591 research outputs found
Transient Analysis of Warm Electron Injection Programming of Double Gate SONOS Memories by means of Full Band Monte Carlo Simulation
In this paper we investigate "Warm Electron Injection" as a mechanism for NOR
programming of double-gate SONOS memories through 2D full band Monte Carlo
simulations. Warm electron injection is characterized by an applied VDS smaller
than 3.15 V, so that electrons cannot easily accumulate a kinetic energy larger
than the height of the Si/SiO2 barrier. We perform a time-dependent simulation
of the program operation where the local gate current density is computed with
a continuum-based method and is adiabatically separated from the 2D full Monte
Carlo simulation used for obtaining the electron distribution in the phase
space. In this way we are able to compute the time evolution of the charge
stored in the nitride and of the threshold voltages corresponding to forward
and reverse bias. We show that warm electron injection is a viable option for
NOR programming in order to reduce power supply, preserve reliability and CMOS
logic level compatibility. In addition, it provides a well localized charge,
offering interesting perspectives for multi-level and dual bit operation, even
in devices with negligible short channel effects
Two Dimensional Quantum Mechanical Modeling of Nanotransistors
Quantization in the inversion layer and phase coherent transport are
anticipated to have significant impact on device performance in 'ballistic'
nanoscale transistors. While the role of some quantum effects have been
analyzed qualitatively using simple one dimensional ballistic models, two
dimensional (2D) quantum mechanical simulation is important for quantitative
results. In this paper, we present a framework for 2D quantum mechanical
simulation of a nanotransistor / Metal Oxide Field Effect Transistor (MOSFET).
This framework consists of the non equilibrium Green's function equations
solved self-consistently with Poisson's equation. Solution of this set of
equations is computationally intensive. An efficient algorithm to calculate the
quantum mechanical 2D electron density has been developed. The method presented
is comprehensive in that treatment includes the three open boundary conditions,
where the narrow channel region opens into physically broad source, drain and
gate regions. Results are presented for (i) drain current versus drain and gate
voltages, (ii) comparison to results from Medici, and (iii) gate tunneling
current, using 2D potential profiles. Methods to reduce the gate leakage
current are also discussed based on simulation results.Comment: 12 figures. Journal of Applied Physics (to appear
Natural versus anthropic influence on north adriatic coast detected by geochemical analyses
This study focused on the geochemical and sedimentological characterization of recent sediments from two marine sites (S1 and E1) located in the North Adriatic Sea, between the Po River prodelta and the Rimini coast. Major and trace metal concentrations reflect the drainage area of the Po River and its tributaries, considered one of the most polluted areas in Europe. Sediment geochemistry of the two investigated sites denote distinct catchment areas. High values of Cr, Ni, Pb and Zn detected in sediments collected in the Po River prodelta (S1 site) suggest the Po River supply, while lower levels of these elements characterize sediments collected in front of the Rimini coast (E1 site), an indication of Northern Apennines provenance. Historical trends of Pb and Zn reconstructed from the sedimentary record around the E1 site document several changes that can be correlated with the industrialization subsequent to World War II, the implementation of the environmental policy in 1976 and the effects of the Comacchio dumping at the end of 1980. At the S1 site, the down core distributions of trace elements indicate a reduction of contaminants due to the introduction of the Italian Law 319/76 and the implementation of anti-pollution policies on automotive Pb (unleaded fuels) in the second half of the 1980s
Evaluation of Androgen Receptor in Relation to Estrogen Receptor (AR/ER) and Progesterone Receptor (AR/PgR): A New Must in Breast Cancer?
