Home About us Contact
|
Home About us Contact | ||
|
|
||
Data Interpretation (data + interpretation)
Selected AbstractsUsing Nano-Cast Model Porous Media and Integrated Gas Sorption to Improve Fundamental Understanding and Data Interpretation in Mercury PorosimetryPARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 1 2006Sean P. Rigby Abstract The mechanisms of entrapment, and the nanoscopic spatial distribution, of the residual mercury within nano-cast and amorphous porous media (pore sizes ~1,100 nm) following high-pressure penetration have been studied. It has been shown that, even at the nano-scale, one of the same two principle mechanisms that have been observed previously in mercury porosimetry experiments on macroscopic glass pore models also occur within a given amorphous, nanoporous solid. Using percolation theory to interpret novel, integrated gas sorption experiments, entrapment was shown to arise, either because of the presence of sufficiently narrow pore necks interspersed between larger voids, or due to non-random, longer-range structural heterogeneity. The threshold "snap-off" ratio parameter for the entrapment process has also been directly measured but found to be considerably smaller than seen previously for macroporous materials. The techniques employed here enable information not previously available for nanoporous systems to be determined, and therefore to be incorporated into simulations of mercury porosimetry on those materials. [source] Physicochemical characterization of carrageenans,A critical reinvestigationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Gisela Berth Abstract Kappa-, iota-, and lambda-carrageenan (food grade) were analyzed by static light scattering (MALS in batch mode) in 0.1M NaNO3 at 25 and 60°C, earlier heated up to 90°C or not. At 25°C, there was a strong tendency for a concentration-dependent aggregation in the order lambda < kappa < iota. At 60°C, all samples were molecularly dispersed. The strongly temperature-dependent refractive index increments (equilibrium dialysis) differ. Data interpretation in terms of the wormlike chain model using the Skolnik-Odijk-Fixman approach led to an intrinsic persistence length around 3 to 4 nm and expansion factors as high as 1.5 and above in a thermodynamically good solvent for all three types. Triple-detector HPSEC (DRI, MALS, viscometry) on the three commercial samples plus a degraded (by acidic hydrolysis) kappa-carrageenan in the same solvent/eluant at 60°C yielded a uniform and slightly curved [,]- M relationship for 5 × 103 , M/(g mol) , 3 × 106 and a nearly identical molar mass dependence of the radius of gyration. HPSEC at 25°C on kappa-carrageenan confirmed formation of soluble aggregates. Special emphasis was put on analytical and methodological aspects. The reliability of the experimental data was demonstrated by analogous measurements on dextran calibration standards. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Reference-Free Damage Classification Based on Cluster AnalysisCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 5 2008Hoon Sohn The ultimate goal of this study was to develop an in-site non-destructive testing (NDT) technique that can continuously and autonomously inspect the bonding condition between a carbon FRP (CFRP) layer and a host reinforced concrete (RC) structure, when the CRFP layer is used for strengthening the RC structure. The uniqueness of this reference-free NDT is two-fold: First, features, which are sensitive to CFRP debonding but insensitive to operational and environmental variations of the structure, have been extracted only from current data without direct comparison with previously obtained baseline data. Second, damage classification is performed instantaneously without relying on predetermined decision boundaries. The extraction of the reference-free features is accomplished based on the concept of time reversal acoustics, and the instantaneous decision-making is achieved using cluster analysis. Monotonic and fatigue load tests of large-scale CFRP-strengthened RC beams are conducted to demonstrate the potential of the proposed reference-free debonding monitoring technique. Based on the experimental studies, it has been shown that the proposed reference-free NDT technique may minimize false alarms of debonding and unnecessary data interpretation by end users. [source] Dynamic centrifuge tests of concrete damEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 12 2005Y. Uchita Abstract Dynamic tests of a concrete gravity dam are, for the first time, performed inside a centrifuge. Details of the experimental procedure, data interpretation, and results are presented. It is shown (in conjunction with a parallel paper) that these tests cannot only provide a direct assessment of certain aspects of dam safety, but more importantly provide a data base for possible non-linear finite element code validation. Copyright © 2005 John Wiley & Sons, Ltd. [source] Complex Formation in the Region of Metal Hydrolysis and M(OH)2 Precipitation.ELECTROANALYSIS, Issue 7 2006(AMPSO)x, (OH)y, (OH)y Systems, A Glass Electrode Potentiometric, Polarographic Study of