Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Computing Methodologies”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,369 records · Page 76Linked to original sources
PubMed1993

The incidence of child sexual abuse in Northern Ireland.

This is part of a major epidemiological survey of the reported incidence (new cases) of child sexual abuse in Northern Ireland. Based on multi-source methodology, the study used computer-based record linkage techniques to find the number of incident cases occurring in the Province in 1987. Reporters involved with the incident cases were interviewed by OEV who recorded details of the child, the abuse, and the abuser using a specially designed questionnaire. Age-sex specific incidence rates adjusted for potential misclassification were computed and allowance made for under-ascertainment. Overall, 408 Established cases were reported during 1987. The corresponding incidence rate for Northern Ireland was 0.9 cases per 1000 children. When Suspected and Alleged cases were compared with Established cases, a further 119 cases were allocated by discriminant function analysis to the Established group, and the rate rose to 1.16 per thousand. Selected reporters were interviewed about ascertainment which was estimated to lie between 62% and 74%. If the lowest level of ascertainment applied the corresponding incidence rate for Northern Ireland would increase to 1.87. These figures are higher than those currently reported elsewhere in the UK, but methodological differences in study design hamper interregional comparisons. A number of relevant methodological problems are discussed.

Adolescent↗
PubMed1998

Yohimbine for erectile dysfunction: a systematic review and meta-analysis of randomized clinical trials.

PURPOSE: Erectile dysfunction is a common problem, particularly in diabetics. It is associated with a considerable burden of suffering. No generally accepted drug treatment exists. We systematically reviewed and meta-analyzed all randomized, placebo controlled trials of yohimbine monotherapy for erectile dysfunction to determine its therapeutic efficacy. Our secondary aim was to evaluate the safety of yohimbine. MATERIALS AND METHODS: We used computerized literature searches and standardized data extraction to rate methodological quality in a meta-analysis using computer statistical software. RESULTS: Seven trials fit the predefined inclusion criteria. Overall methodological quality of these studies was satisfactory. The meta-analysis demonstrated that yohimbine is superior to placebo in the treatment of erectile dysfunction (odds ratio 3.85, 95% confidence interval 6.67 to 2.22). Serious adverse reactions were infrequent and reversible. CONCLUSIONS: The benefit of yohimbine medication for erectile dysfunction seems to outweigh its risks. Therefore, yohimbine is believed to be a reasonable therapeutic option for erectile dysfunction that should be considered as initial pharmacological intervention.

Adrenergic alpha-Antagonists↗
PubMed1993

[Radiological reasoning and its computer-based simulation. Reasons to use computer-based diagnostic systems developed on shells].

Research on the medical applications of artificial intelligence has increased the knowledge of logical and methodological principles of clinical reasoning. Thus, computer-based diagnostic systems are developed on the basis of progress in this field, because thorough knowledge is necessary to obtain efficient simulation. This work was aimed at analyzing the structure of medical and radiological reasoning and at discussing the modalities to simulate it with computer-based diagnostic systems. The diagnostic process includes two steps: data collection and data interpretation; radiological reasoning involves the following 5 steps: procedural, executive, observative, interpretative and communicative. Each of them needs a different approach to simulation, considering, in its development, the different characteristics of each kind of reasoning. The expert system shells on the market are necessary tools to develop expert systems, but they cannot cover the whole of processes taking place during radiological work. Therefore, a particular, radiology-aimed shell should be developed to help the radiologist.

Artificial Intelligence↗
PubMedDate not supplied

Machine vision guided sensor positioning system for leaf temperature assessment.

A sensor positioning system was developed for monitoring plants' well-being using a non-contact sensor. Image processing algorithms were developed to identify a target region on a plant leaf. A novel algorithm to recover view depth was developed by using a camera equipped with a computer-controlled zoom lens. The methodology has improved depth recovery resolution over a conventional monocular imaging technique. An algorithm was also developed to find a maximum enclosed circle on a leaf surface so the conical field-of-view of an infrared temperature sensor could be filled by the target without peripheral noise. The center of the enclosed circle and the estimated depth were used to define the sensor 3-D location for accurate plant temperature measurement.

Algorithms↗
PubMed2007

Estimation of population pharmacokinetic parameters of saquinavir in HIV patients with the MONOLIX software.

