Easy Way (easy + way)

Distribution by Scientific Domains


Selected Abstracts


Spark Plasma Sintering: An Easy Way to Make Infrared Transparent Glass,Ceramics

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2010
Gaelle Delaizir
Infrared transparent glass,ceramics have been prepared in the system GeS2,Sb2S3,CsCl using spark plasma sintering in shorter times in comparison with conventional thermal treatments. The combined effects of pressure, time, and temperature allow the controlled crystallization of Cs-based crystals. The different glass,ceramics have been characterized by scanning electron microscopy and X-ray diffraction. The optical properties were also investigated. [source]


Performance and effectiveness trade-off for checkpointing in fault-tolerant distributed systems

CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 1 2007
Panagiotis Katsaros
Abstract Checkpointing has a crucial impact on systems' performance and fault-tolerance effectiveness: excessive checkpointing results in performance degradation, while deficient checkpointing incurs expensive recovery. In distributed systems with independent checkpoint activities there is no easy way to determine checkpoint frequencies optimizing response-time and fault-tolerance costs at the same time. The purpose of this paper is to investigate the potentialities of a statistical decision-making procedure. We adopt a simulation-based approach for obtaining performance metrics that are afterwards used for determining a trade-off between checkpoint interval reductions and efficiency in performance. Statistical methodology including experimental design, regression analysis and optimization provides us with the framework for comparing configurations, which use possibly different fault-tolerance mechanisms (replication-based or message-logging-based). Systematic research also allows us to take into account additional design factors, such as load balancing. The method is described in terms of a standardized object replication model (OMG FT-CORBA), but it could also be applied in other (e.g. process-based) computational models. Copyright © 2006 John Wiley & Sons, Ltd. [source]


Performance comparison of checkpoint and recovery protocols

CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 15 2003
Himadri Sekhar Paul
Abstract Checkpoint and rollback recovery is a well-known technique for providing fault tolerance to long-running distributed applications. Performance of a checkpoint and recovery protocol depends on the characteristics of the application and the system on which it runs. However, given an application and system environment, there is no easy way to identify which checkpoint and recovery protocol will be most suitable for it. Conventional approaches require implementing the application with all the protocols under consideration, running them on the desired system, and comparing their performances. This process can be very tedious and time consuming. This paper first presents the design and implementation of a simulation environment, distributed process simulation or dPSIM, which enables easy implementation and evaluation of checkpoint and recovery protocols. The tool enables the protocols to be simulated under a wide variety of application, system, and network characteristics. The paper then presents performance evaluation of five checkpoint and recovery protocols. These protocols are implemented and executed in dPSIM under different simulated application, system, and network characteristics. Copyright © 2003 John Wiley & Sons, Ltd. [source]


A simple Tenax® extraction method to determine the availability of sediment-sorbed organic compounds

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2001
Gerard Cornelissen
Abstract A simple method to determine the availability of sediment-sorbed organic contaminants was developed and validated. For 10 polycyclic aromatic hydrocarbons, 4 polychlorinated biphenyls, and 9 chlorobenzenes in 6 sediments, we measured the fraction extracted by Tenax® in 6 and 30 h. These fractions were compared with the rapidly desorbing fractions determined by consecutive Tenax extraction. Extraction by Tenax for 30 h completely removed the rapidly desorbing fraction plus some part of the slowly desorbing fraction. The fraction removed after 30 h was about 1.4 times the rapidly desorbing fraction. The fraction extracted by Tenax after 6 h is about 0.5 times the rapidly desorbing fraction for chlorobenzenes (CBs)/polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). The rapidly desorbing fraction probably represents the fraction of sorbed organic compound that poses actual risks for transport to (ground) water and determines the uptake by organisms and that can be microbially degraded. Extraction by Tenax for 6 h provides an easy way to address these issues more accurately than does the measurement of total concentrations. [source]


Contact Angle Analysis During the Electro-oxidation of Self-Assembled Monolayers Formed by n -Octadecyltrichlorosilane

