis of insulin resistance and the Metabolic syndrome. In this review, we focus on the interconnection between obesity, inflammation and insulin resistance. Pro‐inflammatory cytokines can cause insulin resistance in adipose tissue, skeletal muscle and liver by inhibiting insulin signal transduction. The sources of cytokines in insulin resistant states are the insulin target tissue themselves, primarily fat and liver, but to a larger extent the activated tissue resident macrophages. While the initiating factors of this inflammatory response remain to be fully determined, chronic inflammation in these tissues could cause localized insulin resistance via autocrine/paracrine cytokine signaling and systemic insulin resistance via endocrine cytokine signaling all of which contribute to the abnormal metabolic state.
Microfluidic System for Automated Cell-Based Assays
Authors: Lee Philip J. , Ghorashian Navid , Gaige Terry A. , Hung Paul J.
Published: December 2007

Microfluidic cell culture is a promising technology for applications in the drug screening industry. Key benefits include improved biological function, higher-quality cell-based data, reduced reagent consumption, and lower cost. In this work, we demonstrate how a microfluidic cell culture design was adapted to be compatible with the standard 96-well plate format. Key design features include the elimination of tubing and connectors, the ability to maintain long-term continuous perfusion cell culture using a passive gravity-driven pump, and direct analysis on the outlet wells of the microfluidic plate. A single microfluidic culture plate contained eight independent flow units, each with 104 cells at a flow rate of 50 μL/day (6 min residence time). The cytotoxicity of the anticancer drug etoposide was measured on HeLa cells cultured in this format, using a commercial lactate dehydrogenase plate reader assay. The integration of microfluidic cell culture methods with commercial automation capabilities offers an exciting opportunity for improved cell-based screening.
Dilution Effect in Multichannel Liquid-Handling System Equipped with Fixed Tips: Problems and Solutions for Bioanalytical Sample Preparation
Authors: Gu Huidong , Deng Yuzhong
Published: December 2007

This paper presents an in-depth investigation of the dilution effect from the liquid handlers equipped with fixed tips resulting from mixing with residues of the system liquid used to wash the inside and outside of the fixed tips. The impact of the dilution in bioanalytical sample preparation was evaluated. The liquid-transfer steps, where the dilution effect should be minimized or eliminated in bioanalytical sample preparation, were the sample dilution, and the standard (STD) and quality control (QC) sample preparation steps. The level of the dilution effect for the red dye was quantified by using the dual-dye photometric measurement. A significant dilution effect was observed for the red dye, indicating that without a proper liquid-transfer strategy to minimize it, it would be impossible to prepare serially diluted STD and QC samples because of the cumulative dilution effect. The impact on the bioanalytical results was substantial, especially when a multistep dilution scheme was used for the sample dilutions. A unique liquid-transfer strategy was designed in our lab to minimize the dilution effect for the sample dilution. The effectiveness of this strategy was demonstrated using the dual-dye photometric measurement and by generating a successful STD curve preparation of a model compound, Compound A, in dog plasma for an LC/MS/MS assay. With this strategy, high-quality bioanalytical sample preparation without the dilution effect could be achieved by using the liquid handlers equipped with fixed tips.
A Successful LIMS Implementation: Case Study at Southern Research Institute
Authors: Rasmussen Lynn , Maddox Clinton B. , Harten Bill , White E. Lucile
Published: December 2007

Laboratory process tracking is a critical part of any high-throughput operation. With increased throughput comes increased risk and increased cost of failure. As throughput increases, so does the need to track all aspects of the workflow that can contribute to success or failure. Personnel training, instrument validation, reagent expiration, and instrument performance are just a few of the many parameters that need to be tracked to ensure success in a high-throughput environment. An effective method of mitigating these risks is a well-designed laboratory information management system (LIMS). Cost, flexibility, ease of use, and ease of implementation are all important considerations when choosing a commercially available LIMS product. An analysis of these issues and a description of the design and implementation of the UNIConnect LIMS, called UNIFlow, in the high-throughput screening center (HTS Center) at Southern Research Institute is presented as a case study.
Iodine deficiency in pregnant women and neonates in Thailand
Authors: Rajatanavin Rajata
Published: December 2007

Objective: To present data on the relationship between the concentration of thyroid-stimulating hormone (TSH) in whole blood or serum from neonates and the concentration of iodine in their mother's urine collected at birth to contribute to the contention that the recommended iodine intake during pregnancy should be increased.