In nonlinear mixed-effects models, estimation methods based on a linearization of the likelihood are widely used although they have several methodological drawbacks. Kuhn and Lavielle (Comput. Statist. Data Anal. 49:1020-1038 (2005)) developed an estimation method which combines the SAEM (Stochastic Approximation EM) algorithm, with a MCMC (Markov Chain Monte Carlo) procedure for maximum likelihood estimation in nonlinear mixed-effects models without linearization. This method is implemented in the Matlab software MONOLIX which is available at http://www.math.u-psud.fr/~lavielle/monolix/logiciels. In this paper we apply MONOLIX to the analysis of the pharmacokinetics of saquinavir, a protease inhibitor, from concentrations measured after single dose administration in 100 HIV patients, some with advance disease. We also illustrate how to use MONOLIX to build the covariate model using the Bayesian Information Criterion. Saquinavir oral clearance (CL/F) was estimated to be 1.26 L/h and to increase with body mass index, the inter-patient variability for CL/F being 120%. Several methodological developments are ongoing to extend SAEM which is a very promising estimation method for population pharmacockinetic/pharmacodynamic analyses.

Administration, Oral↗
PubMed2004

Radiation dosimetry of O-(3-[18F]fluoropropyl)-L-tyrosine as oncologic PET tracer based on the mice distribution data.

The absorbed and effective radiation doses resulting from the intravenous administration of the potential tumor-imaging PET radiopharmaceutical O-(3-[18F]fluoropropyl)-L-tyrosine (FPT) were estimated using biodistribution data from normal mice. The computer program 3P97 and the methodology recommended by MIRD were used to estimate the doses. The highest uptake of FPT was found in the urinary bladder and pancreas, followed by the liver and kidneys. The urinary bladder wall received the highest absorbed dose of 101.0 microGy/MBq for a 70-kg standard man. The brain received the lowest dose, 6.5 microGy/MBq. Other organs received doses in the range of 6.5-37.5 microGy/MBq. The effective dose was 18.2 microSv/MBq. The data show that a 370-MBq (10 mCi) injection of FPT would lead to an estimated effective dose of 6.7 mSv, which is in the accepted range of routine nuclear medicine investigations.

Animals↗
PubMed1999

Improvement of radiologists' characterization of mammographic masses by using computer-aided diagnosis: an ROC study.

PURPOSE: To evaluate the effects of computer-aided diagnosis (CAD) on radiologists' classification of malignant and benign masses seen on mammograms. MATERIALS AND METHODS: The authors previously developed an automated computer program for estimation of the relative malignancy rating of masses. In the present study, the authors conducted observer performance experiments with receiver operating characteristic (ROC) methodology to evaluate the effects of computer estimates on radiologists' confidence ratings. Six radiologists assessed biopsy-proved masses with and without CAD. Two experiments, one with a single view and the other with two views, were conducted. The classification accuracy was quantified by using the area under the ROC curve, Az. RESULTS: For the reading of 238 images, the Az value for the computer classifier was 0.92. The radiologists' Az values ranged from 0.79 to 0.92 without CAD and improved to 0.87-0.96 with CAD. For the reading of a subset of 76 paired views, the radiologists' Az values ranged from 0.88 to 0.95 without CAD and improved to 0.93-0.97 with CAD. Improvements in the reading of the two sets of images were statistically significant (P = .022 and .007, respectively). An improved positive predictive value as a function of the false-negative fraction was predicted from the improved ROC curves. CONCLUSION: CAD may be useful for assisting radiologists in classification of masses and thereby potentially help reduce unnecessary biopsies.

Breast↗
PubMed1988

Computer-automated structure evaluation of flavonoids and other structurally related compounds as glyoxalase I enzyme inhibitors.

The Computer-Automated Structure Evaluation (CASE) methodology has been applied to a set of flavonoids and other structurally related compounds tested for glyoxalase I enzyme inhibition. CASE identified several structural features believed to be responsible for activity. A total of five fragments were isolated. The most important structural feature is the alpha-hydroxy-alpha,beta-unsaturated carbonyl group attached to a fused ring carbon atom. This fragment tautomerizes into a transition state analog of the substrate of the enzyme. Five tested compounds initially removed from the database were submitted to CASE in the predictive mode. The predictions generally matched the tested values for enzyme inhibition. A set of chromones and phenyl-pyrones, although untested, were also submitted to CASE. CASE predicts that, as a class of compounds, chromones would be more effective inhibitors than phenyl-pyrones.

Computer Simulation↗
PubMedDate not supplied

Medium term planning of biopharmaceutical manufacture with uncertain fermentation titers.

