Photocytotoxic activity of a nitrosyl phthalocyanine ruthenium complex - A system capable of producing nitric oxide and singlet oxygen

The synthesis, structural aspects, pharmacological assays, and in vitro photoinduced cytotoxic properties of [Ru(NO)(ONO)(pc)] (pc = phthalocyanine) are described. Its biological effect on the B16F10 cell line was studied in the presence and absence of visible light irradiation. At comparable irradiation levels, [Ru(NO) (ONO)(pc)] was more effective than [Ru(pc)] at inhibiting cell growth, suggesting that occurrence of nitric oxide release following singlet oxygen production upon light irradiation may be an important mechanism by which the nitrosyl ruthenium complex exhibits enhanced biological activity in cells. Following visible light activation, the [Ru(NO)(ONO)(pc)] complex displayed increased potency in B16F10 cells upon modifications to the photoinduced dose; indeed, enhanced potency was detected when the nitrosyl ruthenium complex was encapsulated in a drug delivery system. The liposome containing the [Ru(NO)(ONO)(pc)] complex was over 25% more active than the corresponding ruthenium complex in phosphate buffer solution. The activity of the complex was directly proportional to the ruthenium amount present inside the cell, as determined by inductively coupled plasma mass spectroscopy. Flow cytometry analysis revealed that the photocytotoxic activity was mainly due to apoptosis. Furthermore, the vasorelaxation induced by [Ru(NO)(ONO)(pc)], proposed as NO carrier, was studied in rat isolated aorta. The observed vasodilation was concentration-dependent. Taken together, the present findings demonstrate that the [Ru(NO)(ONO)(pc)] complex induces vascular relaxation and could be a potent anti-tumor agent. Nitric oxide release following singlet oxygen production upon visible light irradiation on a nitrosyl ruthenium complex produces two radicals and may elicit phototoxic responses that may find useful applications in photodynamic therapy. Crown Copyright (C) 2011 Published by Elsevier Inc. All rights reserved.

Precursor system of liquid crystalline phase containing propolis microparticles for the treatment of periodontal disease: Development and characterization

Precursor systems of liquid crystalline phase were prepared using the surfactant PPG-5-Ceteth-20, isopropyl myristate, and water; gelatin microparticles containing propolis were then added into these systems. Homogeneity of dispersion, the in-system microparticle morphology, and sedimentation behavior of each formulation were evaluated. The rheological and mechanical properties (hardness, compressibility, and adhesiveness), the work of syringing, and the propolis release profile were also evaluated. All the formulations exhibited pseudoplastic flow and thixotropy, and they displayed storage modulus, loss modulus, dynamic viscosity, and loss tangent that depended on temperature, frequency, and composition. Mechanical properties varied significantly among the formulations being affected by changes in the composition and temperature. Raising the concentration of surfactant and adding propolis microparticles significantly decreased the work of syringing. The drug release was non-Fickian (anomalous) and there was no significant difference between the tested systems in the times required for 10%, 30%, and 50% release of the initial drug loading.

Attainment of O/W emulsions containing liquid crystal from annatto oil (Bixa orellana), coffee oil, and tea tree oil (Melaleuca alternifolia) as oily phase using HLB system and ternary phase diagram

Emulsions containing liquid crystals present interesting properties and advantages such as the skin moisturize increase, active release modulation, and emulsion stabilization. In this work, emulsions containing annatto, coffee and tea tree oils, and nonionic surfactants were developed. The HLB method was used for selection of surfactants. The required HLB value was established (9.0). Liquid crystals were attained when used the surfactant mixture Ceteareth-5 and Steareth-2 and identified as lamellar. The emulsions showed pseudoplastic behavior and tixotropy. The ternary diagram was useful in the selection of the proportion of surfactant and oily phase considering skin compatibility and liquid crystal presence.

In vitro evaluation of the antioxidant activity of liposomal flavonols by the HRP--H(2)O(2)--luminol system

Considering that antioxidant flavonols have been reported to be beneficial to human health, but that their low water solubility and bioavailability limit their administration through systemic route, the development of suitable flavonol-carriers is of great importance for clinical therapeutics. The aim of this study was to prepare liposomes containing flavonols or not and evaluate their antioxidant activity. Vesicles were obtained by ethanol injection method and characterized in terms of entrapment efficiency, size and zeta potential. Inhibitory activity of liposomal flavonols on reactive oxygen species generation was assessed in vitro using luminol--H(2)O(2)--horseradish peroxidase technique. Antioxidant activity of liposomal flavonols is dependent on concentration and chemical structure of active compound. Quercetin and myricetin are the most active flavonols (IC(50) == 0.6--0.9 mu A mu mol/L), followed by kaempferol (IC(50) == 3.0--4.5 mu A mu mol/L) and galangin (IC(50) == 4.0--7.0 mu A mu mol/L). Our results suggest that antioxidant-loaded liposomes may be promising tools for therapy of diseases where oxidative stress is involved.