Steroid nuclear receptors are known to be involved in the regulation of epithelial-mesenchymal transition process with important roles in invasion and metastasis initiation. Androgen receptor (AR) has been extensively studied, but its role in relation to breast cancer patient prognosis remains to be clarified. AR/ER ratio has been reported to be an unfavorable prognostic marker in early primary breast cancer, but its role in the patients with advanced disease has to be cleared. We retrospectively analyzed ER, PgR, and AR expression on a case series of 159 specimens of primary BC samples by using immunohistochemistry and 89 patients of these had luminal tumors for which AR and ER expression and survival data were available. For twenty-four patients both primary and metastatic tumors were available. A significantly shorter overall survival was observed in primary tumors with AR/PgR ratio 65 1.54 (HR = 2.27; 95% CI 1.30-3.97; p = 0.004). Similarly OS was significantly shorter when ER/PgR ratio 652 in primary tumors (HR = 1.89; 95% CI 1.10-3.24; p = 0.021). The analysis of the 24 patients who had biomarker determinations both in primary tumors and metastasis showed a better OS when AR/ER ratio in the metastasis was 65 0.90 (p = 0.022). Patients with a high AR/ER ratio in primary tumor that remained high in the metastasis had better prognosis in terms of OS (p = 0.011). Despite we suggested that the ratios AR/ER and AR/PgR could be used to identify patients with different prognosis, their real value needs to be better clarified in different BC settings through prospective studies
Planning and designing an integrated management of coastal hypoxia in the Emila Romagna region water (Northern Adriatic Sea)
Abstract The design of an integrated monitoring network useful for the early-warning, the management and mitigation of both the environmental and socio-economic costs of hypoxia/anoxia events in the Northern Adriatic coastal zone, south of the mouth of the Po river, is described in the contribute. It has been developed within the EMMA research project (Environmental Management through Monitoring and Modelling of Anoxia; LIFE04ENV/IT/0479) (2004-2007). Over the past few decades, hypoxia events have recurrently affected the coastal zone of Emilia Romagna Region (Italy). Data collected by the C.Z. lying in the Province of Rimini, because of its economic importance, are presented. The area is subjected to intense anthropogenic pressure due to its high population (416 000 equivalent inhabitants) with tourist seasonal peaks of up to 973 110 equivalent inhabitants (in summer time), to industrial and agricultural activity, to maritime traffic and nutrient river discharges (about 600 tons y-1 of nitrogen and 300 tons y-1 of phosphorus, in 2002). Hypoxia and anoxia have a negative effect on the quality of bathing waters as well as on fishing and mussel farming, which are important activities for the economy of the area. The planning of the monitoring network has been carried out by analyzing the scientific knowledge on hypoxia in the local area; its integration with other existing monitoring activities, available facilities and data resources was considered in order to optimize cost effectiveness of the network
Antibiotic prophylaxis in patients with cirrhosis: Current evidence for clinical practice
Patients with cirrhosis show an increased susceptibility to infection due to disease-related immune-dysfunction. Bacterial infection therefore represents a common, often detrimental event in patients with advanced liver disease, since it can worsen portal hypertension and impair the function of hepatic and extrahepatic organs. Among pharmacological strategies to prevent infection, antibiotic prophylaxis remains the first-choice, especially in high-risk groups, such as patients with acute variceal bleeding, low ascitic fluid proteins, and prior episodes of spontaneous bacterial peritonitis. Nevertheless, antibiotic prophylaxis has to deal with the changing bacterial epidemiology in cirrhosis, with increased rates of gram-positive bacteria and multidrug resistant rods, warnings about quinolones-related side effects, and low prescription adherence. Short-term antibiotic prophylaxis is applied in many other settings during hospitalization, such as before interventional or surgical procedures, but often without knowledge of local bacterial epidemiology and without strict adherence to antimicrobial stewardship. This paper offers a detailed overview on the application of antibiotic prophylaxis in cirrhosis, according to the current evidence
Operational evaluation of the Mediterranean Monitoring and Forecasting Centre products: implementation and results
A web-based validation platform has been developed at the Istituto Nazionale di Geofisica e Vulcanologia (INGV) for the Near Real Time validation of the MyOcean-Mediterranean Monitoring and Forecasting Centre products (Med-MFC). A network for the collection of the in-situ observations, the nested sub-basin forecasting systems model data (provided by the partners of the Mediterranean Operational Oceanography Network, MOON) and the Sea Surface Temperature (SST) satellite data has been developed and is updated every day with the new available data. The network collects temperature, salinity, currents and sea level data. The validation of the biogeochemical forecast products is done by use of ocean colour satellite data produced for the Mediterranean Sea. All the data are organized in an ad hoc database interfaced with a dedicated software which allows interactive visualizations and statistics (CalVal SW). This tool allows to evaluate NRT products by comparison with independent observations for the first time. The heterogeneous distribution and the scarcity of moored observations reflect with large areas uncovered with measurements. Nevertheless, the evaluation of the forecast at the locations of observations could be very useful to discover sub-regions where the model performances can be improved, thus yielding an important complement to the basin-mean statistics regularly calculated for the Mediterranean MFC products using semi-independent observations
