Transceiver Front-End Technology for Software Radio Implementation of Wideband Satellite Communication Systems

The evolution of satellite communication systems for the design of both the satellite’s communication payload and the ground-station are towards the implementation of such systems using the Software Radio (SR) technology. This paper focuses on a key element of the SR, that is, the wideband front-end which still poses the greatest technological challenge for design and proliferation of SR. In particular, we look at the front-end architecture of wideband receivers, outline the key aspects of the design of such front-end systems, specify the performance metrics associated with their design, present an architecture of a promising wideband analog to digital converter, and finally present the results of our design, implementation, and test campaign of a prototype PC-based SR system. This revised version was published online in July 2006 with corrections to the Cover Date.     

Surface analyses of polycrystalline and Cz–Si wafers

The performance of photovoltaic devices is greatly influenced by the surface characteristics such as surface roughness and presence of organic contaminants; therefore, their measurement is of great importance for photovoltaic industry. Moreover, these parameters should be measured by non-contact, fast methods capable of application as in-line techniques in photovoltaic industry. Surface roughness measurements and detection of organic contaminants by work-function measurements are the subject of this contribution. Monocrystalline and multicrystalline silicon wafers have been analyzed by Scanning Kelvin Probe (SKP ) in order to obtain work-function maps. These presented regions of higher work-function values correspond to organic contaminants, which are deliberately deposited on the wafer surface. In this way we have demonstrated the capability of work-function measurements for the detection of the contaminants. Moreover, unintentional organic contamination has been detected on multicrystalline Si wafers by SKP analyses. At the same time, the surface roughness has been obtained from surface topography maps.     

Risk analysis of underground infrastructures in urban areas

The paper presents an integrated approach for vulnerability and resilience analysis for underground infrastructures, i.e. a societal risk analysis of the failures of underground services for an urban area. The approach is based on the detailed study of (1) domino-effects for the components of a single infrastructure and for a given set of infrastructures interoperated and/or belonging to the same area; (2) risk and vulnerability analysis of a given area; (3) identification of a set of intervention guidelines, in order to improve the overall system resilience. The use of an integrated (interoperability and area) approach, breaking down the analysis area extent into sub-areas and assessing the dependencies among sub-areas both in terms of interoperability and damage propagation of critical infrastructures, demonstrates a useful advantage in terms of resilience analysis, more consistent with the “zoned” nature of failures of the underground infrastructures. An applied case, describing the interoperability and damage propagation analysis with the evaluation of time-dependency for the infrastructures and targets and of different kinds of interventions of the underground infrastructures of a town, is presented for this purpose.     

Characterization of Pt/AlN/Pt-based structures for high temperature, microwave electroacoustic devices applications

Highly c-axis oriented AlN films, 3.15 μm thick, were grown by rf reactive sputtering technique at 200 °C on bare and Pt-covered Si(100) substrates previously oxidized to a thickness of about 2 μm in wet oxygen atmosphere. A Pt film, 2200 Å thick, was then sputtered on the free surface of the AlN/Pt/SiO₂/Si multilayer at 200 °C without breaking the vacuum in order to avoid any oxidation effects of the layers. The multilayers were then annealed in air at 900 °C for different time lengths up to 32 h in order to test the materials' resistivity to harsh environment. The influence of this high temperature annealing (HTA) on the thin films' crystallinity, as well as on the c-AlN piezoelectricity and Pt sheet resistivity was investigated at room temperature before and after each annealing. X ray diffraction investigations revealed that the films' crystallinity was improved by the HTA: the full width of half maximum of the AlN(002) and Pt(111) peaks decreases from 0.39° to 0.24°, and from 0.42° to 0.28° after 32-hours-HTA. Scanning electron microscopy, four points probe and piezoelectricity tests revealed that the morphology and the sheet resistivity (in the range from 0.6 to 0.5 Ω/sq) of the outer Pt film, as well as the AlN piezoelectric constants d₃₃ (in the range from 6.2 to 7.4⋅10⁻¹² C/N) was quite unaffected by the HTA even after 32 h of annealing.     

Clinical Significance of Molecular Subtypes in Western Advanced Gastric Cancer: A Real-World Multicenter Experience

In recent years, the molecular subtyping of gastric cancer has led to the identification of novel clinically relevant biomarkers as well as promising therapeutic targets. In parallel, the advent of checkpoint inhibitors has expanded treatment options beyond conventional chemotherapy. Compelling evidence has shown unprecedented efficacy results for anti-PD1-based therapies in the molecular subgroups of dMMR/MSI-h, EBV+ and PD-L1 CPS+ patients, to the point that these are granted approval for gastric cancer adenocarcinoma (AGC) in several countries. Despite this, cytotoxic chemotherapy remains the only treatment choice for the considerable proportion of biomarkers-negative patients. In this context, little is known about the association between subtypes-defining biomarkers (HER2, MMR/MSI, PD-L1, and EBV) and the efficacy of standard chemotherapy in non-Asian AGC. Here, we aimed to investigate the prevalence, the clinic-pathologic features, and the impact on treatment outcome of clinical molecular subtypes in a new-diagnosed Western cohort of AGC.     