Cd Abstract The interaction between cadmium or zinc and AMPSO was investigated by DCP and GEP, at fixed total ligand to total metal concentration ratios and various pH values, at 25.0,°C and 0.1,M KNO3 ionic strength. For Cd,(AMPSO)x,(OH)y system, CdL and CdL(OH) species, were identified, with stability constants values set to (as log,,): 2.1±0.1 and 6.2±0.2, respectively. For Zn,(AMPSO)x,(OH)y system, the proposed final model with stability constants set to (as log,,) is: ZnL=2.5±0.1 and ZnL(OH)2=12.9±0.2. For both systems, the fact that AMPSO deprotonation occurs in the metal hydrolysis and M(OH)2 precipitation and the complexes formed are not too strong added a real challenge to data interpretation. [source] Cover Picture: Electrophoresis 14'2010ELECTROPHORESIS, Issue 14 2010Article first published online: 21 JUL 2010 Issue no. 14 is a "mini special issue" on "Microscale Separation Methods for Metabolomics" comprising 9 manuscripts on metabolomics and 12 manuscripts on various topics in nucleic acids, biomarkers, proteomics, miniaturization, etc. Part I has 9 manuscripts on metabolomics featuring new technological developments and the potential of CE-MS, targeted analysis of one class of metabolites and non-targeted analysis, and data interpretation that is essential to acquire useful biological information. In short, the importance of CE and, generally, of microscale separation methods for metabolomics is rapidly increasing and the papers published in this issue give an overview of this field. Part II has 2 research papers on biomarkers while Part III is on various aspects of nucleic acids including but not limited to genotyping, PCR, SSCP, PCR and detection of DNA. Part IV describes various aspects of fundamentals and methodology in microfluidics, cell lysates by 2-DE, CE-LIF of plasmid DNA, whole blood assay of trypsin activity, etc. [source] Evaluation of different warping methods for the analysis of CE profiles of urinary nucleosidesELECTROPHORESIS, Issue 16 2007Ewa Szyma Abstract Nowadays, numerous metabolite concentrations can readily be determined in a given biological sample by high-throughput analytical methods. However, such raw analytical data comprise noninformative components due to many disturbances normally occurring in the analyses of biological material. To eliminate those unwanted original analytical data components, advanced chemometric data preprocessing methods might be of help. Here, such methods are applied to electrophoretic nucleoside profiles in urine samples of cancer patients and healthy volunteers. In this study, three warping methods: dynamic time warping (DTW), correlation optimized warping (COW), and parametric time warping (PTW) were examined on two sets of electrophoretic data by means of quality of peaks alignment, time of preprocessing, and way of customization. The application of warping methods helped to limit shifting of peaks and enabled differentiation between whole electropherograms of healthy and cancer patients objectively by a principal component analysis (PCA). The evaluation of preprocessed data and raw data by PC analysis confirms differences between the applied warping tools and proves their suitability in metabonomic data interpretation. [source] Wrinkles in the rare biosphere: pyrosequencing errors can lead to artificial inflation of diversity estimatesENVIRONMENTAL MICROBIOLOGY, Issue 1 2010Victor Kunin Summary Massively parallel pyrosequencing of the small subunit (16S) ribosomal RNA gene has revealed that the extent of rare microbial populations in several environments, the ,rare biosphere', is orders of magnitude higher than previously thought. One important caveat with this method is that sequencing error could artificially inflate diversity estimates. Although the per-base error of 16S rDNA amplicon pyrosequencing has been shown to be as good as or lower than Sanger sequencing, no direct assessments of pyrosequencing errors on diversity estimates have been reported. Using only Escherichia coli MG1655 as a reference template, we find that 16S rDNA diversity is grossly overestimated unless relatively stringent read quality filtering and low clustering thresholds are applied. In particular, the common practice of removing reads with unresolved bases and anomalous read lengths is insufficient to ensure accurate estimates of microbial diversity. Furthermore, common and reproducible homopolymer length errors can result in relatively abundant spurious phylotypes further confounding data interpretation. We suggest that stringent quality-based trimming of 16S pyrotags and clustering thresholds no greater than 97% identity should be used to avoid overestimates of the rare biosphere. [source] Age-matched lymphocyte subpopulation reference values in childhood and adolescence: application of exponential regression analysisEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 6 2008Sabine Huenecke Abstract Background:, Normal values of lymphocyte subpopulations for healthy children and adults have been published in defined age groups exclusively, which results in difficult data interpretation for patients close to the limit of contiguous age