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At least 739 records · Page 41Linked to original sources
PubMed1997

Early prenatal diagnosis of hydrocephalus.

The aim of the present study was to assess the accuracy of various measurements of the lateral ventricles (LVs) for the early prenatal diagnosis of evolving congenital hydrocephalus. A prospective study was conducted among 61 normal pregnancies, and 20 pregnancies complicated by neural axis malformations, between 19 and 24 weeks' gestation. The following ultrasound measurements were obtained: atrial width (AW); atrial-width/cerebro-atrial distance (CAD); left ventricular width/hemispheric distance, and cerebro-frontal horn/hemispheric width (HW) distance. Atrial width or AW/CAD had the highest diagnostic accuracy of 97.1% between 19-21 weeks; and 100% between 22-24 weeks. The other two parameters had improved accuracy as gestational age increased. However, between 19-21 weeks the other parameters were below 90% in their diagnostic accuracy. These data demonstrate that the simple measurement of the AW, used either singly or as a ratio with the CAD is effective for the early prenatal diagnosis of evolving hydrocephalus.

Agenesis of Corpus Callosum↗
PubMed2005

Accounting for correlations with core electrons by means of the generalized relativistic effective core potentials: atoms Hg and Pb and their compounds.

A way to account for correlations between the chemically active (valence) and innermore (core) electrons in the framework of the generalized relativistic effective core potential (GRECP) method is suggested. The "correlated" GRECP's (CGRECP's) are generated for the Hg and Pb atoms. Only correlations for the external 12 and 4 electrons of them, correspondingly, should be treated explicitly in the subsequent calculations with these CGRECP's whereas the innermore electrons are excluded from the calculations. Results of atomic calculations with the correlated and earlier GRECP versions are compared with the corresponding all-electron Dirac-Coulomb values. Calculations with the above GRECP's and CGRECP's are also carried out for the lowest-lying states of the HgH molecule and its cation and for the ground state of the PbO molecule, as compared to earlier calculations and experimental data. The accuracy for the vibrational frequencies is increased up to an order of magnitude and the errors for the bond lengths (rotational constants) are decreased in about two times when the correlated GRECP's are applied instead of earlier GRECP versions employing the same innercore-outercore-valence partitioning.

Journal Article↗
PubMed2002

A neural computational aid to the diagnosis of acute myocardial infarction.

STUDY OBJECTIVE: Accurate identification of the presence of acute myocardial infarction in adult patients who present to the emergency department with anterior chest pain remains elusive. The artificial neural network is a powerful nonlinear statistical paradigm for the recognition of complex patterns, with the ability to maintain accuracy when some data required for network function are missing. Earlier studies revealed that the artificial neural network is able to accurately identify acute myocardial infarction in patients experiencing chest pain. However, these studies did not measure network performance in real time, when a significant amount of data required for network function may not be available. They also did not use chemical cardiac marker data. METHODS: Two thousand two hundred four adult patients presenting to the ED with anterior chest pain were used to train an artificial neural network to recognize the presence of acute myocardial infarction. Only data available at the time of initial patient evaluation were used to replicate the conditions of real-time patient evaluation. Forty variables from patient histories, physical examinations, ECG results, and chemical cardiac marker determinations were used to train and then test the network. RESULTS: The network correctly identified 121 of the 128 patients (sensitivity 94.5%; 95% confidence interval 90.6% to 97.9%) with myocardial infarction at a specificity of 95.9% (95% confidence interval 93.0% to 98.5%), despite the fact that an average of 5% (individual range 0% to 35%) of the input data required by the network were missing on all patients. CONCLUSION: Network accuracy and the maintenance of that accuracy when some data required for function are unavailable suggest that the artificial neural network may be a potential real time aid to the diagnosis of acute myocardial infarction during initial patient evaluation.

Acute Disease↗
PubMed2002

In vitro wear of indirect composite restoratives.