The growing trend of employing multiproduct manufacturing facilities along with the randomness inherent in the biopharmaceutical manufacturing environment is creating significant scheduling and planning challenges for the biopharmaceutical industry. This work focuses on capturing the effect of uncertainty in fermentation titers when optimizing the planning of biopharmaceutical manufacturing campaigns. A mixed integer linear programming (MILP) model based on previous work is derived via chance constrained programming (CCP). The methodology is applied to two illustrative examples, and the results are compared with those from the deterministic model and a multiscenario model accompanied by an iterative construction algorithm. The computational results indicate that the proposed methodology offers significant improvements in solution quality over the compared approaches and presents an opportunity for biopharmaceutical manufacturers to make better medium term planning decisions, particularly under uncertain manufacturing conditions.

Algorithms↗
PubMed2004

Estimation of the tissue composition of the tumour mass in neuroblastoma using segmented CT images.

Neuroblastoma is the most common extra-cranial, solid, malignant tumour in children. Advances in radiology have made possible the detection and staging of the disease. Nevertheless, there is no method available at present that can go beyond detection and qualitative analysis, towards quantitative assessment of the tissue composition of the primary tumour mass in neuroblastoma. Such quantitative analysis could provide important information and serve as a decision-support tool to the radiologist and the oncologist, result in better treatment and follow-up and even lead to the avoidance of delayed surgery. The problem investigated was the improvement of the analysis of the primary tumour mass, in patients with neuroblastoma, using X-ray computed tomography (CT) images. A methodology was proposed for the estimation of the tissue content of the mass: it comprised a Gaussian mixture model for estimation, from segmented CT images, of the tissue composition of the primary tumour. To demonstrate the potential of the method, the results are presented of its application to ten CT examinations of four patients. The method provides quantitative information, and it was observed that the tumour in one of the patients reduced from 523 cm3 to 81 cm3 in volume, with an increase in calcification from about 20% to about 88% of the tumour volume, in response to chemotherapy over a period of five months. Results indicate that the proposed technique may be of considerable value in assessing the response to therapy of patients with neuroblastoma.

Child↗
PubMed2003

The reporting of sensitive behavior by adolescents: a methodological experiment in Kenya.

Does audio computer-assisted self-interviewing (ACASI) produce more valid reporting of sexual activity and related behaviors than face-to-face interviews or self-administered interviews? This analysis, based on data collected from over 6,000 unmarried adolescents in two districts of Kenya--Nyeri and Kisumu--indicates substantial and significant differences in reported rates of premarital sex across interview modes, although not always in the expected direction. Our assumption that girls underreport sexual activity in face-to-face interviews by comparison with ACASI is not confirmed by the Nyeri data, but our results from Kisumu are considerably more promising. As for boys, who we believe exaggerate their level of sexual activity in face-to-face interviews, a more nuanced set of expectations regarding the reporting of sensitive behaviors was offered; our results from Kisumu, although not always significant, by and large conform to expectations.

Adolescent↗
PubMed2006

Classification of EMG signals using wavelet neural network.

An accurate and computationally efficient means of classifying electromyographic (EMG) signal patterns has been the subject of considerable research effort in recent years. Quantitative analysis of EMG signals provides an important source of information for the diagnosis of neuromuscular disorders. Following the recent development of computer-aided EMG equipment, different methodologies in the time domain and frequency domain have been followed for quantitative analysis. In this study, feedforward error backpropagation artificial neural networks (FEBANN) and wavelet neural networks (WNN) based classifiers were developed and compared in relation to their accuracy in classification of EMG signals. In these methods, we used an autoregressive (AR) model of EMG signals as an input to classification system. A total of 1200 MUPs obtained from 7 normal subjects, 7 subjects suffering from myopathy and 13 subjects suffering from neurogenic disease were analyzed. The success rate for the WNN technique was 90.7% and for the FEBANN technique 88%. The comparisons between the developed classifiers were primarily based on a number of scalar performance measures pertaining to the classification. The WNN-based classifier outperformed the FEBANN counterpart. The proposed WNN classification may support expert decisions and add weight to EMG differential diagnosis.

Adolescent↗
PubMed1995

Prediction of traffic noise: a screening technique.

