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1.
Front Public Health ; 4: 44, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27047912

RESUMO

INTRODUCTION: The objectives of this study were to identify and assess the impact of capacity-building biosafety initiatives and programs that have taken place in the broader Middle East and North Africa (BMENA) region between 2001 and 2013, to highlight gaps that require further development, and to suggest sustainable ways to build cooperative regional biosafety opportunities. METHODS: A cross-sectional study was conducted with two aspects (1) thorough desktop review of literature for all biosafety/biosecurity-related activities in the study countries, such as seminars, conferences, workshops, policy documents, technology transfer, sustained scientific endeavors between countries, etc. and (2) an online survey of scientists in countries in the region to get first-hand information about biosafety and biosecurity initiatives and gaps in their country. RESULTS: A total of 1832 initiatives of biosafety/biosecurity were recorded from 97 web links; 70.68% (n = 1295) initiatives were focused on raising general awareness among the scientific community about biosafety/biosecurity/biocontainment. The most frequent areas of interest were biorisk management in biomedical and biotechnology laboratories 13% (n = 239), followed by living modified organisms (LMOs) 9.17% (n = 168). Hands-on training accounted for 2.67% (n = 49) of initiatives. Online survey results confirmed desktop review findings; however, the response rate was 11%.

3.
Talanta ; 78(2): 370-6, 2009 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-19203597

RESUMO

In this work, a new alternative for the electrochemical determination of catecholamines based on beta-cyclodextrin-Sonogel-Carbon electrodes is reported. The incorporation of beta-CD and graphite in the preparation of the Sonogel-Carbon material leads to a modification of the electrode surface properties which causes a significant increase in the oxidation peak current of biomolecules such as dopamine, L-epinephrine, D,L-norepinephrine and catechol. This phenomenon might be attributed to the formation of an inclusion complex between beta-CD and the catecholamines. The amount of beta-CD necessary to form the Sonogel electrode was studied and optimization of electrochemical parameters, perm selectivity and mechanical stability of the sensor are discussed. Scanning electron microscopy and electrochemical impedance spectroscopy measurements were employed to characterize the electrical parameters and the structural properties of the new electrode surface, respectively. Cyclic voltammetry (CV) and Adsorptive differential pulse voltammetry (AdDPV) measurements were also used to explore the electrochemical behaviour of the electrode versus the quoted catecholamines. The beta-CD-Sonogel-Carbon electrode offers fast and linear responses towards dopamine, norepinephrine, epinephrine and catechol, with good and low detection limits: 0.164, 0.294, 0.699 and 0.059 micromol L(-1), respectively.


Assuntos
Catecolaminas/análise , Eletroquímica/métodos , Eletrodos , Carbono , Catecóis/análise , Dopamina/análise , Eletroquímica/instrumentação , Epinefrina/análise , Norepinefrina/análise , Oxirredução , beta-Ciclodextrinas
4.
Biosens Bioelectron ; 20(11): 2228-35, 2005 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-15797320

RESUMO

Gamma-cyclodextrin is an eight glucose unit conical structure, which possesses a hydrophobic internal cavity exhibiting supramolecular complexing properties and a hydrophilic exterior due to the presence of hydroxyl groups. In this work, we have synthesized for the first time a functionalized stable film of poly-3-methylthiophene combined with gamma-cyclodextrin (P3MT/gamma-CD) in tetrabutylammonium hexafluorophosphate/acetonitrile solution. A potentiostatic mode was employed for the film growth. Cyclic voltammetry and electrochemical impedance spectroscopy were used for the characterization of the new film. The resulting conducting polymer sensor offers interesting analytical performances such as: (a) fast and linear responses towards the neurotransmitters dopamine and l-dopa towards the neuroleptic chlorpromazine with low detection limits of 2 x 10(-7), 10(-6), and 10(-7)M, respectively, and (b) simultaneous detection and well-resolved signals between the compounds of interest and ascorbic acid. To the best of our knowledge, these LOD are among the lowest found in the literature. Optimization of parameters such as interference effect, perm-selectivity, and mechanical stability of the sensor are discussed.


