159 research outputs found

    AntArr – Etna Low Frequency Antenna Array

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    AbstractA project called AntArr as a new application of the DBBC3 (Digital Base Band Converter, 3rd generation) is under development. A group of antennas operating at low frequency, in the range from 10 MHz up to 1500 MHz, are phased up for VLBI, pulsar and more recently for FRB observations. Part of the scientific programme is also dedicated to SETI activities in piggy-back mode. Dedicated elements can even be added to reach still lower frequencies to observe the range down to kHz frequencies. The DBBC3 manages the array operations in a selected portion of the band and the main characteristic is to synthesize a beam with an innovative approach. The final product of the array is a single station standard VLBI data stream for correlation with other antennas, or a synthesized beam for single dish observations. A number of antennas and array prototypes are under test at a location on the Etna volcano slope, with the aim to form a complete radio telescope of up to 1024 elements in 2020 and beyond. This project completes the lower part of the frequency spectrum covered in VLBI by the BRAND EVN project. The project AntArr is hosted and financed by HAT-Lab Ltd., which is the manufacturer of the DBBC family backends

    HER2 Status in Premalignant, Early, and Advanced Neoplastic Lesions of the Stomach

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    Objectives. HER2 expression in gastric cancer (GC) has received attention as a potential target for therapy with Trastuzumab. We reviewed the current knowledge on HER2 status in premalignant gastric lesions and in early (EGC) and advanced (AGC) GC to discuss the possible pathogenetic and prognostic roles of HER2 overexpression in GC. Results. HER2 overexpression was documented in gastric low-grade (LG) and high-grade intraepithelial neoplasia (HG-IEN), with higher frequency in gastric type dysplasia. HER2 overexpression was significantly associated with disease recurrence and poor prognosis in EGC representing an independent risk factor for lymph node metastases. HER2 overexpression was more frequent in AGC characterized by high grade, advanced stage, and high Ki-67 labeling index. The discordance in HER2 status was evidenced between primitive GC and synchronous or metachronous metastases. Conclusions. HER2 overexpression in premalignant gastric lesions suggests its potential involvement in the early steps of gastric carcinogenesis. The assessment of HER2 status in EGC may be helpful for the identification of patients who are at low risk for developing nodal metastases. Finally, the possible discordance in HER2 status between primary GC and its synchronous metastases support routine assessment of HER2 both in the primary GC and in its metastatic lesions

    Human Epidermal Growth Factor Receptor 2 Status in Gastric Carcinomas with Distinctive Prevalent Cribriform Component

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    A cribriform architectural pattern has been reported in 9% of one unselected consecutively collected series of gastric carcinomas (GC) with unfavourable prognostic outcome. Taking into consideration the biological relevance of the human epidermal growth factor receptor 2 (HER2) status, we have analyzed a cohort of GC with a cribriform component more than 40% (CGC) to evaluate the HER2 amplification rate as a potential target for therapy with trastuzumab

    Immunohistochemical localization and functional characterization of somatostatin receptor subtypes in a corticotropin releasing hormone-secreting adrenal phaeochromocytoma: review of the literature and report of a case

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    Somastostatin receptors are frequently expressed in phaeochromocytoma but data on somatostatin receptor subtyping are scanty and the functional response to the somatostatin analogue octretide is still debated.We report an unusual case of pheochromocytoma, causing ectopic Cushing’s syndrome due to CRH production by the tumour cells, in a 50-yr-old woman. Abdominal computed tomography revealed an inhomogeneous, 9-cm mass in the right adrenal gland, and [111In-DTPA0] octreotide scintigraphy showed an abnormal uptake of the radiotracer in the right perirenal region, corresponding to the adrenal mass. The patient underwent laparoscopic surgery and formalin-fixed and paraffin-embedded samples were studied. The tumour was extensively characterized by immunohistochemistry and somatostatin receptor (SSTRs) subtypes expression was analyzed. Histological and immunohistochemical examination of the surgical specimens displayed a typical pheochromocytoma, which was found to be immunoreative to S-100, chromogranin A and neurofilaments. Immunostaining for SSTR subtypes showed a positive reaction for SSTR1, SSTR2A, SSTR2B, antisera on tumour cells. The intense and diffuse immunostaining for corticotropin releasing hormone (CRH) antiserum indicated that Cushing’s disease was dependent on CRH overproduction by the pheochromocytoma, in which no immunostaining for adrenocorticotropic hormone was found. Our report confirms the heterogeneity of the pattern of SSTR expression in pheochromocytomas, and provide further evidence for functional SSTR subtype SSTR2a in a subgroup of pheochromocytomas, suggesting that these tumours may represent potential target for octreotide treatment

    Actinic keratosis associated with squamous and basal cell carcinomas: an evaluation of neoplastic progression by a standardized AgNOR analysis.

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    In an attempt to investigate the neoplastic progression in different stages of actinic keratosis (AK), a standardized AgNOR analysis was performed in 94 cases of AK, 35 of which were associated with squamous cell carcinoma (SCC) or basal cell carcinoma (BCC), and in 31 cases of SCC and 22 cases of BCC. The cases were subdivided into low- and high- AgNOR-expressing (AgNOR status) AK by using the mean area of AgNORs per cell (NORA) value (3.996 ?m2) as the cut-off. In AK samples, a progressive increase of the mean NORA value from Stage I to Stage IV was encountered. In addition, a significantly higher mean NORA value was found in the AK cases associated with SCC, in comparison to those without SCC; by contrast, no significant differences in the mean NORA value were noted between AK cases with or without BCC. A highly significant association between a high AgNOR quantity and the coexistence of SCC was encountered in AK; no association was appreciable between the AgNOR quantity and the co-occurrence of BCC. Moreover, when the co-existence of SCC in AK was considered as the reference point, the AK cases associated with SCC mostly (95.5%) presented a high AgNOR quantity (high sensitivity), but only 57.6% of cases without SCC displayed a low AgNOR quantity (low specificity). Additionally, our data document that the standardised AgNOR analysis represents a strong negative predictor for the association between SCC and AK. Indeed, a low AgNOR quantity mostly is associated with AK cases without SCC
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