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At least 1,081 records · Page 60Linked to original sources

PubMed2004

Experimental on-line identification of an electromechanical system.

Identification of electromechanical systems operating in open-loop or closed-loop conditions has long been of prime interest in industrial applications. This paper presents experimental on-line identification of an electromechanical system represented by a digital input/output model. The paper also bridges the theory and practice gap for applied researchers. Studies are carried out by formulating the mathematical model using differential equations and experimental discrete-time identification using on-line plant input-output data. A recursive least-squares method is used to estimate the unknown parameters of the system. Discrete-time data for the parameter identification are obtained experimentally from a setup constructed in the laboratory. A root-mean-square error criterion is used for model validation. Results are presented which show variations in parameters of the electromechanical system. It is demonstrated that identified model output and actual system output match. All tests are performed with no previous results from finite element simulations.

Journal Article↗

PubMed2002

Surface and wastewater quality monitoring: combination of liquid chromatography with (geno)toxicity detection, diode array detection and tandem mass spectrometry for identification of pollutants.

Identification of unknown water pollutants with liquid chromatography and tandem mass spectrometry (LC-MS-MS) is often more complex and time consuming than identification with gas chromatography and mass spectrometry (GC-MS). In order to focus the identification effort on relevant compounds, unknown peaks need to be selected carefully. Based on its frequency of occurrence in the LC-Diode Array Detection (LC-DAD) chromatograms of surface and infiltrated waters, an unknown peak was selected for identification with LC-MS-MS. This compound was identified as hexamethoxymethylmelamine (HMMM), a chemical often used in the coating industry. This is the first time the presence of this chemical in surface waters has been reported. In addition to HMMM, two other structurally related compounds were found to be present in the investigated surface water. A standard mixture of HMMM and its by-products did not exhibit (geno)toxicity under the test conditions applied in this study. In another example, a genotoxic fraction of an industrial wastewater was isolated and examined by LC-MS-MS using a modern quadrupole-orthogonal acceleration-time-of-flight mass spectrometer (Q-TOF). Four compounds were detected. The structures of two compounds present are proposed to be 9-amino-2-hydroxy-acridine and 9-hydroxy-acridine-N-oxide or its structural isomer dihydroxy-acridine. Confirmation with standards could not be carried out, as pure compounds are not available. The other two compounds (structural isomers) could not be identified based on the data available within this study.

Chromatography, High Pressure Liquid↗

PubMed2002

Structure-retention diagrams of ceramides established for their identification.

Molecular species analysis of ceramides was carried out using porous graphitic carbon with gradient elution: chloroform-methanol from 45:55 to 85:15 with a slope at 2.7%/min. These conditions gave a linear relationship between retention data and structure of ceramides. It was demonstrated that linearity occurred when a high slope value of linear gradient elution was used. Thereby the linear diagram was evolved by plotting the adjusted retention time against the total number of carbon atoms of ceramide molecules. Each line represents one ceramide class. Such a Structure-Retention Diagram describes ceramide retention and thus constitutes an identification method using only retention data. This Structure-Retention Diagram was assessed and compared to another obtained from octadesyl-grafted silica in terms of their reproducibility, precision and ability to provide ceramide identification. Better identification was obtained using the results from both Structure-Retention Diagrams. This approach with a two-dimensional separation system allowed to take advantage of the specificity of both identification models.

Ceramides↗

PubMed2000

Increasing the reliability of the identification by high-performance liquid chromatography by means of selective and/or sensitive detection.

An approach for quantitative assessment of the reliability of identification at high-performance liquid chromatography is proposed. The quantitative assessment of identification is useful for determination of selectivity at validation of the analytical methods. Chromatograms and spectra of the analytes are presented as maps in which characteristics as retention times, detector's signals, maxima and minima and another characteristics of spectra are used for identification. A formula for quantitative determination of the contribution of these characteristics on the reliability of identification is given. Using the more selective diode array detector than the convenient UV detector increases the reliability by several orders. A similar result was obtained when the UV detector was replaced with the more sensitive and selective fluorescence detector. Despite of the small contribution of the separation to the reliability its influence is very important for distinguishing of isomers because their spectra are identical.

Chromatography, High Pressure Liquid↗

PubMed2002

An overview of toxicant identification in sediments and dredged materials.

