Search results for "PAM"
showing 10 items of 1768 documents
O Antropoceno: Entre o risco e a oportunidad6
2008
Neste artigo analisam-se as razões que têm levado a falar do Antropoceno como uma nova era geológica, marcada pelo facto de as grandes mudanças no planeta - e, mais concretamente, na biosfera - serem devidas à acção humana. Por outro lado, tenta-se mostrar que esta nova era não pode ser olhada unicamente como uma situação de risco, mas antes como uma oportunidade para romper com comportamentos humanos que têm conduzido a uma situação de emergência planetária e comprometermo-nos decididamente na construção de um futuro sustentável. Summary We analyze in this paper the reasons why has been introduced the concept of Antropoceno as a new geological era in which the great changes suffered by the…
Ciencia de la Sostenibilidad. Una revolución científica a la que Educación Química quiere contribuir
2014
La Ciencia de la Sostenibilidad tiene como objetivo integrar el estudio del desarrollo social y los procesos naturales para favorecer a ambos y posibilitar la transición hacia la sostenibilidad. Esta profunda revolución científica no puede ser el resultado de solo una nueva disciplina del conocimiento: debe convertirse en un nuevo paradigma que impregne el conjunto de las disciplinas científicas y las actividades sociales.
Química i Sostenibilitat
2014
Quan es va decidir proclamar 2011 com l'Any Internacional de la Química, el aleshores Director General d'UNESCO va assenyalar que "Sensibilitzar al públic de la importància de les ciències químiques és una tasca de gran rellevància, pels reptes que ha d'afrontar el desenvolupament sostenible. És indubtable que la Química jugarà un paper molt important en el desenvolupament de fonts alternatives d'energia i l'alimentació de la creixent població mundial". Segons el president en aquests moments de l'IUPAC, amb aquesta celebració esperaven augmentar l'apreciació pública i la comprensió de la Química, augmentar l' interès dels joves per la ciència i generar entusiasme per un futur de creativitat…
Educació química i sostenibilitat
2008
Aquest treball vol ser una contribució a la crida de les Nacions Unides als educadors de totes les àrees i de tots els nivells perquè contribuïm a formar una ciutadania conscient dels problemes als quals ha de fer front avui la humanitat i preparada per participar en la presa de decisions fonamentades. Una tasca que resulta particularment funcional des de l'educació química i que pot ajudar a desfer prejudicis envers la tasca realitzada pels químics.
Measuring progress from 1990 to 2017 and projecting attainment to 2030 of the health-related Sustainable Development Goals for 195 countries and terr…
2018
BACKGROUND: Efforts to establish the 2015 baseline and monitor early implementation of the UN Sustainable Development Goals (SDGs) highlight both great potential for and threats to improving health by 2030. To fully deliver on the SDG aim of 'leaving no one behind', it is increasingly important to examine the health-related SDGs beyond national-level estimates. As part of the Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017), we measured progress on 41 of 52 health-related SDG indicators and estimated the health-related SDG index for 195 countries and territories for the period 1990-2017, projected indicators to 2030, and analysed global attainment. METHODS: We mea…
2,4,6-Triphenylpyrylium Ion Encapsulated into Zeolite Y as a Selective Electrode for the Electrochemical Determination of Dopamine in the Presence of…
2002
2,4,6-Triphenylpyrylium ion immobilized inside the supercages of zeolite Y enhances by 1-2 orders of magnitude the response of electrochemical oxidation of dopamine in neutral aqueous media accompanied by a remarkable inhibition of post-electron-transfer reactions. The negative charge of the zeolite framework in which the 2,4,6-triphenylpyrylium ion is incorporated blocks the electrochemical oxidation of the negative ascorbate ion, enabling the determination of micromolar concentrations of dopamine in the presence of a large excess (10(3)-10(4) times) of ascorbate in phosphate buffer (pH 7.4). Under optimized conditions, linear calibration plots were obtained for a differential pulse detect…
Low-temperature phosphorescence of 1,4-benzodiazepines
1991
Abstract A highly sensitive method for the low-temperature phosphorescence determination of a series of 1,4-benzodiazepines has been developed. Oxazepam has been used as a test molecule to study the effects of instrumental parameters, such as time decay, gate time, excitation and emission slits, and ordinate, on the phosphorescence spectra. The corresponding analytical parameters have been established for different concentration levels. Under the best sensitivity conditions a limit of detection of 16 parts per trillion (ppt) for oxazepam, 3.8 ppt for medazepam, 2 ppt for prazepam, 5 × 10 −3 ppt for diazepam, and 0.09 ppt for lorazepam could be obtained. The proposed method is thus the most …
Interaction of diazepam with surfactants. Spectrophotometric and spectrofluorometric study
1986
Abstract The interaction of diazepam with non-ionic, anionic and cationic surfactants has been studied spectrophotometrically and fluorometrically. It has been verified that the absorption spectrum of diazepam is not modified in micellar medium. However, a dramatic five-fold increase in fluorescence sensitivity is observed in the presence of sodium lauryl sulphate (SDS). The experimental conditions, temperature, pH and surfactant concentration have been optimized to improve the fluorometric determination of diazepam and a detection limit of 0,04 ppmhas been obtained.
Use of micellar mobile phases for the chromatographic determination of clorazepate, diazepam, and diltiazem in pharmaceuticals
2001
An ODS-2 column, a micellar mobile phase of high elution strength containing 0.1M sodium dodecyl sulfate and 3% (v/v) butanol, and ultraviolet detection at 230 nm are used for the determination of either of two benzodiazepines (clorazepate and diazepam) and a benzothiazepine (diltiazem) in pharmaceuticals. The procedure is shown to be competitive against conventional chromatography with methanol-water mobile phases, especially for diltiazem. The composition of the micellar mobile phase is selected using a predictive strategy based on an accurate retention model and assisted by computer simulation. Calibration graphs are linear at least in the 2.5 to 20 microg/mL, 4 to 20 microg/mL, and 5 to…
MICELLAR LIQUID CHROMATOGRAPHIC DETERMINATION OF ANTI-CONVULSANT DRUGS IN PILLS AND CAPSULES
2000
A simple chromatographic procedure is reported for the determination of several anti-convulsant drugs in pharmaceuticals: carbamazepine, and the benzodiazepines bentazepam, halazepam, oxazepam, pinazepam, and tetrazepam. The procedure utilizes a C18 column, a hybrid micellar mobile phase of 0.1 M SDS-3% butanol-0.1% triethylamine-0.01 M phosphate buffer (pH 3), and UV detection (230 nm). The drugs eluted in less than 13 min, in accordance to their relative polarities, as indicated by their octanol-water partition coefficients. The limits of detection (μg/mL), and intra and inter-day repeatabilities (%), for 4 μg/mL were: carbamazepine (0.03, 1.0, 4.1), bentazepam (0.05, 1.3, 1.6), halazepam…