group ranges. In addition, normal values for a number of lymphocyte subpopulations have not been established to date. Objective:, The aim of this study was to develop a model which provides continuous age-dependent reference values. This model was applied for lymphocyte subpopulations such as naďve and memory T cells as well as their activation profile with diagnostic relevance in children and adults. Study design:, A total of 100 blood samples, obtained from 80 healthy children and 20 adults were analysed by means of four colour-flow cytometry. Continuous age-dependent reference values were computed based on the residual values in an exponential regression model. Results:, We calculated a continuous age-related regression model for both, absolute cell counts and percentages of CD3+CD4+ T helper (TH) cells, CD3+CD8+ cytotoxic T cells, CD56+CD3, natural killer (NK) cells, CD56+CD3+ T cells, CD3+CD4+CD45RA+ naďve TH cells, CD3+CD4+CD45RO+ memory TH cells, CD3+CD8+CD45RA+CD28+ naďve cytotoxic T cells, CD3+CD8+CD45RO+ memory cytotoxic T cells, CD3+CD8+CD69+ early activated cytotoxic T cells and CD3+CD8+HLA-DR+ late activated cytotoxic T cells, respectively, to obtain reference values. Conclusion:, Based on an exponential regression model, the obtained reference values reflect the continuous maturation of lymphocyte subsets during childhood. [source] Discovering hidden knowledge in data classification via multivariate analysisEXPERT SYSTEMS, Issue 2 2010Yisong Chen Abstract: A new classification algorithm based on multivariate analysis is proposed to discover and simulate the grading policy on school transcript data sets. The framework comprises three major steps. First, factor analysis is adopted to separate the scores of several different subjects into grading-related ones and grading-unrelated ones. Second, multidimensional scaling is employed for dimensionality reduction to facilitate subsequent data visualization and interpretation. Finally, a support vector machine is trained to classify the filtered data into different grades. This work provides an attractive framework for intelligent data analysis and decision making. It also exhibits the advantages of high classification accuracy and supports intuitive data interpretation. [source] The bright spot in the West Carpathian upper mantle: a trace of the Tertiary plate collision,and a caveat for a seismologistGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2010Piotr SUMMARY The 2-D full waveform modelling of the mantle arrivals from the CELEBRATION 2000 profiles crossing the Carpathian orogen suggests two possible tectonic models for the collision of ALCAPA (Alpine-Carpathian-Pannonian) and the European Plate in the West Carpathians in southern Poland and Slovakia. Due to an oblique (NE-SW) convergence of plates, the character of the collision may change along the zone of contact of the plates: in the western part of the area an earlier collision might have caused substantial crustal shortening and formation of a crocodile-type structure, with the delaminated lower crust of ,100 km length acting as a north-dipping reflecting discontinuity in the uppermost mantle. In the eastern part, a less advanced collision only involved the verticalization of the subducted slab remnant after a slab break-off. The lower crustal remnant of ,10 km size in the uppermost mantle acts as a pseudo-diffractor generating observable mantle arrivals. Due to the similarity of synthetic data generated by both models, the question of the non-uniqueness of seismic data interpretation, that may lead to disparate tectonic inferences, is also discussed. [source] Crustal structure deduced from receiver functions via single-scattering migrationGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 2 2002E. Bertrand Summary An investigation of the teleseismic P -wave coda is performed using the single-scattering approximation. The method allows one to image short-wavelength scale (,2 km) velocity and density heterogeneities and structures that are barely detected by traveltime tomography. Source effects are removed by using receiver functions for data interpretation, but the amplitude (especially the sign of the signal) is synthesized. Both broad-band seismological stations in the southwestern Alps (France) and Campanian plain (Italy) are used for the illustration of the proposed method. Because of the large aperture of our arrays, laterally small-scale heterogeneities are difficult to image and we must assume lateral continuity of the detectable structure. If so, we show that this depth migration based on a single-scattering approach can recover both the depth and the geometry of the main discontinuities below the studied areas. In the southwestern Alps, we underline a complex crustal structure and Moho dipping topography. The Moho depth increases from 20 to 30 km between the coastline and the Mercantour range. In the Campanian plain (surrounding Mount Vesuvius) we also find a southeastwards-dipping Moho. Furthermore, the three main discontinuities are imaged, showing a relatively shallow mantle,crust discontinuity and a deeper one near the coastline. [source] Self-potential