Conversion from linear to circular polarization in FPGA

Context: Radio astronomical receivers are now expanding their frequency range to cover large (octave) fractional bandwidths for sensitivity and spectral flexibility, which makes the design of good analogue circular polarizers challenging. Better polarization purity requires a flatter phase response over increasingly wide bandwidth, which is most easily achieved with digital techniques. They offer the ability to form circular polarization with perfect polarization purity over arbitrarily wide fractional bandwidths, due to the ease of introducing a perfect quadrature phase shift. Further, the rapid improvements in field programmable gate arrays provide the high processing power, low cost, portability and reconfigurability needed to make practical the implementation of the formation of circular polarization digitally. Aims: Here we explore the performance of a circular polarizer implemented with digital techniques. Methods: We designed a digital circular polarizer in which the intermediate frequency signals from a receiver with native linear polarizations were sampled and converted to circular polarization. The frequency-dependent instrumental phase difference and gain scaling factors were determined using an injected noise signal and applied to the two linear polarizations to equalize the transfer characteristics of the two polarization channels. This equalization was performed in 512 frequency channels over a 512 MHz bandwidth. Circular polarization was formed by quadrature phase shifting and summing the equalized linear polarization signals. Results: We obtained polarization purity of -25 dB corresponding to a D-term of 0.06 over the whole bandwidth. Conclusions: This technique enables construction of broad-band radio astronomy receivers with native linear polarization to form circular polarization for VLBI.Comment: 11 pages 8 figure

her2 status in premalignant dysplastic gastric lesions

Abstract is not required for Editorialis not required for Editorial (This page in not part of the published article.) International Journal of Case Reports and Images, Vol. 6 No. 8, August 2015. ISSN – [0976-3198] Int J Case Rep Images 2015;6(8):530–533. www.ijcasereportsandimages.com Barresi et al. 530 CASE REPORT OPEN ACCESS HER2 status in premalignant dysplastic gastric lesions Valeria Barresi, Antonio Ieni, Giovanni Tuccari The epidermal growth factor receptor family is constituted by four members with similar structures: HER1/erbB1, HER2/erbB2, HER3/erbB3 and HER4/ erbB4. These receptors play an important role in the processes of proliferation and differentiation of normal cells [1]. The binding of the ligand to these receptors causes the creation of homodimers and heterodimers as well as the activation of downstream signaling pathways [1]. Hence, any aberrations in their structure or function can cause transformation of normal cells to malignant cells with consequent tumor development and progression [1]. However, on the basis of results from an international randomized controlled trial (ToGA), the patients with advanced gastric adenocarcinoma (GC) positive for HER2 over-expression could be eligible for a target treatment with trastuzumab [2]. A significant reduction in the risk of mortality was appreciable when trastuzumab was added to the chemotherapy regimen [2]. There is general agreement with regard to a higher HER2 positivity in gastroesophageal junction cancer (24–35%) compared with GC (9.5–21%) [3]. The rate of HER2 immunoreactivity seemed to be vary variable in relation to the different neoplastic histotype of the stomach [4]. Generally, all studies have reported a prevalence of HER2 amplification in advanced GC of Valeria Barresi1, Antonio Ieni1, Giovanni Tuccari1 Affiliations: 1Azienda Ospedaliera Universitaria "Gaetano Martino" and Department of Human Pathology "Gaetano Barresi", Section of Anatomic Pathology, University of Messina, Messina 98123, Italy. Corresponding Author: Giovanni Tuccari, MD, Full Professor of Pathology Department of Human Pathology, "Gaetano Barresi" University of Messina, A.O.U. "Policlinico G. Martino" Pad. D, Via Consolare Valeria, 98125 – MESSINA (Italy); Ph: +39-90-2212539; Fax:+39-90-2928150 E-mail: [email protected] Received: 16 June 2015 Published: 01 August 2015 EdiTO iAlS OPEN A CE S intestinal type (81.6–91%) in comparison with diffuse or mixed ones (4–7.9%) [4]. In addition, a progressive increase in HER2 overexpression has been appreciated moving from the poorly cohesive WHO histotype to mitochondrion-rich adenocarcinomas (MRC), tubular adenocarcinomas and hepatoid carcinomas (HAS), these latter representing the top rate of HER2 positivity, characterized by an extremely poor prognosis [4]. Furthermore, HER2 overexpression was also significantly associated with a high grade, advanced stage and high Ki67-LI value, becoming thus an additional morphological parameter able to affect the mortality of patients with GC [5]. Finally, some investigations have been recently reported regarding the concordance of HER status in primary gastric cancer and corresponding lymph nodes or distant metastases, with either positive or negative conversion in HER2 overexpression [6, 7]. Generally speaking, chronic atrophic gastritis and intestinal metaplasia of the stomach have been regarded to as pre-neoplastic lesions, even if data from literature points towards the existence of other pathways, in which intestinal metaplasia may not play a role, as described by Japanese authors [8]. However, the true precancerous gastric lesion should be considered dysplasia, which includes cellular and structural atypia, also codified under the term intraepithelial neoplasia (IEN), a pathological condition that lies between atrophic gastritis and GC [9]. It is well known, that IEN may develop in the gastric or intestinal metaplastic epithelium and it can be categorized into four categories: indefinite for intraepithelial neoplasia, low-grade intraepithelial neoplasia (LG-IEN), high-grade intraepithelial neoplasia (HG-IEN) and suspicious for invasive cancer [10]. The IEN histological distinction as low or high-grade depends on the severity of architectural and cytological atypia. In LG-IEN, the mucosal structure is only faintly modified maintaining tubular differentiation with the proliferative zone limited to the outward portion, whereas HG-IEN exhibits increasing distortion of the mucosal architecture, resulting in crowded possibly irregular glands with obvious cellular atypia and proliferative activity distributed throughout the lesion [10]. High-grade intraepithelial neoplasia i

AntArr – Etna Low Frequency Antenna Array

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

Prolegomeni a uno studio in tema di sicurezza alimentare

The article examines, from a legal point of view, the main profiles, problems and perspectives of the so called Food Security and Food Safety in the actual complex and risk society. The paper builds on the relationship between Food Security/Safety and food diversity, in particular the one linked to agro-biodiversity and sustainable rural systems. Then it deals with the evolution of Food Security/Safety, as concept, purpose and system, to end with the analysis of the instruments and mechanisms of protection

An Updated Review of Cribriform Carcinomas with Emphasis on Histopathological Diagnosis and Prognostic Significance

Cribriform is a histopathological term used to describe a neoplastic epithelial proliferation in the form of large nests perforated by many quite rounded different-sized spaces. This growth pattern may be seen in carcinomas arising in different organs, and shows important prognostic implications. Therefore, recent data in literature suggest that cribriform carcinoma is a histologically and clinically distinctive type of tumour that should be separated from other similar tumour types. In this article, the pathology of cribriform adenocarcinoma of the prostate, lung, breast, stomach, colon, thyroid, and skin is discussed with particular reference to morphologic and immunohistochemical features, differential diagnosis, and clinical behaviour

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

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

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