Rheological, mechanical and mucoadhesive properties of thermoresponsive, bioadhesive binary mixtures composed of poloxamer 407 and carbopol 974P designed as platforms for implantable drug delivery systems for use in the oral cavity

This study described the formulation and characterisation of the viscoelastic, mechanical and mucoadhesive properties of thermoresponsive, binary polymeric systems composed of poloxamer (P407) and poly(acrylic acid, C974P) that were designed for use as a drug delivery platform within the oral cavity. Monopolymeric and binary polymeric formulations were prepared containing 10, 15 and 20% (w/w) poloxamer (407) and 0.10-0.25% (w/w) poly(acrylic acid, 934P). The flow theological and viscoelastic properties of the formulations were determined using controlled stress and oscillatory rheometry, respectively, the latter as a function of temperature. The mechanical and mucoadhesive properties (namely the force required to break the bond between the formulation and a pre-hydrated mucin disc) were determined using compression and tensile analysis, respectively. Binary systems composed of 10% (w/w) P407 and C934P were elastoviscous, were easily deformed under stress and did not exhibit mucoadhesion. Formulations containing 15 or 20% (w/w) Pluronic P407 and C934P exhibited a sol-gel temperature T(sol/gel), were viscoelastic and offered high elasticity and resistance to deformation at 37 degrees C. Conversely these formulations were elastoviscous and easily deformed at temperatures below the sol-gel transition temperature. The sol-gel transition temperatures of systems containing 15% (w/w) P407 were unaffected by the presence of C934P; however, increasing the concentration of C934P decreased the T(sol/gel) in formulations containing 20%(w/w) P407. Rheological synergy between P407 and C934P at 37 degrees C was observed and was accredited to secondary interactions between these polymers, in addition to hydrophobic interactions between P407 micelles. Importantly, formulations composed of 20% (w/w) P407 and C934P exhibited pronounced mucoadhesive properties. The ease of administration (below the T(sol/gel)) in conjunction with the viscoelastic (notably high elasticity) and mucoadhesive properties (at body temperature) render the formulations composed of 20% (w/w) P407 and C934P as potentially useful platforms for mucoadhesive, controlled topical drug delivery within the oral cavity. (c) 2009 Published by Elsevier B.V.

Influence of Er:YAG Laser Frequency on Dentin Caries Removal Capacity

The purposes of this study were to evaluate in vitro the influence of different frequencies of Er:YAG laser on the human dentin caries removal capacity. Thirty fragments obtained from third molars were randomly assigned into three groups (n = 10) according to the laser frequency used: 4, 6, and 10 Hz. The caries lesion (+/-1 mm deep) was induced before the irradiation by S. mutans cultures for 6 weeks. The specimens of all groups were irradiated with 200 mJ of energy in noncontact and focused mode under constant refrigeration (water flow: 2.5 mL/min). Quantitative analysis of the caries removal was performed by DIAGNOdent (TM) and the Axion Vision (TM) software. Qualitative analysis was performed by Scanning electron microscope (SEM) and light microscope (LM). Data were analyzed by ANOVA and Fishers` tests. The DIAGNOdent (TM) revealed that the caries removal was similar with 4 and 6 Hz and was superior with 10 Hz (P < 0.05). The analysis with Axion Vision (TM) software revealed that the caries removal was similar with 6 and 10 Hz and the 4 Hz group promoted the lowest caries removal. Through SEM morphologic analysis, some specimens irradiated with 4 Hz presented, under the demineralized dentin, a disorganized collagenous matrix. The LM images revealed that all frequencies used promoted irregular caries removal, being observed over preparations with 6 and 10 Hz. It can be concluded that the increase of Er:YAG laser frequency provided a higher dentin caries removal without selectivity to the disorganized dentin. Microsc. Res. Tech. 74:281-286, 2011. (C) 2010 Wiley-Liss, Inc.

A synchronous multimedia annotation system for secure collaboratories

In this paper, we describe the Vannotea system - an application designed to enable collaborating groups to discuss and annotate collections of high quality images, video, audio or 3D objects. The system has been designed specifically to capture and share scholarly discourse and annotations about multimedia research data by teams of trusted colleagues within a research or academic environment. As such, it provides: authenticated access to a web browser search interface for discovering and retrieving media objects; a media replay window that can incorporate a variety of embedded plug-ins to render different scientific media formats; an annotation authoring, editing, searching and browsing tool; and session logging and replay capabilities. Annotations are personal remarks, interpretations, questions or references that can be attached to whole files, segments or regions. Vannotea enables annotations to be attached either synchronously (using jabber message passing and audio/video conferencing) or asynchronously and stand-alone. The annotations are stored on an Annotea server, extended for multimedia content. Their access, retrieval and re-use is controlled via Shibboleth identity management and XACML access policies.

