bluuebunny/crossref_metadata_2025 huggingface dataset:
An Approximation Method Based on Matrix Formulated Algorithm for the Heat Equation with Nonlocal Boundary Conditions
Authors: Shahmorad Sedaghat , Borhanifar Abdollah , Soltanalizadeh Babak
Published: March 2012

In this paper, we utilize a matrix formulation for the heat equation
with nonlocal boundary conditions. We give details of the method and
verify the existence of a solution for the given equation under a
new suitable condition. A simple and efficient algorithm is
presented for the numerical results illustrating the accuracy of the
method.
A Concept of a Passive Radar with Quadrature Microwave Phase Discriminators
Authors: Rutkowski Adam
Published: March 2012

A Concept of a Passive Radar with Quadrature Microwave Phase Discriminators

Passive radar does not have its own emitter. It uses so-called signals of opportunity emitted by non-cooperative illuminators. During the detection of reflected signals, a direct signal from a non-cooperative emitter is used as the reference signal. Detection of electromagnetic echoes is, in present day radars, performed by finding the maximum of the cross ambiguity function. This function is based on the multiplication of the received signal and the reference signal. Detection of echoes by means of a quadrature microwave phase discriminator QMPD was proposed in the work as an alternative solution for ambiguity function evaluation. This discriminator carries out vectorial summing of the received and the reference signals. The summing operations in QMPD are carried out with the aid of microwave elements and without the use of expensive digital signal processors. Definitions of the phase and phase difference of the so-called simple signals and noise signals were described. A proposal of a passive radar equipped with several independent quadrature microwave phase discriminators was presented. Ideas of algorithms of object detection and of the distance-to-object estimation designed for this radar have been also sketched.
Maturity Assessment of Maintenance Processes at ATC-Service Providers
Authors: Kundler Jörg
Published: March 2012

Maturity Assessment of Maintenance Processes at ATC-Service Providers

The focus of the research is the analysis and assessment of Air Traffic Control (ATC) maintenance and technical service processes. Deriving from the general ATC process model, which is the part of the Air Transport System, the related ATC Services including a Key Performance Indicator System were developed. A theoretical analysis was performed to develop a special correlation matrix between the Air Transport System to ATC service and ATC technical services, which reflect the top-down approach of process modelling proceeding. A particular research of different international ATC service organization, selected by defined parameter was performed for analysis. The analysis was implemented with different scientific research methods. Basing on this international research, a detailed SWOT analysis and conclusions of each ATC organization itself and additionally a parameter-oriented comparison between the different organizations and their specifics were performed. The results of this research were described in a SWOT analysis, rating assessment of utilization of the theoretical methods and qualified evaluation of implemented KPI System. For final maintenance process evaluation an ATC-Maintenance Process Maturity method based on ISO /IEC Standard 15504 was developed. The results and developments of the research will be the essential prerequisite for the further research of dissertation and development of a harmonized ATC Meta Frame Maintenance Process Model as a part of the Air Transport System on macro model level and deriving to the ATC specific Maintenance Service Model on micro level for the specific ATC organization basing on service and business modelling methods.
Fractal morphology of Beta vulgaris L. cell suspension culture permeabilized with Triton X-100®
Authors: Arenas-Ocampo M. , Alamilla-Beltrán L. , Vanegas-Espinoza P. , Camacho-Díaz B. , Campos-Mendiola R. , Gutiérrez-López G. , Jiménez-Aparicio A.
Published: March 2012

Fractal morphology of Beta vulgaris L. cell suspension culture permeabilized with Triton X-100®

In this work, morphology of Beta vulgaris L. cells permeabilized with 0.7mM of Triton X-100® was evaluated using digital image processing and concepts of fractal dimension (perimeter- area relations). Important morphometric changes were found when the contact-time with chemical agent was increased. The size of cells decreased, the cells lost the roundness and their shape was more sinuous; this behaviour was a result of a probable shrinkage caused by the excess of exposure with the permeabilization agent. Morphology of B. vulgaris cells after permeabilization, exhibited a fractal nature since the slope of the ratio of the logarithm of the perimeter vs logarithm of the area was higher than unit. Fractal geometry of the cell morphology was affected as a result of the exposure to Triton X-100®. Those changes can be attributed to the loss of turgor and structure of the cell wall.
Influence of phosphate ions on buffer capacity of soil humic acids
Authors: Boguta P. , Sokołowska Z.
Published: March 2012

Influence of phosphate ions on buffer capacity of soil humic acids

The object of this study was to determine change of natural buffer capacity of humic acids by strong buffering agents, which were phosphate ions. Studies were carried out on the humic acids extracted from peat soils. Additional information was obtained by determination of water holding capacity, density, ash and pH for peats and optical parameter Q4/6for humic acids. Humic acid suspensions exhibited the highest buffer properties at low pH and reached maximum at pH ~ 4. Phosphates possessed buffer properties in the pH range from 4.5 to 8.0. The maximum of buffering was at pH~6.8 and increased proportionally with an increase in the concentration of phosphate ions. The study indicated that the presence of phosphate ions may strongly change natural buffer capacity of humic acids by shifting buffering maximum toward higher pH values. Significant correlations were found for the degree of the secondary transformation with both the buffer capacity and the titrant volume used during titration.
Vertical Stratification and Co-Occurrence Patterns of the Psocoptera Community Associated with Eastern Hemlock, Tsuga canadensis (L.) Carrière, in the Southern Appalachians
Authors: Coots Carla , Lambdin Paris , Grant Jerome , Rhea Rusty , Mockford Edward
Published: March 2012

