Monitoring of UV spectral irradiance at Thessaloniki (1990?2005): data re-evaluation and quality control

International audienceWe present a re-evaluation and quality control of spectral ultraviolet irradiance measurements from two Brewer spectroradiometers operating regularly at Thessaloniki, Greece. The calibration history of the two instruments was re-examined and data flaws were identified by comparing quasi synchronous measurements. Analysis of the sensitivity of both instruments to variations of their internal temperature revealed that they have temperature coefficients of different sign. These coefficients exhibit small variability during the 15-year period. Using averaged temperature coefficients, we corrected both datasets. Corrections were applied for the angular response error using two different approaches depending on the availability of required ancillary data. The uncertainties associated with the measurements have been estimated and presented. Finally, the two datasets are compared using ratios of irradiance integrals at various bands in the UV, in order to assess any dependencies on the internal instrument temperature, solar zenith angle and wavelength

Evidence of impact of aviation on cirrus cloud formation

International audienceThis work examines changes in cirrus cloud cover (CCC) in possible association with aviation activities at congested air corridors. The analysis is based on the latest version of the International Satellite Cloud Climatology Project D2 data set and covers the period 1984-1998. Over the studied areas, the effect of large-scale modes of natural climate variability such as ENSO, QBO and NAO as well as the possible influence of the tropopause variability, were first removed from the cloud data set in order to calculate long-term changes of observed cirrus cloudiness. The results show increasing trends in (CCC) between 1984 and 1998 over the high air traffic corridors of North America, North Atlantic and Europe. Of these upward trends, only in the summertime over the North Atlantic and only in the wintertime over North America are statistically significant (exceeding +2.0% per decade). Over adjacent locations with low air traffic, the calculated trends are statistically insignificant and in most cases negative both during winter and summer in the regions studied. These negative trends, over low air traffic regions, are consistent with the observed large scale negative trends seen in (CCC) over most of the northern middle latitudes and over the tropics. Moreover, further investigation of vertical velocities over high and low air traffic regions provide evidence that the trends of opposite signs in (CCC) over these regions, do not seem to be caused by different trends in dynamics. It is also shown that the longitudinal distribution of decadal changes in (CCC) along the latitude belt centered at the North Atlantic air corridor, parallels the spatial distribution of fuel consumption from highflying air traffic, providing an independent test of possible impact of aviation on contrail cirrus formation. The correlation between the fuel consumption and the longitudinal variability of (CCC) is significant (+0.7) over the middle latitudes but not over the tropics. This could be explained by the fact that over the tropics the variability of (CCC) is dominated by dynamics while at middle latitudes microphysics explain most of its variability. Results from this study are compared with other studies and for different periods of records and it appears that there exists general agreement as to the evidence of a possible aviation effect on high cloud positive trends over regions with congested air traffic.</p

Which are the main fluorophores in skin and oral mucosa? A review with emphasis on clinical applications of tissue autofluorescence

Abstract OBJECTIVES: The present review provides information about which molecules appear to be the main fluorophores in skin and oral mucosa, together with their clinical applications. DESIGN: The MEDLINE database was searched, using "oral mucosa AND fluorophores", "skin AND fluorophores", "epidermal AND fluorophores", "dermal AND fluorophores" and "cutaneous AND fluorophores" as entry terms. We searched the literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The level of evidence in the studies was assessed using the Classification of the Oxford Centre for Evidence-based Medicine (CEBM) Levels for Diagnosis. RESULTS: Five papers and 17 were primarily focused on description of fluorophores in oral mucosa and skin Evidence exists that fluorophores of oral mucosa and skin are mainly proteins such as collagen, elastin, keratin and tryptophan. Other possible fluorophores identified are: porphyrins, advanced glycation end products, flavins, lipopigment, nicotinamide adenine dinucleotide, flavin adenine dinucleotide, pheomelanin, eumelanin and components of lipofuscin. Clinical applications of oral mucosal autofluorescence (AF) are related to management of malignant and potentially malignant lesions. In the skin, AF has been used for acne assessment, diagnosis of sweat-gland pathologies, glycemic control and management of malignant lesions and as a marker for skin aging. CONCLUSION: Fluorophores stimulated through AF devices are implied in different physiologic and pathologic processes. AF seems to be useful for several clinical applications, especially in skin department. Because most of the studies show a low level of evidence, further studies are necessary in such a promising and fascinating field

Histopathological determinants of autofluorescence patterns in oral carcinoma

Biological tissues (including oral mucosa) can absorb and re-emit specific light wavelengths, detectable through spectrophotometric devices. Such a phenomenon is known as \u201cautofluorescence\u201d (AF). Several devices evaluating tissue AF have been developed and commercialized in the last two decades. Among these, the VELscope\uae system has been proposed as a visual diagnostic aid for potentially malignant disorders and malignant lesions of the oral mucosa. In the present pilot study, we investigated which are the main histopathological features possibly related to variations in AF patterns in a set of 20 oral squamous cell verrucous carcinoma. Among all the histological features investigated, only the mean width of keratin was significantly different between hypofluorescent and hyperfluorescent carcinomas. The results of the present study demonstrate that AF features of oral malignant lesions are significantly associated with the width of their keratin layer

Comparison of UV-B measurements performed with a Brewer spectrophotometer and a new UVB-1 broad band detector