ADVANCED FUNCTIONAL MATERIALS, Issue 19 2010
Nicole Herzer
Abstract The electrochemical oxidation process of self-assembled monolayers formed by n -octadecyltrichlorosilane (OTS) molecules on silicon wafers has been studied in a droplet of water by means of in situ water contact angle measurements. The application of different bias voltages between the substrate and a counter electrode placed into the droplet resulted in changes of the chemical nature of the monolayer, which yielded a significant alteration of the surfaces properties. Due to the changes of the wetting properties of the monolayer during the electro-oxidation process a change in the contact angles of the water droplet is concomitantly observed. This allows the in situ monitoring of the electro-oxidation process for large modified areas of several millimeters in diameter. The chosen approach represents an easy way to screen the major parameters that influence the oxidation process. Afterwards, the oxidized regions are characterized by Fourier-transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) measurements, and atomic force microscopy (AFM) investigations to obtain more information about the electro-oxidation process. The observations are correlated to experimental results obtained for oxidations performed on a smaller dimension range in the water meniscus of a conductive, biased AFM tip. A good correlation of the results in the different dimension ranges could be found. [source]


Self-Assembled Robust Dipeptide Nanotubes and Fabrication of Dipeptide-Capped Gold Nanoparticles on the Surface of these Nanotubes,

ADVANCED FUNCTIONAL MATERIALS, Issue 12 2009
Samit Guha
Abstract Three water-soluble dipeptides containing N-terminally located , -alanine residue and C-terminally located , -amino acid residues (, -Ala- L -Xaa, Xaa,=,Val/Ile/Phe) form robust crystalline nanotubes. These dipeptide nanotubes contain a common motif, a hybrid of ,,, -amino acids, which are stable against heat up to 80,°C, a wide range of pH (2,10), and proteolytic degradation. These robust crystalline dipeptide nanotubes are used as a template for fabricating dipeptide-capped gold nanoparticles on their outer surfaces. This is an easy way to develop nanotube/nanoparticle hybrid materials under mild conditions. [source]


Assessment of peat compressibility: is there an easy way?

HYDROLOGICAL PROCESSES, Issue 17 2005
Jonathan S. Price
Abstract Peat compression can significantly alter the hydraulic parameters that govern flow and storage of water. Physical properties of peat (bulk density, state of decomposition (von Post number, vP) and fibre content) were assessed to determine whether they can be used as indicators of peat compressibility. Bulk density and vP were related to each other (positively), and within a given core were related (negatively) to compressibility. Peat from different locations exhibited different compressibility characteristics for a given value of bulk density or vP. Fibre content was unrelated to bulk density, vP, or to peat compressibility. It was concluded that more commonly and relatively easily measured soil parameters are not good indicators of soil compressibility. Copyright © 2005 John Wiley & Sons, Ltd. [source]


One-Pot Solution Synthesis of Cubic Cobalt Nanoskeletons

ADVANCED MATERIALS, Issue 16 2009
Xi Wang
Cubic Co nanoskeletons with an edge length of 100,nm are prepared by a facile one-pot solution method. The cubic Co nanoskeletons synthesized exhibit excellent magnetic properties and mesopore structures. This work may provide an easy way to control the synthesis of hollow metal nanopolyhedra by introducing an appropriate etching agent into the synthetic process. [source]


Ferrocene Redox Controlled Reversible Immobilization of Ruthenium Carbene in Ionic Liquid: A Versatile Catalyst for Ring-Closing Metathesis

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2009
Guiyan Liu
Abstract A ferrocene-tagged ruthenium carbene 15 that can be reversibly immobilized in an ionic liquid (IL) via the controlled oxidation and reduction of a ferrocene tag was prepared. This offers a new strategy which uses redox chemistry to control immobilization and to recycle both the catalyst and the IL. In this experiment, 11 recycles were performed for the ring-closing metathesis (RCM) of a substrate using 16 as the catalyst in an ionic liquid (IL). More importantly, after the reaction was completed, the ruthenium catalyst was easily separated from the supporting IL by just adding decamethylferrocene (DMFc) to reduce the cationic ferrocene and then extracting it with benzene. Thus, this recycle system offers an easy way to recycle both the ruthenium catalyst and the IL. [source]


Influence of dietary lipid source and strain on fatty acid composition of Muscovy duck meat

JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 3-4 2004
A. Schiavone
Summary A trial was conducted to study the effect of dietary 2% soya bean oil and dietary 2% fish oil (FO) on fatty acid composition of breast meat of two different Muscovy duck (Cairina moschata domestica L.) strains. The two strains were a broiler strain selected for meat production and an unselected rural strain. Fatty acid composition of breast muscle was deeply influenced by lipid source. Dietary FO improved the long chain polyunsaturated fatty acids (LC-PUFAs) of omega 3 series content, while the content of LC-PUFAs of omega 6 series was reduced. Differences in susceptibility in lipid manipulation were found between the two groups of animals suggesting the highest capability of animals belonging to the rural strain in stocking arachidonic acid in breast muscle. As the fatty acid profile of Muscovy duck meat can be considerably modified by changing the fatty acid composition of the diet, and dietary FO represents an easy way to reach this goal, human intake of healthy n-3 LC-PUFAs could be enhanced using this enriched poultry meat, even if the influence of FO on organoleptic characteristics (i.e. off-flavours) must be evaluated. [source]


Comparison of ATP and in vivo bioluminescence for assessing the efficiency of immunomagnetic sorbents for live Escherichia coli O157:H7 cells

JOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2002
W. Sun
Aims:,To develop methods to assess the efficiency of immunomagnetic separation (IMS). Methods and Results:,The capturing efficiency of biosorbents for Escherichia coli O157:H7, constructed using streptavidin-coated magnetic beads and biotinylated antibodies, was tested using both in vivo and ATP bioluminescence. Both methods were suitable for the enumeration of bacteria captured by the biosorbents. The level of both ATP and in vivo bioluminescence depended on the media used, but was unaffected by the magnetic beads. The capture efficiency depended on time and sample volume, but did not depend on the length of spacer arm of the biotinylation agent. For cell concentrations of , 105 cfu ml,1, in a 1-ml sample volume, nearly 80,85% recovery of the pathogen was observed after 0·5 h of incubation. For an 11-ml sample containing 104 cfu ml,1, maximum recovery (50% of cells) was achieved only after 2 h incubation. Conclusions:,The detection limit of an ATP-based bioluminescent assay for E. coli O157:H7 was reduced by 1 log cycle after optimization of IMS. The bioluminescent methods could be used for screening and testing the affinity of antibodies or other affinity elements of biosorbents towards live bacterial cells. Significance and Impact of the Study:,Bioluminescent assays provide an easy way to optimize conditions for the capture of bacteria by biosorbents in real time. [source]


Water intoxication following labour and surgery: blaming oxytocin , the easy way out?

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 9 2009
V. Moen
No abstract is available for this article. [source]


Full absorption: The good, the bad, and the ugly

JOURNAL OF CORPORATE ACCOUNTING & FINANCE, Issue 3 2008
Alan Vercio
There are good, bad, and ugly uses associated with full absorption costing. Good characteristics include ensuring that all dollars are accounted for. Bad characteristics include combining costs that do not have similar cost driver patterns. Ugly characteristics include decisions made with fully absorbed cost data that combines different drivers. Financial accounting inventory valuation forces us to combine unlike drivers of cost. But there is a relatively easy way to manage around this for internal reporting. An unfortunate outcome of letting the bad and the ugly creep into the full-absorption costing process is that the value of full absorption has been undermined, and consultants often recommend not using full absorption for decision making (a case of throwing the baby out with the bathwater). This article provides insight and recommendations for getting the full value from full-absorption costing. © 2008 Wiley Periodicals, Inc. [source]


Comparison between three-dimensional volume-selective turbo spin-echo imaging and two-dimensional ultrasound for assessing carotid artery structure and function

JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 3 2005
Lindsey A. Crowe PhD
Abstract Purpose To compare a volume-selective three-dimensional turbo spin echo (TSE) technique with ultrasound (US) for assessing carotid artery wall structure and function. Materials and Methods A three-dimensional volume-selective TSE technique was used to image the carotid artery in 10 healthy subjects and five hypertensive subjects (each of whom were scanned three times while they received different hypertension treatments). Lumen and wall area were measured on MR images. Two-dimensional US measurements of the intima-media thickness (IMT) and lumen diameter were taken in three orientations through a single cross section. The lumen area change over the cardiac cycle was used to determine distension. For validation, a Bland-Altman analysis was used to compare the vessel wall and lumen areas measured by three-dimensional MRI volumes with those obtained by US scans. Results Agreement between the two methods was found. The mean difference in distension between US and MRI was 1.2% (±5.1%). For the wall area measurements, good agreement was shown, but there was a systematic difference due to the visualization of the adventitia by MRI. Both techniques offer an easy way to objectively measure lumen indices. MRI can provide the complete circumference over the length of a vessel, while US is flexible and relatively inexpensive. The application of US is limited, however, when subjects are poorly echogenic. A difference between hypertensive and healthy subjects was found. Conclusion There was a good agreement between MRI and the clinically established two-dimensional US method. The MRI method has the advantage of providing increased vessel coverage, which permits one to assess localized abnormalities without assuming vessel uniformity. J. Magn. Reson. Imaging 2005;21:282,289. © 2005 Wiley-Liss, Inc. [source]