Design and Setting: Data were provided by current programmes of neonatal screening of congenital hypothyroidism in Bangkok and rural areas of Thailand.

Subjects: A total of 5144 cord serum samples were collected in 2003 and measured for TSH concentrations. Paired samples of blood and urine were collected in 2000 from 203 infants and their mothers and from 1182 infant-mother pairs in 2002-03 in six rural provinces. Iodine was measured in the urine and TSH was measured in cord serum.

Results: The urinary iodine concentration of mothers in rural Thailand is adequate, with a median of 103 μg l-1. However, in 2000, the median urinary iodine concentration of mothers in Bangkok was only 85 μg l-1. The concentration of TSH in whole blood collected on filter paper from neonates was not sensitive enough to be used as a monitoring tool for iodine nutrition in the neonates, as there was no relationship with the concentration of iodine in the urine of the children's mothers. This was in contrast to the concentration of TSH in serum collected from cord blood.

Conclusions: Several conclusions were drawn from this data: 1) Neonatal TSH screening using whole blood collected from a heel prick at 3 days of age is not sensitive enough to assess the iodine nutrition of neonates; 2) Neonatal TSH screening using cord sera can be used to assess iodine nutrition in neonates; 3) The optimum median maternal urinary iodine concentration in Thailand appears to be 103 μg l-1; 4) The criteria proposed by WHO, UNICEF, and ICCIDD to assess iodine nutrition using data on neonatal TSH concentrations should be reassessed; and 5) Neonatal TSH screening can be effectively performed by collecting cord serum in district hospitals in Thailand.
Iron-regulatory proteins: molecular biology and pathophysiological implications
Authors: Cairo Gaetano , Recalcati Stefania
Published: December 2007

Iron is required for key cellular functions, and there is a strong link between iron metabolism and important metabolic processes, such as cell growth, apoptosis and inflammation. Diseases that are directly or indirectly related to iron metabolism represent major health problems. Iron-regulatory proteins (IRPs) 1 and 2 are key controllers of vertebrate iron metabolism and post-transcriptionally regulate expression of the major iron homeostasis genes. Here we discuss how dysregulation of the IRP system can result from both iron-related and unrelated effectors and explain how this can have important pathological consequences in several human disorders.
The evolution of the damage zone with fault growth in sandstone and its multiscale characteristics
Authors: de Joussineau Ghislain , Aydin Atilla
Published: December 2007

We document the formation and evolution of the damage zones associated with strike‐slip faults in porous sandstone, through detailed field and statistical studies of faults of increasing slip magnitudes. The faults initiate as sheared joints with discontinuous damage zone located primarily at fault tips and fault surface irregularities. With increasing slip, the damage zone develops by progressive fracture infilling and is organized into two components with different characteristics. The first of these components is the inner damage zone flanking the fault core with a high fracture frequency and a thickness scaling with fault slip. It contributes to the progressive widening of the fault core with increasing deformation. The second of these components is the outer damage zone with a larger and more variable thickness and a lower fracture frequency than the inner zone. The origin and evolution of the inner and outer damage zones are closely related to the history of fault development, as presented in a new conceptual model for damage zone evolution with fault growth. The statistical properties of the fault networks, determined by scan line surveys, evolve with fault growth. This is attributed to the progressive saturation of the fault networks. Well‐developed fault networks have multifractal properties with important consequences in forecasting and characterizing faults from limited data sets. The conceptual model and statistical data presented here may be used as predictive tools to better estimate the geometrical and statistical properties of the damage zones associated with large faults with remotely resolvable slip magnitude in the subsurface.
Effect of land‐ice melting and associated changes in the AMOC result in little overall impact on oceanic CO2 uptake
Authors: Swingedouw D. , Bopp L. , Matras A. , Braconnot P.
Published: December 2007