STATEMENT OF PROBLEM: Indirect composite restoratives have been improved in their wear resistance and physical properties. Several new indirect composites claim to be successfully used for full coverage crowns, but there is limited information for wear values of these new indirect composites. PURPOSE: The purpose of this study was to evaluate the wear characteristics of 7 indirect composite restoratives and to compare them with a type III gold alloy by means of an in vitro wear test. MATERIAL AND METHODS: Seven indirect composites (2 photopolymerized and 5 photo/heat-polymerized types) and a type III gold alloy (control) were used. Cylindrical Class I cavities (4-mm diameter and 3-mm depth) were prepared in occlusally flattened extracted human molars. Inlays with respective materials were fabricated on duplicated stone casts according to the manufacturers' instructions. Three types of in vitro wear tests were completed by use of the University of Alabama wear simulator. The wear tests included generalized wear as simulation of the wear during mastication, localized wear as simulation of attrition by occlusal contact, and antagonistic enamel wear, which simulated the wear of enamel created by direct contact with the restorative materials. Seven specimens were tested for each material and wear mode, and the wear depths were measured on profilometric tracings with a 2-dimensional profilometer with 1-microm accuracy. All data were analyzed by 1-way analysis of variance, and multiple comparisons were performed with Fisher's test, for which the significant level was set at.05. RESULTS: The gold alloy control exhibited a very small amount of wear in both generalized wear (0.2 +/- 0.1 microm) and localized wear (13.8 +/- 5.0 microm) as compared with all composite specimens. The antagonistic enamel wear of gold alloy was similar with the value of Sculpture. The material group, which was post polymerized or post heat-treated, included BelleGlass, Sculpture, Estenia, and Cristobal+ and showed small values ranging from 1.6 to 2.2 microm in the generalized wear. For the localized wear, Estenia exhibited the minimum value (12.8 +/- 4.9 microm) that was statistically the same as the value of the gold alloy control. However, Estenia exhibited the greatest antagonistic enamel wear value (66.0 +/- 14.0 microm) of all materials tested in this study. It was statistically significant with other materials (P</=.05). CONCLUSION: Within the limitations of this study, it was concluded that some indirect composite restoratives have similar wear resistance to the type III gold alloy tested. Antagonistic enamel was abraded more by highly filled composite materials.

Analysis of Variance↗
PubMed2002

Structural basis and prediction of substrate specificity in protein serine/threonine kinases.

The large number of protein kinases makes it impractical to determine their specificities and substrates experimentally. Using the available crystal structures, molecular modeling, and sequence analyses of kinases and substrates, we developed a set of rules governing the binding of a heptapeptide substrate motif (surrounding the phosphorylation site) to the kinase and implemented these rules in a web-interfaced program for automated prediction of optimal substrate peptides, taking only the amino acid sequence of a protein kinase as input. We show the utility of the method by analyzing yeast cell cycle control and DNA damage checkpoint pathways. Our method is the only available predictive method generally applicable for identifying possible substrate proteins for protein serinethreonine kinases and helps in silico construction of signaling pathways. The accuracy of prediction is comparable to the accuracy of data from systematic large-scale experimental approaches.

Amino Acid Sequence↗
PubMed2003

Predicting aberrant CpG island methylation.