rpoB -PCR amplified gene and temporal temperature gradient gel electrophoresis: a rapid tool to analyse bacterial strains representative of cold-smoked salmon microflora

LETTERS IN APPLIED MICROBIOLOGY, Issue 2 2004
S. Giacomazzi
Abstract Aim:, To evaluate rpoB gene as a biomarker of microbial biodiversity associated to cold-smoked salmon by a novel nested-polymerase chain reaction/temporal temperature gradient gel electrophoresis (PCR/TTGE) technique applied on pure cultures of reference strains. Methods and Results:, DNA obtained from pure cultures of reference strains was used in a succession of a first PCR amplification of rpoB fragment with degenerated nonclamped primers and a nested-PCR with nondegenerated clamped primers. PCR products were then applied on a TTGE gel in order to analyse strains profile. High quantity of nested-PCR products were obtained for each tested strain and TTGE profiles showed a good separation between the different reference bacteria and an easy way to associate one band to one species. Conclusion:, The nested-PCR/TTGE technique used in this study is a promising way of investigating bacterial community structure of cold-smoked salmon or other food matrix. Significance and Impact of the Study:, Because of its single copy state leading to single band profiles in TTGE, rpoB constitute a good potential molecular marker for further development of cold-smoked salmon biodiversity analysis. [source]


Using the Computer to Compare Foreign and Native Language Writing Processes: A Statistical and Case Study Approach

MODERN LANGUAGE JOURNAL, Issue 2 2000
Helga Thorson
Writing process research has attracted significant attention in English composition studies. However, much less research exists on the relationship between foreign language (FL) and first language (L1) writing processes. This study focuses on whether university students studying a FL (in this case German) at an American university use the same processes and writing strategies in FL and L1 writing in two different genres (letter and article). Using a computerized tracking device, individual writing sessions were analyzed through statistical techniques and individual case studies. Statistical results provided evidence that students wrote less, but revised more, when writing in the FL than in the L1. In their L1, students tended to revise less in the letter genre than when writing an article. The author advocates using the computer for writing process research, given that it is an unobtrusive and efficient method of data collection and because it provides researchers with an easy way to replicate research and to share data. [source]


Benefit of using a triple-lumen catheter to monitor left atrial pressure

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2003
H. Ceyran
Background: Left atrial pressure (LAP) monitoring provides a useful option for management of hemodynamic status in pediatric open-heart surgical patients during the postoperative period. Patients and method: We used a triple-lumen catheter placed into the left atrium transseptally to measure left atrial pressure. Twenty children that were operated on in our clinic are included in this study: 11 males and nine females. A 5-Fr. triple-lumen radio-opaque polyethylene catheter was used for the procedure. After the repair of the primary cardiac defect, the distal end of the catheter was repositioned transseptally and advanced into the left atrium. The proximal and middle line's distal orifices were left in the right atrium. Distal line was used as a left atrial pressure line, the middle line as a central venous pressure line, and the proximal line as a route for fluid infusion or drug administration. Results: No mortality and no catheter-related complication were observed. No failure or complication occurred during withdrawal of the catheter. Conclusion: We conclude that this preliminary technique can be a useful and easy way of monitoring LAP, as well as providing central venous access. [source]


Effect of cellulose concentration in NMMO·H2O solution on prediction of MW and MWD of cellulose using a rheology-based method