The impact of Greenland Ice Sheet (GIS) melting and associated weakening in the Atlantic Meridional Overturning Circulation (AMOC) on carbon uptake is quantitatively evaluated using coupled climate and biogeochemistry models. We compare two 140‐yr global warming scenarios, forced by the same increase in atmospheric CO2, but with different GIS melting rates. The AMOC weakening in our 2 scenarios is −47% and −21% at 4 × CO2 when the melting of GIS is or is not considered, respectively. We find that GIS melting and AMOC‐induced weakening have little influence on the CO2 uptake. By isolating the specific effects of salinity and temperature changes on carbon uptake, we find that opposing processes tend to limit the effect of GIS melting. Indeed, in the GIS melting scenario, less saline and cooler waters in high latitudes northern seas tend to increase CO2 uptake and counter‐balance the decreasing CO2 uptake that follows from circulation changes alone.
Oxygen ions at Titan's exobase in a Voyager 1–type interaction from a hybrid simulation
Authors: Sillanpää I. , Kallio E. , Jarvinen R. , Janhunen P.
Published: December 2007

Titan's extensive atmosphere and exosphere interact with Saturn's rotating magnetospheric flow. We have studied this interaction with an advanced hybrid simulation model which employs a realistic ion composition in the upstream flow (subsonic O+and H+) and has improved spatial resolution. We present results for both the general characteristics of the interaction and the behavior of the O+flow ions near the exobase for the conditions during the Voyager 1 flyby. Our model shows that the ionotail and the magnetotail bend in a direction opposite to the convection electric field. This is validated with the total force on the incident flow species derived from basic plasma equations. We also present a simulated impact map for the oxygen ions of the flow with total O+precipitation rate 1.3 × 1024 s−1 at Titan's exobase. Although this rate indicates that the plasma conditions above the exobase do not inhibit O+precipitation on the exobase, the direction of the O+flow is shown to turn drastically near the exobase. The energy deposition of the medium‐weight flow ions (such as O+) thus seems to be orders of magnitude larger than the energy deposition by pickup ions formed near Titan. However, the lightweight flow ions (H+) are effectively deflected by the magnetic barrier formed around Titan.
A thermodynamically consistent kinetic framework for binary nucleation
Authors: Flagan Richard C.
Published: December 2007

The traditional theory for binary homogeneous nucleation follows the classical derivation of the nucleation rate in the supposition of a hypothetical constrained-equilibrium distribution in the calculation of the cluster evaporation rate. This model enables calculation of the nucleation rate, but requires evaluation of the cluster distribution and cluster properties for an unstable equilibrium with supersaturated vapor. An alternate derivation of the classical homomolecular nucleation rate eliminated the need for this nonphysical approximation by calculating the evaporative flux at full thermodynamic equilibrium. The present paper develops that approach for binary nucleation; the framework is readily extended to ternary nucleation. In this analysis, the evaporative flux is evaluated by applying mass balance at full thermodynamic equilibrium of the system under study. This approach eliminates both the need for evaluating cluster properties in an unstable constrained-equilibrium state and ambiguity in the normalization constant required in the nucleation-rate expression. Moreover, it naturally spans the entire composition range between the two pure monomers. The cluster fluxes derived using this new model are similar in form to those of classical derivations, so previously developed methods for evaluation of the net nucleation rate can be applied directly to the new formulation.
KMC-1: A high resolution and high flux soft x-ray beamline at BESSY
Authors: Schaefers F. , Mertin M. , Gorgoi M.
Published: December 2007