Epigenetic silencing associated with aberrant methylation of promoter region CpG islands is one mechanism leading to loss of tumor suppressor function in human cancer. Profiling of CpG island methylation indicates that some genes are more frequently methylated than others, and that each tumor type is associated with a unique set of methylated genes. However, little is known about why certain genes succumb to this aberrant event. To address this question, we used Restriction Landmark Genome Scanning to analyze the susceptibility of 1,749 unselected CpG islands to de novo methylation driven by overexpression of DNA cytosine-5-methyltransferase 1 (DNMT1). We found that although the overall incidence of CpG island methylation was increased in cells overexpressing DNMT1, not all loci were equally affected. The majority of CpG islands (69.9%) were resistant to de novo methylation, regardless of DNMT1 overexpression. In contrast, we identified a subset of methylation-prone CpG islands (3.8%) that were consistently hypermethylated in multiple DNMT1 overexpressing clones. Methylation-prone and methylation-resistant CpG islands were not significantly different with respect to size, C+G content, CpG frequency, chromosomal location, or promoter association. We used DNA pattern recognition and supervised learning techniques to derive a classification function based on the frequency of seven novel sequence patterns that was capable of discriminating methylation-prone from methylation-resistant CpG islands with 82% accuracy. The data indicate that CpG islands differ in their intrinsic susceptibility to de novo methylation, and suggest that the propensity for a CpG island to become aberrantly methylated can be predicted based on its sequence context.

Base Sequence↗
PubMed1989

Effect of depression on processing interactions in group psychotherapy.

Two studies were conducted to investigate the possibility of individual differences in the ability of inpatients to process interactions in group psychotherapy. The first was a pilot study conducted on groups of major depressive patients and matched normal subjects. Subjects were asked to give process comments after viewing simulations of typical group therapy interactions. These comments were later rated on the extent to which they reflected process qualities and accuracy. These data led to a more rigorous and extensive study that included more appropriate control groups as well as measures of potential confounding factors, such as simulation realism, verbal ability, and interaction comprehension. Results indicated that major depressives suffer from deficits in the ability to process group interactions, relative to three types of control groups, including normals. These differences in processing were not significantly positively correlated with any of the potential confounding factors. The implications for understanding interactional processing and group psychotherapy are discussed.

Adult↗
PubMed2006

Computed tomography colonography: current issues.

OBJECTIVE: Direct and indirect evidence supports the concept of screening for adenomas and early stage colorectal cancer in reducing the incidence and disease-specific mortality. Controversy remains as to the appropriateness of and preferred methods for screening an asymptomatic population. METHODS: Review of computed tomography (CT) colonography based on the literature and personal experience. RESULTS AND CONCLUSIONS: Current discrepancies in the data on accuracy and patient acceptance of CT colonography reflect differences in the performance and evaluation of this examination. Before CT colonography can be implemented in colorectal cancer screening, factors that cause this variability must be elucidated. Studies in which high-resolution scanning, three-dimensional review methods and an enhanced colonoscopic reference are used achieve an accuracy that is similar to colonoscopy. At the same time the evidence that ultra-low radiation dose CT colonography is feasible is mounting, a development that dramatically reduces one of the largest obstacles for large-scale application of this technique.

Adenoma↗
PubMed1986

Birth forecasting based on birth order probabilities, with application to U.S. data.

"A model for birth forecasting based on prediction of the so-called 'birth order probabilities' is constructed. The relation between this model and recent models of fertility prediction is derived. Birth forecasts with approximate probability limits for the U.S. for the period 1983-1997 are generated. The performance of the proposed model in predicting future fertility is tested by fitting time series models to part of the available series (1917-1982) and ultimately generating birth forecasts for the remainder of the period, then comparing these forecasts with the actual data." The accuracy of the fertility forecasts made are compared with those made by other methods.

Americas↗
PubMed1987

Synthesis and proton-NMR studies of oligonucleotides containing an apurinic (AP) site.