The identification of toxicants affecting aquatic benthic systems is critical to sound assessment and management of our nation's waterways. Identification of toxicants can be useful in designing effective sediment remediation plans and reasonable options for sediment disposal. Knowledge of which contaminants affect benthic systems allows managers to link pollution to specific dischargers and prevent further release of toxicant(s). In addition, identification of major causes of toxicity in sediments may guide programs such as those developing environmental sediment guidelines and registering pesticides, while knowledge of the causes of toxicity which drive ecological changes such as shifts in benthic community structure would be useful in performing ecological risk assessments. To this end, the US Environmental Protection Agency has developed tools (toxicity identification and evaluation (TIE) methods) that allow investigators to characterize and identify chemicals causing acute toxicity in sediments and dredged materials. To date, most sediment TIEs have been performed on interstitial waters. Preliminary evidence from the use of interstitial water TIEs reveals certain patterns in causes of sediment toxicity. First, among all sediments tested, there is no one predominant cause of toxicity; metals, organics, and ammonia play approximately equal roles in causing toxicity. Second, within a single sediment there are multiple causes of toxicity detected; not just one chemical class is active. Third, the role of ammonia is very prominent in these interstitial waters. Finally, if sediments are divided into marine or freshwater, TIEs perforMed on interstitial waters from freshwater sediments indicate a variety of toxicants in fairly equal proportions, while TIEs performed on interstitial waters from marine sediments have identified only ammonia and organics as toxicants, with metals playing a minor role. Preliminary evidence from whole sediment TIEs indicates that organic compounds play a major role in the toxicity of marine sediments, with almost no evidence for either metal or ammonia toxicity. However, interpretation of these results may be skewed because only a small number of interstitial water (n = 13) and whole sediment (n = 5) TIEs have been completed. These trends may change as more data are collected.

Environmental Monitoring↗

PubMed2002

Neurophysiological evidence for two processing times for visual object identification.

Event-related brain potentials (ERPs) were recorded to fragmented pictures of objects that were named correctly or were not to investigate the time course of visual object identification. The first ERP difference distinguishing identified from unidentified pictures estimates the upper limit of the time by which human brain regions have begun to activate long-term memory (LTM) representations specifying the identity of a visual object. Data from 15 young adults indicate that this time varies with the extent to which object parts are recoverable from the visual input, being approximately 200 ms earlier with recoverable than unrecoverable parts. Successful identification is evident by approximately 300 ms when object parts and overall structural configuration are readily recoverable but not until approximately 550 ms when object parts are difficult or impossible to recover (i.e. too poorly specified by the available contours to be recovered). In both cases, successful identification is associated with greater relative positivity. However, unidentified recoverable pictures are associated with an enhanced frontal negativity (N350), linked to object matching operations, not seen for non-recoverable pictures. Taken together, these results implicate two distinct processing sequences in the successful identification of visual objects.

Adult↗

PubMed2002

Strategies for the identification, the assembly and the classification of integrated biological systems in completely sequenced genomes.

The proteins involved in a single biological process may form a stable supra-molecular assembly or be transiently in interaction. Although, the first annotation steps of a complete genome may allow the identification of the different partners, their assembly in a functional system, referred to as an integrated system, is a domain where methodological effort has to be done. Indeed, the knowledge required to assemble partners of such systems should be explicitly included in annotation software. The availability of a complete genome, and therefore of all the proteins encoded by that genome, motivated the development of automated approaches through the coordinated combination of different bio-informatic methods allowing the identification of the different partners, their assembly and the classification of the reconstructed systems in functional categories. In this data flux, the identification of the sequence partners represents the principal bottleneck. Here, we describe and compare the results obtained with different classes of methods (BLASTP2, PSI-BLAST, MAST and META-MEME) applied to the identification in complete genomes of a given family of integrated systems: the ABC transporters. PSI-BLAST appears to significantly outperform motif-based methods, and the results are discussed according to the nature of the proteins and the structure of the sub-families.

Binding Sites↗

PubMed1996

Rapid detection and identification of mycobacteria by combined method of polymerase chain reaction and hybridization protection assay.