data interpretation using standard deviations of depths computed from moving-average residual anomaliesGEOPHYSICAL PROSPECTING, Issue 4 2006E.M. Abdelrahman ABSTRACT We have developed a least-squares minimization approach to determine simultaneously the shape (shape factor) and the depth of a buried structure from self-potential (SP) data. The method is based on computing the standard deviation of the depths determined from all moving-average residual anomalies obtained from SP data, using filters of successive window lengths for each shape factor. The standard deviation may generally be considered a criterion for determining the correct depth and shape factor of the buried structure. When the correct shape factor is used, the standard deviation of the depths is less than the standard deviations computed using incorrect shape factors. This method is applied to synthetic data with and without random errors, complicated regionals and interference from neighbouring sources, and is tested on a known field example from Turkey. In all cases, the shape and depth solutions obtained are in a good agreement with the actual values. [source] Aquifer interactions with a polluted mountain river of NicaraguaHYDROLOGICAL PROCESSES, Issue 13 2008Jose Alfredo Mendoza Abstract The interactions between a stream and nearby shallow aquifers were investigated in a mountain basin being polluted by mercury released during mining in central Nicaragua. Hourly data series of water levels and temperatures were analysed using cross-correlation. Resistivity imaging was used to map the subsurface and to complement the hydrological data interpretation. The results show the complex hydrogeological conditions that characterize the region, with weathering and fractured rock as main contributors to groundwater transport. The resistivity images suggest the presence of two vertical dykes perpendicular to the stream, and zones rich in clay. The data series indicate a rapid response from the aquifers to recharge events, followed by immediate discharge on a yearly basis. Furthermore, alternating periods of stream infiltration and aquifer discharge were identified. This work demonstrates that surface water pollution is a threat to groundwater quality in the area. Copyright © 2007 John Wiley & Sons, Ltd. [source] From fuzzy sets to shadowed sets: Interpretation and computingINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 1 2009Witold Pedrycz In this study, we discuss a concept of shadowed sets and present their applications. To establish some sound compromise between the qualitative Boolean (two-valued) description of data and quantitative membership grades, we introduce an interpretation framework of shadowed sets. Shadowed sets are discussed as three-valued constructs induced by fuzzy sets assuming three values (that could be interpreted as full membership, full exclusion, and uncertain membership). The algorithm of converting membership functions into this quantification is a result of a certain optimization problem guided by the principle of uncertainty localization. We revisit fundamental ideas of relational calculus in the setting of shadowed sets. We demonstrate how shadowed sets help in problems in data interpretation in fuzzy clustering by leading to the three-valued quantification of data structure that consists of core, shadowed, and uncertain structure. © 2008 Wiley Periodicals, Inc. [source] Fuzzy logic-based networks: A study in logic data interpretationINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 12 2006Xiaofeng Liang Fuzzy neurons may have outstanding learning abilities and are endowed with significant interpretation capabilities. In this study, we are concerned with the development of logic networks composed of fuzzy neurons. The main phase of the design includes the granulation of the output space (via triangular fuzzy sets) being realized with the use of fuzzy equalization. In the sequel these fuzzy sets are used to guide the construction of a family of fuzzy sets in the input space. Further processing of the resulting fuzzy sets deals with some additional aggregation of those that are not sufficiently distinct. This helps reduce the size of the logic network. We include comprehensive experimentation and offer a thorough interpretation of the networks. Experiments concerning real-world continuous data help evaluate the network's appealing properties: transparent interpretability and practical feasibility. © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 1249,1267, 2006. [source] The adrenal cortex and steroidogenesis as cellular and molecular targets for toxicity: critical omissions from regulatory endocrine disrupter screening strategies for human health?JOURNAL OF APPLIED TOXICOLOGY, Issue 2 2003Philip W. Harvey Abstract Current testing strategies to assess the endocrine disrupting properties of chemicals have omitted examination of the adrenal gland and do not adequately cover the process of steroidogenesis. Steroidogenesis is critical for adrenocortical function as well as that of the testes and ovaries, and presents multiple molecular targets for toxicity, ranging from general effects