In order to elucidate the conformational properties of base-deleted oligodeoxyribonucleotides, the molecules d-CpS(pCpG)n (n = 1,2; S = sugar) were synthesized by the phosphotriester method and characterized by 1H-NMR spectroscopy. Complete assignment of all non-exchangeable proton resonances of both compounds was obtained by 1D- and 2D-NMR techniques. In combination with computer simulation, these spectra yielded proton-proton and proton-phosphorus coupling constants of high accuracy. These data provide valuable information about the sugar and the backbone conformation. It appears that d-Cp1Sp2Cp3G4 does not form a duplex under any of the conditions studied. On the contrary, the base-deleted hexamer d-Cp1Sp2Cp3Gp4Cp5G6 occurs as a right-handed' staggered' DNA duplex at 280 K: the core of this duplex is formed by the residues C(3)-G(6); two 'dangling' residues C(1) and S(2) are located at the two 5'-ends of the duplex. The assignment of the corresponding imino proton resonances for [d-CpS(pCpG)2]2 was based on their thermal behavior: the line broadening of these resonances was studied as a function of temperature. The chemical shift and the number of imino proton resonances accord well with the number and type of Watson-Crick base pairs which can be formed in the staggered duplex described above. Thermodynamic parameters of duplex formation were obtained from an analysis of the chemical shift versus temperature profiles of aromatic base and H-1' protons. It is suggested that the cytosine ring of C(1) stacks, at least part of the time, with the guanine ring on the nucleotide residue, G(6), situated in the complementary strand. The binding of Lys-Trp-Lys to [d-CpS(pCpG)2]2 as well as to [d-CpGpCpG]1 was investigated. It is concluded that the indole ring of the tryptophan residue probably stacks on top of the 3'-terminal guanine base of both duplexes, but not on the nucleic acid bases next to the apurinic (AP) site.

Base Composition↗
PubMed2003

Active knee joint velocity replication measures are stable and accurate in healthy individuals.

The purpose of this study was to determine the stability and accuracy of active knee joint velocity replication methods in healthy subjects. We used a repeated measures design with 14 healthy volunteers. Measures of velocity replication were performed in two ranges of knee joint flexion (0 degrees -30 degrees and 60 degrees -90 degrees ), across four testing velocities (5, 10, 15, and 30 degrees /s) in two movement directions (flexion and extension). Statistical analysis included intraclass correlation coefficients (ICCs; 2, k) and associated standard error of the measures calculated between day 1 and 2. We performed z-tests between all possible combinations of ICC pairs using Fisher's Z transformations to determine if any significant differences existed between observed ICCs. We also calculated correlation ratios (eta2) to explain the source of variability in the calculated ICCs. To assess measurement accuracy, we calculated constant error and absolute error between criterion and replication velocities. Results on ICCs and standard error of the measurements (SEMs) ranged from r = -0.44 +/- 7.00 to 0.88 +/- 0.72 degrees /s. Calculated z-tests indicated six paired ICCs were significantly different ( p < 0.1). In all six pairs, the faster test velocity had a lower ICC magnitude. The eta2 calculations demonstrated that inconsistent performance between day 1 and 2 caused the low ICC magnitudes observed with faster testing velocities. Significantly more absolute error occurred at 30 and 15 degrees /s compared with 5 degrees /s. Significantly less constant error was observed for 30 degrees /s compared with 15 degrees /s. A significant direction by range of motion interaction indicated less constant error for flexion movements in the 60 degrees -90 degrees range of motion (ROM) as compared with extension movements in either ROM. Healthy individuals could actively replicate slower criterion velocities in the mid and end ranges of knee joint motion in both movement directions with an acceptable amount of consistency and accuracy. The data support the use of velocity replication in future investigations on proprioceptive function.

Adult↗
PubMed2002

Effects of conditioned food aversions on nutritional behavior in humans.

Conditioned food aversion (CFA) and taste aversion (CTA) are widely occurring phenomena mediating rejection of solids or liquids, the ingestion of which has induced the onset of post-ingestional malaise. It is a powerful and durable imprint learning that may influence food choice and intake in all animals, including humans. For ethical reasons, CTA has been extensively investigated in a wide variety of laboratory animal's species but only incidentally in humans. Nevertheless, convincing evidence has been provided that CFA and CTA learning are possible in a wide range of human subjects. The results in humans may have some limitations in accuracy since data are sparse, sometimes indirect, and poorly controlled. There is only limited information on the extent of CFA in the elderly since most studies have employed questionnaire and/or interview methods on young people (i.e. college students). The present review evaluates the literature derived both from laboratory animals and humans. In the first instance, the salient features of food and taste aversion learning and the neural mechanisms involved in this learning behavior will be examined. Then, the problems encountered when trying to assess the role of learned food and taste aversions in the nutritional status of healthy as well as sick young or elderly people will be considered. In particular, the importance of CFA on the nutritional status of cancer patients and treatment of alcoholism will be examined. It is concluded that the data are compelling enough to warrant further research and, some indications and recommendations are suggested.