A new method for the rapid detection and identification of mycobacteria, combining polymerase chain reaction (PCR) with DNA probe, was developed. The mycobacterial 16S rRNA encoding gene was amplified by nested PCR, and the PCR product was identified by hybridization protection assay using acridinium ester labelled DNA probe. The optimum temperature for hybridization of PCR product and DNA probe was estimated as 55 degrees C. The specificity of the combined method was excellent in the detection and identification of Mycobacterium tuberculosis and Mycobacterium avium-intracellulare complex (MAC). The detection limit was 10 fg DNA for M. tuberculosis, and 100 fg DNA for MAC. Results of preliminary clinical investigation of this method using 207 clinical specimens demonstrated an efficient detection and identification of M. tuberculosis and MAC. These results indicate that the new combined method may be a useful test for the rapid detection and identification of M. tuberculosis and MAC in clinical specimens.

Humans↗

PubMed1997

Competing demands in psychosocial care. A model for the identification and treatment of depressive disorders in primary care.

A considerable body of knowledge noe exists in the area of depressive disorders in primary care. Primary care clinicians appear to identify less than half of patients with major depressive disorder and adequately treat only a portion of those they identify. However, recent research suggests that identification and treatment of depressive disorders in primary care is a far more complex process than previously assumed. The presence of significant differences in patient expectations, the process of care, and the clinical epidemiology of depression between psychiatric and primary care settings makes it difficult to interpret existing studies of primary care clinician performance. This paper describes an alternative conceptual model for the identification and management of depression in primary care which incorporates the concept of "competing demands" derived from the preventive services literature. The central premise of this model is that primary care encounters present competing demands for the attention of the clinician and that there is not enough time to address each demand. The identification and treatment of depression represents an active choice from multiple clinician and patient priorities such as treatment of acute illness, provision of preventive services, and response to patient requests. Choice is influenced by three sets of interrelated "domains," representing the clinician, the patient, and the practice ecosystem. Each domain is indirectly influenced by the general policy environment. Detection and treatment of depression in this model occurs over time as clinicians work through these competing demands. Although the competing demands model contains many unproven elements, it is likely to have a great deal of "face validity" for practicing primary care clinicians, and its validity can be empirically tested. Using the model as a framework to guide inquiry into the identification and management of depression and other mood disorders in primary care may lead to the discovery of more creative and effective solutions to the problem of underdiagnosis and undertreatment.

Antidepressive Agents↗

PubMed1999

Monorhinal odor identification and depression scores in patients with seasonal affective disorder.

BACKGROUND: Visual and olfactory pathways are interconnected. Olfactory deafferentation unmasks photoperiodic responsiveness in some nonphotoperiodic animals such as laboratory rats. By analogy, we hypothesized that olfactory deficits may unmask seasonal rhythms in certain individuals, namely those with seasonal affective disorder (SAD). Since previous studies suggest lateralized hemispheric dysfunction in SAD, and since olfactory neurons' primary projections are largely ipsilateral, we assessed olfactory identification performance on both the right and left side of the nose. METHODS: Twenty-four patients with SAD and 24 matched controls were studied using a phenyl ethyl alcohol detection threshold test bilaterally and the University of Pennsylvania Smell Identification Test unilaterally. Subjects rated their mood using the Self Assessment Mood Scale for SAD. Patients' testing was done in both 'depressed' and 'improved on light' states. RESULTS: No difference in olfactory performance was found between patients and controls or between patients before and after light treatment. However, right-side identification scores were negatively correlated with 'typical' depression scores (r = -0.56, P = 0.006), while left-side olfactory scores were not. Atypical depression scores were unrelated to olfactory performance. Similar correlations emerged between the olfactory identification laterality quotient (Right - Left)/(Right + Left) and typical depressive scores (r = - 0.64, P < 0.001) and total depression scores (r = - 0.59, P < 0.004). LIMITATIONS: We studied a demographically heterogeneous sample and did not control for menstrual factors. DISCUSSION: Our results add to previous evidence of lateralized hemispheric involvement in SAD and suggest that olfaction may be related to seasonal emotional rhythms in humans.

Adult↗

PubMed2003

A brief smell identification test discriminates between deficit and non-deficit schizophrenia.