POLYMER ENGINEERING & SCIENCE, Issue 3 2009
Huiru Zhang
Prediction of molecular weight (MW) and molecular weight distribution (MWD) of cellulose by means of a rheology-based method is developed. In this method, the effect of cellulose concentration in N -methlymorpholine- N -oxide monohydrate (NMMO·H2O) solution on predicting results is discussed. It is shown that there is no significant effect of cellulose concentration on predicting results when the cellulose concentration in NMMO·H2O solution is high enough. Meanwhile, the obtained results are compared with those of gel permeation chromatograghy (GPC) method. The comparison shows that the calculated peak MW, polydispersity index (PDI) and MWD curves have the same trends. Consequently, it may be feasible to compare the MW and MWD of cellulose by using the rheology-based method. In addition, the rheology-based method is simple and fast. Therefore it is a useful and easy way to analyze the MW and MWD of cellulose in the fiber industry. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers [source]


Approximate Pole Placement with Dominance for Continuous Delay Systems by PID Controllers

THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 4 2007
Qing-Guo Wang
Abstract It is well known that a continuous-time feedback system with time delay has infinite spectrum and it is not possible to assign such infinite spectrum with a finite-dimensional controller. In such a case, only the partial pole placement may be feasible and hopefully some of the assigned poles are dominant. But there is no easy way to guarantee dominance of the desired poles. In this paper, an analytical PID design method is proposed for continuous-time delay systems to achieve approximate pole placement with dominance. Its idea is to bypass continuous infinite spectrum problem by converting a delay process to a rational discrete model and getting back continuous PID controller from its discrete form designed for the model with pole placement. Simulation results are included to illustrate the effectiveness of this method. Il est bien établi qu'un système de rétroalimentation continu dans le temps avec retard a un spectre infini et qu'il n'est pas possible d'assigner un tel spectre à un contrôleur à dimensions finies. Dans un tel cas, seul le placement de pôles partiels peut être réalisable, et heureusement, certains des pôles assignés sont dominants. Mais il n'y a pas de manière facile de garantir la dominance des pôles désirés. Dans cet article, on propose une méthode de conception PID analytique pour les systèmes avec retard continu dans le temps, afin d'effectuer le placement de pôles approximatif avec dominance. L'idée est de contourner le problème des spectres infinis continus en convertissant le procédé de retard en un modèle discret rationnel et de récupérer le contrôleur PID continu de sa forme discrète conçue pour le modèle avec placement de pôles. Les résultats des simulations sont inclus pour illustrer l'efficacité de cette méthode. [source]


Measurement and Correlation of Critical Gas and Liquid Velocities for Complete Circulation of Solid Particles in External Loop Airlift Bubble Columns

THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 3-4 2003
Katsumi Nakao
Abstract The external loop airlift bubble column provides an easy way of good contacting among gas, liquid and solid phases due to a relatively high recirculating liquid velocity UL. The critical gas and liquid velocities for complete circulation of solid particles, UG,C and UL,C, were measured in two different scales of columns with air, tap water and aqueous CMC solutions, and ion exchange resin and glass beads (155,3834 µm) were employed. The UG,C was determined as the inflection point on the plot of the pressure drop due to the suspended solid particles in the downcomer as a function of the gas velocity UG. The critical liquid velocity UL,C corresponding to the UG,C was obtained from the measured relationship between UL and UG. As a result, a unified dimensionless empirical correlation of UL,C was obtained within an error of ±20% and a dimensionless empirical relationship between UL and UG was developed within an error of ±15%. La colonne à bulles de type airlift à boucle externe offre un moyen facile pour le contact entre les phases gazeuse, liquide et solide grâce à la vitesse de liquide en recirculation UL relativement élevée. Les vitesses de gaz et de liquide critiques pour la circulation complète des particules solides, UG,C et UL,C, ont été mesurées dans deux colonnes d'échelle différente avec de l'air, de l'eau du robinet et des solutions aqueuses de CMC, et des billes de verre et de résine échandeuse d'ions (155,3834 µm) ont été employées. La vitesse UG,C est déterminée comme étant le point d'inflexion sur la courbe de la perte de chgarge causée par les particules solides suspendues dans le déversoir en fonction de la vitesse de gaz UG. La vitesse de liquide critique UL.C correspondant à la vitesse UG.C est obtenue à partir de la relation mesurée entre UL et UG. Ainsi, on obtient une corrélation empirique adimensionnelle unifiée de UL.C avec une erreur de ± 20% et une relation empirique adimensionnelle entre UL et UG est établie avec une erreur de ±15%. [source]