on all steroidogenic tissues (e.g. via StAR protein or CYP11A1 cholesterol side-chain cleavage) through to speci,c targets affecting only adrenocortical function (e.g. CYP11,/18 and glucocorticoid synthesis). Numerous chemicals of environmental relevance are now being shown to affect adrenocortical function both in vivo in aquatic species and in vitro in human cell lines, and given the vital role of the adrenal gland to human health and development, there is a strong case for including dedicated assessment techniques in screening batteries for endocrine-disrupting chemicals, not least to assist in general data interpretation (e.g. whether adrenal hypertrophy is due to stress or to a more sinister adrenocortical insuf,ciency). Cell lines such as H295R (derived from a human adrenocortical adenocarcinoma) currently exist that will allow assessment of cortisol production and most of the major enzymes and functional proteins in the steroidogenic pathway (e.g. StAR; CYP11A1/scc; CYP11,/18; CYP17; CYP19; CYP21; 3, -hydroxysteroid dehydrogenase). Adequate assessment of adrenocortical function, as with any component of the integrated endocrine system, probably also will require the development of speci,c in vivo methodology to include effects on hypothalamo-pituitary function. Finally, although there is currently no direct evidence that environmental exposure to endocrine-disrupting (oestrogenic) chemicals has actually caused adverse human health effects, lessons have been learned on their potential from the diethylstilboestrol case. Similar evidence exists from aminoglutethimide and etomidate on the lethal impact of unpredicted chemically induced adrenal insuf,ciency in sensitive human subgroups, and it would seem prudent to incorporate relevant tests for adrenal function and steroidogenesis into current regulatory validation programmes. Published in 2003 by John Wiley & Sons, Ltd. [source] Direct analysis of clinical relevant single bacterial cells from cerebrospinal fluid during bacterial meningitis by means of micro-Raman spectroscopyJOURNAL OF BIOPHOTONICS, Issue 1-2 2009Michaela Harz Abstract Bacterial meningitis is a relevant public health concern. Despite the availability of modern treatment strategies it is still a life-threatening disease that causes significant morbidity and mortality. Therefore, an initial treatment approach plays an important role. For in-time identification of specific bacterial pathogens of the cerebrospinal fluid (CSF) and emerged antimicrobial and adjunctive treatment, microbiological examination is of major importance. This contribution spotlights the potential of micro-Raman spectroscopy as a biomedical assay for direct analysis of bacteria in cerebrospinal fluid of patients with bacterial meningitis. The influence of miscellaneous artificial environments on several bacterial species present during bacterial meningitis was studied by means of Raman spectroscopy. The application of chemometric data interpretation via hierarchical cluster analysis (HCA) allows for the differentiation of in vitro cultured bacterial cells and can also be achieved on a single cell level. Moreover as proof of principle the investigation of a CSF sample obtained from a patient with meningococcal meningitis showed that the cerebrospinal fluid matrix does not mask the Raman spectrum of a bacterial cell notably since via chemometric analysis with HCA an identification of N. meningitidis cells from patients with bacterial meningitis could be achieved. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Computer utilization and clinical judgment in psychological assessment reportsJOURNAL OF CLINICAL PSYCHOLOGY, Issue 1 2006Elizabeth O. Lichtenberger The process of assessment report writing is a complex one, involving both the statistical evaluation of data and clinical methods of data interpretation to appropriately answer referral questions. Today, a computer often analyzes data generated in a psychological assessment, at least in part. In this article, the author focuses on the interaction between the decision-making processes of human clinicians and the test interpretations that are computer-based. The benefits and problems with computers in assessment are highlighted and are presented alongside the research on the validity of automated assessment, as well as research comparing clinicians and computers in the decision-making process. The author concludes that clinical judgment and computer-based test interpretation each have weaknesses. However, by using certain strategies to reduce clinicians' susceptibility to errors in decision making and to ensure that only valid computer-based test interpretations are used, clinicians can optimize the accuracy of conclusions that they draw in their assessment report © 2005 Wiley Periodicals, Inc. J Clin Psychol. [source] Proper Assessment of the JFK Assassination Bullet Lead Evidence from Metallurgical and Statistical PerspectivesJOURNAL OF FORENSIC SCIENCES, Issue 4 2006Erik Randich Ph.D. ABSTRACT: The bullet evidence in the JFK assassination investigation was reexamined from metallurgical and statistical standpoints. The questioned specimens are