Search results for "ALGORITHMS"
showing 10 items of 1716 documents
Scavengers on the move: behavioural changes in foraging search patterns during the annual cycle
2013
Background: Optimal foraging theory predicts that animals will tend to maximize foraging success by optimizing search strategies. However, how organisms detect sparsely distributed food resources remains an open question. When targets are sparse and unpredictably distributed, a Lévy strategy should maximize foraging success. By contrast, when resources are abundant and regularly distributed, simple Brownian random movement should be sufficient. Although very different groups of organisms exhibit Lévy motion, the shift from a Lévy to a Brownian search strategy has been suggested to depend on internal and external factors such as sex, prey density, or environmental context. However, animal re…
Toluidine Blue Test for Sperm DNA Integrity and Elaboration of Image Cytometry Algorithm
2003
Background: Sperm DNA integrity is of paramount importance in the prognosis of fertility. We applied image cytometry to a toluidine blue (TB) test we recently proposed. Methods: Sperm samples from 33 men were assayed for standard sperm parameters and classified as normal or abnormal. Sperm smears were subjected to the TB test, DNA denaturation testing with acridine orange (AO), and terminal deoxyuridine triphosphate biotin nick end labeling (TUNEL). In CCD image analysis, TB-stained sperm cell heads were microscopically assigned to one of four color groups (dark, blue, light violet, and light blue). The optical densities of 6,600 cells in green and red CCD images were used to elaborate an a…
An adapted optical flow algorithm for robust quantification of cardiac wall motion from standard cine-MR examinations
2012
International audience; This paper presents a method for local myocardial motion estimation from a conventional steady-state free precession cine-MRI sequence using a modified phase-based optical flow (OF) technique. Initially, the technique was tested on synthetic images to evaluate its robustness with regards to Rician noise and to brightness variations. The method was then applied to cardiac images acquired on 11 healthy subjects. Myocardial velocity is measured in centimeter per second in each studied pixel and visualized as colored vectors superimposed on MRI images. The estimated phase-based OF results were compared with a reference OF method and gave similar results on synthetic imag…
Model-Based Dose Calculation Algorithms for Brachytherapy Dosimetry
2019
The purpose of this study was to review the limitations of dose calculation formalisms for photon-emitting brachytherapy sources based on the American Association of Physicists in Medicine (AAPM) Task Group No. 43 (TG-43) report and to provide recommendations to transition to model-based dose calculation algorithms. Additionally, an overview of these algorithms and approaches is presented. The influence of tissue and seed/applicator heterogeneities on brachytherapy dose distributions for breast, gynecologic, head and neck, rectum, and prostate cancers as well as eye plaques and electronic brachytherapy treatments were investigated by comparing dose calculations based on the TG-43 formalism …
Clinical predictors and algorithm for the genetic diagnosis of pheochromocytoma patients.
2009
Abstract Purpose: Six pheochromocytoma susceptibility genes causing distinct syndromes have been identified; approximately one of three of all pheochromocytoma patients carry a predisposing germline mutation. When four major genes (VHL, RET, SDHB, SDHD) are analyzed in a clinical laboratory, costs are ∼$3,400 per patient. The aim of the study is to systematically obtain a robust algorithm to identify who should be genetically tested, and to determine the order in which genes should be tested. Experimental Design: DNA from 989 apparently nonsyndromic patients were scanned for germline mutations in the genes VHL, RET, SDHB, SDHC, and SDHD. Clinical parameters were analyzed as potential predic…
Genome-wide association scan of quantitative traits for attention deficit hyperactivity disorder identifies novel associations and confirms candidate…
2008
Contains fulltext : 70192.pdf (Publisher’s version ) (Closed access) Attention deficit hyperactivity disorder (ADHD) is a complex condition with environmental and genetic etiologies. Up to this point, research has identified genetic associations with candidate genes from known biological pathways. In order to identify novel ADHD susceptibility genes, 600,000 SNPs were genotyped in 958 ADHD proband-parent trios. After applying data cleaning procedures we examined 429,981 autosomal SNPs in 909 family trios. We generated six quantitative phenotypes from 18 ADHD symptoms to be used in genome-wide association analyses. With the PBAT screening algorithm, we identified 2 SNPs, rs6565113 and rs5526…
Troponin I Assay for Identification of a Significant Coronary Stenosis in Patients with Suspected Acute Myocardial Infarction and Wide QRS Complex
2016
Background Common ECG criteria such as ST-segment changes are of limited value in patients with suspected acute myocardial infarction (AMI) and bundle branch block or wide QRS complex. A large proportion of these patients do not suffer from an AMI, whereas those with ST-elevation myocardial infarction (STEMI) equivalent AMI benefit from an aggressive treatment. Aim of the present study was to evaluate the diagnostic information of cardiac troponin I (cTnI) in hemodynamically stable patients with wide QRS complex and suspected AMI. Methods In 417 out of 1818 patients presenting consecutively between 01/2007 and 12/2008 in a prospective multicenter observational study with suspected AMI a pro…
Unique pharmacology of KAR-2, a potential anti-cancer agent: absorption modelling and selective mitotic spindle targeting.
2008
Abstract Bis-indols are a large group of the anti-cancer agents, which effectively arrest the uncontrolled division of the cancerous cells. Their use in clinical chemotherapy is still limited because of: (i) the non-specific targeting of the mitotic cells; (ii) low bioavailability of the drugs. KAR-2 has been identified as a tubulin binding agent which displays significantly lower cytotoxicity but favourable anti-cancer potency than its mother molecule, vinblastine. The objective of this paper, on one hand, was to show that the human intestinal epithelial Caco-2 cells, used for pharmacokinetic studies display distinct sensitivity against KAR-2 and vinblastine due to their distinct targeting…
Usefulness of high-sensitivity troponin T for the evaluation of patients with acute chest pain and no or minimal myocardial damage
2012
Although high-sensitivity troponins allow early diagnosis of acute myocardial infarction, their role for identification of acute coronary syndrome in patients with normal conventional troponin remains unclear.A total of 446 patients presenting to the emergency department with chest pain and normal troponin (common practice assays) in 2 serial samples were included. Both samples were also centrally analyzed for high-sensitivity troponin T (hs-TnT) (Roche Diagnostics, Basel, Switzerland). Detection (3 ng/L) and 99th percentile (≥ 14 ng/L) cutoffs of the maximum hs-TnT levels (hs-TnTmax) were considered. The end points were acute coronary syndrome diagnosis and the composite of in-hospital rev…
Diagnostic accuracy of 64-slice computed tomography coronary angiography in patients with low-to-intermediate risk
2007
Purpose. Our aim was to evaluate the diagnostic accuracy of 64- slice computed tomography coronary angiography (MSCT-CA) for detecting significant stenosis (≥50% lumen reduction) in a population of patients at low to intermediate risk. Materials and methods. We studied 72 patients (38 men, 34 women, mean age 53.9±8.0 years) with atypical or typical chest pain and stratified in the low- to intermediate risk category. MSCT-CA (Sensation 64 Cardiac, Siemens, Germany) was performed after IV administration of 100 ml of iodinated contrast material (Iomeprol 400 mgI/ml, Bracco, Italy). Two observers, blinded to the results of conventional coronary angiography (CAG), assessed the MSCT-CA scans in c…