Alcoholism↗
PubMed2003

A feasibility study on the predictive emission monitoring system applied to the Hsinta power plant of Taiwan Power Company.

The continuous emission monitoring system (CEMS) can monitor flue gas emissions continuously and instantaneously. However, it has the disadvantages of enormous cost, easily producing errors in sampling periods of bad weather, lagging response in variable ambient environments, and missing data in daily zero and span tests and maintenance. The concept of a predictive emission monitoring system (PEMS) is to use the operating parameters of combustion equipment through thermodynamic or statistical methods to construct a mathematic model that can predict emissions by a computer program. The goal of this study is to set up a PEMS in a gas-fired combined cycle power generation unit at the Hsinta station of Taiwan Power Co. The emissions to be monitored include nitrogen oxides (NOx) and oxygen (O2) in flue gas. The major variables of the predictive model were determined based on the combustion theory. The data of these variables then were analyzed to establish a regression model. From the regression results, the influences of these variables are discussed and the predicted values are compared with the CEMS data for accuracy. In addition, according to the cost information, the capital and operation and maintenance costs for a PEMS can be much lower than those for a CEMS.

Automation↗
PubMedDate not supplied

Impact of prompt defibrillation on cardiac arrest at a major international airport.

OBJECTIVE: To describe the impact of a rapidly deployable, automated external defibrillator (AED)-equipped first-responder service at Boston's Logan International Airport on the rate of survival to hospital discharge after cardiac arrest. METHODS: A prospective observational outcome study was undertaken for cardiac arrests taking place on the airport grounds from January 1, 1995, to December 31, 1999. Patients were included if they were unresponsive, they had no palpable pulse and no spontaneous respirations, an AED was turned on, and the cardiac arrest took place on airport grounds. Airport fire rescue and emergency medical services (EMS) personnel submitted resuscitation records and AED memory modules for each cardiac arrest. Each author independently reviewed all cardiac arrest reports and code summaries to ensure accuracy and data integrity. Relevant dispatch and response times were determined from airport fire rescue and EMS dispatch records. Patient outcome was determined from hospital patient records. Descriptive statistics were calculated. RESULTS: The airport fire rescue crew responded to 53 cardiac arrests. Of those, 38 met inclusion criteria. In 36 of 38 cases (94.7%), the airport fire rescue crew was first to apply the defibrillator, and the first to deliver a shock in 28 of 32 cases (87.5%) where a shock was delivered. The median response time for the airport fire rescue crew was 2 minutes, with a mode of 1 minute. The EMS response times were 5:29 (95% CI 4:37-6:19) for basic life support crews and 8:07 (95% CI 7:17-8:57) for advanced life support crews. All patients who survived to hospital admission (n = 15) and hospital discharge (n = 8) received their first shock by the airport fire rescue crew. Eight patients (21.1%) survived to hospital discharge. In five of the eight survivors to hospital discharge, defibrillation by the airport crew alone achieved a return of spontaneous circulation. CONCLUSIONS: A rapidly deployable first-responder service permits early defibrillation minutes before arrival of EMS personnel. This rapid response positively impacts the return of spontaneous circulation and survival to hospital discharge after cardiac arrest.

Aged↗
PubMed2005

Bayesian estimation of diagnostic tests accuracy for semi-latent data with covariates.