comprised of soft lead, possibly from full-metal-jacketed Mannlicher-Carcano (MC), 6.5-mm ammunition. During lead refining, contaminant elements are removed to specified levels for a desired alloy or composition. Microsegregation of trace and minor elements during lead casting and processing can account for the experimental variabilities measured in various evidentiary and comparison samples by laboratory analysts. Thus, elevated concentrations of antimony and copper at crystallographic grain boundaries, the widely varying sizes of grains in MC bullet lead, and the 5,60 mg bullet samples analyzed for assassination intelligence effectively resulted in operational sampling error for the analyses. This deficiency was not considered in the original data interpretation and resulted in an invalid conclusion in favor of the single-bullet theory of the assassination. Alternate statistical calculations, based on the historic analytical data, incorporating weighted averaging and propagation of experimental uncertainties also considerably weaken support for the single-bullet theory. In effect, this assessment of the material composition of the lead specimens from the assassination concludes that the extant evidence is consistent with any number between two and five rounds fired in Dealey Plaza during the shooting. [source] Utilization of high-accuracy FTICR-MS data in protein quantitation experimentsJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 11 2009Martin Strohalm Abstract Human acute T-lymphoblastic leukemia cell line (CEM) treated with cisplatin, and the stable isotope labeling by amino acids in cell culture (SILAC) strategy were used to present an improved method of data processing in high-accuracy mass spectrometry (MS). By using peptide mass fingerprinting with low mass tolerance, we were able to utilize far more data retained in MS scans which would normally be missed by a standard processing method. This new way of data interpretation results in an improvement of the relevance of quantitation experiments and enabled us to search and quantify different types of posttranslational modifications. Furthermore, we used this technique to distinguish among different protein isoforms, commonly returned by Mascot search engine. Copyright © 2009 John Wiley & Sons, Ltd. [source] Dimerization of ionized 4-(methyl mercapto)-phenol during ESI, APCI and APPI mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 9 2009Lianming Wu Abstract A novel ion/molecule reaction was observed to occur under electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), and atmospheric pressure photo ionization (APPI) conditions, leading to dimerization of ionized 4-(methyl mercapto)-phenol followed by fast H· loss. The reaction is particularly favored during ESI, which suggests that this ion/molecule reaction can occur both in the solution inside the ESI-charged droplets and in the gas-phase environment of most other atmospheric pressure ionization techniques. The dimerization reaction is inherent to the electrolytic process during ESI, whereas it is more by ion/molecule chemistry in nature during APCI and APPI. From the tandem mass spectrometry (MS/MS) data, accurate mass measurements, hydrogen/deuterium (H/D) exchange experiments and density functional theory (DFT) calculations, two methyl sulfonium ions appear to be the most likely products of this electrophilic aromatic substitution reaction. The possible occurrence of this unexpected reaction complicates mass spectral data interpretation and can be misleading in terms of structural assignment as reported herein for 4-(methyl mercapto)-phenol. Copyright © 2009 John Wiley & Sons, Ltd. [source] Solvation of acylium fragment ions in electrospray ionization quadrupole ion trap and Fourier transform ion cyclotron resonance mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 3 2001Ziqiang Guan Abstract In electrospray ionization (ESI) quadrupole ion trap and Fourier transform ion cyclotron resonance mass spectrometry, certain fragment ions (e.g. acylium ions) generated either during the ion transportation process (in the source interface region) or in the ion trap are found to undergo ion,molecule reactions with ESI solvent molecules (water, acetonitrile and aliphatic alcohols) to form adduct species. These unexpected solvated fragment ions severely complicate the interpretation of mass spectrometic data. High-resolution accurate mass measurements are important in establishing the elemental compositions of these adduct species and preventing erroneous data interpretation. Copyright © 2001 John Wiley & Sons, Ltd. [source] Bone mass is preserved in a critical-sized osteotomy by low energy pulsed electromagnetic fields as quantitated by in vivo micro-computed tomographyJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2004Michael O. Ibiwoye Abstract The effectiveness of non-invasive pulsed electromagnetic fields (PEMF) on stimulating bone formation in vivo to augment fracture healing is still controversial, largely because of technical ambiguities in data interpretation within several previous studies. To address this uncertainty, we implemented a rigorously