The crystal monochromator beamline KMC-1 at a BESSY II bending magnet covers the energy range from soft (1.7keV) to hard x-rays (12keV) employing the (n,−n) double crystal arrangement with constant beam offset. The monochromator is equipped with three sets of crystals, InSb, Si (111), and Si (422) which are exchangeable in situ within a few minutes. Beamline and monochromator have been optimized for high flux and high resolution. This could be achieved by (1) a windowless setup under ultrahigh-vacuum conditions up to the experiment, (2) by the use of only three optical elements to minimize reflection losses, (3) by collecting an unusually large horizontal radiation fan (6mrad) with the toroidal premirror, and (4) the optimization of the crystal optics to the soft x-ray range necessitating quasibackscattering crystal geometry (θBragg,max=82°) delivering crystal limited resolution. The multipurpose beamline is in use for a variety of user facilities such as extended x-ray absorption fine structure, ((Bio-)EXAFS) near-edge x-ray absorption fine structure (NEXAFS), absorption and fluorescence spectroscopy. Due to the windowless UHV setup the k edges of the technologically and biologically important elements such as Si, P, and S are accessible. In addition to these experiments this beamline is now extensively used for photoelectron spectroscopy at high kinetic energies. Photon flux in the 1011–1012photons∕s range and beamline resolving powers of more than E∕ΔE≈100.000 have been measured at selected energies employing Si (nnn) high order radiation in quasibackscattering geometry, thus photoelectron spectroscopy with a total instrumental resolution of about 150meV is possible. This article describes the design features of the beamline and reports some experimental results in the above mentioned fields.
Cylindrical stationary striations in surface wave produced plasma columns of argon
Authors: Kumar Rajneesh , Kulkarni Sanjay V. , Bora Dhiraj
Published: December 2007

Striations are a good example of manifestation of a glow discharge. In the present investigation, stationary striations in the surface wave produced plasma column are formed. Physical parameters (length, number, etc.) of such striations can be controlled by operating parameters. With the help of bifurcation theory, experimental results are explained by considering two-step ionization in the surface wave discharge mechanism in argon gas. It is also observed that the bifurcation parameter is a function of input power, working pressure, and tube radius.
Simulations on the electromechanical poling of ferroelectric ceramics
Authors: Wu Yin-Zhong , Tao Yong-Mei
Published: December 2007

Based on the two-step-switching model, the process of electromechanical poling of ferroelectric ceramics is simulated. A difference of the remnant polarizations between two poling protocols (mechanical stress is applied before and after the application of poling field) is found from our simulations, which is also observed in the experiment. An explanation is given to illustrate why the remnant polarization for the case that mechanical stress is loaded after the application of the electric field is larger than the case that mechanical stress is loaded before the application of the electric field. Our simulation results supply proof for the validity of the two-step-switching model in the electromechanical poling of polycrystalline ferroelectric ceramics.
Characterization of triplet-triplet annihilation in organic light-emitting diodes based on anthracene derivatives
Authors: Kondakov D. Y.
Published: December 2007

We report that the steady-state electroluminescence in organic light-emitting diodes (OLEDs) based on anthracene derivatives has a substantial contribution from annihilation of triplet states generated by recombining charge carriers. For the OLED devices of the following general structure: indium tin oxide∕N,N′-diphenyl-N,N′-bis(1-naphthyl)-1,1′-biphenyl-4,4′-diamine∕9,10-bis(2-naphthyl)-2-t-butylanthracene∕Alq3 (tris(8-hydroxyquinolate)aluminum)∕LiF∕Al, triplet-triplet annihilation contributes as much as 3%–6% of the overall electroluminescence. The intensity of triplet-triplet annihilation-related emission strongly varies with the current density and pulse width, being quadratic and linear functions of current density at low (<5mA∕cm2) and high (>10mA∕cm2) current density regimes, respectively. We find that quenching by charge carriers is the dominant decay process for the triplet states under a wide range of operating conditions, yielding triplet-state lifetimes from tens to hundreds of microseconds. The decrease in charge-carrier concentrations through improved injection and transport may be expected not only to lower operational voltage but also to enhance triplet-triplet annihilation and, consequently, overall electroluminescence efficiency.
Fine positioning of a poloidal probe array
Authors: Yamada T. , Nagashima Y. , Inagaki S. , Kawai Y. , Yagi M. , Itoh S.-I. , Maruta T. , Shinohara S. , Terasaka K. , Kawaguchi M. , Fukao M. , Fujisawa A. , Itoh K.
Published: December 2007

Multipoint detection is an essential requirement for investigating plasma turbulence which is a highly nonlinear phenomenon in space and time. We have fabricated an array of 64-channel poloidal probes surrounding the linear cylindrical plasma named LMD-U in order to study turbulence properties, particularly the nonlinear mode couplings, in the domain of poloidal wave number and frequency. However, misalignments of probe tips produce spurious modes, which do not exist in the real plasma, to distort the precise wave number measurements. The paper presents the description of the 64-channel poloidal probe array with means to adjust the probe positions, with discussion on the effects of the misalignments on the wave number measurements.
Scanning electron microscope for in situ study of crystallization of Ge2Sb2Te5 in phase-change memory
Authors: Yin You , Niida Daisuke , Ota Kazuhiro , Sone Hayato , Hosaka Sumio
Published: December 2007