Traffic noise is ubiquitous in many communities and is an important environmental concern, especially for persons located near major roadways. Several different methods are available to estimate noise levels resulting from roadway traffic. These include computational, graphical, and computer modeling techniques. The prediction methodology presented here is a simplified technique that can be used for estimating noise resulting from traffic and for screening traffic noise impacts. This Traffic Noise Screening (TNS) approach consists of a series of traffic noise level prediction graphs developed for different roadway configurations. The graphs are based on the results from using the Federal Highway Administration (FHWA) STAMINA2.0 computerized noise prediction model for various scenarios. Data inputs to the TNS approach include roadway genometries, traffic volumes, vehicle travel speed, and centerline distance to the receptors. The TNS graphs allow easy estimation of traffic noise levels for use in predicting traffic-related noise impacts. This TNS approach is not intended as a substitute for detailed modeling, such as with STAMINA2.0, but as a screening tool to aid in determining when detailed modeling may be necessary. If screening results indicate that noise estimates are significant, or if the scenario is rather complex, then additional, more detailed modeling can be performed.

Automobiles↗
PubMed2001

Connective tissue growth factor in drug-induced gingival overgrowth.

BACKGROUND: Drug-induced gingival overgrowth is a known side effect of certain chemotherapeutic agents used for the treatment of systemic disorders. The pathogenesis and mechanisms responsible for this condition are not fully understood. This study assesses for the presence and localization of connective tissue growth factor (CTGF) in drug-induced gingival overgrowth tissues. CTGF immunostaining was compared with sections stained with transforming growth factor (TGF)-beta1 and CD31 antibodies in order to investigate possible pathogenic mechanisms. METHODS: Gingival overgrowth samples were obtained from patients undergoing therapy with phenytoin (n = 9), nifedipine (n = 4), cyclosporin A (n = 5), and control tissues from systemically healthy donors (n = 9). Tissue sections were subjected to peroxidase immunohistochemistry and were stained with CTGF and TGF-beta1 polyclonal primary antibodies. Possible relationships between CTGF staining and angiogenesis were also studied using an anti-CD31 antibody as a marker for endothelial cells. Staining was analyzed by computer-assisted quantitative and semiquantitative methodology at 5 defined sites in all samples based on the location of specific landmarks including epithelium and underlying connective tissues. RESULTS: Cellular and extracellular CTGF content in phenytoin gingival overgrowth tissues was significantly (P<0.05) higher compared to the other gingival overgrowth tissues and the controls. Higher CTGF staining in phenytoin gingival overgrowth tissues was accompanied by an increased abundance of fibroblasts and connective tissue fibers. No strong association of CTGF staining with TGF-beta1 or CD31 staining was found. CONCLUSIONS: The data from the present study show significantly higher CTGF staining in phenytoin-induced gingival overgrowth tissues compared to controls, cyclosporin A-, or nifedipine-induced gingival overgrowth. Moreover, semiquantitative analyses of histologic samples support the concept that the phenytoin overgrowth tissues are fibrotic. These associations suggest a possible role for CTGF in promoting development of fibrotic lesions in phenytoin-induced gingival overgrowth.

Adult↗
PubMed2006

QGS ejection fraction reproducibility in gated SPECT comparing pre-filtered and post-filtered reconstruction.

INTRODUCTION: The aim of this investigation was to compare the QGS determined functional parameters using pre-filtering to that using post-filtering in the gated myocardial perfusion single photon emission computed tomography (SPECT) reconstruction process. METHODOLOGY: A total of 25 patient files were examined, each with both a gated rest and gated stress study, and were reconstructed using two strategies. The first employed pre-filtering with a Butterworth low pass filter (order 4.0 and cut-off 0.21) and the second employed post-filtering with a Butterworth low pass filter (order 5.0 and cut-off 0.21). Following reconstruction and reorientation, gated short axis slices were evaluated with QGS software. RESULTS: The mean ejection fraction for the post-filtered data was 49.5% (95% CI, 45.8-53.1%) and for the pre-filtered data was 54.8% (95% CI, 51.4-58.1%). Excellent correlation was demonstrated between the pre- and post-filtered ejection fractions with a correlation coefficient of 0.964. The mean difference between matched pairs of pre- and post-filtered ejection fraction data was 5.3% (95% CI, 4.3-6.3%). The match pair t-test demonstrated a statistically significant difference between matched pairs (P<0.0001) and a statistically significant difference was shown between the means (P=0.005). CONCLUSION: The impact of performing pre-filtering on data in the reconstruction process is significant with a 5.3% increase in the calculated ejection fraction over post-filtering. Clearly, this has the potential to undermine diagnostic and prognostic roles of functional parameters.

Algorithms↗