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Biomedical subjects

G Zappa

Publications and source records attributed to G Zappa.

8 recordsLinked to original sources
PubMed2005

HPLC screening of natural vitamin E from mediterranean plant biofactories--a basic tool for pilot-scale bioreactors production of alpha-tocopherol.

The study was performed in order to investigate a simple, efficient, reliable and rapid method of extracting and quantifying natural vitamin E for pressurized liquid extraction (PLE) as well as high-performance liquid chromatography (HPLC) analysis. Lyophilized Corylus avellana L. nut samples were powdered by high-speed milling with Waring blender for 40 s. alpha-Tocopherol was extracted from the nut tissue powder using dehydrated hexane fortified with 0.01% butylated hydroxytoluene (BHT, co-antioxidant). The rate of alpha-tocopherol accumulation showed differences among nut samples collected in different areas of Italy. Sarda Piccola nut biofactory contained higher amount (81.17 microg/g d.w) of alpha-tocopherol than other-local eleven Italian cultivar nuts. These results provide insight into the biofactory basis for alpha-tocopherol accumulation in hazelnut and give the suitable cultivar tissues to establish pilot-scale bioreactors production of natural bioactive vitamin E.

Bioreactors↗
PubMed2004

Pesticides re-entry dermal exposure of workers in greenhouses.

This research has the aim to evaluate the risk of pesticide dermal exposure for workers in greenhouses. We considered the following crops: tomato, cucumber and strawberry, largely spread in Bracciano lake district. The pesticides monitored were: tetradifon on strawberry: metalaxyl, azoxystrobin and fenarimol on cucumber; acrinathrin, azoxystrobin and chlorpyrifos ethyl on tomato. The dermal exposure was evaluated by Dislodgeable Foliar Residue (DFR) measurements employing transfer coefficients got from literature. For risk evaluation, we have compared the dermal exposures with Acceptable Operator Exposure Levels (AOEL). The re-entry time were obtained intercepting the dose decay curves with AOEL values. The re-entry times result higher than two days in the cases of chlorpyrifos on tomato (re-entry time: 3 days), azoxystrobin on tomato (4 days), and tetradifon on strawberry (8 days). The need of measuring specific transfer coefficients is pointed out.

Agriculture↗
PubMed2001

Ion chromatographic preconcentration of Cu and Cd from ultra-high-purity water and determination by electrothermal atomic absorption spectrometry.

A method based on preconcentration of Cu and Cd from ultra-high-purity water by ion chromatography (IC) and determination by electrothermal atomic absorption spectrometry is described. A small low-capacity ion-exchange concentrator Dionex HPIC-CG5 and mobile phase of 3 mM pyridine-2,6-dicarboxylic acid (PDCA) are used. Water samples are loaded onto the preconcentration column at a flow-rate ranging from 1 to 3.5 ml min(-1). Large sample volumes (up to 200 ml) can be loaded onto the concentrator without losing metal ions. Elution is carried out in the reverse direction of sample loading and the volumes of effluent are as small as 0.150 and 0.200 ml for copper and cadmium, respectively. Under these conditions the preconcentrated ions coelute. The detection limits, based on the Hubaux-Vos method, for Cu using a 1300-fold preconcentration in the IC step was found to be 1 pg ml(-1), and was limited due to impurity in PDCA, while the detection limit found for Cd using a 1000-fold preconcentration was 0.02 pg ml(-1). Ultra-high-purity water produced by a Millipore system is successfully analysed by the proposed method and the content of Cu and Cd are found to lie in the range 1-10 pg ml(-1).

Cadmium↗
PubMedDate not supplied

[Splinting technique for traumatic luxation of anterior permanent teeth].

Extrusive luxations of both, upper and lower incisors, represent a frequent event in dental traumatology. The Authors present some cases in which elastic splints have been used. In fact recent researches show that, even soon after a traumatic event, is not indicated to immobilize teeth with rigid fixed splints because they don't allow any dental function. It is therefore preferable the use of elastic splints for 2-4 weeks, instead of rigid splints for long periods. The Authors then describe the techniques, the methods and the radiographic controls and pulp tests used in this kind of traumatic pathology, showing the positive long term results obtained by using elastic splints instead of rigid splints which often present as result root resorptions or pulp necrosis. In fact with elastic splints is possible to replace and maintain luxated teeth, allowing at the same time a certain function of teeth and their support tissues.

Dental Pulp Necrosis↗