By introducing electrical connections into the chamber of a scanning electron microscope (SEM) via its holder assembly, it has become feasible to in situ observe and electrically characterize electronic devices. The in situ SEM was applied to investigate electric-pulse-induced behavior of Ge2Sb2Te5 in a lateral phase-change memory cell. Randomly distributed nuclei with sizes from 20to80nm were initiated at a low voltage pulse. Initially, grain growth depended strongly on pulse amplitude at around 60.3nm∕V and then a weak pulse amplitude dependence was observed at around 13.5nm∕V. Device resistance during crystallization dropped by two to three orders of magnitude with two falling steps, which probably resulted from amorphous to face-centered-cubic and subsequently to hexagonal transitions, respectively.
Strong perturbation of the guided light within Y2O3:Eu3+ thin-film phosphors coated with two-dimensional air-hole photonic crystal arrays
Authors: Lee Young Kwang , Oh Jeong Rok , Do Young Rag , Huh Young-Duk
Published: December 2007

Two-dimensional (2D) triangular-lattice air-hole nanoarrays of either SiO2 or SiNx were fabricated with nanosphere lithography as photonic crystal layers (PCLs) on sol-gel derived Y2O3:Eu3+ thin-film phosphors (TFPs). The effects of varying the air fill factor of the 2D PCLs on the light extraction efficiency of the TFPs were investigated. The integrated and normally directed photoluminescence extraction efficiencies were found to be improved by coating with 2D SiNx PCLs by factors of above 5.9 and 9.4, respectively; the 2D SiNx PCLs perturb the guided light more effectively than the 2D SiO2 PCLs because of their larger refractive index contrast.
Rheological properties of nanofluids flowing through microchannels
Authors: Chevalier J. , Tillement O. , Ayela F.
Published: December 2007

Results on the viscosity of SiO2 nanofluids submitted to very strong shear rates are reported. Experiments were conducted with micromachined capillary viscometers equipped with local pressure probes. For particle sizes of 35, 94, and 190nm, and solid volume fractions from 1.4% to 7%, a Newtonian behavior has been observed up to 5×104s−1. The increase in the nanofluid viscosity obeys a classical model but with a crowding factor which is a function of the diameter of the particles. This size dependence is explained by the influence of the shearing motion on the aggregates aspect ratio.
Mechanism of vertical correlation in Ge/Si(001) islands multilayer structures by chemical vapor deposition
Authors: Yam V. , Débarre D. , Bouchier D. , Laval J.-Y.
Published: December 2007

The aim of this paper is to study the mechanism of vertical correlation of Ge/Si(001) islands in multilayered structures grown by ultrahigh vacuum chemical vapor deposition. We used in situ reflexion high energy electron diffraction, ex situ atomic force microscopy, photoluminescence spectroscopy, and high resolution and analytical field emission transmission electron microscopy in order to determine the morphological properties of the layered structures at each step of their formation. For Si spacer thickness below 90 nm, a roughness is observed above the top of each Ge island. The local composition of the multilayers measured by x-ray nanoanalysis shows an inhomogeneous Ge distribution in the wetting layers and in the islands. The roughness can then be explained by the existence of a difference of Si growth rate over Ge islands and Ge wetting layers. This roughness on the Si cap surface layer leads, on the one hand, to a preferential nucleation of Ge above each buried island, and consequently to the vertical correlation in multilayers, and, on the other hand, to an increase of island density on upper layers.
Spin-glass-like behavior in rhombohedral Li(Mn,Cr)O2
Authors: Du Fei , Huang Zu-Fei , Wang Chun-Zhong , Meng Xing , Chen Gang , Chen Yan , Feng Shou-Hua
Published: December 2007