Evidence is accumulating that smell identification deficits (SID) and social dysfunction in schizophrenia may share a common pathophysiology. While most schizophrenia studies utilize the lengthy 40-item University of Pennsylvania Smell Identification Test (UPSIT) to assess smell identification ability, a brief 12-item smell identification test (B-SIT) has recently been constructed as a culturally neutral substitute for the UPSIT. By selecting the 12 items of the UPSIT from which the B-SIT was originally derived, we constructed a proxy for the B-SIT and compared the performance of 83 patients with schizophrenia to 69 normal subjects. We examined select properties of the B-SIT proxy in relation to the UPSIT to determine its efficacy for use in psychiatric populations. We considered the sensitivity of the B-SIT proxy and evaluated a cutoff score for identifying deficit syndrome schizophrenia (DS). The UPSIT and B-SIT proxy were significantly related in the patients (n=83, r=0.85, P=0.01) and in comparison subjects (n=69, r=0.83, P=0.01), and both measures similarly distinguished DS from non-deficit syndrome (non-DS) patients. The results of this study support the utility of the B-SIT for schizophrenia research and highlight the robustness of the relationship between SID and social dysfunction in schizophrenia.

Adult↗

PubMed1998

A confirmation analysis method for identification of chromosomal fragile sites.

Fragile sites are chromosome bands that do not manifest a presumed breakage pattern. Identification of fragile sites is a way to investigate the mechanism of carcinogenesis because the fragility at a specific chromosome position may be the causation of an associated cancer. A problem in the identification of fragile sites is the high false positive rate arising from simultaneously carrying out a large number of significance tests. To control it, we propose to find a reference study to confirm the identification result of an objective study. We utilize the Bayesian concept for linking two studies. Basically, our method demonstrates a conservative way to take account of the prior information of a binomial parameter. The derived estimate of breakage probability can be interpreted as a resampling weighted sample-pooling method. It is applied to confirm the identification of fragile sites for a data set of neuroblastoma patients.

Chromosome Banding↗

PubMed1999

A PCR test for the identification and discrimination of Legionella longbeachae serogroups 1 and 2.

A PCR test has been developed for the specific identification of Legionella longbeachae. The test targeted sequence unique to both L. longbeachae serogroups 1 and 2 within the mip gene and permitted both species and serogroup identification. The test was trialed on a range of closely related species and 20 clinical isolates originating from Australia, the USA and Israel. Results were consistent with previous identification analyses. From 20 water samples known to contain Legionella spp. one sample yielded isolates which consistently tested positive by L. longbeachae serogroup 1 PCR. DNA sequencing of the PCR product, 5S rRNA gene sequence and hybridisation analysis with a specific oligonucleotide probe definitively identified one isolate as L. longbeachae serogroup 1. PCR testing was demonstrated as a superior method of identification to traditional seroagglutination reactions, which were ambiguous and could explain the previous failure to identify the presence of this microorganism in water.

Base Sequence↗

PubMed2002

Critical spectral regions for vowel identification.

The first two formant frequencies (F1 and F2) are the cues important for vowel identification. In the categorization of the naturally spoken vowels, however, there are overlaps among the vowels in the F1 and F2 plane. The fundamental frequency (F0), the third formant frequency (F3) and the spectral envelope have been proposed as additional cues. In the present study, to investigate the spectral regions essential for the vowel identification, untrained subjects performed the forced-choice identification task in response to Japanese isolated vowels (/a, o, u, e, i/), in which some spectral regions were deleted. Minimum spectral regions needed for correct vowel identification were the two regions including F1 and F2 (the first and fourth in the quadrisected F1-F2 regions in Bark scale). This was true even when phonetically different vowels had a similar combination of F1 and F2 frequency components. F0 and F3 cues were not necessarily needed. It is concluded that the relative importance in the spectral region is not equivalent, but weighted on the two critical spectral regions. The auditory system may identify the vowels by analyzing the information of the spectral shapes and the formant frequencies (F1 and F2) in these critical spectral regions.

Female↗

PubMed2003

Methods used for the isolation, enumeration, characterisation and identification of Enterococcus spp. 2. Pheno- and genotypic criteria.

This paper reviews the methodology applied for the identification and characterisation of enterococci and covers phenotypic, genotypic and phylogenetic techniques. Although conventional phenotypic typing schemes are useful for rapid and simple identification of enterococcal species for routine applications, other methods like standardised sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE), multilocus enzyme electrophoresis (MLEE), antimicrobial susceptibility testing, serotyping, pyrolysis mass spectrometry (pyMS) and vibrational spectroscopic methods allow a more in-depth characterisation of enterococci. Many of the recently described enterococcal species exhibit deviations from hitherto so-called classical enterococci with regard to their phenotypical properties. Therefore, genotypic methods have to be used to clarify their possible assignment to the genus Enterococcus. In this review, special emphasis is given on recently developed polymerase chain reaction (PCR)-based typing methods such as random amplified polymorphic DNA (RAPD), amplified fragment length polymorphism (AFLP), specific and random amplification (SARA) and modifications of PCR-ribotyping as well as pulsed-field gel electrophoresis (PFGE) and partial sequence analysis. The use of PCR and probes for genus and species identification of enterococci is also considered like the application of sequence data of conserved DNA regions (e.g., ribosomal ribonucleic acid (rRNA) genes) in the case of species identification.

