Acquisition efficiency of Flavescence dorée phytoplasma by Scaphoideus titanus Ball from infected tolerant or susceptible grapevine cultivars or experimental host plants

The rate of Flavescence dorée phytoplasma (FDP) acquisition by the leafhopper vector Scaphoideus titanus Ball was tested under field and glass house conditions confining healthy reared nymphs on canes of FDP-infected grapevines or on FDP-infected cuttings collected in the field during the dormant season. Acquisition tests were performed using FD-tolerant (Merlot) or highly susceptible (Pinot blanc) grapevine cultivars, or alternatively using experimentally infected broadbean plants. Frequency of FDP acquisition by leafhoppers was evaluated using a polymerase chain reaction (PCR) assay. Different batches of insects were confined on the same infected source plants in the vineyard for acquisition access periods (AAP) of 7 d at a time at intervals of 15-20 d during spring and summer. When diseased Pinot blanc grapevines were used as source plants, acquisition by leafhoppers and transmission to healthy grapevines increased over summer, while almost no acquisition or transmission was observed when diseased Merlot grapevines were used as source plants. Tests conducted under controlled conditions confirmed that Merlot is a poorer source of FDP than Pinot blanc; the optimum FDP source for S. titanus was broadbean although this plant is not a natural host of the leafhopper. It is assumed that grapevine cultivars play an important role in influencing the proportion of FDP-infected leafhoppers in the vineyards and therefore influencing the rate of disease progress.

Minimal Extrathyroidal Extension in Predicting 1-Year Outcomes: A Longitudinal Multicenter Study of Low-to-Intermediate-Risk Papillary Thyroid Carcinoma (ITCO#4)

Background: The role of minimal extrathyroidal extension (mETE) as a risk factor for persistent papillary thyroid carcinoma (PTC) is still debated. The aims of this study were to assess the clinical impact of mETE as a predictor of worse initial treatment response in PTC patients and to verify the impact of radioiodine therapy after surgery in patients with mETE. Methods: We reviewed all records in the Italian Thyroid Cancer Observatory database and selected 2237 consecutive patients with PTC who satisfied the inclusion criteria (PTC with no lymph node metastases and at least 1 year of follow-up). For each case, we considered initial surgery, histological variant of PTC, tumor diameter, recurrence risk class according to the American Thyroid Association (ATA) risk stratification system, use of radioiodine therapy, and initial therapy response, as suggested by ATA guidelines. Results: At 1-year follow-up, 1831 patients (81.8%) had an excellent response, 296 (13.2%) had an indeterminate response, 55 (2.5%) had a biochemical incomplete response, and 55 (2.5%) had a structural incomplete response. Statistical analysis suggested that mETE (odds ratio [OR] 1.16, p = 0.65), tumor size >2 cm (OR 1.45, p = 0.34), aggressive PTC histology (OR 0.55, p = 0.15), and age at diagnosis (OR 0.90, p = 0.32) were not significant risk factors for a worse initial therapy response. When evaluating the combination of mETE, tumor size, and aggressive PTC histology, the presence of mETE with a >2 cm tumor was significantly associated with a worse outcome (OR 5.27 [95% confidence interval], p = 0.014). The role of radioiodine ablation in patients with mETE was also evaluated. When considering radioiodine treatment, propensity score-based matching was performed, and no significant differences were found between treated and nontreated patients (p = 0.24). Conclusions: This study failed to show the prognostic value of mETE in predicting initial therapy response in a large cohort of PTC patients without lymph node metastases. The study suggests that the combination of tumor diameter and mETE can be used as a reliable prognostic factor for persistence and could be easily applied in clinical practice to manage PTC patients with low-to-intermediate risk of recurrent/persistent disease

Radiation performance of new semiconductor power devices for the LHC experiment upgrades

11th International Conference on Large Scale Applications and Radiation Hardness of Semiconductor Detectors, RD 201

The Asymmetrical Half-Bridge Flyback Converter: A Reexamination

Isolated Zero-Voltage-Switching (ZVS) dc-dc converter topologies are attractive solutions in the continuous ride toward higher switching frequencies, allowing more compact power supplies. Among them, the Asymmetrical Half-Bridge Flyback Converter (AHBFC) represents an interesting solution, featuring a simple duty-cycle control at a constant switching frequency, as opposed to the popular LLC converter. The majority of the papers dealing with this topology, present an approximated voltage gain which is similar to an isolated Buck converter, i.e. proportional to the duty-cycle. However, when the converter is designed for a resonant operation, so as to eliminate any reverse recovery problem of the rectifier diode, its voltage gain can be quite different, becoming non monotonic and a function of the switching frequency. This paper investigates this aspect, deriving a theoretical framework capable of capturing its real voltage gain behavior. The proposed analytical model has been verified through simulations as well as experimental measurements taken on a 160W prototype working at 400kHz

Line-frequency commutated rectifier complying with IEC 1000-3-2 standards

Consumer and household appliances require cheap ac/dc power supplies complying with EMC standards. The commonly employed passive solutions are bulky and do not provide output voltage stabilization. Active solutions, based on PFC's with high-frequency switching, provide compactness and regulation capability, but are generally expensive due to the need for fast-recovery diodes and complex EMI filters. This paper presents a high power factor rectifier, based on a modified conventional rectifier with passive L-C filter, which improves both the harmonic content of the input current and the power factor, by means of a low frequency commutated switch and a small line-frequency transformer, and allows to comply with IEC 1000-3-2 standard with reduced overall inductive components' volume

Conducted EMI Issues in a Boost PFC Design

Abstract -The paper presents the results of an experimental activity concerned with the development of a 600W Boost Power Factor Corrector (PFC) complying with the EMC standards for conducted EMI in the 150kHz-30MHz range. In order to accomplish this task, different circuit design and layout solutions are taken into account and their effect on the conducted EMI behavior of the converter is experimentally evaluated. Common-mode and differential-mode switching noise, together with input filters' design and topology and with the PCB layout (in terms of track length and spacing, ground and shielding planes etc.) are the key aspects which have been analyzed. In particular, the paper reports the conducted EMI measurements for different filter capacitor placements and values, for different power switch drive circuits together with several other provisions which have turned out to be decisive in the reduction of the generated EMI

Conducted EMI issues in a Boost PFC design

The paper presents the results of an experimental activity concerned with the development of a 600 W Boost Power Factor Corrector (PFC) complying with the EMC standards for conducted EMI in the 150 kHz-30 MHz range. In order to accomplish this task, different circuit design and layout solutions are taken into account and their effect on the conducted EMI behavior of the converter is experimentally evaluated. Common-mode and differential-mode switching noise, together with input filters' design and topology and with the PCB layout (in terms of track length and spacing, ground and shielding planes etc.) are the key aspects which have been analyzed. In particular, the paper reports the conducted EMI measurements for different filter capacitor placements and values, for different power switch drive circuits together with several other provisions which have turned out to be decisive in the reduction of the generated EMI