Of the more than 300 species of Psocoptera described in North America, 44 species have been documented on eastern hemlock, Tsuga canadensis (L.) Carrière, in the southern Appalachians. However, the distribution and co-occurrence patterns of these species throughout the tree canopy are unknown. This study was initiated to evaluate specimen abundance, species richness and species composition among three designated strata in the canopy of eastern hemlock, assess species for vertical stratification patterns, and determine if co-occurrence patterns of Psocoptera species are random or non-random. During this study, 27 species representing 18 genera and 10 families were evaluated. Psocopteran specimen abundance, species richness and composition differed among the lower, middle, and upper strata. Unique assemblages were identified in each stratum, indicating vertical stratification. The upper stratum of the canopy had five exclusive species, the middle had four exclusive species, and the lower stratum had 14 exclusive species. The co-occurrence pattern of Psocoptera species in the canopy of eastern hemlock was non-random.
Effects of temperature and desiccation on ex situ conservation of nongreen fern spores
Authors: Ballesteros Daniel , Estrelles Elena , Walters Christina , Ibars Ana M.
Published: March 2012

•Premise of the study:Fern spores are unicellular and haploid, making them a potential model system to study factors that regulate lifespan and mechanisms of aging. Aging rates of nongreen spores were measured to compare longevity characteristics among diverse fern species and test for orthodox response to storage temperature and moisture.

•Methods:Aging of spores from 10 fern species was quantified by changes in germination and growth parameters. Storage temperature ranged from ambient room to −196°C (liquid nitrogen); spores were dried to ambient relative humidity (RH) or using silica gel.

•Key results:Survival of spores varied under ambient storage conditions, with one species dying within a year and two species having greater than 50% survival after 3 years. Few changes in germination or growth were observed in spores stored at either −80°C or −196°C over the same 3‐yr study period. Spores stored at −25°C aged anomalously quickly, especially those dried to ambient RH or subjected to repeated freeze–thaw cycles.

•Conclusions:Spore longevity is comparable to orthodox seed longevity under ambient storage conditions, with wide variation among species and shelflife extended by drying or cooling. However, faster aging during freezer storage may indicate a similar syndrome of damage experienced by seeds categorized as “intermediate”. The damage is avoided by storage at −80°C or liquid nitrogen temperatures, making cryoconservation an effective and broadly applicable tool to extend fern spore longevity. The study demonstrates that spore banks are a feasible approach for ex situ conservation of this important plant group.
Phylogeny, divergence times, and historical biogeography of New World Dryopteris (Dryopteridaceae)
Authors: Sessa Emily B. , Zimmer Elizabeth A. , Givnish Thomas J.
Published: March 2012

• Premise of the study: Dryopteris is a large, cosmopolitan fern genus ideal for addressing questions about diversification, biogeography, hybridization, and polyploidy, which have historically been understudied in ferns. We constructed a highly resolved, well‐supported phylogeny for New World Dryopteris and used it to investigate biogeographic patterns and divergence times.

• Methods: We analyzed relationships among 97 species of Dryopteris, including taxa from all major biogeographic regions, with analyses based on 5699 aligned nucleotides from seven plastid loci. Phylogenetic analyses used maximum parsimony, maximum likelihood, and Bayesian inference. We conducted divergence time analyses using BEAST and biogeographic analyses using maximum parsimony, maximum likelihood, Bayesian, and S‐DIVA approaches. We explored the monophyly of subgenera and sections in the most recent generic classification and of geographic groups of taxa using Templeton tests.

• Key results: The genus Dryopteris arose ca. 42 million years ago (Ma). Most of the Central and South American species form a well‐supported clade which arose 32 Ma, but the remaining New World species are the result of multiple, independent dispersal and vicariance events involving Asia, Europe, and Africa over the last 15 Myr. We identified six long‐distance dispersal events and three vicariance events in the immediate ancestry of New World species; reconstructions for another four lineages were ambiguous.

• Conclusions: New World Dryopteris are not monophyletic; vicariance has dominated the history of the North American species, while long‐distance dispersal prevails in the Central and South American species, a pattern not previously seen in plants.
Industrial Information Security, Safety, and Trust
Authors: Tyagi Sapna , Sirohi Preeti , Khan Mohammad Yahiya , Darwish Ashraf
Published: March 2012

The presented chapter elaborates fundamentals issues in information security, safety, and trust in industrial settings. The chapter introduces basics of information security that includes confidentially, integrity, and availability (CIA), which are some of the essential ingredients of information security. The chapter also discusses various reasons for security loop-holes prevalent in industrial setting. A majority of the chapter focuses on security framework and control implementation, which includes various authorizations and authentication methods. The shared secret systems, passwords, token systems, public key infrastructure (PKI), and biometrics system are most common methods used for authentication.
Linux Based Real-Time Control over Industrial Networks
Authors: Fodrek Peter , Blaho Michal , Foltin Martin , Lichý Matúš , Murgaš Tomáš
Published: March 2012

