1,720,974 research outputs found
Contemporary administration of pilocarpine and timolol increases the aqueous humor pilocarpine levels in the rabbit
No full textPerformance evaluation of an efficient fixed microwave communication system to be added to an operating UMTS network
No full textThis paper deals with the proposal and performance evaluation of a fixed microwave communication (FMC) system that shares the same bandwidth as that of an existing UMTS network. The main application of the FMC system is for wireless connections between remote base stations and a core network access point for an UMTS network implementation in a dense urban environment, where a wired connection could be very expensive for service providers. Besides, sharing of the same frequency band could be attractive for the actual cost and lack of frequency spectrum. The mutual interference effects between the FMC and the existing UMTS systems are investigated by focusing on typical application scenarios. The performance for the two systems under consideration has been evaluated in terms of bit error rate by means of computer simulations for proposed receiving scheme where mutual interference are, firstly, detected and then canceled from the other system. The obtained results between the proposed FMC system and an existing UMTS network and the improvement of performance in terms of bit error rate with proposed receiving system
Preparazione e valutazione "in vitro" di un complesso mucoadesivo econazolo-polycarbophil
No full textCharacterization and in vitro evaluation of an (ipn)-hydrogel for transdermal delivery of diltiazem.
No full textAim
The aim of this work was the preparation and the evaluation of an interpenetrating polymer network (IPN)-hydrogel composed of a polyvinyl alcohol (PVA)/chitosan (CS) mixture for transdermal drug delivery.
Materials and Methods
The IPN-hydrogel was prepared by dissolving the CS in 10% (w/w) solution of PVA acidified with lactic acid, and adding Glyoxal at 50°C as crosslinking agent and was characterized by Fourier-transform infrared spectroscopy (FTIR) and by Differential Scanning Calorimetry (DSC). The dynamic swelling behavior of the PVA/chitosan IPN-hydrogel was studied at 32°C by immersion of the hydrogel both in pH 5.2 phosphate buffer solution (PBS) and in deionised water. It was used to prepare matrices containing diltiazem hydrochloride as a model drug, alone (M1) or added of penetration enhancers: PEG-8 caprylic/capric glycerides (Labrasol®, M2) and C1-C9-Br-morpholinium (a room temperature ionic liquid, M3). Each matrix was submitted to in vitro release test using the paddle-over-disk method (Apparatus 5, USP 29) and 500 ml of PBS pH 5.2 as dissolution medium; the drug concentration in dissolution medium, withdrawn at predetermined time intervals, was quantified by HPLC method. Moreover, in vitro permeation through hairless rat skin of drug from the formulations was determined using Gummer-type vertical cells.
Results and Discussion
The FTIR spectra of crosslinked IPN-hydrogel showed a reduction of the peak intensity at 1580 cm-1 with respect to uncrosslinked hydrogel, probably due to the reduction of free-NH2 groups of chitosan. DCS analysis highlighted an increase of tg value when compared to uncrosslinked matrix. The formation of a crosslinked polymeric structure leads to a considerable reduction in mobility and to an increase rigidity of the polymer. The swelling index (SI) of the IPN-hydrogel was higher in deionised water, arising up to 1400 % of the initial weight, while the SI was 30 % in PBS solution. The drug release from M1, M2 and M3 formulations was characterized by a diffusive mechanisms and the amount of drug permeated through the skin was related to the physico – chemical characteristics of the matrices.
The preliminary results confirm that INP-hydrogel could be useful to diffusion-controlled system for hydrophilic drug solubilised in the matrix
Aqueous ophthalmic formulations containing formocortal solubilised by surfactants or complexing agents
No full textPharmacokinetics and anti-inflammatory activity in rabbits of a novel indomethacin ophthalmic solution
No full textThe formulation of aqueous ophthalmic solutions containing indomethacin (IND) presents serious problems due to poor solubility and stability of the drug. The purpose of this study was to evaluate a novel 0.1% IND formulation containing a poly(oxyethylene)poly(oxypropylene) block copolymer (poloxamer 407) as solubilizer. This formulation was evaluated for stability, bioavailability and anti-inflammatory activity in comparison with an ophthalmic IND solution currently on the market. The experimental solution, tested for IND stability at different temperatures, compared favorably with the commercial solution. In rabbits, it produced significantly higher IND levels in the aqueous humor and, in an immunogenic uveitis model, it induced a comparatively faster resolution of the symptoms, as determined by inflammation scores and by IOP measurements. The data indicate poloxamer 407 as a potentially valuable nonirritating, solubilizing and stabilizing agent for indomethacin
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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