The magnetic properties of Cr-doped rhombohedral LiMnO2 are investigated. Two paramagnetic regions are separated at 95K with a reduction in the effective moment due to the change in spin-orbit coupling. Spin-glass-like behavior is suggested at low temperature based on the dc magnetization and magnetic hysteresis measurements.
Observation of oxide precipitates in InN nanostructures
Authors: Kwon Soon-Yong , Ren Zaiyuan , Sun Qian , Han Jung , Kim Young-Woon , Yoon Euijoon , Kong Bo Hyun , Cho Hyung Koun , Kim Il-Joong , Cheong Hyeonsik
Published: December 2007

We observed the formation of oxide precipitates (bcc-In2O3) in InN nanostructures formed during metal-organic chemical vapor deposition (MOCVD) and/or subsequent postgrowth procedures in H2 ambient. It was found that InN is extremely unstable in H2 ambient and the activation energy of N2 desorption of InN is measured to be ∼0.28eV, which is one order of magnitude smaller than that of reported value of InN in vacuum. Instability of InN nanostructures under H2 ambient together with residual oxidant in the reactor facilitates the formation of indium oxide precipitates in the nanostructure matrix during MOCVD or the oxidation of residual indium at the surface, resulting in indium oxide dots.
Ultrasensitive mass balance based on a bulk acoustic mode single-crystal silicon resonator
Authors: Lee J. E.-Y. , Bahreyni B. , Zhu Y. , Seshia A. A.
Published: December 2007

A single-crystal silicon resonant bulk acoustic mass sensor with a measured resolution of 125pg∕cm2 is presented. The mass sensor comprises a micromachined silicon plate that is excited in the square-extensional bulk acoustic resonant mode at a frequency of 2.182MHz, with a quality factor exceeding 106. The mass sensor has a measured mass to frequency shift sensitivity of 132Hzcm2∕μg. The resonator element is embedded in a feedback loop of an electronic amplifier to implement an oscillator with a short term frequency stability of better than 7ppb at an operating pressure of 3.8mTorr.
MicroRNA expression signatures accurately discriminate acute lymphoblastic leukemia from acute myeloid leukemia
Authors: Mi Shuangli , Lu Jun , Sun Miao , Li Zejuan , Zhang Hao , Neilly Mary Beth , Wang Yungui , Qian Zhijian , Jin Jie , Zhang Yanming , Bohlander Stefan K. , Le Beau Michelle M. , Larson Richard A. , Golub Todd R. , Rowley Janet D. , Chen Jianjun
Published: December 2007

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer, whereas acute myeloid leukemia (AML) is the most common acute leukemia in adults. In general, ALL has a better prognosis than AML. To understand the distinct mechanisms in leukemogenesis between ALL and AML and to identify markers for diagnosis and treatment, we performed a large-scale genome-wide microRNA (miRNA, miR) expression profiling assay and identified 27 miRNAs that are differentially expressed between ALL and AML. Among them, miR-128a and -128b are significantly overexpressed, whereas let-7b and miR-223 are significantly down-regulated in ALL compared with AML. They are the most discriminatory miRNAs between ALL and AML. Using the expression signatures of a minimum of two of these miRNAs resulted in an accuracy rate of >95% in the diagnosis of ALL and AML. The differential expression patterns of these four miRNAs were validated further through large-scale real-time PCR on 98 acute leukemia samples covering most of the common cytogenetic subtypes, along with 10 normal control samples. Furthermore, we found that overexpression of miR-128 in ALL was at least partly associated with promoter hypomethylation and not with an amplification of its genomic locus. Taken together, we showed that expression signatures of as few as two miRNAs could accurately discriminate ALL from AML, and that epigenetic regulation might play an important role in the regulation of expression of miRNAs in acute leukemias.
In vitamin B
12
deficiency, higher serum folate is associated with increased total homocysteine and methylmalonic acid concentrations
Authors: Selhub Jacob , Morris Martha Savaria , Jacques Paul F.
Published: December 2007

