Search results for " Combination"
showing 10 items of 923 documents
Über die Schnittzahlen mehrfach balancierter blockpläne
1991
Abstract For a finite incidence structure D with a set X of blocks let [ X ] be the number of points common with all blocks contained in X . We define the functions M(t)(B1,…; B1)=ΣB [B1, B]…[B1,B], and, for every partition ϖ = ϖ1,…,ϖ1) of t, the function Mϖ(B1,…,B1) = Σ Πm [Bi | i ϵ Rm], sum over all decompositions {l, …, t} = R1, ⊃ … ⊃ Rl, |Rm| = ϖm. We show: If D is t-fold balanced, then M(t) = Σϖ cϖMϖ, where the, coefficients cϖ are linear combinations of the parameters b1,…,bt, the constant numbers of blocks through any l,…, t distinct points. Conversely, if the rank of the b × b-matrix ([B, B∗])B,B∗ is equal to the number ν of points and M(t) is a rational linear combination of the fu…
Approximate convex hull of affine iterated function system attractors
2012
International audience; In this paper, we present an algorithm to construct an approximate convex hull of the attractors of an affine iterated function system (IFS). We construct a sequence of convex hull approximations for any required precision using the self-similarity property of the attractor in order to optimize calculations. Due to the affine properties of IFS transformations, the number of points considered in the construction is reduced. The time complexity of our algorithm is a linear function of the number of iterations and the number of points in the output convex hull. The number of iterations and the execution time increases logarithmically with increasing accuracy. In additio…
Discrete Derivatives for Atom-Pairs as a Novel Graph-Theoretical Invariant for Generating New Molecular Descriptors: Orthogonality, Interpretation an…
2013
This report presents a new mathematical method based on the concept of the derivative of a molecular graph (G) with respect to a given event (S) to codify chemical structure information. The derivate over each pair of atoms in the molecule is defined as ∂G/∂S(vi , vj )=(fi -2fij +fj )/fij , where fi (or fj ) and fij are the individual frequency of atom i (or j) and the reciprocal frequency of the atoms i and j, respectively. These frequencies characterize the participation intensity of atom pairs in S. Here, the event space is composed of molecular sub-graphs which participate in the formation of the G skeleton that could be complete (representing all possible connected sub-graphs) or comp…
3D-Printed Solid Dispersion Drug Products.
2019
With the well-known advantages of additive manufacturing methods such as three-dimensional (3D) printing in drug delivery, it is disappointing that only one product has been successful in achieving regulatory approval in the past few years. Further research and development is required in this area to introduce more 3D printed products into the market. Our study investigates the potential of fixed dose combination solid dispersion drug products generated via 3D printing. Two model drugs&mdash
Could resveratrol be a useful drug for the treatment of malignant hemopathies?
2013
Resveratrol is a poly-phenol with many beneficial effects: not only as an antioxidant, anti-inflammatory, and antiatherogenic agent, as well as a platelet aggregation inhibitor, but also as an antiproliferative and proapoptotic factor in various types of cancers. There are reviews about the mechanisms responsible for its effects in leukemia and lymphomas, emphasizing the chemosensitizing role of resveratrol, which allows overcoming the multidrug resistance of cancers. The action of resveratrol occurs preferentially on leukemic cells, and not on the normal ones. In addition, it is one of the few drugs that act on leukemic stem cells. If experimental results are promising, its application in …
Drug combination studies of curcumin and genistein against rhodesain of Trypanosoma brucei rhodesiense
2018
Curcumin and genistein are two natural products obtained from Curcuma longa L. and soybeans, endowed with many biological properties. Within the last years they were shown to possess also a promising antitrypanosomal activity. In the present paper, we investigated the activity of both curcumin and genistein against rhodesain, the main cysteine protease of Trypanosoma brucei rhodesiense; drug combination studies, according to Chou and Talalay method, allowed us to demonstrate a potent synergistic effect for the combination curcumin-genistein. As a matter of fact, with our experiments we observed that the combination index of curcumin-genistein is < 1 for the reduction from 10 to 90% of rhode…
Differential interactions of the broad spectrum drugs artemisinin, dihydroartemisinin and artesunate with serum albumin
2013
Artemisinin is a drug, widely used in malaria treatment. As the binding affinity of artemisinin and its derivatives dihydroartemisinin and artesunate to blood serum proteins might influence the effectiveness of the drug, binding of artemisinin and derivatives to serum albumin was studied under near physiological conditions. Binding kinetics indicate a simple, single-step association process for all artemisinin derivatives. The determined changes in enthalpy and entropy upon drug binding clearly indicate that hydrophobic forces are most important for artemisinin and dihydroartemisinin binding, whereas binding of artesunate is governed by both hydrophilic and hydrophobic forces. Key residues,…
Cue combination in a combined feature contrast detection and figure identification task
2006
AbstractTarget figures defined by feature contrast in spatial frequency, orientation or both cues had to be detected in Gabor random fields and their shape had to be identified in a dual task paradigm. Performance improved with increasing feature contrast and was strongly correlated among both tasks. Subjects performed significantly better with combined cues than with single cues. The improvement due to cue summation was stronger than predicted by the assumption of independent feature specific mechanisms, and increased with the performance level achieved with single cues until it was limited by ceiling effects. Further, cue summation was also strongly correlated among tasks: when there was …
Sealing ability of five different retrograde filling materials.
1996
The sealing ability of Amalgam, Harvard-Cement, Diaket, gold-leaf, and Ketac-Endo as retrofilling materials was investigated. Paper cones were fixed with Harvard-Cement in the instrumented roots of 100 extracted human incisors. Apicectomy was performed and a 2-mm-deep retrograde cavity was prepared. Teeth were assigned to five groups (n = 20); each group received a different filling material. Surfaces of the roots were isolated with nail polish. Teeth, were stored in 1% methylene blue dye for 72 h. Roots were sectioned, and the depth of dye penetration was evaluated through a stereomicroscope. Retrofills with Ketac-Endo showed significantly less leakage compared with amalgam. There was no s…
On the stability of stablecoins
2021
This paper investigates the volatility processes of stablecoins and their potential stochastic interdependencies with Bitcoin volatility. We employ a novel approach to choose the optimal combination for the power law exponent and the minimum value for the volatilities bending the power law. Our results indicate that Bitcoin volatility is well-behaved in a statistical sense with a finite theoretical variance. Surprisingly, the volatilities of stablecoins are statistically unstable and contemporaneously respond to Bitcoin volatility. Also, whereas the volatilities of stablecoins are not Granger-causal for Bitcoin volatility, lagged Bitcoin volatility exhibits Granger-causal effects on the vol…