Measurements of the UV-B erythemal dose, based on solar spectra acquired with a Brewer spectrophotometer at Thessaloniki, Greece, are compared to measurements performed with the recently introduced, by the Yankee Environmental Systems, (Robertson type) broad band solar UV-B detector. The spectral response function of this detector, when applied to the Brewer spectral UV-B measurements, results in remarkably comparable estimates of the erythemal UV-B dose. The two instruments provide similar information on the UV-B dose when they are cross-examined under a variety of meteorological and atmospheric conditions and over the a large range of solar zenith angles and total ozone

A single case report of granular cell tumor of the tongue successfully treated through 445 nm diode laser

Oral granular cell tumor (GCT) is a relatively rare, benign lesion that can easily be misdiagnosed. Particularly, the presence of pseudoepitheliomatous hyperplasia might, in some cases, lead to the hypothesis of squamous cell carcinoma. Surgical excision is the treatment of choice. Recurrence has been reported in up to 15% of cases treated with conventional surgery. Here, we reported a case of GCT of the tongue in a young female patient, which was successfully treated through 445 nm diode laser excision. Laser surgery might reduce bleeding and postoperative pain and may be associated with more rapid healing. Particularly, the vaporization effect on remnant tissues could eliminate GCT cells on the surgical bed, thus hypothetically leading to a lower rate of recurrence. In the present case, complete healing occurred in 1 week, and no recurrence was observed after 6 months. Laser surgery also allows the possibility to obtain second intention healing. Possible laser-induced histopathological artifacts should be carefully considered

Study of the effect of different type of aerosols on UV-B radiation from measurements during EARLINET

International audienceRoutine lidar measurements of the vertical distribution of the aerosol extinction coefficient and the extinction-to-backscatter ratio have been performed at Thessaloniki, Greece using a Raman lidar system in the frame of the EARLINET project since 2000. Spectral and broadband UV-B irradiance measurements, as well as total ozone observations, were available whenever lidar measurements were obtained. From the available measurements several cases could be identified that allowed the study of the effect of different types of aerosol on the levels of the UV-B solar irradiance at the Earth's surface. The TUV radiative transfer model has been used to simulate the irradiance measurements, using total ozone and the lidar aerosol data as input. From the comparison of the model results with the measured spectra the effective single scattering albedo was determined using an iterative procedure, which has been verified against results from the 1998 Lindenberg Aerosol Characterization Experiment. It is shown that the same aerosol optical depth and same total ozone values can show differences up to 10% in the UV-B irradiance at the Earth's surface, which can be attributed to differences in the aerosol type. It is shown that the combined use of the estimated single scattering albedo and the measured extinction-to-backscatter ratio leads to a better characterization of the aerosol type probed

Metabolomic analysis of actinic keratosis and scc suggests a grade-independent model of squamous cancerization

Background—Actinic keratoses (AKs) are the most common sun-induced precancerous lesions that can progress to squamocellular carcinoma (SCC). Recently, the grade-independent association between AKs and SCC has been suggested; however, the molecular bases of this potential association have not been investigated. This study has assessed the metabolomic fingerprint of AK I, AK II, AK III and SCC using high resolution magic angle spinning (HR-MAS) nuclear magnetic resonance (NMR) spectroscopy in order to evaluate the hypothesis of grade-independent association between AK and SCC. Association between AKs and SCCs has also been evaluated by histopathology. Methods—Metabolomic data were obtained through HR-MAS NMR spectroscopy. The whole spectral profiles were analyzed through multivariate statistical analysis using MetaboAnalyst 5.0. Histologic examination was performed on sections stained with hematoxylin and eosin; statistical analysis was performed using STATA software version 14. Results—A group of 35 patients affected by AKs and/or SCCs and 10 healthy controls were enrolled for metabolomics analysis. Histopathological analysis was conducted on 170 specimens of SCCs and AKs (including the ones that underwent metabolomic analysis). SCCs and AK I were found to be significantly associated in terms of the content of some metabolites. Moreover, in the logistic regression model, the presence of parakeratosis in AKs appeared to be less frequently associated with SCCs, while AKs with hypertrophy had a two-fold higher risk of being associated with SCC. Conclusions—Our findings, derived from metabolomics and histopathological data, support the notion that AK I are different from healthy skin and share some different features with SCCs. This may further support the expanding notion that all AKs should be treated independently from their clinical appearance or histological grade because they may be associated with SCC

Nine years of UV aerosol optical depth measurements at Thessaloniki, Greece

Spectral measurements of the aerosol optical depth (AOD) and the &Aring;ngström coefficient were conducted at Thessaloniki, Greece (40.5&deg; N, 22.9&deg; E) between January 1997 and December 2005 with a Brewer MKIII double-monochromator spectroradiometer. The dataset was compared with collocated measurements of a second spectroradiometer (Brewer MKII) and a CIMEL sun-photometer, showing correlations of 0.93 and 0.98, respectively. A seasonal variation of the AOD was observed at Thessaloniki, with AOD values at 340 nm of 0.52 and 0.28 for August and December respectively. Back trajectories of air masses for up to 4 days were used to assess the influence of long-range transport from various regions to the aerosol load over Thessaloniki. It is shown that part of the observed seasonality can be attributed to air masses with high AOD originating from North-Eastern and Eastern directions during summertime. The analysis of the long-term record (9 years) of AOD showed a downward tendency. A similar decreasing tendency was found in the record of the PM$_{10}$ aerosol measurements, which are conducted near the surface at 4 air-quality monitoring stations in the area of the city of Thessaloniki