Bacterial Typing Techniques↗

PubMed1999

Use of the RAPID ID 32 A system for rapid identification of Clostridium species important in food hygiene.

The identification of Clostridium species using conventional biochemical reactions or commercially available miniaturized ready-to-use test kits often yields uncertain results. One of these test kits, the RAPID ID 32 A identification system for anaerobes (bioMérieux, Marcy-l'Etoile, France), is based on the evaluation of the action of preformed bacterial enzymes and allows classification to the species level within 4 h. This study intended to assess the suitability and reliability of this system for the rapid identification of Clostridium species relevant to food hygiene. For this purpose, 122 test strains of 18 different Clostridium species were examined via RAPID ID 32 A. Of these, 110 (90.2%) were correctly identified to the species level within 4 h. In addition, six strains were successfully classified after examination with supplementary biochemical reactions suggested by the manufacturer, which required an overall examination time of 72 h. The identity of five Clostridium strains could not be determined and in one case the test kit yielded a wrong species classification. Altogether, a correct identification was possible for 116 (95.1%) of the isolates, the total error rate was 4.9%. Using the RAPID ID 32 A system a great number of Clostridium species which are relevant to food hygiene and are often difficult to identify can be correctly and reliably classified within 4 h. Nevertheless, the test system has to be regarded as not yet completely satisfactory, e.g., because C. tyrobutyricum isolates were only insufficiently identified. Further improvements of the system are desirable in order to make it universally applicable in food microbiology.

Clostridium↗

PubMed2001

Parallel cascade identification and its application to protein family prediction.

Parallel cascade identification is a method for modeling dynamic systems with possibly high order nonlinearities and lengthy memory, given only input/output data for the system gathered in an experiment. While the method was originally proposed for nonlinear system identification, two recent papers have illustrated its utility for protein family prediction. One strength of this approach is the capability of training effective parallel cascade classifiers from very little training data. Indeed, when the amount of training exemplars is limited, and when distinctions between a small number of categories suffice, parallel cascade identification can outperform some state-of-the-art techniques. Moreover, the unusual approach taken by this method enables it to be effectively combined with other techniques to significantly improve accuracy. In this paper, parallel cascade identification is first reviewed, and its use in a variety of different fields is surveyed. Then protein family prediction via this method is considered in detail, and some particularly useful applications are pointed out.

Computational Biology↗

PubMedDate not supplied

Hazard identification by methods of animal-based toxicology.

This paper is one of several prepared under the project "Food Safety In Europe: Risk Assessment of Chemicals in Food and Diet" (FOSIE), a European Commission Concerted Action Programme, organised by the International Life Sciences Institute, Europe (ILSI). The aim of the FOSIE project is to review the current state of the science of risk assessment of chemicals in food and diet, by consideration of the four stages of risk assessment, that is, hazard identification, hazard characterisation, exposure assessment and risk characterisation. The contribution of animal-based methods in toxicology to hazard identification of chemicals in food and diet is discussed. The importance of first applying existing technical and chemical knowledge to the design of safety testing programs for food chemicals is emphasised. There is consideration of the presently available and commonly used toxicity testing approaches and methodologies, including acute and repeated dose toxicity, reproductive and developmental toxicity, neurotoxicity, genotoxicity, carcinogenicity, immunotoxicity and food allergy. They are considered from the perspective of whether they are appropriate for assessing food chemicals and whether they are adequate to detect currently known or anticipated hazards from food. Gaps in knowledge and future research needs are identified; research on these could lead to improvements in the methods of hazard identification for food chemicals. The potential impact of some emerging techniques and toxicological issues on hazard identification for food chemicals, such as new measurement techniques, the use of transgenic animals, assessment of hormone balance and the possibilities for conducting studies in which common human diseases have been modelled, is also considered.

Animals↗