controlled, blinded protocol using a bilateral, mid-diaphyseal fibular osteotomy model in aged rats that achieved a non-union status within 3,4 weeks post-surgery. Bilateral osteotomies allowed delivery of a PEMF treatment protocol on one hind limb, with the contralateral limb representing a within-animal sham-treatment. Bone volumes in both PEMF-treated and sham-treated fibulae were assessed simultaneously in vivo using highly sensitive, high-resolution micro-computed tomography (,CT) over the course of treatment. We found a significant reduction in the amount of time-dependent bone volume loss in PEMF-treated, distal fibular segments as compared to their contralateral sham-treated bones. Osteotomy gap size was significantly smaller in hind limbs exposed to PEMF over sham-treatment. Therefore, our data demonstrate measurable biological consequences of PEMF exposure on in vivo bone tissue. © 2004 Orthopaedic Research Society. Published y Elsevier Ltd. All rights reserved. [source] Chromatographic classification and comparison of commercially available perfluorinated stationary phases for reversed-phase liquid chromatography using Principal Component AnalysisJOURNAL OF SEPARATION SCIENCE, JSS, Issue 3-4 2003Melvin R. Euerby Abstract A range of ten perfluorophenyl and perfluoroalkyl stationary phases has been evaluated using standard chromatographic tests and probes. Principal Component Analysis of the data has indicated that the phases can be divided into distinct groupings. Extending the dataset to include standard alkyl and phenyl phases provided further data interpretation to support the orthogonal selectivity claims made for perfluorinated phases. The analysis of a range of basic analytes showed an unusual extended retention of hydrophilic basic analytes with perfluorophases. Furthermore, a non-linear relationship between the amount of organic modifier and the logarithm of the retention factor was observed, for the hydrophilic bases, which could not be modelled with LC prediction softwares. This was in sharp contrast to the alkyl and phenyl phases examined. Basic analyte retention on perfluoroalkyl phases could be modelled adequately for the lipophilic bases. Exploration of the retention mechanism of these perfluoro phases indicated that silanol interactions were important in retention and selectivity. Using a rapid, isocratic, high organic modifier methodology, it was possible to analyse a mixture containing a lipophilic steroid, hydrophilic base and an internal standard in < 4 minutes with a perfluorophenyl phase. This had previously only been achievable with an alkyl phase under gradient elution conditions. [source] Stress Development During Drying of Aqueous Zirconia Based Tape Casting Slurries Measured by Transparent Substrate Deflection MethodJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 6 2009Christiane Bauer During drying of water-based tape casting slurries, high stresses can occur, which lead to crack formation. Under the variety of different techniques to measure the drying stresses, the deflect measurement technique is very common. Due to the nontransparent substrate, this technique has the disadvantage, that a direct observation of the changes in the drying regions during the drying process is not possible. Thus, it cannot be ensured that homogeneous drying occurs, which is the prerequisite for the validity of the Corcoran's equation. Nonuniform drying causes cracks and might lead to errors in data interpretation, if nonuniformity of drying is not visible. To make drying uniformity visible, the deflect measurement technique was improved by the usage of a transparent substrate. The benefit of the new technique is the direct observation of saturation uniformity during drying. The differentiation of nonuniform drying and uniform drying, which is characterized by an optimum permeation of the solvent to the surface, is ensured. The advantage of the method is demonstrated by the characterization of the drying behavior of water-based stabilized zirconia slurries in the presence of dispersants and latex binders. Particularly with regard to slurries containing latex particles as a binder, progress was achieved in understanding drying. Measures to decrease drying stresses are summarized. [source] Analysis of multilocus fingerprinting data sets containing missing dataMOLECULAR ECOLOGY RESOURCES, Issue 2 2006PHILIPP M. SCHLÜTER Abstract Missing data are commonly encountered using multilocus, fragment-based (dominant) fingerprinting methods, such as random amplified polymorphic DNA (RAPD) or amplified fragment length polymorphism (AFLP). Data sets containing missing data have been analysed by eliminating those bands or samples with missing data, assigning values to missing data or ignoring the problem. Here, we present a method that uses random assignments of band presence,absence to the missing data, implemented by the computer program famd (available from http://homepage.univie.ac.at/philipp.maria.schlueter/famd.html), for analyses based on pairwise similarity and Shannon's index. When missing values group in a data set, sample or band elimination is likely to be the most appropriate