Assuntos
Clorpromazina/análise , Materiais Revestidos Biocompatíveis/química , Eletroquímica/instrumentação , Eletrodos , Neurotransmissores/análise , Polímeros/química , Tiofenos/química , Transdutores , gama-Ciclodextrinas/química , Eletroquímica/métodos , Desenho de Equipamento , Análise de Falha de Equipamento , Teste de Materiais , Membranas Artificiais
5.
Talanta ; 66(1): 111-7, 2005 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-18969969

RESUMO

The supramolecular complexing properties of cyclodextrins (CDs) have been investigated inside a conducting polymer environment. In this work, we report the synthesis and characterization of a polypyrrole/beta-cyclodextrin (Ppy/beta-CD) film at a glassy carbon (GC) electrode surface. The polypyrrole/beta-cyclodextrin (Ppy/beta-CD) film was prepared by a simple electropolymerization of a 20:1 mixture of the CD and the pyrrole monomer LiClO(4) supporting electrolyte. The resulting functionalized polymer film features interesting electrochemical properties such as selective, simultaneous and quantitative detection of some organic compounds of interest such as polyhydroxyphenyls and neurotransmitters derived from pyrogallol and catechol. The fabricated electrochemical sensor exhibits a fast and reversible linear response toward catechol within the concentration range of 1.5x10(-7) to 8x10(-6)M and towards pyrogallol within the concentration range of 1x10(-6) to 1x10(-5)M. The detection limit was 4x10(-7) and 1.8x10(-6)M for catechol and pyrogallol, respectively. Studies of neurotransmitters such as epinephrine, metanephrine and l-dopa (l-3,4-dihydroxyphenylalanine), showed better response toward epinephrine and l-dopa than for metanephrine. Calibration curves for these two neurotransmitters were linear over the concentration range of 1x10(-6) to 1x10(-5)M. The detection limit was 4x10(-6) and 1x10(-6), respectively. The complexation capability of the Ppy/beta-CD system is addressed here in terms of structure-electrochemical activity relationship. The mechanical stability of the film is also discussed. Measurements were performed using cyclic voltammetry (CV), scanning electron microscopy (SEM) coupled to energy dispersive analysis of X-ray (EDAX) and electrochemical impedance spectroscopy (EIS).

6.
Talanta ; 68(1): 79-85, 2005 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-18970288

RESUMO

The sonogel-carbon electrode is a new class of sol-gel electrode that exhibit favourable mechanics and electrics properties to be used as electrochemical sensor. In this paper, a modified sonogel-carbon electrode is proposed to determine mercury at trace levels. The modified electrode is obtained by electropolymerization of 3-methylthiophene on the surface of a bare sonogel-carbon electrode. This electrode shows high selectivity and sensitivity and linear response towards Hg(II), with a detection limit of 1.4x10(-3)mgl(-1). The electrode is reusable by a simple chemical cleaning procedure. No deterioration was observed in the electrode response during at least 1 week of successive measurements.

7.
Talanta ; 58(4): 739-45, 2002 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-18968803

RESUMO

Exploitation of the physical, chemical and electrically conductive properties of poly(3-dodecylthiophene) (P3DDT) for the preconcentration and release in solid phase microextraction (SPME) of organometallic arsenobetaine (AsB) from aqueous media was investigated. Hydrophobic interactions between this neutral arsenic species and an undoped polythiophene (no applied potential) with n-substituted alkyl groups (n=12) in the three position were used for the diffusion-controlled preconcentration. After absorption into the polymer matrix, the chemical properties of this conductive polymer were changed by applying an external potential. This potential provides a sufficient driving force for desorption of the analyte from the extraction phase into an aqueous solution for subsequent analysis. The applied positive potential oxidizes the polymer to its charged hydrophilic state, which releases the neutral analyte. The concentration and speciation of the analyte from the sample matrix was analyzed by HPLC coupled to an ICP-MS. The diffusion-controlled uptake was fast (equilibrium attained within minutes) and did not require pretreatment of the analyte. The electrochemically-controlled release of the analyte is also very rapid (within minutes). This conducting polymer film system, therefore, can offer analytical applications for the convenient preconcentration and subsequent analysis of neutral environmental species.

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