Gut Microbiota,Metabolic Disorders and Breast Cancer: Could Berberine Turn Out to Be a Transversal Nutraceutical Tool? A Narrative Analysis

Metabolic disorders, mainly characterized as the marked alteration of the lipid and carbohydrate profile, in addition to the clinical presence of the direct consequences of these alterations, are pathological conditions that have considerably increased in prevalence in recent years. They are directly linked to the onset of various pathologies, including cancer, particularly breast cancer, and are hormone-responsive. Alongside the known conditions responsible for this scenario, such as nutrition and lifestyle in general, the importance of both the colonic microbiota and the various organs and systems is becoming increasingly evident. In fact, it is now evident that microbial dysbiosis plays a fundamental role in the onset of these metabolic disorders, and therefore how these conditions are indirectly responsible for the onset and progression of neoplasms. Indirect mechanisms such as an altered Firmicutes/Bacteroidetes ratio; the formation of metabolites such as short-chain fatty acids (SCFAs), in particular, butyrate, which is capable of acting as a tumor suppressor; and the glucuronidase activity of estroboloma (bacteria responsible for estrogen metabolism) are just some of the most important mechanisms that contribute to the history of breast cancer. It is therefore understandable that in clinical terms, it is essential to associate the modulation of metabolic disorders and the microbial conditions that contribute to generating them with common therapies, preferably using compounds and solutions that are effective and acceptable for the patient without side effects. Nutraceuticals such as berberine (active both in metabolic scenarios and in the microbiota) and interventions modulating the microbial structure such as the use of probiotics and prebiotics seem to be ideal solutions for these preventive and no-longer-ignorable strategies in the light of numerous data now present in the literature.     

Gabexate for the prevention of pancreatic damage related to endoscopic retrograde cholangiopancreatography. Gabexate in digestive endoscopy--Italian Group

BACKGROUND: Endoscopic retrograde cholangiopancreatography (ERCP) is associated with elevated levels of pancreatic enzymes and pancreatitis. Gabexate, a protease inhibitor, has been used to prevent pancreatic damage related to ERCP. METHODS: We conducted a multicenter, double-blind comparison of gabexate (1 g given by intravenous infusion starting 30 to 90 minutes before endoscopy and continuing for 12 hours afterward) with placebo (mannitol and sodium chloride, administered in the same fashion). A total of 435 adults scheduled to undergo ERCP and, when indicated, endoscopic sphincterotomy underwent randomization; 17 were excluded from the final analysis for various reasons. The remaining 418 patients (mean age, 60.4 years)--208 in the gabexate group and 210 in the placebo group--were analyzed. Acute pancreatitis was considered to be present if serum amylase or lipase levels (or both) were five times greater than the upper limits of normal in association with the onset of pancreatic pain. RESULTS: After the procedures, 276 patients (66 percent) had elevated pancreatic-enzyme levels; the frequency was similar in the two groups. Mean serum amylase values were higher in the placebo group than in the gabexate group through 24 hours of observation (P=0.03). Twelve patients in the gabexate group and 29 in the placebo group had abdominal pain (6 percent vs. 14 percent, P=0.009). Sixteen patients in the placebo group and five in the gabexate group had acute pancreatitis (8 percent vs. 2 percent, P=0.03). Two patients treated with gabexate and six given placebo had adverse events, all of which resolved. Two patients given placebo died of acute pancreatitis; one was excluded from the evaluation because pancreatitis was present before endoscopy. One patient in the gabexate group died, from a myocardial infarction. CONCLUSION: Prophylactic treatment with gabexate reduced pancreatic damage related to ERCP, as reflected by reductions in the extent but not the frequency of elevated enzyme levels and in the frequency of pancreatic pain and acute pancreatitis.     

Using MPC to control middle-vessel continuous distillation columns

The use of model predictive control (MPC) in middle-vessel continuous distillation column (MVCC) is discussed. It is shown that using a 5 × 5 MPC implementation (where all levels are included in MPC as integral process variables) allows using a smaller middle-vessel, particularly when disturbances can be measured: a good performance is ensured without having the middle vessel drained or overfilled. Also, it is shown that MPC practically circumvents the issue of tuning the middle-vessel level controller. Furthermore, the MVCC design makes conventional decentralised control perform comparably to MPC.     

Selective CO-oxidation over Ru-based catalysts in H2-rich gas for fuel cell applications

Topics in Catalysis - Ru-based catalysts supported on A zeolites and alumina were synthesised, characterised (XRD, SEM-EDS, TPR) and tested under realistic conditions for the preferential oxidation...