This chapter deals with industrial networked control systems. These systems are the most modern means of industrial control. The current approach contains several problems. Mostly discussed problem in the control theory is a network-caused variable transport delay problem. On the software point of view there is problem of the system latency, which limits time period of the discrete control. State of art research in hardware part of the system shows that latency source and transport delay variations are caused by unpredictable hardware behavior as well. Another problem is the control system security. This was the case of the Mexico gulf oil rig disaster in 2010, as well as Iran nuclear program three months later the same year, caused by worm attack at its centrifuges. Therein lies the question; how can security issues be avoided? The authors demonstrate how via using GNU/Linux, which solves timing correctness by their project of the plasma cutting machine design.
Performance Evaluation of a Dynamic Model of a Photovoltaic Module for Real-Time Maximum Power Tracking
Authors: Alam M. S. , Alouani A. T.
Published: March 2012

This case study deals with the modeling and maximum power tracking of a stand-alone photovoltaic (PV) power generator. A dynamic model of a solar cell has been developed, simulated, and validated using experimental data. Effects of parameter variations have been accounted for in the dynamic model. The dynamic model developed in MATLAB®/Simulink® environment is embedded in the LabVIEW® environment for real time hardware in the loop verification of the simulation results. It was found that the actual real-time maximum power that a PV can produce is significantly different from the average power provided by the manufacturer. Preliminary experimental testing showed that one can extract as much as 20% more power from the PV than what is suggested by the manufacturer. The three week long experiment is documented, and the model is then validated through the design of experiment. Finally, the conclusions of the case study are outlined and the future work is proposed.
A Bayesian Image Retrieval Framework
Authors: Zhang Rui , Guan Ling
Published: March 2012

Conventional approaches to content-based image retrieval exploit low-level visual information to represent images and relevance feedback techniques to incorporate human knowledge into the retrieval process, which can only alleviate the semantic gap to some extent. To further boost the performance, a Bayesian framework is proposed in which information independent of the visual content of images is utilized and integrated with the visual information. Two particular instances of the general framework are studied. First, context which is the statistical relation across the images is integrated with visual content such that the framework can extract information from both the images and past retrieval results. Second, characteristic sounds made by different objects are utilized along with their visual appearance. Based on various performance evaluation criteria, the proposed framework is evaluated using two databases for the two examples, respectively. The results demonstrate the advantage of the integration of information from multiple sources.
QiVMDL - Towards a Socially Constructed Virtual Museum and Digital Library for the Preservation of Cultural Heritage
Authors: Theng Yin-Leng , Luo Yanling , Sau-Mei Gladys Theng
Published: March 2012

Museums and libraries are treasure houses of human history and knowledge with rich repositories on cultural heritage. With advanced technological developments in digital libraries and Web 2.0, cultural institutions are beginning to explore new forms of universal and dynamic accessibility. Using a case example of the Chinese “qipao”, this paper proposes a socially constructed virtual museum prototype incorporating interactivity of Web 2.0 to promote cultural communication and exchange while improving user interaction and participation. In this paper, the authors describe the design, prototyping, and evaluation process of QiVMDL (Qipao Virtual Museum and Digital Library). The paper concludes with implications for digital library research and development supporting virtual museums for the preservation of cultural heritage.
Digital Approaches to Visualization of Geometric Problems in Wooden Sangaku Tablets
Authors: Constant Jean
Published: March 2012

This chapter describes the digitalization process of 19th century scientific representations from the Japanese culture – a set of mathematical problems etched on wooden boards. The object of the demonstration is to apply computing techniques to the creation of artistic statements based on geometrical problems, highlight the dynamics of interaction between art and science, and examine how much both fields enrich the larger discourse and appreciation of Art. The following text describes the steps adopted in a visualization project. First, the data collection included selecting specific geometry problems from various Sangaku wooden tablets and converting them into digital information as a single black and white outline to define shapes, volumes, and textures. The vectorization of the underlying shapes transferred the exact mathematical information onto the virtual canvas. In the next step, the vector outlines were converted into bitmaps. Each individual plate was assigned a specific color scheme to enhance object size, positioning, and dynamic of the composition. At the last stage, vector-based sketches, colorizations, and the monochrome sketches were blended together to complete full color visualization. Finally, the step-by-step development of the creative process was recorded as a QuickTime movie, including an original soundtrack. Discussion refers to the dissemination of the project in art galleries and online, its potential instructional use, and it examines the audience responses.
Three Years of Salvage IMRT for Prostate Cancer: Results of the Montpellier Cancer Center
Authors: Riou Olivier , Fenoglietto Pascal , Laliberté Benoit , Menkarios Cathy , Llacer Moscardo Carmen , Hay Meng Huor , Ailleres Norbert , Dubois Jean-Bernard , Rebillard Xavier , Azria David
Published: March 2012

Background. To assess the feasibility of salvage intensity-modulated radiation Therapy (IMRT) and to examine clinical outcome. Patients and Methods. 57 patients were treated with salvage IMRT to the prostate bed in our center from January, 2007, to February, 2010. The mean prescription dose was 68 Gy in 34 fractions. Forty-four patients received concomitant androgen deprivation. Results. Doses to organs at risk were low without altering target volume coverage. Salvage IMRT was feasible without any grade 3 or 4 acute gastrointestinal or urinary toxicity. With a median follow-up of 21 months, one grade 2 urinary and 1 grade ≥2 rectal late toxicities were reported. Biological relapse-free survival was 96.5% (2.3% (1/44) relapsed with androgen suppression and 7.7% (1/13) without). Conclusion. Salvage IMRT is feasible and results in low acute and chronic side-effects. Longer follow-up is warranted to draw conclusions in terms of oncologic control.
Filter Performance: A Key Component for LT2ESWTR Compliance
Authors: Bishop Mark , Becker William
Published: March 2012