The influence of self-citation corrections and the fractionalised counting of multi-authored manuscripts on the Hirsch index

ANNALEN DER PHYSIK, Issue 9 2009
M. Schreiber
Abstract The Hirsch index or h -index is widely used to quantify the impact of an individual's scientific research output, determining the highest number h of a scientist's papers that received at least h citations. Fractionalised counting of the publications is an appropriate way to distribute the impact of a paper among all the coauthors of a multi-authored manuscript in an easy way, leading to a simple modification hm of the h -index. On the other hand the exclusion of self-citations allows one to sharpen the index, what is appropriate, because self-citations are usually not reflecting the significance of a publication. I have previously analysed the citation records of 26 physicists discussing the sharpened index hs as well as the modification hm of the original h -index. In the present investigation I combine these two procedures yielding the modified sharpened index hms. For a better comparison, interpolated indices are utilized. The correlations between the indices are rather strong, but nevertheless the positions of some datasets change, in a few cases significantly, depending on whether they are put into order according to the values of h, hm, hs, or hms. This leads to the conclusion that the additional effort in determining the modified sharpened index hms is worth performing in order to obtain a fairer evaluation of the citation records. [source]


Effects of Head-Up Tilt-Table Test on the QT Interval

ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 3 2010
Michael Findler M.D.
Background. The QT interval shortens in response to sympathetic stimulation and its response to epinephrine infusion (in healthy individuals and patients with long QT syndrome) has been thoroughly studied. Head-up tilt-table (HUT) testing is an easy way to achieve brisk sympathetic stimulation. Yet, little is known about the response of the QT interval to HUT. Methods. We reviewed the electrocardiograms of HUT tests performed at our institution and compare the heart rate, QT, and QTc obtained immediately after HUT with the rest values. Results. The study group consisted of 41 patients (27 females and 14 males) aged 23.9 ± 8.4 years. Head-up tilting led to a significant shortening of the RR interval (from 825 ± 128 msec at rest phase to 712 ± 130 msec in the upward tilt phase, P < 0.001) but only to a moderate shortening of the QT interval (from 363.7 ± 27.9 msec during rest to 355 ± 30.3 msec during upward tilt, P = 0.001). Since the RR interval shortened more than the QT interval, the QTc actually increased (from 403 ± 21.5 msec during rest phase to 423.2 ± 27.4 msec during upward tilt, P < 0.001). The QTc value measured for the upward tilt position was longer than the resting QTc value in 33 of 41 patients. Of those, 4 male patients and 2 female patients developed upward-tilt QTc values above what would be considered abnormal at rest. Conclusions. During HUT the QT shortens less than the RR interval. Consequently, the QTc increases during head-up tilt. Ann Noninvasive Electrocardiol 2010;15(3):245,249 [source]


Anomalous signal indicators in protein crystallography

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 11 2005
P. H. Zwart
A Monte Carlo procedure is described that generates random structure factors with simulated errors corresponding to an X-­ray data set of a protein of a specific size and given heavy-atom content. The simulated data set can be used to estimate Bijvoet ratios and figures of merit as obtained from SAD phasing routines and can be used to gauge the feasibility of solving a structure via the SAD method. In addition to being able to estimate results from phasing, the simulation allows the estimation of the correlation coefficient between |,F|, the absolute Bijvoet amplitude difference, and FA, the structure-factor amplitude of the heavy-atom model. As this quantity is used in various substructure-solution routines, the estimate provides a rough estimate of the ease of substructure solution. Furthermore, the Monte Carlo procedure provides an easy way of estimating the number of significant Bijvoet intensity differences, denoted as the measurability, and is proposed as an intuitive measure of the quality of anomalous data. [source]


Modellierung von kurzwelliger solarer Strahlung bei der hygrothermischen Bauteilsimulation , numerische Lösung und analytischer Ansatz

