Search results for "Correlation"
showing 10 items of 2282 documents
Atom, atom-type and total molecular linear indices as a promising approach for bioorganic and medicinal chemistry: theoretical and experimental asses…
2004
Abstract Helminth infections are a medical problem in the world nowadays. In this paper a novel atom-level chemical descriptor has been applied to estimate the anthelmintic activity. Total and local linear indices and linear discriminant analysis were used to obtain a quantitative model that discriminates between anthelmintic and non-anthelmintic drug-like compounds. The discriminant model has an accuracy of 90.11% in the training set, with a high Matthews’ correlation coefficient (MCC = 0.80). To assess the robustness and predictive power of the obtained model, internal (leave-n-out) and external validation process was performed. The QSAR model correctly classified 88.55% of compounds in t…
QSAR Modeling ANTI-HIV-1 Activities by Optimization of Correlation Weights of Local Graph Invariants
2004
Results of using descriptors calculated with the correlation weights (CWs) of local graph invariants for modeling of anti-HIV-1 potencies of two groups of reverse transcriptase (RT) inhibitors are reported. Presence of different chemical elements in molecular structure of the inhibitors and the presence of Morgan extended connectivity values of zeroth-, first- and second order have been examined as local graph invariants in the labeled hydrogen-filled graphs. By Monte Carlo method optimization procedure, values of the CWs which produce as large values as possible of correlation coefficient between the numerical data on the anti-HIV-1 potencies and values of the descriptors on the training s…
Correlation spectroscopy in molten and supercooled antimony trichloride.
1990
Correlation spectroscopy measurements performed on molten and supercooled antimony trichloride with the homodyne technique show correlation functions that have a nonexponential behavior. Two well-defined distributions of correlation times can be observed in different temporal regions. This behavior is discussed in terms of a structural relaxation of clusters dynamically formed by intermolecular and interchain bonds. The Arrhenius plot of these correlation times shows a linear behavior with the same activation energy for both. In contrast, the activation energy of shear viscosity has a different value, showing that the processes determining the temperature behavior of \ensuremath{\tau} and $…
Statistical shape analysis of ascending thoracic aortic aneurysm: Correlation between shape and biomechanical descriptors
2020
An ascending thoracic aortic aneurysm (ATAA) is a heterogeneous disease showing different patterns of aortic dilatation and valve morphologies, each with distinct clinical course. This study aimed to explore the aortic morphology and the associations between shape and function in a population of ATAA, while further assessing novel risk models of aortic surgery not based on aortic size. Shape variability of n = 106 patients with ATAA and different valve morphologies (i.e., bicuspid versus tricuspid aortic valve) was estimated by statistical shape analysis (SSA) to compute a mean aortic shape and its deformation. Once the computational atlas was built, principal component analysis (PCA) allow…
Lipids, Lipoproteins and Apolipoproteins A<sub>I</sub> A<sub>II</sub>, B, C<sub>II</sub>, C<sub>III</sub…
1991
In this study lipid and apolipoprotein patterns were investigated at birth and compared with those of adults. In cord sera, cholesterol, triglycerides, low-density lipoprotein (LDL) cholesterol and high-density lipoprotein (HDL) cholesterol were 38.2, 46.2, 50.5, and 31.9%, respectively, of adult values. Apolipoprotein A<sub>II</sub>, B and C<sub>III</sub> were 48.6, 30.6 and 44.5% of adult values, while apo A<sub>I</sub>, apo C<sub>II</sub> and apo E showed values approaching those of adults (63.4, 73.3 and 89.7%, respectively). Also cholesterol/HDL cholesterol and LDL cholesterol/HDL cholesterol ratios were lower in newborns. In cord sera, l…
Sequestration of alkyltin(IV) cations by complexation with amino-polycarboxylic chelating agents
2013
Abstract The binding capacity of four amino-polycarboxylic ligands (APCs) [nitrilotriacetate (NTA), ethylenediamine- N , N , N′ , N′ -tetraacetate (EDTA), (S,S)-ethylenediamine- N , N ′-disuccinic acid (S,S-EDDS) and diethylenetriamine- N , N , N′ , N″ , N″ -pentaacetate (DTPA)] towards mono-, di- and tri-alkyltin(IV) cations [(CH 3 )Sn 3 + , (CH 3 ) 2 Sn 2 + , (C 2 H 5 ) 2 Sn 2 + , (CH 3 ) 3 Sn + or (C 2 H 5 ) 3 Sn + ] was studied, in aqueous solutions, by ISE-H + potentiometry, at I = 0.1 mol L − 1 (NaCl) and at T = 298.15 K. In all the systems R x Sn (4 − x)+ − APC (R = CH 3 or C 2 H 5 ) a strong 1:1 species is formed together with protonated, hydroxo and dinuclear complexes. The valu…
Áreas y suelos: El tamaño de los yacimientos de superficie. Una propuesta metodológica
2011
En los estudios sobre el patrón de asentamiento y en los análisis del territorio, la variable"tamaño" del asentamiento juega un papel importante. Considerada como"proxy" de la población, no siempre resulta fácil de calcular en ausencia de estructuras arqueológicas construidas: aterrazamientos o fortificaciones. En este trabajo se presenta una aproximación al cálculo de dicha variable en los asentamientos de superficie caracterizados simplemente por la dispersión de materiales, que toma como punto de partida la correlación entre aquélla y la presencia de los horizontes edáficos ah. La reciprocidad positiva de ambos factores permite sugerir diversas hipótesis sobre la relación entre la formac…
Comparison of the planimetry and point-counting methods for the assessment of the size of the mandible cysts on orthopantomograms
2011
Sahin, Bunyamin/0000-0001-8538-8443 WOS: 000304343300015 PubMed: 22143725 Objective: The purpose of this study is to compare the computer-assisted planimetry and point-counting methods in evaluating the sizes of the mandibular cysts with respect to their agreement and the time required to analyze. Study Design: The surface areas of 46 mandibular cyst lesions on orthopantomograms were estimated using the point-counting and computer-assisted planimetry methods. Three observers evaluated the outlined areas twice, using the point-counting (PC) and computer-assisted planimetry (CAP) methods with an interval of two weeks. In the planimetry technique, digitalized images and ImageJ software were us…
Modelling and Analysis of Nonstationary Vehicle-to-Infrastructure Channels with Time-Variant Angles of Arrival
2018
In mobile radio channel modelling, it is generally assumed that the angles of arrival (AOAs) are independent of time. This assumption does not in general agree with real-world channels in which the AOAs vary with the position of a moving receiver. In this paper, we first present a mathematical model for the time-variant AOAs. This model serves as the basis for the development of two nonstationary multipath fading channels models for vehicle-to-infrastructure communications. The statistical properties of both channel models are analysed with emphasis on the time-dependent autocorrelation function (ACF), time-dependent mean Doppler shift, time-dependent Doppler spread, and the Wigner-Ville sp…
Statistical modeling, simulation, and experimental verification of wideband indoor mobile radio channel
2018
This paper focuses on the modeling, simulation, and experimental verification of wideband single-input single-output (SISO) mobile fading channels for indoor propagation environments. The indoor reference channel model is derived from a geometrical rectangle scattering model, which consists of an infinite number of scatterers. It is assumed that the scatterers are exponentially distributed over the two-dimensional (2D) horizontal plane of a rectangular room. Analytical expressions are derived for the probability density function (PDF) of the angle of arrival (AOA), the PDF of the propagation path length, the power delay profile (PDP), and the frequency correlation function (FCF). An efficie…