Treatment options for meeting LT2ESWTR's more stringent turbidity limits range from expensive to less costly. Optimizing filter performance offers an economical solution.
What's Your Ammonia IQ?
Authors: Brandhuber Philip J.
Published: March 2012

This is the first of three articles to help water system operators understand ammonia and how to monitor and control its effects at the plant and in the distribution system. This article provides background information about ammonia, its chemistry, origin, and the problems it can cause. Next month's article will discuss ammonia treatment options. The final article will provide case studies explaining how utilities have dealt with ammonia.
Cluster Analysis of Autistic Patients Based on Principal Pathogenetic Components
Authors: Sacco Roberto , Lenti Carlo , Saccani Monica , Curatolo Paolo , Manzi Barbara , Bravaccio Carmela , Persico Antonio M.
Published: March 2012

We have recently described four principal pathogenetic components in autism: (I) circadian and sensory dysfunction, (II) immune abnormalities, (III) neurodevelopmental delay, and (IV) stereotypic behaviors. Using hierarchical and k‐means clustering, the same 245 patients assessed in our principal component analysis can be partitioned into four clusters: (a) 43 (17.6%) have prominent immune abnormalities accompanied by some circadian and sensory issues; (b) 44 (18.0%) display major circadian and sensory dysfunction, with little or no immune symptoms; (c) stereotypies predominate in 75 (31.0%); and (d) 83 (33.9%) show a mixture of all four components, with greater disruptive behaviors and mental retardation. The “immune” component provides the largest contributions to phenotypic variance (P = 2.7 x 10–45), followed by “stereotypic behaviors.” These patient clusters may likely differ in genetic and immune underpinnings, developmental trajectories, and response to treatment. Autism Res 2012,••:••–••. © 2012 International Society for Autism Research, Wiley Periodicals, Inc.
Conformational preferences of 4‐chloroproline residues
Authors: Park Hae Sook , Byun Byung Jin , Motooka Daisuke , Kawahara Kazuki , Doi Masamitsu , Nakazawa Takashi , Kobayashi Yuji , Kang Young Kee
Published: March 2012

Conformational preferences of the (2S,4R)‐4‐chloroproline (Clp) and (2S,4S)‐4‐chloroproline (clp) residues are explored at the M06‐2X/cc‐pVTZ//M06‐2X/6‐31+G(d) level of theory in the gas phase and in water, where solvation free energies were calculated using the implicit solvation model, and by an X‐ray diffraction study in the solid state. In the gas phase, the down‐puckered γ‐turn structure with the trans prolyl peptide bond is most preferred for both Ac‐Clp‐NHMe and Ac‐clp‐NHMe, in which the C7 hydrogen bond between two terminal groups seems to play a role, as found for Ac‐Pro‐NHMe. In water, the Clp residue has a strong preference for the up‐puckered PPII structure, whereas the up‐puckered PPII structure prevails a little over the down‐puckered PPII structure for the clp residue, similar to the Pro residue. Hence, our calculated results on the puckering preference of the Clp and clp residues in water are in accord with the observed results deduced from the relative stabilities of the triple helices of the collagen model peptides. The X‐ray structure of Ac‐clp‐NHMe was found to be the most preferred in water but that of Ac‐Clp‐NHMe was located as a local minimum with ΔG = 2.0 kcal/mol. In particular, the X‐ray structure of Ac‐Clp‐NHMe was quite different from that of Ac‐Clp‐OMe but similar to that of Ac‐Pro‐NHMe. The lowest rotational barriers to the prolyl cis–trans isomerization for Ac‐Clp‐NHMe become nearly the same as those for Ac‐Pro‐NHMe in water, whereas the barriers are lower by ∼2 kcal/mol for Ac‐clp‐NHMe. It was found that the cis–trans isomerization may proceed through the clockwise or anticlockwise rotations for Ac‐Clp‐NHMe and the anticlockwise rotation for Ac‐clp‐NHMe and Ac‐Pro‐NHMe in water. © 2012 Wiley Periodicals, Inc. Biopolymers 97: 629–641, 2012.
Development of QSARs for the toxicity of chlorobenzenes to the soil dwelling springtail Folsomia candida
Authors: Giesen Daniel , Jonker Michiel T.O. , van Gestel Cornelis A. M.
Published: March 2012

To meet the goals of Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH) as formulated by the European Commission, fast and resource-effective tools are needed to predict the toxicity of compounds in the environment. We developed quantitative structure-activity relationships (QSARs) for the toxicity of nine chlorinated benzenes to the soil-dwelling collembolan Folsomia candida in natural LUFA2.2 (Landwirtschaftliche Untersuchungs und Forschungsanstalt [LUFA]) standard soil and in Organisation for Economic Co-operation and Development artificial soil. Toxicity endpoints used were the effect concentrations causing 10% (EC10) and 50% (EC50) reduction in the reproduction of the test organism over 28 d, while lethal effects on survival (LC50) were used for comparisons with earlier studies. Chlorobenzene toxicity was based on concentrations in interstitial water as estimated using nominal concentrations in soil and literature soil–water partition coefficients. Additionally, for LUFA2.2 soil the estimated concentrations in interstitial water were experimentally determined by solid-phase microextraction measurements. Measured and estimated concentrations showed the same general trend, but significant differences were observed. With the exception of hexachlorobenzene, estimated EC10 and EC50 values were all negatively correlated with their logKow and QSARs were developed. However, no correlation for the LC50 could be derived and 1,2,4,5-tetrachlorobenzene and hexachlorobenzene had no effect on adult survival at all. The derived QSARs may contribute to the development of better ecotoxicity-based models serving the REACH program. Environ. Toxicol. Chem. 2012; 31: 1136–1142. © 2012 SETAC
Multiple electrosprays generated from a single polycarbonate microstructured fibre
Authors: Gibson Graham T. T. , Wright Ramin D. , Oleschuk Richard D.
Published: March 2012

