Quercetin-PVP K25 solid dispersions

Quercetin is a flavonoid very well studied and has already entered clinical trials emerging as prospective anticancer drug candidate. In addition, quercetin has being reported to its free-radical scavenging activity and suggests potential uses for the prevention and treatment of pathologies as atherosclerosis, chronic inflammation, and others. However, quercetin is sparingly soluble in water, which may be responsible for its limited absorption upon oral administration. The solid dispersion of quercetin with polyvinylpyrrolidone Kollidon^® 25 (PVP K25) suggests an interesting way to increase quercetin solubility, antioxidant activity, and consequently bioavailability. Then, the purpose of this study was to prepare solid dispersions of quercetin with PVP K25 and evaluate their thermal characterization, antioxidant activity and quercetin improvement solubility. For this purpose, quercetin-PVP K25 solutions were dried and quercetin-PVP K25 solids were obtained. The formation of quercetin-PVP K25 solid dispersion was evaluated by solubility studies, powder X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetry (TG), and antioxidant activity. It was observed that PVP K25 was able to provide quercetin clear aqueous solutions and that quercetin solubility was increased in a PVP K25 concentration dependent manner, improving solubility even 436-fold the pure quercetin. The results obtained with XRD, FT-IR, DSC, and TG demonstrated possible quercetin-PVP K25 solid dispersion formation. Besides, the antioxidant activity of the quercetin-PVP K25 solid dispersions dissolved in aqueous solution and pure quercetin dissolved in methanol showed IC₅₀ value of 0.61 ± 0.03 and 1.00 ± 0.02 μg/mL, respectively, demonstrating that the solid dispersions presented a significant increase in antioxidant activity (P < 0.05). Putting results together, it was possible to conclude there was the formation of quercetin-PVP K25 solid dispersion.     

Phenolic chemical composition of Petroselinum crispum extract and its effect on haemostasis

From the aqueous extract (Pc) of Petroselinum crispum (Mill) flat leaves specimens were isolated and identified the flavonoids apigenin (1), apigenin-7-O-glucoside or cosmosiin (2), apigenin-7-O-apiosyl-(1 --> 2)-O-glucoside or apiin (3) and the coumarin 2",3"-dihydroxyfuranocoumarin or oxypeucedanin hydrate (4). The inhibitory activity toward clotting formation and platelet aggregation was assessed for Pc flavonoids (1) and (2), and the coumarin (4). Pc showed no inhibition on clotting activity when compared with the control. On the other hand, a strong antiplatelet aggregation activity was observed for Pc (IC50 = 1.81 mg/mL), apigenin (IC50 = 0.036 mg/mL) and cosmosiin (IC50 = 0.18 mg/mL). In all cases ADP was used as inductor of platelet aggregation. Our results showed that Pc, apigenin and cosmosiin interfere on haemostasis inhibiting platelet aggregation. To the best of our knowledge this is the first report for the cosmosiin antiplatelet aggregation in vitro activity.     

Equilibrium programming using proximal-like algorithms

We compute constrained equilibria satisfying an optimality condition. Important examples include convex programming, saddle problems, noncooperative games, and variational inequalities. Under a monotonicity hypothesis we show that equilibrium solutions can be found via iterative convex minimization. In the main algorithm each stage of computation requires two proximal steps, possibly using Bregman functions. One step serves to predict the next point; the other helps to correct the new prediction. To enhance practical applicability we tolerate numerical errors. Research supported partly by the Norwegian Research Council, project: Quantec 111039/401.     

A Sol-Gel Synthesis for Thermally Stable Aniline/Silica Material

Aniline/silica sol-gel material was obtained. The aniline was immobilized on the silica surface using chloropropyltrimethoxysilane as bridge reagent. The base activator NaH was used to produce a fast SN₂ reaction between the base and the alkylorganosilane. The resulting modified silica was characterized by elemental analysis and infrared spectroscopy using an oven cell. The organic coverage on the surface was proportional to the organic precursor concentration. The aniline/silica materials are thermally stable up to 300°C, in high vacuum.     

A study of gluon scattering and gluon fragmentation in highp T interactions at the ISR

Gluon scattering processes are studied in hadronic highp _T events using data obtained with the Split Field Magnet detector (SFM) at the CERN ISR. The experimental set-up allowed the scanning of a wide range of parton energies and scattering angles. It is shown that for positive pions as trigger particles, the parton composition of the recoil jet is correlated with the polar angle and transverse momentum of the triggering pion. Over the kinematical region studied, the recoil jet originates predominantly from scatered gluons, with an increasing prevalence of the gluon component towards forward triggering angles. The variation of the momentum structure of the recoil jet with the trigger angle indicates that the fragmentation function of gluons is softer than that of quarks.     

Δπ decay of baryons in a flux-tube-breaking mechanism

Based on the flux-tube-breaking mechanism, we have previously studied the strong decay of nonstrange baryons into the elastic and several inelastic channels. Here, we extend these studies toΔ π decay. We compare our results with those of Koniuk and Isgur and with recently improved experimental data. We also present results of a new and improved calculation ofN π decay and discuss the problem of resonance identification.     

Beiträge zur Chemie der Pyrrolpigmente, 65. Mitt.

The title compound1 is found to be protonated corresponding topK _a 's of 2.5 and 0.5, thereby being two orders of magnitude less basic than bilatrienes-abc. Its deprotonation (pK _a =17.1) is found to be less easy than in case of the bilatrienes.1 is shown to exhibit a very pronounced reactivity for nucleophiles at the methine positions 10 and 15—a thiole adduct and the 10,15-dihydroderivative of1 are isolated and characterised. In contrast to the bilatrienes the adduct formation is irreversible. Accordingly, no diastereomers at exocyclic double bonds could be produced photochemically. Complexation of the lactam oxygens is achieved in case ofLewis acids (eg. AlCl₃), chelation after addition of a proton acceptor is observed in a few cases only (Zn⁺⁺, Hg⁺⁺, In⁺⁺⁺).

Herrn Prof. Dr.K. Kratzl zum 70. Geburtstag gewidmet.     

High-accuracy attitude control of satellites in elliptic orbits

A class of feedback attitude-control systems which efficiently result in high-accuracy (10^–4 radians), Earth-pointing motions of satellites of different configurations in elliptic orbits is developed. Gas jets provide the control torque. The state of the attitude motion is assumed to be completely known. Linear differential equations, which have time-varying coefficients and include terms for the gravity torque due to an oblate Earth and terms for the aerodynamic torque, are used to describe the attitude motion when the satellite is practically Earth-pointing. Pontryagin's maximum principle, the necessary conditions for exact solutions of optimal bounded-phase-coordinate problems, and guidelines obtained from the minimum-fuel attitude controls devised for single-axis systems are used in the development. The motions of somestable and someunstable satellites with the developed attitude-control systems are simulated on an analog computer. The overall control system, which is reliable as well as efficient, is simple to realize.This research was sponsored by the National Aeronautics and Space Administration under Grant No. G-133-61.     

Paths to constrained Nash equilibria

We propose and analyze a primal-dual, infinitesimal method for locating Nash equilibria of constrained, non-cooperative games. The main object is a family of nonstandard Lagrangian functions, one for each player. With respect to these functions the algorithm yields separately, in differential form, directions of steepest-descent in all decision variables and steepest-ascent in all multipliers. For convergence we need marginal costs to be monotone and constraints to be convex inequalities. The method is largely decomposed and amenable for parallel computing. Other noteworthy features are: non-smooth data can be accommodated; no projection or optimization is needed as subroutines; multipliers converge monotonically upward; and, finally, the implementation amounts, in essence, only to numerical integration.