Accuracy and reproducibility of contrast-enhanced mammography in the assessment of response to neoadjuvant chemotherapy in breast cancer patients with calcifications in the tumor bed
This study aimed to evaluate contrast-enhanced mammography (CEM) accuracy and reproducibility in the detection and measurement of residual tumor after neoadjuvant chemotherapy (NAC) in breast cancer (BC) patients with calcifications, using surgical specimen pathology as the reference. Pre-and post-NAC CEM images of 36 consecutive BC patients receiving NAC in 2012–2020, with calcifications in the tumor bed at diagnosis, were retrospectively reviewed by two radiologists; described were absence/presence and size of residual disease based on contrast enhancement (CE) only and CE plus calcifications. Twenty-eight patients (77.8%) had invasive and 5 (13.9%) in situ-only residual disease at surgical specimen pathology. Considering CE plus calcifications instead of CE only, CEM sensitivity for invasive residual tumor increased from 85.7% (95% CI = 67.3–96%) to 96.4% (95% CI = 81.7–99.9% ) and specificity decreased from 5/8 (62.5%; 95% CI = 24.5–91.5%) to 1/8 (14.3%; 95% CI = 0.4–57.9%). For in situ-only residual disease, false negatives decreased from 3 to 0 and false positives increased from 1 to 2. CEM pathology concordance in residual disease measurement increased (R squared from 0.38 to 0.45); inter-reader concordance decreased (R squared from 0.79 to 0.66). Considering CE plus calcifications to evaluate NAC response in BC patients increases sensitivity in detection and accuracy in measurement of residual disease but increases false positives
Making patient centered care a reality: A survey of patient educational programs in Italian Cancer Research and Care Institutes
Background: Educational intervention represents an essential element of care for cancer patients; while several single institutions develop their own patient education (PE) programs on cancer, little information is available on the effective existence of PE programs at the level of research and care institutes. In Italy such institutes - Istituti di Ricovero e Cura a Carattere Scientifico - are appointed by the Ministry of Health, and 11 (Cancer Research & Care Istitute-CRCI) of the 48 are specific for cancer on the basis of specific requirements regarding cancer care, research and education. Therefore, they represent an ideal and homogeneous model through which to investigate PE policies and activities throughout the country. The objective of this study was to assess PE activities in Italian CRCI. Methods: We carried out a survey on PE strategies and services through a questionnaire. Four key points were investigated: a) PE as a cancer care priority, b) activities that are routinely part of PE, c) real involvement of the patients, and d) involvement of healthcare workers in PE activities. Results: Most CRCI (85 %) completed the survey. All reported having ongoing PE activities, and 4 of the 11 considered PE an institutional activity. More than 90 % of CRCI organize classes and prepare PE handouts, while other PE activities (e.g., Cancer Information Services, mutual support groups) are less frequently part of institutional PE programs. Patients are frequently involved in the organization and preparation of educational activities on the basis of their own needs. Various PE activities are carried out for caregivers in 8 (73 %) out of 11 institutes. Finally, health care workers have an active role in the organization of PE programs, although nurses take part in these activities in only half of CRCI and pharmacists are seldom included. Conclusions: The information arising from our research constitutes a necessary framework to identify areas of development and to design new strategies and standards to disseminate the culture of PE. This may ultimately help and stimulate the establishment of institutional integrated PE programs, including policies and interventions that can benefit a significant proportion of cancer patients
Modelling approach to the assessment of biogenic fluxes at a selected Ross Sea site, Antarctica
Several biogeochemical data have been collected in the last 10 years of Italian activity in Antarctica (ABIOCLEAR, ROSSMIZE, BIOSESO-I/II). A comprehensive 1-D biogeochemical model was implemented as a tool to link observations with processes and to investigate the mechanisms that regulate the flux of biogenic material through the water column. The model is ideally located at station B (175° E–74° S) and was set up to reproduce the seasonal cycle of phytoplankton and organic matter fluxes as forced by the dominant water column physics over the period 1990–2001. Austral spring-summer bloom conditions are assessed by comparing simulated nutrient drawdown, primary production rates, bacterial respiration and biomass with the available observations. The simulated biogenic fluxes of carbon, nitrogen and silica have been compared with the fluxes derived from sediment traps data. The model reproduces the observed magnitude of the biogenic fluxes, especially those found in the bottom sediment trap, but the peaks are markedly delayed in time. Sensitivity experiments have shown that the characterization of detritus, the choice of the sinking velocity and the degradation rates are crucial for the timing and magnitude of the vertical fluxes. An increase of velocity leads to a shift towards observation but also to an overestimation of the deposition flux which can be counteracted by higher bacterial remineralization rates. Model results suggest that the timing of the observed fluxes depends first and foremost on the timing of surface production and on a combination of size-distribution and quality of the autochtonous biogenic material. It is hypothesized that the bottom sediment trap collects material originated from the rapid sinking of freshly-produced particles and also from the previous year's production period
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