Iulian Stoleriu

Coarsening in an integro-differential model of phase transitions

Coarsening of solutions of the integro-differential equationformula herewhere Ω ⊂ ℝn, J(·) [ges ] 0, e > 0 and f(u) = u3 − u (or similar bistable nonlinear term), is examined, and compared with results for the Allen–Cahn partial differential equation. Both equations are used as models of solid phase transitions. In particular, it is shown that when e is small enough, solutions of this integro-differential equation do not coarsen, in contrast to those of the Allen–Cahn equation. The special case J(·) ≡ 1 is explored in detail, giving insight into the behaviour in the more general case J(·) [ges ] 0. Also, a numerical approximation method is outlined and used on tests in both one- and two-space dimensions to verify and illustrate the main result.

Alendronate-Loaded Modified Drug Delivery Lipid Particles Intended for Improved Oral and Topical Administration

The present paper focuses on solid lipid particles (SLPs), described in the literature as the most effective lipid drug delivery systems that have been introduced in the last decades, as they actually combine the advantages of polymeric particles, hydrophilic/lipophilic emulsions and liposomes. In the current study, we present our most recent advances in the preparation of alendronate (AL)-loaded SLPs prepared by hot homogenization and ultrasonication using various ratios of a self-emulsifying lipidic mixture of Compritol 888, Gelucire 44/14, and Cremophor A 25. The prepared AL-loaded SLPs were investigated for their physicochemical, morphological and structural characteristics by dynamic light scattering, differential scanning calorimetry, thermogravimetric and powder X-ray diffraction analysis, infrared spectroscopy, optical and scanning electron microscopy. Entrapment efficacy and actual drug content were assessed by a validated HPLC method. In vitro dissolution tests performed in simulated gastro-intestinal fluids and phosphate buffer solution pH 7.4 revealed a prolonged release of AL of 70 h. Additionally, release kinetics analysis showed that both in simulated gastrointestinal fluids and in phosphate buffer solution, AL is released from SLPs based on equal ratios of lipid excipients following zero-order kinetics, which characterizes prolonged-release drug systems.

Synergic Effects of Pregabalin-Acetaminophen Combination in Somatic and Visceral Nociceptive Reactivity

Background/Aims: The present study investigates the effects of pregabalin (PGB), acetaminophen (ACET) and tenoxicam (TNX) administration in somatic and visceral nociception, using the tail flick test and the writhing test in mice. Methods: In the tail flick test, the substances were administered orally and the latency time response was recorded 15, 30, 60, 90 and 120 min after administration. In the writhing test, pain responses were scored every 5 min during a 30-min period after intraperitoneal injection of diluted acetic acid. Results: Our study demonstrated that oral administration of the combination PGB-ACET resulted in a stronger increase of latency reaction - statistically significant after 15 min compared to TNX and after 30 min compared to PGB in tail flick test. In the writhing test, the combination PGB-ACET, but also PGB-TNX, resulted in a stronger decrease of writhe numbers - statistically significant compared to the effects of the separate administration of each substance. This decrease was more intense in animals treated with the combination PGB-ACET than with PGB-TNX. Conclusion: These results suggest an antinociceptive activity which may be a consequence of the synergic action of the substances.

Inhibition of bcl-2 and cox-2 Protein Expression after Local Application of a New Carmustine-Loaded Clinoptilolite-Based Delivery System in a Chemically Induced Skin Cancer Model in Mice

Our research has focused on in vitro and in vivo evaluations of a new Carmustine (BCNU)-loaded clinoptilolite-based delivery system. Two clinoptilolite ionic forms—hydrogen form (HCLI) and sodium form (NaCLI)—were prepared, allowing a loading degree of about 5–6 mg BCNU/g of zeolite matrix due to the dual porous feature of clinoptilolite. Clinoptilolite-based delivery systems released 35.23% of the load in 12 h for the BCNU@HCLI system and only 10.82% for the BCNU@NaCLI system. The BCNU@HCLI system was chosen to develop gel and cream semisolid dosage forms. The cream (C_BCNU@HCLI) released 29.6% of the loaded BCNU after 12 h in the Nylon synthetic membrane test and 31.6% in the collagen membrane test, higher by comparison to the gel. The new cream was evaluated in vivo in a chemically induced model of skin cancer in mice. Quantitative immunohistochemistry analysis showed stronger inhibition of B-cell lymphoma-2 (bcl-2) and cyclooxygenase 2 (cox-2) protein expression, known markers for cancer survival and aggressiveness, after the treatment with C_BCNU@HCLI by comparison to all the control treatment types, including an off-label magistral formula commercially available Carmustine cream as reference, bringing evidence that a clinoptilolite-based delivery systems could be used as a cancer drug carriers and controlled release systems (skin-targeted topical delivery systems).

NONHOLONOMIC DYNAMICS OF SECOND ORDER AND THE HEISENBERG SPINNING PARTICLE

The equations of motion for the associated constrained Lagrangian to a nonholonomic Lagrangian of second order are computed. The spinning particle subject to the Heisenberg constraint is treated as example and its dynamics is completely described.

Non-Coarsening for Solutions to a Class of Evolution Equations

Non-Coarsening for Solutions to a Class of Evolution Equations We deal with some qualitative properties of solutions to an evolution equation that depends on a positive parameter. The main result of the paper is the fact that the solutions starting from two-phase initial data cannot converge to a one-phase state, if the parameter is small enough. This can be particularly important if one employs equations of this type to model phase transitions in solids. The main tool in proving this result is the comparison principle that solutions to this equation obey. By considering particular cases, we rediscover two results that have been already proved in the literature.

A fuzzy approach regarding the analysis of wine production depending on different environmental parameters based on statistical signal processing

A very important issue for the producers of wine and related vineyard products is the high level of instability for different environmental parameters. Because of that, the quantity of the final products have dramatically declined in some areas and for some producers. Although many chemical methods have been introduced in the last years, which were meant to limit the production decline, such measures are not wanted because of their harmful effects on humans health. The aim of this paper is to analyze the factors that are responsible for the decline in the production using an intelligent method and, together with the experts in this field, to find solutions to stop this decline without using chemical methods. The development in optimal conditions of some vineyard crops is close related to the final products being offered to customers, therefore it is important for these products to have the best quality the money can buy.