Electrospray ionization (ESI) has been invaluable to the mass spectrometric detection of biomolecules, due largely to the sensitivity afforded by the ionization technique. Lower flow rates, e.g. in the nanoelectrospray regime, result in smaller initial electrosprayed droplets, leading to higher ionization efficiency and greater signal. One approach to improving sensitivity without lowering flow rate is to generate multiple electrosprays (MESs) from the same sample, essentially splitting one larger flow into smaller flows in the nanoESI regime. Presented here is a series of novel MES emitters in the form of polycarbonate fibres. Based on microstructured fibre (MSF) technology whereby a set of homogeneous parallel channels are formed in a heat‐drawn fibre intended to conduct light, a custom design was fabricated in which 3, 6, 9 and 12 holes were arranged in a radial pattern to prevent inhomogeneities in the electric field. The MSFs have dimensions that are compatible with current standards in nanoESI equipment, and the tip is more compatible with standard MS orifices than other larger multielectrospray emitters. By measuring the spray current provided by the various emitters under the same solvent/voltage/total flow rate conditions, a plot was obtained clearly demonstrating the expected dependence on the square root of the number of holes, i.e. the number of independent electrosprays. With this firm proof of principle using this design/format, further effort is justified in developing similar emitters in alternative materials that better prevent surface wetting and allow greater hole density, ultimately leading to greater signal enhancement. Copyright © 2012 John Wiley & Sons, Ltd.
Collision‐induced dissociation of oligonucleotide anions fully modified at the 2'‐position of the ribose: 2'‐F/‐H and 2'‐F/‐H/‐OMe mix‐mers
Authors: Gao Yang , McLuckey Scott A.
Published: March 2012

Gas‐phase dissociation of various 2'‐position modified oligonucleotide anions has been studied as a function of precursor ion charge state using ion trap and low energy beam‐type collision‐induced dissociation (CID). For a completely 2'‐O‐methyl modified 6‐mer, all possible dissociation channels along the phosphodiester linkage, generating complementary (a‐B)/w‐, b/x‐, c/y‐, d/z‐ion series, were observed with no single dominant type of dissociation pathway. Full sequence information was generated from each charge state via ion trap CID. More sequential fragmentation was noted under beam‐type CID conditions. Comparison with model DNA, in which all 2'‐OH groups are converted to 2'‐H, and RNA anions suggests that the 2'‐OMe substitution stabilizes the phosphodiester linkage with respect to fragmentation relative to both DNA and RNA oligomers. For modified mix‐mer anions, comprised of DNA nucleotides and 2'‐F substituted nucleotides or a mixture of DNA nucleotides and 2'‐O‐methyl (2'‐OMe) and 2'‐F substituted nucleotides, 3'‐side backbone cleavage was found to be inhibited by the 2'‐OMe or 2'‐F modification on the nucleotides under ion trap CID conditions. Thus, the sequence information was limited to the a‐Base/w‐fragments from the cleavage of the 3' C‐O bond of the 2'‐H (DNA) nucleotides. Under beam‐type CID conditions, limited additional cleavage adjacent to 2'‐OMe substituted nucleotides was noted but 2'‐F modified residues remained resistant to cleavage. Copyright © 2012 John Wiley & Sons, Ltd.
‘Wrong‐way‐round ionization’ and screening for doping substances in human urine by high‐performance liquid chromatography/orbitrap mass spectrometry
Authors: Virus E. D. , Sobolevsky T. G. , Rodchenkov G. M.
Published: March 2012

To free analytical resources for new classes of doping substances, such as banned proteins, maximization of the number of compounds that can be determined with high sensitivity in a single run is highly urgent. This study demonstrates an application of ‘wrong‐way‐round ionization’ for the simultaneous detection of multiple classes of doping substances without the need to switch the polarity. A screening method for the detection of 137 compounds from various classes of prohibited substances (stimulants, diuretics, β2‐agonists, β‐blockers, antiestrogens, glucocorticosteroids and anabolic agents) has been developed. The method involves an enzymatic hydrolysis, liquid–liquid extraction and detection by liquid chromatography/orbitrap mass spectrometry with wrong‐way‐round ionization. Up to 64% of compounds had a 10‐fold lower limit of detection (LOD) than the minimum required performance limit. To compare the efficiency of conventional ionization relative to wrong‐way‐round ionization of doping substances in + ESI, a fortified blank urine sample at the minimum required performance limit was analyzed using two ESI approaches. All compounds were detected with markedly better S/N in a high‐pH mobile phase, with the exception of acetazolamide (minimal change in S/N, < 20%).The method was validated by spiking 10 different blank urine samples at five different concentrations. Validation parameters included the LOD, selectivity, ion suppression, extraction recovery and repeatability. Copyright © 2012 John Wiley & Sons, Ltd.
Characteristics of electrical field and ion motion in surface‐electrode ion traps
Authors: Zhou Xiaoyu , Xu Gaoping , Xiong Caiqiao , Chen Rui , Qiao Haoxue , Nie Zongxiu
Published: March 2012

