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PubMed2005

Automatic classification of graphite in cast iron.

A method for automatic classification of the shape of graphite particles in cast iron is proposed. In a typical supervised classification procedure, the standard charts from the ISO-945 standard are used as a training and validation population. Several shape and size parameters are described and used as discriminants. A new parameter, the average internal angle, is proposed and is shown to be relevant for accurate classification. The ideal parameter sets are determined, leading to validation success rates above 90%. The classifier is then applied to real cast iron samples and provides results that are consistent with visual examination. The method provides classification results per particle, different from the traditional per field chart comparison methods. The full procedure can run automatically without user interference.

Journal Article↗
PubMed2000

Automatic on-line coupling of supercritical fluid extraction and capillary electrophoresis.

An interface for the automatic coupling of a supercritical fluid extractor (SFE) with capillary electrophoretic (CE) equipment, both commercially available, was developed with a view to improving sample treatment, which is a crucial step in capillary electrophoresis. Extracted analytes were collected in a trap following depressurization in the SFE and were transferred to the CE equipment across the interface. The key elements of the experimental assembly are a laboratory-made programmable arm and the autosampler of the CE equipment, both of which are controlled by a built-in microprocessor using an appropriate electronic interface and customized software. This combined system was successfully used to determine cresols and chlorophenols in liquid samples (river water and human urine) with increased precision, throughput, and automatability. The proposed arrangement opens up interesting prospects for the direct determination of analyte traces in solid samples without human intervention.

Journal Article↗
PubMed1993

Automatic precursor-ion switching in a four-sector tandem mass spectrometer and its application to acquisition of the MS/MS product ions derived from a partially (18)O-labeled peptide for their facile assignments.

We developed an acquisition processor unit to control MS1 and MS2 in a four-sector tandem mass spectrometer simultaneously. The magnetic field strength of MS1 corresponding to the precise centers of the precursor ions, whose masses are determined by MS1 in advance, is recalibrated using an appropriate standard just before an MS/MS experiment, which allows consecutive acquisition of the MS/MS spectra from multiprecursor ions by B2/E2-linked scanning of MS2 synchronized with automatic B1 switching to the centers of each precursor ion on MS1. The accuracy of the automatic precursor-ion switching and the efficiency of consecutive B2/E2-linked scannings were demonstrated by measurement of a peptide mixture. The new MS/MS control system was further applied to rapid acquisition of the MS/MS spectra of isotopic ions of MH+ and (M + 3)+ with normal oxygen and (18)O at the alpha-carboxyl group of a partly (18)O-labeled peptide, which can be easily prepared by enzymatic hydrolysis of a protein in buffer containing 40 atom % H2(18)O. MS/MS analysis of an (18)O-labeled peptide by the present system allowed facile and reliable assignment of MS/MS product ions to a peptide sequence. The usefulness of the method was also demonstrated by measurement of some peptides that give MS/MS product ions incidentally observed at the same mass or assignable to some incorrect sequence.

Amino Acid Sequence↗
PubMed2002

Automatic buffer capacity model building for advanced interpretation of titration curves.

An automatic buffer capacity model building algorithm was developed. The objective of this algorithm is to characterize multiple buffer systems from experimental titration curves. Starting from a simple mathematical model that incorporates the available prior knowledge on the buffer system, the model is sequentially extended by incorporating additional monoprotic buffer equations. To select the most appropriate model from the resulting set of automatically built models, a model structure selection technique was constructed from existing methods.

Algorithms↗
PubMed2005

Detection and automatic repair of nucleotide base-pair mutations by coherent light.

We show that phase-coherent optical techniques allow for the detection and automatic repair of mutations in nucleotide pairs. We demonstrate computationally that there is a laser pulse sequence that can detect the occurrence of a mutation caused by a double proton transfer between hydrogen-bonded nucleotide pairs and automatically repair it by converting the mutated nucleotide pair to the nonmutated one. The specific system chosen for this demonstration is the hydrogen-bonded 2-pyridone.2-hydroxypyridine dimer at typical internucleotide distances, a well-established model for tautomeric acid base pairs.

Base Pairing↗
PubMed2006

Automatic determination of O-glycan structure from fragmentation spectra.

Glycosylation is one of the most important classes of post-translational protein modifications, but the identification of glycans is difficult because of their branched structures and numerous isomers. We describe an algorithm called CartoonistTwo that proposes structures for O-linked glycans by automatically analyzing fragmentation mass spectra. CartoonistTwo improves upon previous glycan identification software primarily in its scoring function, which can more successfully distinguish among a number of similar structures. CartoonistTwo was designed and tested with FTICR mass spectra, and includes automatic recalibration and peak selection especially tuned for such data, yet it can be easily adapted to fragmentation spectra (MS2 or MSn) from other instrument types. On a validated test set of 34 SORI-CID MSn FTICR spectra from Xenopus egg jelly, CartoonistTwo gave the manually determined structural assignment either the first or second highest score over 90% of the time. And for over 50% of these spectra, CartoonistTwo selected a unique highest scoring structure that agreed with the manually determined one.