action. However, when missing values are scattered across the data set, minimum, maximum and average similarity coefficients are a simple means of visualizing the effects of missing data on tree structure. Our approach indicates the range of values that a data set containing missing data points might generate, and forces the investigator to consider the effects of missing values on data interpretation. [source] Perceived benefits and barriers to joint protection among people with rheumatoid arthritis and occupational therapists.MUSCULOSKELETAL CARE, Issue 3 2010A mixed methods study Abstract Background:,Deciding whether or not to perform a health behaviour is an active decision-making process which has an impact on current and future behaviour and can be influenced by the beliefs both of patients and their healthcare professionals. The aim of this study was to explore rheumatoid arthritis (RA) patients' and occupational therapists' (OTs) perceptions of the benefits of and barriers to performing joint protection (JP). Methods:,A mixed methods design was used. Questionnaires applied a theoretical framework of key themes to assess the relevance of JP benefits and barriers both to people with RA and OTs. Focused interviews with people with RA then enabled data triangulation. Investigator triangulation was used to check the validity of data interpretation. Findings:,Ten people with RA and nine OTs participated. From the questionnaires, both groups agreed that highly relevant key themes for JP benefits were physical well-being, potential benefit and personal control. By contrast, the three key themes for JP barriers , negative attitude of others, negative impact on others and taking time from other things , were relevant for the majority of the OTs but not patients. The interviews enabled an understanding of the meaning behind RA patients' ratings, particularly their differences from OTs. People with RA explained JP benefits, and disease acceptance had altered some initial barriers into perceived benefits over time. Conclusions:,Emphasizing benefits and identifying individually relevant barriers could be an important communication strategy for OTs in understanding patients' rationale for whether or not to adopt JP methods. Copyright © 2010 John Wiley & Sons, Ltd. [source] Semi-automatic tool to describe, store and compare proteomics experiments based on MIAPE compliant reportsPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 6 2010Salvador Martínez-Bartolomé Abstract The Human Proteome Organization's Proteomics Standards Initiative aims to develop new standards for data representation and exchange. The Proteomics Standards Initiative has defined the Minimum Information About a Proteomics Experiment (MIAPE) guidelines that specify the information that should be reported with a published experiment. With the aim of promoting the implementation of standard reporting guidelines, we have developed a web tool that helps to generate and store MIAPE compliant reports describing gel electrophoresis and MS-based experiments. The tool can be used in the reviewing phase of the proteomics publication process and can facilitate data interpretation through the comparison of related studies. [source] Software utilities for the interpretation of mass spectrometric data of glycoconjugates: application to glycosphingolipids of human serumRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2010Jamal Souady Glycosphingolipids (GSLs) are major components of the outer leaflet of the cell membrane. These lipids are involved in many cell surface events and show disease-related expression changes. GSLs could thus serve as useful targets for biomarker discovery. The GSL structure is characterized by two entities: a hydrophilic glycan and a hydrophobic ceramide moiety. Both components exhibit numerous structural variations, the combination of which results in a large diversity of GSL structures that can potentially exist. Mass spectrometry (MS) is a powerful tool for high-throughput analysis of GSL expression analysis and structural elucidation. Yet, the assignment of GSL structures using MS data is tedious and demands highly specialized expertise. SysBioWare, a software platform developed for MS data evaluation in glycomics, was here applied for the MS analysis of human serum GSLs. The program was tuned to provide automated compositional assignment, supporting a variety of glycan and ceramide structures. Upon in silico fragmentation, the masses of predicted ions arising from cleavages in the glycan as well as the ceramide moiety were calculated, thus enabling structural characterization of both entities. Validation of proposed structures was achieved by matching in silico calculated fragment ions with those of experimental MS/MS data. These results indicate that SysBioWare can facilitate data interpretation and, furthermore, help the user to deal with large sets of data by supporting management of MS and non-MS data. SysBioWare has the potential to be a powerful tool for high-throughput glycosphingolipidomics in clinical applications. Copyright © 2010 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||||||||