In this article, we calculated the potential function of the surface‐electrode ion trap (SEIT) by using Green's function method, optimized trap size, obtained the coefficients of the multipoles and analyzed ion trajectories in the RF potential. The optimized SEIT not only increases its trapping well depth by a factor of about 15, but also has relatively good linearity of the field (or large quadrupole component). The current design of SEIT can work well either as the ion guide for ion transmission or as the ion trap for ion confinement. Our research can be used to calculate the potential function in the SEIT with different device parameters, understand ion motions in the traps and optimize instrument performance. The method for calculating potential function can be expanded to planar and halo ion traps. Copyright © 2012 John Wiley & Sons, Ltd.
Cluster TOF‐SIMS imaging of human skin remains: analysis of a South‐Andean mummy sample
Authors: Cersoy Sophie , Richardin Pascale , Walter Philippe , Brunelle Alain
Published: March 2012

A skin sample from a South‐Andean mummy dating back from the XIth century was analyzed using time‐of‐flight secondary ion mass spectrometry imaging using cluster primary ion beams (cluster‐TOF‐SIMS). For the first time on a mummy, skin dermis and epidermis could be chemically differentiated using mass spectrometry imaging. Differences in amino‐acid composition between keratin and collagen, the two major proteins of skin tissue, could indeed be exploited. A surprising lipid composition of hypodermis was also revealed and seems to result from fatty acids damage by bacteria. Using cluster‐TOF‐SIMS imaging skills, traces of bio‐mineralization could be identified at the micrometer scale, especially formation of calcium phosphate at the skin surface. Mineral deposits at the surface were characterized using both scanning electron microscopy (SEM) in combination with energy‐dispersive X‐ray spectroscopy and mass spectrometry imaging. The stratigraphy of such a sample was revealed for the first time using this technique. More precise molecular maps were also recorded at higher spatial resolution, below 1 µm. This was achieved using a non‐bunched mode of the primary ion source, while keeping intact the mass resolution thanks to a delayed extraction of the secondary ions. Details from biological structure as can be seen on SEM images are observable on chemical maps at this sub‐micrometer scale. Thus, this work illustrates the interesting possibilities of chemical imaging by cluster‐TOF‐SIMS concerning ancient biological tissues. Copyright © 2012 John Wiley & Sons, Ltd.
Micromechanical model of weakly‐cemented sediments
Authors: Holtzman R.
Published: March 2012

Experiments indicate that the bulk stiffness of weakly‐cemented granular materials increases significantly with the applied load, a nonlinearity which is not captured by most micromechanical models. Here, we study the deformation of weakly‐cemented materials through grain‐scale simulations. We show that the frequently‐made assumption of linear‐elastic cement and intergranular contact area which varies according to a Hertzian‐type model cannot explain the observed nonlinearity of the bulk response. We introduce the micromechanical effect of mechanisms such as closure and opening of microcracks, granular cement and material heterogeneity through an effective contact stiffness which depends on the local deformation. We find that an exponential dependence between the effective stiffness and the local deformation, with a high exponent value, provides bulk stiffness which is in good agreement with experimental data. The inability of models with weaker intergranular stiffness‐deformation dependence to reproduce the experimental data demonstrates the highly‐nonlinear nature of the intergranular deformation. Our results highlight the importance of accounting for grain‐scale mechanisms in modeling granular materials, and provide a plausible explanation for the nonlinear behavior of weakly‐cemented sediments. Copyright © 2012 John Wiley & Sons, Ltd.
A space–time multiscale method for computing statistical moments in strongly heterogeneous poroelastic media of evolving scales
Authors: Azevedo Juarez S. , Murad Márcio A. , Borges Marcio R. , Oliveira Saulo P.
Published: March 2012

A new multiscale procedure is proposed to compute flow in compressible heterogeneous porous media with geology characterized by power‐law covariance structure. At the fine scale, the deformable medium is modeled by the partially coupled formulation of poroelasticity with Young's modulus and permeability treated as stationary random fields represented by their Karhunen–Loève decompositions. The framework underlying the multiscale procedure is based on mapping these random parameters to an auxiliary domain and constructing a family of equivalent stochastic processes at different length scales characterized by the same ensemble mean and covariance function. The poromechanical variables inherit a space–time version of the scaling relations of the random input parameters which allows for constructing a set of multiscale solutions of the same governing equations posed at different space and time scales. A notable feature of the multiscale method proposed herein is the feasibility of solving both the poroelastic model and the Fredholm integral equation for the eigenpairs of the Karhunen–Loève expansion in an auxiliary domain with much lower computational effort and then derive the long term behavior at a coarser scale from a straightforward rescaling of the auxiliary solution. Within the framework of the finite element approximation, in conjunction with the Monte Carlo algorithm, numerical simulations of fluid withdrawal and injection problems in a heterogeneous poroelastic reservoir are performed to illustrate the potential of the method in drastically reducing the computational burden in the computation of the statistical moments of the poromechanical unknowns in large‐scale simulations. Copyright © 2012 John Wiley & Sons, Ltd.
Lapacho Tea (Tabebuia impetiginosa) Extract Inhibits Pancreatic Lipase and Delays Postprandial Triglyceride Increase in Rats
Authors: Kiage‐Mokua Beatrice Nyanchama , Roos Nils , Schrezenmeir Jürgen
Published: March 2012