Algorithms↗
PubMed1997

Clinical evaluation of an automatic blood pressure controller during cardiac surgery.

OBJECTIVE: During surgery, computers can be of great use to support the anesthesiologist in providing task automation. In this paper we describe a closed loop blood pressure controller and show the results of its clinical evaluation. METHODS: The controller is based on a simple and robust Proportional-Integral controller and a supervising, rule based, expert system. Adaptive control is necessary because the sensitivity of the patients to sodium nitroprusside varies over a wide range. Thirty-three clinical tests during cardiac surgery, including the cardiopulmonary bypass phase, were performed. RESULTS: On average the controller was in automatic mode for 90.6 +/- 9.6% of the time. The performance during automatic control showed the mean arterial pressure to be within 10 mmHg of the setpoint for 71.4 +/- 15.5% of the time. The average absolute distance to the setpoint was 8.1 +/- 7.2 mmHg. CONCLUSIONS: The overall performance of the controller was noted as very satisfactory by the anesthesiologists.

Algorithms↗
PubMed2001

Case report: spontaneous atriofascicular pathway automaticity simulating ventricular tachycardia.

Atriofascicular pathways most commonly present electrocardiographically as an antidromic reciprocating AV reentrant tachycardia. We report the case of a child who presented in infancy with a wide QRS complex tachycardia thought to be supraventricular tachycardia with aberrant conduction, associated with tachycardia-induced cardiomyopathy. Later in life the same patient represented with episodes of palpitations secondary to a wide QRS complex tachycardia, thought to be ventricular tachycardia. Electrophysiologic mapping demonstrated the origin of the wide QRS complex tachycardia was from automatic activity originating from a right anterolateral atriofascicular pathway, which also participated in a reentrant antidromic AV reciprocating tachycardia. Radiofrequency ablation of the atriofascicular pathway successfully eliminated both arrhythmias. The mechanism of the wide QRS complex tachycardia appeared to result from spontaneous automaticity of the atriofascicular pathway.

Catheter Ablation↗
PubMed2002

The automatic lung parameter estimator (ALPE) system: non-invasive estimation of pulmonary gas exchange parameters in 10-15 minutes.

OBJECTIVE: Clinical measurements of pulmonary gas exchange abnormalities might help prevent hypoxaemia and be useful in monitoring the effects of therapy. In clinical practice single parameters are often used to describe the abnormality e.g., the "effective shunt." A single parameter description is often insufficient, lumping the effects of several abnormalities. A more detailed picture can be obtained from experiments where FiO2 is varied and two parameters estimated. These experiments have previously taken 30-40 minutes to complete, making them inappropriate for routine clinical use. However with automation of data collection and parameter estimation, the experimental time can be reduced to 10-15 minutes. METHODS: A system has been built for non-invasive, Automatic, Lung Parameter Estimation (ALPE). This system consists of a ventilator, a gas analyser with pulse oximeter, and a computer. Computer programs control the experimental procedure, collect data from the ventilator and gas analyser, and estimate pulmonary gas exchange parameters. Use of the ALPE system, i.e. in estimating gas exchange parameters and reducing experimental time, has been tested on five normal subjects, two patients before and during diuretic therapy, and on 50 occasions in patients before and after surgical intervention. RESULTS: The ALPE system provides estimation of pulmonary gas exchange parameters from a simple, clinical, non-invasive procedure, automatically and quickly. For normal subjects and in patients receiving diuretic therapy, data collection by clinicians familiar with ALPE took (mean +/- SD) 13 min 40 sec +/- 1 min 23 sec. For studies on patients before and after surgery, data collection by an intensive care nurse took (mean +/- SD) 10 min 47 sec +/- 2 min 14 sec. Parameter estimates were: for normal subjects, shunt = 4.95% +/- 2.64% and fA2 = 0.89 +/- 0.01; for patients with heart failure prior to diuretic therapy, patient 1, shunt = 11.50% fA2 = 0.41, patient 2 shunt = 11.61% fA2 = 0.55; and during therapy: patient 1, shunt = 11.51% fA2 = 0.71, patient 2, shunt = 11.22% fA2 = 0.49. CONCLUSIONS: The ALPE system provides quick, non-invasive estimation of pulmonary gas exchange parameters and may have several clinical applications. These include, monitoring pulmonary gas exchange abnormalities in the ICU, assessing post-operative gas exchange abnormalities, and titrating diuretic therapy in patients with heart failure.

