1,720,981 research outputs found
Acquisizione in pista delle sollecitazioni su ramponi di battipista per la previsione di vita a fatica
Full text linkAim of the work was the design of instrumented trackbars to be mounted on rotating tracks of modern groomers for strain data acquisition in normal snow field operations: the knowledge of field load spectra and material fatigue properties allows for lightweight trackbars development.
A rugged and compact acquisition system was adopted and applied to the trackbars in a protective case. Two trackbars were strain gauged with ten strain channels each, applied at two significant structural sections in correspondence of the support wheel and of the traction wheel, in order to measure the bending actions in two planes.
Load acquisitions were performed to record the strain spectra for significant severe events and for typical use and compared with fatigue test data from a fatigue test bench developed at the company
Objective diagnosi of hronic alcohol abuse - determination of Carbohydrate Deficient Transferrin 8CDT with capillary electrophoresis
No full textNutritional supplementation with copper in the rat. I Effects on adjuvant arthritis development and some in vivo- and ex vivo- markers of blood neutrophils
No full textOBJECTIVE AND DESIGN: The aims of the work were: 1) to confirm the preliminarily observed anti-arthritic potential of a 200 ppm copper-supplemented diet in the rat: 2) to study the impact of the nutritional treatment and of the experimental pathology on neutrophil activity. ANIMALS AND CELLS: Two hundred female Sprague-Dawley rats were used. Polymorphonuclear leukocytes were isolated from these animals for the ex vivo studies. TREATMENT: Control-rats were maintained on a standard diet containing 5 ppm of copper. Supplemented-rats were kept on a diet containing 200 ppm of the metal. METHODS: Mycobacterium butyricum-induced arthritis was studied. Flame atomic absorption spectroscopy was used to assess copper and zinc levels. The "microplate-assay" technique was used to determine serum lysozyme concentration (lysis of Micrococcus lysodeikticus cell walls), as well as neutrophil O2- generation (superoxide dismutase-inhibitable reduction of ferricytochrome-c), and adhesion (activity of the membrane enzyme acid phosphatase). The results were statistically evaluated by the Student's t test. RESULTS: The nutritional copper-supplementation: 1) significantly inhibited the adjuvant-arthritis development (33% +/- 5, P<0.01); 2) did not modify lysozyme secretion or superoxide production; 3) significantly decreased the percentage of cell adhesion by an average of 41% +/- 19 (P<0.01). CONCLUSIONS: The copper-supplemented diet has an anti-arthritic effect which may be also primed by the effect of copper on the expression of the neutrophil cell-adhesion molecules
A simplified approach to capillary electrophoretic separation of polymerase chain reaction fragments of forensic interest
No full textHair analysis for abused drugs by capillary zone electrophoresis with field-amplified sample stacking.
No full textThe present paper describes the methodological optimisation and validation of a capillary zone electrophoresis method for the determination of morphine, cocaine and 3,4-methylenedioxymethamphetamine (MDMA) in hair, with injection based on field-amplified sample stacking. Diode array UV absorption detection was used to improve analytical selectivity and identification power. Analytical conditions: running buffer 100 mM potassium phosphate adjusted to pH 2.5 with phosphoric acid, applied potential 10 kV, temperature 20degreeC, injection by electromigration at 10 kV for 10 s, detection by UV absorption at the fixed wavelength of 200 nm or by recording the full spectrum between 190 and 400 nm. Injection conditions: the dried hair extracts were reconstituted with a low-conductivity solvent (0.1 mM formic acid), the injection end of the capillary was dipped in water for 5 s without applying pressure (external rinse step), then a plug of 0.1 mM phosphoric acid was loaded by applying 0.5 psi for 10 s and, finally, the sample was injected electrokinetically at 10 kV for 10 s. Under the described conditions, the limit of detection was 2 ng/ml for MDMA, 8 ng/ml for cocaine and 6 ng/ml for morphine (with a signal-to-noise ratio of 5). The lowest concentration suitable for recording interpretable spectra was about 10 - 20 times the limit of detection of each analyte. The intraday and day-to-day reproducibility of migration times (n = 6), with internal standardisation, was characterised by R.S.D. values <= 0.6%; peak area R.S.D.s were better than 10% in intraday and than 15% in day-to-day experiments. Analytical linearity was good with Rsup 2 better than 0.9990 for all the analytes
Field-amplified sample stacking capillary zone electrophoresis applied to the analysis of opiate drugs in hair
No full textThe present paper describes the methodological optimization and validation of capillary zone electrophoresis (CZE) for the determination of major opiates (morphine, codeine, 6-monoacetylmorphine, acetylcodeine, heroin) in hair samples by using a field-amplified sample stacking injection before the separation in a binary running buffer (0.1 M sodium phosphate, pH 2.5, with 40% ethylene glycol). The applied potential was 20 kV, at 25°C. Detection was by UV absorption at the fixed wavelength of 214 nm or by recording the full spectrum between 190—400 nm, thus improving the analytical selectivity and identification power of CZE. Hair samples were liquid/liquid extracted; dried extracts, reconstituted with a low-conductivity solvent (0.1 mM phosphoric acid, with 80% 1-propanol), were injected by electromigration at 10 kV for 99 s, after a 0.5 mm plug of water. Under the described conditions, the limit of detection (with a signal-to-noise ratio of 3) in hair extracts was 100 pg/mL for codeine, 75 pg/mL for morphine and 6-monoacetylmorphine (6-MAM), 150 pg/mL for ethylmorphine, and 0.75 ng/mL for acetylcodeine and heroin. The precision of the method was validated for standards in pure solution by using internal standardization, providing for intraday and day-to-day assays, in terms of migration times, relative standard deviation (RSD) values ≤0.2%, and in terms of peak areas, RSD values <5.71
Pharmacokinetics of a new nitroderivative of acetylsalicylic acid after a single dose in rats
No full textCapillary electrophoresis, a new tool in hair analysis for abused drugs
No full textCapillary electrophoresis, a new tool in hair analysis for abused drug
- …