In a recent study of older participants (age ≥60 years) in the 1999–2002 National Health and Nutrition Examination Survey (NHANES), we showed that a combination of high serum folate and low vitamin B
12
status was associated with higher prevalence of cognitive impairment and anemia than other combinations of vitamin B
12
and folate status. In the present study, we sought to determine the joint influence of serum folate and vitamin B
12
concentrations on two functional indicators of vitamin B
12
status, total homocysteine (tHcy) and methylmalonic acid (MMA), among adult participants in phase 2 of the NHANES III (1991–1994) and the NHANES 1999–2002. Exclusion of subjects who were <20 years old, were pregnant, had evidence of kidney or liver dysfunction, or reported a history of alcohol abuse or recent anemia therapy left 4,940 NHANES III participants and 5,473 NHANES 1999–2002 participants for the study. Multivariate analyses controlled for demographic factors, smoking, alcohol use, body mass index, self-reported diabetes diagnosis, and serum concentrations of creatinine and alanine aminotransferase revealed significant interactions between serum folate and serum vitamin B
12
in relation to circulating concentrations of both metabolites. In subjects with serum vitamin B
12
>148 pmol/liter (L), concentrations of both metabolites decreased significantly as serum folate increased. In subjects with lower serum vitamin B
12
, however, metabolite concentrations increased as serum folate increased starting at ≈20 nmol/L. These results suggest a worsening of vitamin B
12
's enzymatic functions as folate status increases in people who are vitamin B
12
-deficient.
Impact of an Oil-Based Lubricant on the Effectiveness of the Sterilization Processes
Authors: Rutala William A. , Gergen Maria F. , Weber David J.
Published: December 2007

Surgical instruments, including hinged instruments, were inoculated with test microorganisms (ie, methicillin-resistantStaphylococcus aureus,approximately 2 × 106colony-forming units [cfu];Pseudomonas aeruginosa,approximately 3 x 106cfu;Escherichia coli,approximately 2 × 105cfu; vancomycin-resistant enterococci, 1 × 105cfu;Geobacillus stearothermophilusspores, 2 × 105cfu or more; orBacillus atrophaeusspores, 9 × 104cfu or more), coated with an oil-based lubricant (hydraulic fluid), subjected to a sterilization process, and then samples from the instruments were cultured. We found that the oil-based lubricant did not alter the effectiveness of the sterilization process because high numbers of clinically relevant bacteria and standard test spores (which are relatively resistant to the sterilization process) were inactivated.
Naturally Occurring Broad-Spectrum Powdery Mildew Resistance in a Central American Tomato Accession Is Caused by Loss of Mlo Function
Authors: Bai Yuling , Pavan Stefano , Zheng Zheng , Zappel Nana F. , Reinstädler Anja , Lotti Concetta , De Giovanni Claudio , Ricciardi Luigi , Lindhout Pim , Visser Richard , Theres Klaus , Panstruga Ralph
Published: December 2007

The resistant cherry tomato (Solanum lycopersicum var. cerasiforme) line LC-95, derived from an accession collected in Ecuador, harbors a natural allele (ol-2) that confers broad-spectrum and recessively inherited resistance to powdery mildew (Oidium neolycopersici). As both the genetic and phytopathological characteristics of ol-2–mediated resistance are reminiscent of powdery mildew immunity conferred by loss-of-function mlo alleles in barley and Arabidopsis, we initiated a candidate-gene approach to clone Ol-2. A tomato Mlo gene (SlMlo1) with high sequence-relatedness to barley Mlo and Arabidopsis AtMLO2 mapped to the chromosomal region harboring the Ol-2 locus. Complementation experiments using transgenic tomato lines as well as virus-induced gene silencing assays suggested that loss of SlMlo1 function is responsible for powdery mildew resistance conferred by ol-2. In progeny of a cross between a resistant line bearing ol-2 and the susceptible tomato cultivar Moneymaker, a 19-bp deletion disrupting the SlMlo1 coding region cosegregated with resistance. This polymorphism results in a frameshift and, thus, a truncated nonfunctional SlMlo1 protein. Our findings reveal the second example of a natural mlo mutant that possibly arose post-domestication, suggesting that natural mlo alleles might be evolutionarily short-lived due to fitness costs related to loss of mlo function.
Learning curves in surgical practice
Authors: Hopper A N , Jamison M H , Lewis W G
Published: December 2007