Earlier work in our laboratory indicated that ethanolic extracts of Tabebuia impetiginosa, Arctium lappa L., Calendula officinalis, Helianthus annuus, Linum usitatissimum and L. propolis, inhibit pancreatic lipase in vitro. In a follow‐up study we assessed their effects on plasma triglycerides in rats fed on a fatty meal. Extracts, orlistat or only ethanol were given orally to the rats together with the test meal and the rate of increase of postprandial triglycerides was assessed over 4 h. Clearing of the triglycerides from the blood compartment was abolished by inhibiting lipoprotein lipase with Triton WR‐1339. Our results showed that out of all the extracts, the bark of Tabebuia impetiginosa led to a significant delay in the postprandial increase of plasma triglycerides. However, lapachol, which is contained in the bark of Tabebuia impetiginosa and soluble in ethanol, had no lipase inhibitory effect in vitro and hence this substance did not seem to mediate the pertinent effect. Copyright © 2012 John Wiley & Sons, Ltd.
Female‐biased sex allocation in wild populations of the eriosomatine aphid Prociphilus oriens: local mate competition or transgenerational effects of maternal investment?
Authors: Akimoto Shin‐ichi , Mitsuhashi Ryota , Yoshino Tomoko
Published: March 2012

Several aphid species exhibit female‐biased sex allocation. Local mate competition (LMC) has been postulated to be the evolutionary factor of the female‐biased sex allocation. We estimated individual sex allocation in the eriosomatine aphid Prociphilus oriens and explained the observed pattern of sex allocation based on a hypothesis other than LMC. On the basis of the relationship between maternal body size and brood size, we estimated the cost of producing a female to be 1.85 times the cost of producing a male. The population‐wide allocation to males was 22–24 %. Winged mothers exhibited a large variation in the number of male and female embryos they had, including 23–30 % of winged mothers producing only female embryos. There was polymorphism in the sex‐ratio expression. Thus, the constant male hypothesis assuming LMC was not supported. Winged mothers that produced an all‐female brood contained larger female embryos than did mothers that produced a bisexual brood. Previous studies have indicated that a large sexual female produces a single large egg, which hatches into a first‐instar larva containing a larger amount of gonads. Thus, in eriosomatine aphids, maternal investment in daughters directly affects the potential fecundity of granddaughters, whereas investment in sons does not. We propose a hypothesis that higher fitness returns from maternal investment in daughters than in sons may have primarily led to the evolution of highly female‐biased sex allocation in P. oriens.
Phospholipases A1 from Armillaria ostoyae Provide Insight into the Substrate Recognition of α/β‐Hydrolase Fold Enzymes
Authors: Dippe Martin , Müller Mathias Q. , Sinz Andrea , Ulbrich‐Hofmann Renate
Published: March 2012

Four enzymes with phospholipase A1 (PLA1) activity were purified from the fruiting bodies of the basidiomycete Armillaria ostoyae. The enzymes (PLA1‐1, ‐2, ‐3 and ‐4) showed similar isoelectric points (4.3, 3.9, 4.0 and 4.0) and apparent molecular masses in the range of 35–47 kDa. Mass spectrometric analyses of proteolytic fragments revealed sequences homologous to α/β‐hydrolase fold enzymes. The enzymes share one conserved region with fungal phospholipases B and the active site sequence with bacterial esterases and PLA1s. PLA1‐1 cleaves phospholipids and lysophospholipids with an optimum activity at pH 5.3. In contrast, PLA1‐2, ‐3 and ‐4 are characterized by broad pH optima in the slightly acidic to neutral range and are additionally capable of hydrolyzing mono‐ and diglycerides as well as fatty acid methyl esters. All enzymes favor glycerol‐based lipids with a single medium‐sized fatty acid moiety in the sn‐1 position but show reduced activity towards the corresponding 1,2‐diacyl derivatives with bulky long‐chain or inflexible saturated fatty acid moieties in the sn‐2 position. The enzymes prefer zwitterionic phospholipid substrates and are unable to hydrolyze triglycerides. From the selectivity of these broad‐spectrum α/β‐hydrolase fold enzymes towards the different classes of their substrates a regiospecific steric hindrance and a head group recognition are concluded.
Consumer Innovativeness Influence on Really New Product Adoption
Authors: Chao Chih-Wei , Reid Mike , Mavondo Felix T.
Published: March 2012

The results of academic research into consumer innovativeness and its influence on product adoption lack consensus. To help close this gap, the study examines the relationship between consumer innate innovativeness, domain specific innovativeness, vicarious innovativeness, and the adoption of really new consumer electronic products. This study employs a quantitative survey-based approach to test several hypotheses related to consumer innovativeness and really new product adoption. In total, 256 Australians above the age of 18 completed an online survey and subsequently form the basis of the analysis. Employing structural equation modeling we find that domain specific innovativeness rather than consumer innate innovativeness is the primary influencer of the adoption of such products. We find however that the relationship between domain specific innovativeness and really new product adoption, although positive, is still quite weak. The result highlight the need for further research to more fully understand what drives or explains the adoption of “really new” products both in Australia and internationally and to further clarify relationships between innovativeness measures.
Analyst responses to stock‐index adjustments: Evidence from MSCI Taiwan Index additions
Authors: Tu Chia‐Jung , Chang Yuanchen
Published: March 2012

