Search results for "Derivative"
showing 10 items of 1074 documents
Optimization of a LC method for the enantioseparation of a non-competitive glutamate receptor antagonist, by experimental design methodology
2006
Abstract The aim of this work was to obtain the direct optical resolution of a new glutamate receptor antagonist (( p -chloro)1-aryl-6,7,-dimethoxy-1,2,3,4-tetrahydroisoquinoline, PS3), by liquid chromatography on Chiralcel ® OD column. A response surface methodology (RSM) was employed to optimize the enantiomeric separation of the racemate with the lowest number of experiments; in particular, a face-centred design (FCD) was applied to evaluate the influence of critical parameters on the experimental response. Furthermore, in order to find the best compromise between several responses, a multicriteria decision-making approach, the Derringer's desirability function, was successful to simulta…
The Nature of Rest Silanol Groups on the Surfaces of Silica Based Solid Phase Extraction Materials
2013
Author's version of an article in the journal: Advanced Materials Research. Also available from the publisher at: http://dx.doi.org/10.4028/www.scientific.net/AMR.650.66 Chemically bonded solid phase materials are very important in separation chemistry. The chemically modified silica gel contains rest silanol groups that can affect the retention properties when they are used for separation of compounds. Some commercially available solid phase extraction (SPE) materials based on silica gel were analysed for rest silanol groups by near infrared spectroscopy. The combination frequency of the water molecules in the 5500- 5000 cm -1 region was used in identifying the nature of water molecules on…
Effect of fluid resuscitation on cerebral integrity: A prospective randomised porcine study of haemorrhagic shock.
2021
BACKGROUND The treatment of haemorrhagic shock is a challenging task. Colloids have been regarded as standard treatment, but their safety and benefit have been the subject of controversial debates. Negative effects, including renal failure and increased mortality, have resulted in restrictions on their administration. The cerebral effects of different infusion regimens are largely unknown. OBJECTIVES The current study investigated the impact of gelatine-polysuccinate, hydroxyethyl starch (HES) and balanced electrolyte solution (BES) on cerebral integrity, focusing on cerebral inflammation, apoptosis and blood flow in pigs. DESIGN Randomised experimental study. SETTING University-affiliated …
Representation of solutions and large-time behavior for fully nonlocal diffusion equations
2017
Abstract We study the Cauchy problem for a nonlocal heat equation, which is of fractional order both in space and time. We prove four main theorems: (i) a representation formula for classical solutions, (ii) a quantitative decay rate at which the solution tends to the fundamental solution, (iii) optimal L 2 -decay of mild solutions in all dimensions, (iv) L 2 -decay of weak solutions via energy methods. The first result relies on a delicate analysis of the definition of classical solutions. After proving the representation formula we carefully analyze the integral representation to obtain the quantitative decay rates of (ii). Next we use Fourier analysis techniques to obtain the optimal dec…
Derivative Disclosure Practices in the Annual Financial Reporting of Large European Banks: A Cross-country Empirical Study
2018
The topic of this paper is derivative reporting in banking. The authors employ content analysis to conduct an empirical study on a sample of large European banks. The research aims to assess the qualitative and quantitative profiles of derivative disclosure in banking institutions. The paper provides evidences that banks differ in their derivative reporting, even though they are subject to similar regulatory requirements and accounting standards. The paper also shows that there is room to improve various aspects of derivatives disclosure in banking.
Rolling Over EUAs and CERs
2012
Whatever derivative contract has a finite life limited by their maturity. The construction of long series, however, is of interest for academic, hedging and investments purposes. In this study, we analyze the relevance of the choice of the rollover date on European Union Allowances (EUAs) and Certified Emissions Reduction (CERs) futures contracts. We have used five different methodologies to construct long series and the results show that, regardless of the criterion applied, there are not significant differences between the resultant return distribution series. Therefore, the least complex method, which is to roll on the last trading day, can be used in order to reach the same conclusions.…
The antitumor activities of curcumin and its isoxazole analogue are not affected by multiple gene expression changes in an MDR model of the MCF-7 bre…
2007
We examined the effects of curcumin and of its isoxazole analogue MR 39 in the MCF-7 breast cancer cell line and in its multidrug-resistant (MDR) variant MCF-7R. In comparison with MCF-7, MCF-7R lacks estrogen receptor alpha (ERalpha) and overexpressess P-glycoprotein (P-gp), different IAPs (inhibitory of apoptosis proteins) and COX-2. Through analyses of the effects on cell proliferation, cycling and death, we have observed that the antitumor activity of curcumin and of the more potent (approximately two-fold) MR 39 is at least equal in the MDR cell line compared to the parental MCF-7. Similar results were observed also in an MDR variant of HL-60 leukemia. RT-PCR evaluations performed in M…
Free radical scavenging abilities of flavonoids as mechanism of protection against mutagenicity induced by tert-butyl hydroperoxide or cumene hydrope…
2003
Mutagenicity induced by tert-butyl hydroperoxide (BHP) or cumene hydroperoxide (CHP) in Salmonella typhimurium TA102 was effectively reduced by flavonols with 3',4'-hydroxyl groups such as fisetin, quercetin, rutin, isoquercitrin, hyperoxide, myricetin, myricitrin, robinetin, and to a lesser extent also by morin and kaempferol (ID50=0.25-1.05 micromol per plate). With the exception of isorhamnetin, rhamnetin, morin, and kaempferol, closely similar results were obtained with both peroxides. Hydrogenation of the double bond between carbons 2 and 3 (dihydroquercetin, dihydrorobinetin) as well as the additional elimination of the carbonyl function at carbon 4 (catechins) resulted in a loss of a…
Synthesis, characterization and foaming of PHEA-PLLA, a new graft copolymer for biomedical engineering
2014
Abstract In this study a chemical grafting procedure was set up in order to link high molecular weight poly L-lactic acid (PLLA) chains to the hydrophilic α,β-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA) backbone. A graft copolymer named PHEA-g-PLLA (or simply PHEA–PLLA) was obtained bearing a degree of derivatization of 1.0 mol.% of PLLA as grafted chain. This new hybrid derivative offers both the opportune crystallinity necessary for the production of scaffolds trough a thermally induced phase separation (TIPS) technique and the proper chemical reactivity to perform further functionalizations with bio-effectors and drugs. PHEA–PLLA porous scaffolds for tissue engineering applications were…
Adaptive backstepping based consensus tracking of uncertain nonlinear systems with event-triggered communication
2021
Abstract This paper investigates the consensus tracking problem for a class of uncertain high-order nonlinear systems with parametric uncertainties and event-triggered communication. Under a directed communication condition, a totally distributed adaptive backstepping based control scheme is presented. Specifically, a decentralized triggering condition is adopted in this paper such that continuous monitoring of neighboring states, as required in some existing results, can be avoided. Besides, to handle the non-differentiability problem of virtual controllers, which arises from the utilization of neighboring states collected only at the triggering instants, the virtual controllers in each re…