178 research outputs found
Applicability of the polysulphone horizontal calibration to differently inclined dosimeters
No full textPolysulphone (PS) dosimetry has been a widely used technique for more than 30 years to quantify the erythemally effective UV dose received by anatomic sites (personal exposure). The calibration of PS dosimeters is an important issue as their spectral response is different from the erythemal action spectrum. It is performed exposing a set of PS dosimeters on a horizontal plane and measuring the UV doses received by dosimeters using calibrated spectroradiometers or radiometers. In this study, data collected during PS field campaigns (from 2004 to 2006), using horizontal and differently inclined dosimeters, were analyzed to provide some considerations on the transfer of the horizontal calibration to differently inclined dosimeters, as anatomic sites usually are. The role of sky conditions, of the angle of incidence between the sun and the normal to the slope, and of the type of surrounding surface on the calibration were investigated. It was concluded that PS horizontal calibrations apply to differently inclined dosimeters for incidence angles up to approximately 70 degrees and for surfaces excluding ones with high albedo. Caution should be used in the application of horizontal calibrations for cases of high-incidence angle and/or high albedo surfaces
E,volution of a Mural Thrombus in False Aneurysm: CT Demonstration
No full textA case of postoperative false aneurysm of the ascending aorta with
serial CT and angiographic demonstration is described. Some considerations
on the behavior of early thrombosis are discussed
Multiple system atrophy presenting as parkinsonism: clinical features and diagnostic criteria
No full textTo evaluate the possibility that parkinsonian signs may be the only presenting feature of multiple system atrophy (MSA), parkinsonian patients were studied who had no atypical clinical signs and had no symptoms of autonomic dysfunction, but who reported that they had not experienced the anticipated good response to dopaminergic treatment. These stringent criteria identified 20 patients from a series of 298 consecutive parkinsonian outpatients. The following clinical pointers were analysed: (a) rate of disease progression; (b) symmetry of parkinsonian symptoms and signs; (c) occurrence of resting tremor during the first three years from onset. In addition, all patients underwent (d) acute and chronic challenge with dopaminergic drugs; (e) cardiovascular reflex autonomic function tests; (f) high field MRI. Rapid progression of disease was seen in 45% of patients, onset was symmetric in 25%, tremor was absent at onset in 70%, response to dopaminergic drug challenges was inadequate in 40%, abnormal cardiovascular reflexes occurred in 50%, and some abnormal MRI finding occurred in 35% of cases. Each of these features was equally weighted by giving to each patient a 0 to 6 point score corresponding to the number of abnormal findings. Fifteen patients scoring higher than 1 were considered at risk for having MSA: five of them were classified as clinically possible (score 2), six as clinically probable (score 3-4), and four patients were classified as clinically definite multiple system atrophy (score 5). The six pointers considered were variably combined in each patient, none of them being universally abnormal in patients with high scores. The patients were followed up for a mean 2.1 (SEM 0.65) years. All but one of the 10 patients prospectively classified as probable or definite MSA developed unequivocal clinical signs of fully symptomatic MSA. A receiver operator characteristic cure was plotted for the prospective score based on follow up diagnosis. The best compromise for trade off between sensitivity and specificity was a cut off value at a score of 3. The sensitivity and specificity of the individual pointers considered to predict fully symptomatic MSA varied considerably, and no single item could predict whether patients presenting with just parkinsonian signs went on during the two year follow up period to develop fully symptomatic MSA. Instead, the number of abnormalities offered a predictive value for the clinical prognosis of these parkinsonian patients
Solar ultraviolet radiation at the earth’s surface: factors affecting its impact on human beings
No full textEXPOSURE TO SOLAR UV RADIATION IN ITALY UNDER DIFFERENT ENVIRONMENTAL CONDITIONS
No full textThe exposure to UV radiation was studied for the following relatively homogeneous targeted groups of people under
peculiar environmental conditions: a) sunbathers (marine environment); b) skiers (alpine environment); c) winegrowers
(rural environment).