Using data from MSCI Taiwan Index adjustments, we study analyst responses to stock additions from 1999 to 2007. The empirical results show that the magnitudes of changes in analysts' earnings‐per‐share forecasts are similar to those of their two benchmarks for new additions to the index. Therefore, in our sample we find no significant information effect from the additions. We also find that the absolute forecast errors made by analysts are smaller for new additions and those foreign analysts are more accurate than local analysts. This finding demonstrates that new additions to the index exhibit significant performance improvements.
Mandibular body ostectomy for correction of mandibular prognathism – A technical note
Authors: Mori Yoshiyuki , Susami Takafumi , Saijo Hideto , Okubo Kazumi , Uchino Natsuko , Hoshi Kazuto , Takato Tsuyoshi
Published: March 2012

The patient presented with a large mandibular body and acceptable occlusion in the molar region with no lateral crossbite.

After presurgical orthodontic treatment, mandibular body ostectomy was performed in the missing second premolar region. To avoid nerve injury, we considered removal of the lateral cortical plate around the mental foramen and temporary wire fixation of the detached bone segments during contralateral body ostectomy.

Neurosensory supply of the mental region recovered within 3 months after surgery. Three years after surgery, the occlusion and periodontal health were good.
Structural and Functional Changes of Carotid Wall Properties in Patients with Acromegaly are not Restored after 1 year of GH/IGF1 Normalization
Authors: Găloiu S. , Jurcuţ R. , Vlădaia A. , Florian A. , Purice M. , Popescu B. , Ginghină C. , Coculescu M.
Published: March 2012

Vascular changes are common in acromegaly (ACM). Current therapies can normalise the levels of both growth hormone (GH) and insulin-like growth factor (IGF1).

To establish whether the ACM vascular changes in patients with effectively managed disease are different from those in patients with an active condition.

64 ACM patients were tested for serum GH (random and during an oral glucose tolerance test) and IGF1. Ultrasonography of the right common carotid (RCC) explored structural (the carotid diameter and intima-media thickness index (IMT)) and functional (the augmentation index (AIx), elastic modulus (Ep), and local pulse wave velocity (PWV)) arterial parameters in the ACM patients (groups A and B) and an age- and sex-matched control group of 21 patients without acromegaly (group C).

The ACM patients were divided into 2 subgroups that had similar cardiovascular risk factor profiles: A (n=10, with controlled ACM), and B (n=54, with active ACM). The AIx was higher in groups A (27.7% [2.2–54.3]) and B (20.0% [ − 38.2–97.1]) than in group C (3.5% [ − 11.3–31.1]), p=0.01 and 0.002, respectively. The group B patients presented with poorer functional carotid wall parameters than the control subjects: Ep-95.5 [33–280] KPa vs. 77.5 [39–146] KPa, p=0.01; and PWV-6 [3.6–10.4] m/s vs. 5.4 [3.9–7.2] m/s, p=0.03.

The ACM patients had greater RCC diameters (6.4±0.6 mm vs. 5.7±0.6 mm, p<0.001) and IMT values (0.72±0.13 mm vs. 0.58±0.08 mm, p<0.001) than the subjects in group C.

Both the controlled and active ACM patients showed structural arterial changes. After 1 year of disease control, the patients with controlled ACM showed improvements in the functional, but not the structural, arterial parameters compared with the patients with an active condition.
Temperature-induced droplet coalescence in microchannels
Authors: Xu Bin , Nguyen Nam-Trung , Wong Teck Neng
Published: March 2012

This paper reports a technique for temperature-induced merging of droplets in a microchannel. The multiphase system consists of water droplet and oil as the dispersed phase and the carrying continuous phase. A resistive heater provides heating in a rectangular merging chamber. The temperature of the chamber is controlled by the voltage applied to the heater. The merging process of two neighboring droplets was investigated with different applied voltage, flow rate ratio between water and oil and total flowrate. Merging is found to be effective at high flow rate ratio, high temperature, and low total flowrate. The presented technique could be used for merging and mixing in droplet-based lab-on-a-chip platforms
Efficient manipulation of microparticles in bubble streaming flows
Authors: Wang Cheng , Jalikop Shreyas V. , Hilgenfeldt Sascha
Published: March 2012

Oscillating microbubbles of radius 20–100 μm driven by ultrasound initiate a steady streaming flow around the bubbles. In such flows, microparticles of even smaller sizes (radius 1–5 μm) exhibit size-dependent behaviors: particles of different sizes follow different characteristic trajectories despite density-matching. Adjusting the relative strengths of the streaming flow and a superimposed Poiseuille flow allows for a simple tuning of particle behavior, separating the trajectories of particles with a size resolution on the order of 1 μm. Selective trapping, accumulation, and release of particles can be achieved. We show here how to design bubble microfluidic devices that use these concepts to filter, enrich, and preconcentrate particles of selected sizes, either by concentrating them in discrete clusters (localized both stream- and spanwise) or by forcing them into narrow, continuous trajectory bundles of strong spanwise localization.