Diuretics↗
PubMed2002

Automatic analysis and monitoring of burst suppression in anesthesia.

OBJECTIVE: We studied the spectral characteristics of the EEG burst suppression patterns (BSP) of two intravenous anesthetics, propofol and thiopental. Based on the obtained results, we developed a method for automatic segmentation, classification and compact presentation of burst suppression patterns. METHODS: The spectral analysis was performed with the short time Fourier transform and with autoregressive modeling to provide information of frequency contents of bursts. This information was used when designing appropriate filters for segmentation algorithms. The adaptive segmentation was carried out using two different nonparametric methods. The first one was based on the absolute values of amplitudes and is referred to as the ADIF method. The second method used the absolute values of the Nonlinear Energy Operator (NLEO) and is referred to as the NLEO method. Both methods have been described earlier but they were modified for the purposes of BSP detection. The signal was classified to bursts, suppressions and artifacts. Automatic classification was compared with manual classification. Results. The NLEO method was more accurate, especially in the detection of artifacts. NLEO method classified correctly 94.0% of the propofol data and 92.8% of the thiopental data. With the ADIF method, the results were 90.5% and 88.1% respectively. CONCLUSIONS: Our results show that burst suppression caused by the different anesthetics can be reliably detected with our segmentation and classification methods. The analysis of normal and pathological EEG, however, should include information of the anesthetic used. Knowledge of the normal variation of the EEG is necessary in order to detect the abnormal BSP of, for instance, seizure patients.

Adult↗
PubMed2003

Impact of automatic adjustment of stimulation outputs on pacemaker longevity in a new dual-chamber pacing system.

INTRODUCTION: Automatic capture verification using the Autocapture (AC) feature enabled by paced evoked response detection and delivery of high energy back-up pulses intends to increase patient safety. Furthermore, adjustment of stimulation outputs can save energy and potentially improve pacemaker (PM) longevity. The purpose of this study was to evaluate the theoretical longevity of a new dual chamber PM with the integrated AC feature (Affinity DR, St. Jude Medical) in comparison to the longevity of a previous model from the same manufacturer without AC (Trilogy DR). METHOD: Affinity PMs were implanted in 16 patients and connected to a compatible lead with low polarization properties. AC was activated when the evoked response was significantly higher than the polarization voltage. Theoretical PM longevity was calculated with and without AC during follow-up. The measured and calculated values were compared to measurements in 19 patients, who consecutively received Trilogy-PMs during the same time period. RESULTS: In only one patient the evoked response was not adequate, and as a result, AC was not programmed. The calculated longevity of the Affinity-PMs 79 +/- 28 days after implantation was significantly higher in comparison to the Trilogy-PMs (Affinity-PMs: 8.9 +/- 1.2 years without and 9.5 +/- 1.1 years with AC; Trilogy-PMs: 6.5 +/- 0.8 years) (p < 0.005). CONCLUSION: The AC feature is an optional algorithm that can be activated in most patients and it significantly prolongs predicted battery longevity due to automatic adjustment of stimulation outputs.

Adult↗
PubMed1997

The limitations of decision trees and automatic learning in real world medical decision making.

The decision tree approach is one of the most common approaches in automatic learning and decision making. The automatic learning of decision trees and their use usually show very good results in various "theoretical" environments. But in real life it is often impossible to find the desired number of representative training objects for various reasons. The lack of possibilities to measure attribute values, high cost and complexity of such measurements, and unavailability of all attributes at the same time are the typical representatives. For this reason we decided to use the decision trees not for their primary task--the decision making--but for outlining the most important attributes. This was possible by using a well-known property of the decision trees--their knowledge representation, which can be easily understood by humans. In a delicate field of medical decision making, we cannot allow ourselves to make any inaccurate decisions and the "tips," provided by the decision trees, can be of a great assistance. Our main interest was to discover a predisposition to two forms of acidosis: the metabolic acidosis and respiratory acidosis, which can both have serious effects on child's health. We decided to construct different decision trees from a set of training objects. Instead of using a test set for evaluation of a decision tree, we asked medical experts to take a closer look at the generated trees. They examined and evaluated the decision trees branch by branch. Their comments show that trees generated from the available training set mainly have surprisingly good branches, but on the other hand, for some, no medical explanation could be found.

Acidosis↗
PubMed2004

Mars -- robust automatic backbone assignment of proteins.

MARS a program for robust automatic backbone assignment of (13)C/(15)N labeled proteins is presented. MARS does not require tight thresholds for establishing sequential connectivity or detailed adjustment of these thresholds and it can work with a wide variety of NMR experiments. Using only (13)C(alpha)/(13)C(beta) connectivity information, MARS allows automatic, error-free assignment of 96% of the 370-residue maltose-binding protein. MARS can successfully be used when data are missing for a substantial portion of residues or for proteins with very high chemical shift degeneracy such as partially or fully unfolded proteins. Other sources of information, such as residue specific information or known assignments from a homologues protein, can be included into the assignment process. MARS exports its result in SPARKY format. This allows visual validation and integration of automated and manual assignment.

