7 research outputs found

    Er site in Er-implanted Si nanoclusters embedded in SiO2

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    We have investigated by extended x-ray absorption fine structure spectroscopy the local order around Er atoms introduced by ion implantation in substoichiometric silica films prepared by plasma enhanced chemical vapor deposition, where Si nanoclusters have been formed by different preimplantation annealing processes. The results show that Er atoms are surrounded by a first shell of O atoms and no Er-Si direct correlations are observed; moreover, while the variation of the preimplantation annealing temperature has no effect on the Er site, it is observed that the increase of the Er concentration determines an increase of both the Er first shell coordination number and the Er-O interatomic distance, becoming more similar to those of Er2O3. In the presence of an extensive phase separation between Si and SiO2 the local environment around Er plays a crucial role on the efficiency of the photoluminescence emission at 1.54 mu m, which is significantly increased when the first shell of atoms around Er is closer to that one of Er2O3

    Site of Er ions in Er-implanted silica containing Si nanoclusters

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    In this work the site of Er ions in a silica matrix containing Si nanoclusters (nc) is investigated. The Er ions are introduced into a silica matrix containing Si nanoclusters by ion implantation. The X-ray absorption spectroscopy (EXAFS), performed at Er L-III-edge shows that the Er site in the matrix strongly depends on the preparation conditions; the effect of the implantation dose on the local structure around Er is addressed. The data demonstrate that the Er atoms are surrounded in the first shell by O atoms. Moreover, an increasing in the Er implantation dose implies an increase of the number of O atoms in the first shell and of their distance to the Er central atom, leading to the formation of a Er site more similar to that of bulk Er2O3

    Detection of Circulating Tumour Cells in Urothelial Cancers and Clinical Correlations: Comparison of Two Methods

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    Circulating tumour cells (CTC) are identified exploiting their protein/gene expression patterns or distinct size compared to blood cells. Data on CTC in bladder cancer (BC) are still scarce. We comparatively analyzed CTC enrichment by AdnaTest ProstateCancerSelect (AT) and ScreenCell®Cyto (SC) kits, combined with identification by EPCAM, MUC1, and ERBB2 expression and by cytological criteria, respectively, in 19 nonmetastatic (M0) and 47 metastatic (M+) BC patients, at baseline (T0) and during treatment (T1). At T0, CTC positivity rates by AT were higher in M+ compared to M0 cases (57.4% versus 25%, p = 0.041). EPCAM was detected in 75% of CTC-positive samples by AT, showing increasing expression levels from T0 to T1 (median (interquartile range, IQR): 0.18 (0.07–0.42) versus 0.84 (0.33–1.84), p=0.005) in M+ cases. Overall, CTC positivity by SC was around 80% regardless of clinical setting and time point of analysis, except for a lower occurrence at T1 in M0 cases. At T0, circulating tumour microemboli were more frequently (25% versus 8%) detected and more numerous in M+ compared to M0 patients. The approach used for CTC detection impacts the outcome of CTC studies. Further investigations are required to clarify the clinical validity of AT and SC in specific BC clinical contexts

    Norovirus Persistence in Oysters to Prolonged Commercial Purification

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    Depuration is generally the main treatment employed for bivalve mollusks harvested from contaminated sites. Commercial depuration has demonstrated to be effective for removal of bacterial pathogens, although it probably provides only limited efficacy against human enteric viruses. We evaluated the quantitative reduction of norovirus (NoV) genogroups I and II in naturally contaminated oysters after 1, 4, and 9 days of depuration. The process was conducted in an authorized depuration plant, and NoV concentration was determined by RT-qPCR according to ISO 15216-1:2017 method. Regardless of the NoV genogroup, our results showed no significant reduction in NoV concentration after 1 day of depuration. Higher mean reduction (68%) was obtained after 4 days of treatment, while no further increase was observed after 9 days. Overall, reduction was highly variable, and none of the trials showed statistically significant reduction in NoV RNA concentration at the end of each depuration period. Indeed, NoV concentration remained high in 70% of samples even after 9 days of depuration, with values ranging between 4.0 × 102 and 2.3 × 104 g.c./g. These results indicate that an extension of commercial depuration time does not appear to be effective for reducing or eliminating NoV in oysters