Learning curves are often referred to in the context of medical education and training, though their trajectories and natures are a matter of debate. The origins of this concept derive from industry and its relevance to contemporary medicine and surgery remains controversial. We describe the history, derivation, character and possible mechanisms to deal with the implications of learning curves in the current climate of clinical governance and modernising medical careers.
Surveillance of patients post-endovascular aneurysm repair
Authors: Sharma P , Kyriakides C
Published: December 2007

Endovascular aneurysm repair (EVAR) is increasingly being employed as an alternative to open surgical repair for patients with abdominal aortic aneurysms. The surveillance of patients post-EVAR has traditionally been carried out with regular computed tomographic scans which have in part been responsible for the high costs associated with this procedure. Duplex has been proposed as an alternative, but researchers have so far been unable to devise a standardised protocol for this surveillance. This review aims to provide a clear understanding of currently employed imaging modalities and discuss future surveillance possibilities for this patient group.
Biliary tract infection and bacteraemia: presentation, structural abnormalities, causative organisms and clinical outcomes
Authors: Melzer M , Toner R , Lacey S , Bettany E , Rait G
Published: December 2007

Background

Biliary tract infection is a common cause of bacteraemia and is associated with high morbidity and mortality. Few papers describe blood culture isolates, underlying structural abnormalities and clinical outcomes in patients with bacteraemia.

Aims

To determine the proportion of bacteraemias caused by biliary tract infection and to describe patient demographics, underlying structural abnormalities and clinical outcomes in patients with bacteraemia.

Design

Prospective cohort study.

Methods

Biliary tract infection that caused bacteraemia was defined as a compatible clinical syndrome and a blood culture isolate consistent with ascending cholangitis. Patients aged 16 years and over were included in the study. From June 2003 to May 2005, demographic and clinical data were collected prospectively on all adult patients with bacteraemia. Radiological and endoscopic retrograde cholangiopancreatography findings were collected retrospectively.

Results

In 49 patients, the biliary tract was the site of infection for 39/592 (6.6%) community-acquired and 19/466 (4.1%) hospital-acquired episodes of bacteraemia. Three patients had mixed bacteraemias, and four had recurrent bacteraemia. The proportion of patients presenting with a structural abnormality was 34/49 (69%), and, of these structural abnormalities, 18/34 (53%) were pre-existing or newly diagnosed malignancies. Gram-negative organisms caused 55/58 (95%) episodes of bacteraemia. The most common Gram-negative organisms were Escherichia coli (34/55; 62%) and Klebsiella pneumoniae (14/55; 26%). Of the E coli isolates, 6/34 (18%) were extended spectrum β-lactamase producers or multiply drug resistant. Thirty-day mortality was 7/49 (14%). There was no difference in time taken to administer an effective antibiotic to survivors and non-survivors (0.86 vs 1.05 days, respectively, p = 0.92). Of the seven who died, four died from septic shock within 48 h of admission caused by “susceptible” Gram-negative organisms. Two others died from disseminated malignancy.

Conclusions

The proportion of bacteraemias caused by biliary tract infection was 5.5%. The most common infecting organisms were E coli and K pneumoniae. There was a strong association with choledocholithiasis and malignancies, both pre-existing and newly diagnosed. Death was uncommon but when it occurred was often caused by septic shock within 48 h of presentation.
Effects of Oxygen Content on Bioactivity of Titanium Oxide Films Fabricated on Titanium by Electron Beam Evaporation
Authors: Jeong Sang-Hun , Park Yeong-Joon , Kim Bong-Soo , Song Ho-Jun
Published: December 2007

The titanium oxide films were fabricated on titanium metal by e-beam deposition technique in various oxygen partial pressures in order to investigate the effects of oxygen content in titanium oxide film on the bioactivity of titanium implant. The nano-sized titanium oxide particles
were observed on the surface of specimens. Raman spectra showed that titanium oxide films deposited by e-beam evaporator had oxygen deficient TiO2 structure. The oxygen content in oxide films was calculated from the high resolution XPS spectra of Ti 2p. The densities of HA particles
formed on the sample surfaces after immersion test in SBF became higher as the contents of oxygen in titanium oxide films increased. We concluded that the degree of hydroxyl group formation in SBF depended on the stoichiometry of TiO2, which enhanced the bioactivity of titanium.