The performance of a diagnostic test is usually summarized by its sensitivity and specificity. Sensitivity is the probability of a positive result, once the individual is truly ill, and specificity is the probability of a negative result, regarding a healthy individual. These measures are obtained by comparing the test outcome and the results of a reference test generically denominated gold standard. However, in many applied problems considering two diagnostic tests, the gold standard is not available for those individuals with negative results on both tests. In addition, not all diagnostic tests have the same performance across different populations. In this context, we present a Bayesian inference approach for performance measures estimation and we propose an extension of this procedure involving the inclusion of covariates. This Bayesian approach is based on Markov Chain Monte Carlo methods. The conditional dependence between the diagnostic tests was considered. As an example, we applied the proposed methodology to a real data set obtained from the medical literature.

Bayes Theorem↗
PubMed1997

The clinical diagnosis of genital ulcer disease in men.

We report the sensitivity and specificity of physical examination findings for diagnosing primary syphilis, chancroid, and genital herpes. The physical features of genital ulcers in 446 men were measured in accordance with a quantitative scale. Two hundred-twenty of these men had an established, single microbiological diagnosis. Forty-five (20%) had primary syphilis, 118 (54%) had chancroid, and 57 (26%) had genital herpes. There was considerable overlap in the clinical presentation of these three diseases. The classic clinical sign complex attributed to primary syphilis (painless, indurated, clean-based ulcers) was only 31% sensitive but 98% specific. The classic presentation of a chancroid ulcer (a deep, undermined, purulent ulcer) was only 34% sensitive but 94% specific. The classic description of genital herpes ulcers (multiple, shallow, tender ulcers) was only 35% sensitive but 94% specific. Inguinal lymph node findings did not contribute significantly to clinical diagnostic accuracy. These data indicate that the clinical diagnosis of genital ulcer disease can be made with reasonable certainty only for a minority of patients. Rapid, sensitive, and specific diagnostic tests for syphilis, chancroid, and genital herpes are needed.

Adolescent↗
PubMed1976

Quantitative proton tomography: preliminary experiments.

An attempt has been made to see whether energetic protons (158 MeV) could be used instead of X-rays in computerized axial tomography to detect density differences of the order of those at which commercial X-ray tomographs cease to be useful. A circularly symmetrical phantom consisting of Lucite and sugar solutions was used, and density differences of 0-5% were reconstructed with reasonable accuracy from data obtained with very simple equipment. Discontinuities in either density or chemical composition, or both, seem to cause artifacts in the reconstruction. These may be related to the West-Sherwood effect.

Computers↗
PubMed2025

Doblin: inferring dominant clonal lineages from high-resolution DNA barcoding time series.

MOTIVATION: The lineage dynamics and history of cells in a population reflect the interplay of evolutionary forces they experience, including mutation, drift, and selection. When the population is polyclonal, lineage dynamics also manifest the extent of clonal competition among co-existing mutational variants. If the population exists in a community of other species, the lineage dynamics could also reflect the population's ecological interaction with the rest of the community. Recent advances in high-resolution lineage tracking via DNA barcoding, coupled with next-generation sequencing of bacteria, yeast, and mammalian cells, allow for precise quantification of clonal dynamics in these organisms. RESULTS: In this work, we introduce Doblin, an R suite for identifying dominant barcode lineages based on high-resolution lineage tracking data. We first benchmarked Doblin's accuracy using lineage data from evolutionary simulations, showing that it recovers the clones' identity and relative fitness in the simulation. Next, we applied Doblin to analyze clonal dynamics in laboratory evolutions of Escherichia coli populations undergoing antibiotic treatment and in colonization experiments of the gut microbial community. Doblin's versatility allows it to be applied to lineage time-series data across different experimental setups. AVAILABILITY AND IMPLEMENTATION: Doblin is available on CRAN (https://CRAN.R-project.org/package=doblin) and Github (https://github.com/dagagf/doblin).

DNA Barcoding, Taxonomic↗