BAUPHYSIK, Issue 1 2006
Doktorandin Claudia Finkenstein Dipl.-Ing.
Der vorliegende Beitrag präsentiert ein Modell zur Bestimmung der kurzwelligen solaren Strahlung an Bauteilen, das , basierend auf gemessenen Wetterdaten der direkten und diffusen solaren Strahlung auf die Horizontalfläche , für die Einbindung in numerische Simulationsprogramme geeignet ist. Damit wurde ein geschlossenes Konzept erarbeitet, das es erlaubt, die Strahlungswärmestromdichte infolge kurzwelliger direkter und diffuser Sonnenstrahlung auf beliebig orientierte und geneigte Wand- und Dachflächen unter Beachtung der Eigenverschattung an einem beliebigen Ort zu berechnen. Weiterhin stellt der Beitrag einen analytischen Ansatz für das gleiche Problem vor, mit dessen Hilfe auf einfache Weise z. B. Wirkungsanalysen durchgeführt werden können. Den Abschluß des Beitrags bildet die beispielhafte Berechnung einer nach verschiedenen Himmelsrichtungen orientierten Wandkonstruktion. Modelling of shortwave solar radiation within the hygrothermal simulation of building envelope parts , numerical solution and analytical approach. This article presents a model for the determination of shortwave solar radiation on building envelope parts, which is , based on measured weather data of direct and diffuse solar radiation on a horizontal surface , suitable to be integrated in computercodes for hygrothermal building part simulation. Therewith, firstly a well-rounded concept has been worked out, which allows to calculate the radiation flux on any orientated and sloped wall or roof construction at any location taking into account the self-shading. Furthermore, there is presented an analytical approach for the same problem that is suitable to perform sensitivity analyses with in an easy way. At the end of the article, an example calculation of a wall construction orientated into different directions is presented. [source]


On the electrodetection threshold of aquatic vertebrates with ampullary or mucous gland electroreceptor organs

BIOLOGICAL REVIEWS, Issue 3 2007
Rob C. Peters
Abstract Reinterpretation of research on the electric sense in aquatic organisms with ampullary organs results in the following conclusions. The detection limit of limnic vertebrates with ampullary organs is 1 ,Vcm,1, and of marine fish is 20 nVcm,1. Angular movements are essential for stimulation of the ampullary system in uniform d.c. fields. Angular movements in the geomagnetic field also generate induction voltages, which exceed the 20 nVcm,1 limit in marine fish. As a result, marine electrosensitive fish are sensitive to motion in the geomagnetic field, whereas limnic fish are not. Angular swimming movements generate a.c. stimuli, which act like the noise in a stochastic resonance system, and result in a detection threshold in marine organisms as low as 1 nVcm,1. Fish in the benthic space are exposed to stronger electric stimuli than fish in the pelagic space. Benthic fish scan the orientation plane for the maximum potential difference with their raster of electroreceptor organs, in order to locate bioelectric prey. This behaviour explains why the detection threshold does not depend on fish size. Pelagic marine fish are mainly exposed to electric fields caused by movements in the geomagnetic field. The straight orientation courses found in certain shark species might indicate that the electric sense functions as a simple bisensor system. Symmetrical stimulation of the sensory raster would provide an easy way to keep a straight course with respect to a far-field stimulus. The same neural mechanism would be effective in the location of a bioelectric prey generating a near-field stimulus. The response criteria in conditioning experiments and in experiments with spontaneous reactions are discussed. [source]


Chemical Micropatterning of Polycarbonate for Site-Specific Peptide Immobilization and Biomolecular Interactions

CHEMBIOCHEM, Issue 3 2007
Olivier Carion Dr.
Abstract Polycarbonate (PC) is a useful substrate for the preparation of microfluidic devices. Recently, its utility in bioanalysis has attracted much attention owing to the possibility of using compact discs as platforms for the high-throughput analysis of biomolecular interactions. In this article we report a novel method for the chemical micropatterning of polycarbonate based on the printing of functionalized silica nanoparticles. The semicarbazide groups present on the surface of the nanoparticles were used for the site-specific semicarbazone ligation of unprotected peptides derivatized by an ,-oxoaldehyde group. The peptide micropatterns permitted the specific capture of antibodies. We report also the characterization of micropatterns on PC by using a wide-field optical imaging technique called Sarfus; this allows the detection of nm-thick films by using nonreflecting PC substrates and an optical microscope working with reflected differential interference contrast. The method described here is an easy way to modify polycarbonate surfaces for biomolecular interaction studies and should stimulate the use of PC for developing plastic biosensors. [source]


In suspense: an easy way to prevent contamination of the Zoellner sucker

CLINICAL OTOLARYNGOLOGY, Issue 2 2007
I. Street
No abstract is available for this article. [source]