Algorithms↗
PubMed2002

Process-dissociation procedure: a testable model for considering assumptions about the stochastic relation between consciously controlled and automatic processes.

This paper presents an extension of the process-dissociation procedure with wordstem completion, which makes possible the measurement of the stochastic relationship between consciously controlled and automatic processes. By means of an indirect wordstem completion test, the conditional probabilities of conscious remembering with and without automatic processes can be successfully determined. A multinomial model for the evaluation of this extended process-dissociation procedure is presented. This model makes the distinction between voluntary and involuntary conscious memory processes possible and has been applied to two experiments discussed in this paper. The results show that the assumption of stochastic independence is often violated, albeit not as strongly as predicted by the redundancy or exclusivity model variants. Two conscious processes were found, voluntary and involuntary conscious memory processes, each with a different probability of occurrence.

Attention↗
PubMed1987

Automatic activation of self-discrepancies and emotional syndromes: when cognitive structures influence affect.

Different types of self-discrepancies are associated with different negative affects. Two studies were conducted to determine whether automatic activation of specific actual-self: self-guide mismatches, as cognitive structures, would induce distinct emotional states. Subjects possessing significant discrepancies between their actual self and either their ideal self-guide (attributes that someone wishes or hopes the person would possess) or their ought self-guide (attributes that someone believes the person has the duty or obligation to possess) responded verbally to an audiotape while "thinking about other people." Study 1 involved two kinds of priming attributes: self-relevant and yoked (another subject's self-relevant attributes). Activating mismatches induced momentary syndromes of dejection (sadness, decreased arousal) in ideal-discrepant subjects but induced agitation (nervousness, increased arousal) in ought-discrepant subjects. In Study 2, subjects were randomized to either self-relevant/nondiscrepant, self-discrepant, or yoked priming. The findings of Study 1 were replicated for the self-discrepant priming condition alone. Results indicate that (a) mismatches constitute cognitive structures and (b) automatic activation of different mismatches via contextual priming induces distinct types of emotional discomfort.

Adaptation, Psychological↗
PubMed1992

The generality of the automatic attitude activation effect.

Fazio, Sanbonmatsu, Powell, and Kardes (1986) demonstrated that Ss were able to evaluate adjectives more quickly when these adjectives were immediately preceded (primed) by attitude objects of similar valence, compared with when these adjectives were primed by attitude objects of opposite valence. Moreover, this effect obtained primarily for attitude objects toward which Ss were presumed to hold highly accessible attitudes, as indexed by evaluation latency. The present research explored the generality of these findings across attitude objects and across procedural variations. The results of 3 experiments indicated that the automatic activation effect is a pervasive and relatively unconditional phenomenon. It appears that most evaluations stored in memory, for social and nonsocial objects alike, become active automatically on the mere presence or mention of the object in the environment.

Adult↗
PubMed1995

Attractiveness of the underling: an automatic power --> sex association and its consequences for sexual harassment and aggression.

One characteristic of men who sexually harass is that they are not aware that their actions are inappropriate or a misuse of their power (L. F. Fitzgerald, 1993a). We investigated the existence and automaticity of a mental association between the concepts of power and sex, and its consequences for sexual harassment tendencies. Using a subliminal priming paradigm, Experiment 1 demonstrated an automatic link between power and sex, and only for men high in the likelihood to sexually harass or aggress. In Experiment 2, male participants were unobtrusively primed with either power-related or neutral stimuli. For men likely to sexually aggress, but not other participants, attraction ratings of a female confederate were significantly higher in the power priming than the neutral priming condition.

Aggression↗
PubMed1995

Variability in automatic activation as an unobtrusive measure of racial attitudes: a bona fide pipeline?

The research examines an unobtrusive measure of racial attitudes based on the evaluations that are automatically activated from memory on the presentation of Black versus White faces. Study 1, which concerned the technique's validity, obtained different attitude estimates for Black and White participants and also revealed that the variability among White participants was predictive of other race-related judgments and behavior. Study 2 concerned the lack of correspondence between the unobtrusive estimates and Modern Racism Scale (MRS) scores. The reactivity of the MRS was demonstrated in Study 3. Study 4 observed an interaction between the unobtrusive estimates and an individual difference in motivation to control prejudiced reactions when predicting MRS scores. The theoretical implications of the findings for consideration of automatic and controlled components of racial prejudice are discussed, as is the status of the MRS.

Black or African American↗