Search results for "screening"
showing 10 items of 1150 documents
Determination of water-soluble UV-filters in sunscreen sprays by liquid chromatography.
2002
Abstract Liquid chromatography was used for the determination of the three most used water-soluble UV filters, benzophenone-4 (BZ4), terephthalylidene dicamphor sulfonic acid (TDS), and phenylbenzimidazole sulphonic acid (PBS), in aqueous sunscreen sprays. A C 18 stationary phase and an isocratic mobile phase of EtOH–20 m M sodium acetate buffer of pH 4.6 (30:70, v/v) were used at a flow-rate of 0.5 ml min −1 . Mobile phase was also used as solvent for samples and standards. UV detection was at 313 nm. The analytical run took 5.5 min. The limits of detection were 0.5, 0.9 and 2 μg ml −1 for BZ4, TDS and PBS, respectively. The proposed method does not involve highly toxic solvents.
A solid-phase extraction and size-exclusion liquid chromatographic method for polyethylene glycol 25 p-aminobenzoic acid determination in urine: Vali…
2007
No previous publications about percutaneous absorption of polyethylene glycol 25 p-aminobenzoic acid (PEG-25 PABA) have been found in the literature and the expected levels to be found in human urine after sunscreens use are unknown. The method proposed here is suitable to determine PEG-25 PABA in the urine of sunscreens users in order to carry out studies on body accumulation/excretion. It is based on solid-phase extraction (SPE) with size-exclusion liquid chromatography determination. Solid-phase extraction allows the analyte to be retained and subsequently eluted for a clean-up, using a silica-based cartridge. The size-exclusion liquid chromatography of the eluted allows the rest of matr…
Determination of UV-filters in sunscreens by HPLC.
2001
Simultaneous determination of six internationally authorised organic UV-filters in sunscreen formulations was performed by HPLC with UV spectrophotometric detection. The filters determined were: sulisobenzone, oxybenzone, octyl dimethyl PABA, octyl methoxycinnamate, octyl salicylate and homosalate. A C18 stationary phase and a mobile phase of ethanol water acetic acid (70 : 29.5 : 0.5) were used with a flow rate of 0.5 mL/min. UV measurements were carried out at 313 nm. The time required for the analysis was 25 min and the limits of detection were between 0.2 and 2 mg/L, except for sulisobenzone, which gave a limit of detection of 20 mg/L. The procedure proposed provides an accurate, fast a…
Photo-induced chemiluminescence determination of the pesticide Buminafos by a Multicommutation flow-analysis assembly
2008
Abstract The preliminary experiments in this paper deal with the photo-induced chemiluminescent behaviour of Buminafos family, after the experimental screening tests and several of them resulted positive, the herbicide Buminafos was selected to develop a new analytical method. The determination of Buminafos was performed with the aid of a Multicommutation (a solenoid valve set) assembly. The method involves the on-line photo-degradation of the analyte (stopped flow, 5 s) with the selected suitable medium (0.05% hydrogen peroxide) and its subsequent chemiluminescent oxidation by the potassium permanganate. Sample solution alternated segments with the photo-degradation medium; and, after the …
Spin Hyperpolarization in Modern Magnetic Resonance.
2023
Magnetic resonance techniques are successfully utilized in a broad range of scientific disciplines and in a number of practical applications, with medical MRI being the most widely-known example. Currently, both fundamental and applied magnetic resonance are enjoying a major boost owing to the dramatic signal enhancement provided by the rapidly-developing field of spin hyperpolarization. Such techniques are able to enhance signal intensities in magnetic resonance by several orders of magnitude, and thus to largely overcome its major disadvantage of relatively low sensitivity compared to other analytical techniques. This provides new impetus for existing applications, and, even more importan…
Digital holographic microscopy for diabetes screening
2016
A digital holographic microscope operating in telecentric mode could be used to diagnose diabetes and evaluate long-term glycemic control in patients with diabetes.
Atom- and Bond-Based 2D TOMOCOMD-CARDD Approach and Ligand-Based Virtual Screening for the Drug Discovery of New Tyrosinase Inhibitors
2008
Two-dimensional atom- and bond-based TOMOCOMD-CARDD descriptors and linear discriminant analysis (LDA) are used in this report to perform a quantitative structure-activity relationship (QSAR) study of tyrosinase-inhibitory activity. A database of inhibitors of the enzyme is collected for this study, within 246 highly dissimilar molecules presenting antityrosinase activity. In total, 7 discriminant functions are obtained by using the whole set of atom- and bond-based 2D indices. All the LDA-based QSAR models show accuracies above 90% in the training set and values of the Matthews correlation coefficient (C) varying from 0.85 to 0.90. The external validation set shows globally good classifica…
Dottore, mio figlio non impara a leggere”. I Disturbi Specifici dell’Apprendimento (DSA) e il pediatra di famiglia
2015
Si parla di Disturbo Specifico di Apprendimento (DSA) quando sono presenti delle difficoltà isolate e circoscritte nella lettura (Dislessia) e/o nella scrittura (Disortografia) e/o nel calcolo (Discalculia) nonostante la presenza di adeguate capacità cognitive e opportunità scolastiche. Tali difficoltà hanno carattere evolutivo e persistente, presentandosi con diversa espressività clinica nelle varie fasi dello sviluppo. La prevalenza mondiale del disturbo si attesta tra il 5 e il 15% (DSM 5, 2013). L’incidenza è maggiore nei maschi, con un rapporto M/F stimato intorno a 2:1, 3:1 (DSM 5, 2013). In Italia la stima di prevalenza dei DSA fra i bambini in età scolare oscilla fra il 3 e il 5% (C…
Synthesis of N-acyl Derivatives of Aminocombretastatin A-4 and Study of their Interaction with Tubulin and Downregulation of c-Myc.
2021
11 p.-9 fig.-4 tab.