A comparison among different groups/environments was carried out taking advantage of an easy-to-estimate and
reliable exposure index, the Exposure Ratio (ER). In particular, for the members of the most populated group (skiers)
the intra-group variability of individual ER values changed from day to day depending upon the sun exposure of the
preferred ski slopes tracks. In the sunbathers case, the three different groups of people under study were not
distinguishable based on ER values while in the case of winegrowers seasonal occupational activities as well as the
somatic location of dosimeters appeared to be the leading factors influencing ER. All in all, in spite of its essentially physical nature, the ER parameter showed to be a valuable although indirect index of individual behavioural features
A UV Index sundial on compact disk
No full textThis paper provides information on the capability of a compact disk (CD) of estimating the UVI (Ultra Violet
Index). This parameter is an indicator of the erythemally weighted UV radiation at surface. It is defined as
the integration of solar irradiance (280–400 nm) measured on a horizontal plane, weighted by the erythemal (skin reddening) action
spectrum, and properly scaled to become a dimensionless number. The UVI is widely used as an indicator of UV levels at the earth’s
surface providing public awareness of the effects of prolonged exposure to the sun’s rays. Our CD based device is designed for
personal use and may become a valuable tool for a better communication of the UVI to the public with the hope to draw people’s
attention to use it and to adopt adequate sun protection behaviours
Occupational exposure to solar UV radiation. A short review of relevant papers on the quantification of exposure to solar ultraviolet (UV) radiation of outdoor workers
No full textThis paper intends to be a tentative summary of the state of knowledge on the quantifi cation of occupational exposure to solar ultraviolet (UV) radiation by reviewing the relevant literature. The authors have already published some studies on this topic using polysulphone (PS) dosimetry, providing a signifi cant contribution to the few studies on the quantifi cation of UV exposure for professional outdoor workers in Italy. The paper also highlights the importance of such studies in the Mediterranean area and the Italian territory, with high potential to receive intense solar UV doses through most of the yea
La radiazione solare ultravioletta alle Latitudini del Mediterraneo nel trattamento di acque microbiologicamente contaminate
No full textSi stima che circa un miliardo di persone nel mondo sia costretta a fare uso di acqua biologicamente contaminata, con il rischio di contrarre malattie derivanti da microorganismi patogeni (diarrea, colera, febbre tifoide, epatite A (WHO/UNICEF/WSSCC, 2000; WHO/UNICEF, 2012)). Questo problema è fortemente sentito nei Paesi in via di sviluppo, per i quali sono state studiate da tempo tecniche di trattamento delle acque in grado di eliminare o almeno ridurre il rischio di contaminazione. Tali tecniche vanno dalle operazioni di filtraggio fino al riscaldamento al punto di ebollizione o all'uso del cloro. La clorazione, molto utilizzata anche nei Paesi sviluppati, presenta numerosi svantaggi legati alle caratteristiche del cloro, che ha un costo, è un elemento corrosivo, necessita di attenti dosaggi ed altera il sapore dell’acqua (WHO, 1997).
Dall'inizio degli anni 80 del secolo scorso è stata sviluppata ed adottata con successo una metodologia a basso costo per decontaminare acqua biologicamente infetta, in piccole quantità e con bassi livelli di torbidità, basata sull’utilizzo della radiazione solare. Il metodo, denominato SODIS (SOlar DISinfection), funziona grazie all’azione germicida della radiazione ultravioletta prevalentemente nella banda 320-400 nm (UVA) combinata a quella della componente infrarossa (lunghezza d’onda maggiore di 700 nm) in grado di far aumentare la temperatura dell’acqua (Acra et al, 1984). L’uso simultaneo di entrambe le porzioni dello spettro solare durante l’esposizione produce un effetto sinergico che accresce l’efficienza del processo di decontaminazione (Wegelin et al., 1994; Sommer et al., 1997).
E’ stato verificato che, al di sotto di 35° di latitudine, circa 6 ore di esposizione alla radiazione solare in condizioni di cielo sereno possono disinfettare totalmente acqua poco torbida contenuta in bottiglie di PET (Polietilene Tereftalato, materiale plastico che lascia passare la radiazione UVA, a differenza del vetro (SANDEC, 2002; Wegelin et al., 2001)). Se la temperatura dell’acqua supera i 50°C, basta una sola ora di esposizione al sole (SANDEC, 2002). L’efficienza della disinfezione dipende quindi in maniera cruciale dalla disponibilità di radiazione UV alla superficie, principalmente nella banda UVA, ma l’informazione relativa, a differenza di quella sulla radiazione solare globale (integrata cioè su tutto lo spettro), non è di facile reperimento, in quanto sono poche le stazioni nel mondo che realizzano misure spettrali nell’ultravioletto solare (Pawlat and Stryczewska, 2001). Ci si propone quindi di mostrare l'esistenza e la loro utilità nel contesto suddetto in ambito nazionale, sfruttando i dati spettrali di radiazione solare UV disponibili nelle stazioni di Roma Sapienza ed Aosta ARPA VdA (Diémoz et al, 2011).
L'interesse per questo tipo di analisi nasce dalla considerazione che le regioni mediterranee risultano frequentemente esposte, nei periodi di siccità, a problemi legati all’approvvigionamento di acqua soprattutto per uso agricolo. Nel nostro Paese, inoltre, in agricoltura viene spesso usata acqua potabile, con conseguente consumo di preziose risorse naturali e di energia. Si vogliono quindi ottenere informazioni sulla decontaminazione microbiologica delle acque su scala media (quindi non solo sulla piccola scala rappresentata dalla bottiglia di PET ma anche, ad esempio, in vasche di raccolta di dimensione di qualche metro quadrato) nelle regioni mediterranee. E' evidente che tale problema mostra numerose incognite di tipo pratico alla verifica sperimentale.
In questo contributo si vogliono: 1) fornire valutazioni di carattere generale sulla potenzialità delle dosi solari alle nostre latitudini; 2) illustrare sinteticamente la progettazione sperimentale, che verrà realizzata nei prossimi mesi
- …