Biomechanical consequences of impairment: A taxonomically valid basis for classification in a unified disability athletics system

Developing a unified classification system to replace four of the systems currently used in disability athletics (i.e., track and field) has been widely advocated. The diverse impairments to be included in a unified system require severed assessment methods, results of which cannot be meaningfully compared. Therefore, the taxonomic basis of current classification systems is invalid in a unified system. Biomechanical analysis establishes that force, a vector described in terms of magnitude and direction, is a key determinant of success in all athletic disciplines. It is posited that all impairments to be included in a unified system may be classified as either force magnitude impairments (FMI) or force control impairments (FCI). This framework would provide a valid taxonomic basis for a unified system, creating the opportunity to decrease the number of classes and enhance the viability of disability athletics.

Heat transfer and entropy generation optimization of forced convection in a porous-saturated duct of rectangular cross-section

We investigate analytically the first and the second law characteristics of fully developed forced convection inside a porous-saturated duct of rectangular cross-section. The Darcy-Brinkman flow model is employed. Three different types of thermal boundary conditions are examined. Expressions for the Nusselt number, the Bejan number, and the dimensionless entropy generation rate are presented in terms of the system parameters. The conclusions of this analytical study will make it possible to compare, evaluate, and optimize alternative rectangular duct design options in terms of heat transfer, pressure drop, and entropy generation. (c) 2006 Elsevier Ltd. All rights reserved.

DR-NEGOTIATE - A system for automated agent negotiation with defeasible logic-based strategies

This paper reports on a system for automated agent negotiation, based on a formal and executable approach to capture the behavior of parties involved in a negotiation. It uses the JADE agent framework, and its major distinctive feature is the use of declarative negotiation strategies. The negotiation strategies are expressed in a declarative rules language, defeasible logic, and are applied using the implemented system DR-DEVICE. The key ideas and the overall system architecture are described, and a particular negotiation case is presented in detail.

Two-wire waveguide and interferometer for cold atoms

A versatile miniature de Broglie waveguide is formed by two parallel current-carrying wires in the presence of a uniform bias field. We derive a variety of analytical expressions to describe the guide and present a quantum theory to show that it offers a remarkable range of possibilities for atom manipulation on the submicron scale. These include controlled and coherent splitting of the wave function as well as cooling, trapping, and guiding. In particular, we discuss a novel microscopic atom interferometer with the potential to be exceedingly sensitive.

Effect of multiple transverse modes in self-mixing sensors based on vertical-cavity surface-emitting lasers

We investigate the effect of coexisting transverse modes on the operation of self-mixing sensors based on vertical-cavity surface-emitting lasers (VCSELs). The effect of multiple transverse modes on the measurement of displacement and distance were examined by simulation and in laboratory experiment. The simulation model shows that the periodic change in the shape and magnitude of the self-mixing signal with modulation current can be properly explained by the different frequency-modulation coefficients of the respective transverse modes in VCSELs. The simulation results are in excellent agreement with measurements performed on single-mode and multimode VCSELs and on self-mixing sensors based on these VCSELs.

Probabilistic Action System Trace Semantics

Action systems are a construct for reasoning about concurrent, reactive systems, in which concurrent behaviour is described by interleaving atomic actions. Sere and Troubitsyna have proposed an extension to action systems in which actions may be expressed and composed using discrete probabilistic choice as well as demonic nondeterministic choice. In this paper we develop a trace-based semantics for probabilistic action systems. This semantics provides a simple theoretical base on which practical refinement rules for probabilistic action systems may be justified.

The emergence of the determiner system in Mauritian Creole: a syntax semantics mapping

This paper describes the emergence of new functional items in the Mauritian Creole noun phrase, following the collapse of the French determiner system when superstrate and substrate came into contact. The aim of the paper is to show how the new language strived to express the universal semantic contrasts of (in)definiteness and singular vs. plural. The process of grammaticalization of new functional items in the determiner system was accompanied by changes in the syntax from French to creole. An analysis within Chomsky’s Minimalist framework (1995, 2000, 2001) suggests that these changes were driven by the need to map semantic features onto the syntax.

Acquisition of the English article system in SLA and the Missing Surface Inflection Hypothesis

This paper examines the article system in interlanguage grammar focusing on Japanese learners of English, whose native language lacks articles. It will be demonstrated that for the acquisition of the English article system, count/mass distinctions and definiteness are the crucial factors. Although Japanese does not employ the article system to encode these aspects, it will be argued that they are nevertheless syntactically encoded through its classifier system. Hence, the problem for these learners must be to map these features onto the appropriate surface forms as the Missing Surface Inflection Hypothesis predicts (Prévost & White 2000). This suggestion will further be supported empirically by a fill-in-the article task. It will be concluded that these Japanese learners understand the English article system fairly well, possibly due to their native language, yet have problems with realizing the relevant features (i.e. count/mass distinctions and definiteness) in the target language.