1,005 research outputs found

    On the long-period accuracy behavior of inductive and low-power instrument transformers

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    The accuracy evaluation of instrument transformers is always a key task when proper control and management of the power network is required. In particular, accuracy becomes a critical aspect when the grid or the instrumentation itself is operating at conditions different from the rated ones. However, before focusing on the above non-rated conditions, it is important to fully understand the instrument transformer behavior at rated conditions. To this end, this work analyzed the accuracy behavior of legacy, inductive, and low-power voltage transformers over long periods of time. The aim was to find patterns and correlations that may be of help during the modelling or the output prediction of voltage transformers. From the results, the main differences between low-power and inductive voltage transformers were pointed out and described in detail

    Are inductive current transformers performance really affected by actual distorted network conditions? An experimental case study

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    The aim of this work is to assess whether actual distorted conditions of the network are really affecting the accuracy of inductive current transformers. The study started from the need to evaluate the accuracy performance of inductive current transformers in off-nominal conditions, and to improve the related standards. In fact, standards do not provide a uniform set of distorted waveforms to be applied on inductive or low-power instrument transformers. Moreover, there is no agreement yet, among the experts, about how to evaluate the uncertainty of the instrument transformer when the operating conditions are different from the rated ones. To this purpose, the authors collected currents from the power network and injected them into two off-the-shelf current transformers. Then, their accuracy performances have been evaluated by means of the well-known composite error index and an approximated version of it. The obtained results show that under realistic non-rated conditions of the network, the tested transformers show a very good behavior considering their nonlinear nature, arising the question in the title. A secondary result is that the use of the composite error should be more and more supported by the standards, considering its effectiveness in the accuracy evaluation of instrument transformers for measuring purposes

    18F-FDG PET-Derived Volume-Based Parameters to Predict Disease-Free Survival in Patients with Grade III Breast Cancer of Different Molecular Subtypes Candidates to Neoadjuvant Chemotherapy

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    We investigated whether baseline [F-18] Fluorodeoxyglucose (F-18-FDG) positron emission tomography (PET)-derived semiquantitative parameters could predict disease-free survival (DFS) in patients with grade III breast cancer (BC) of different molecular subtypes candidate to neoadjuvant chemotherapy (NAC). For each F-18-FDG-PET/CT scan, the following parameters were calculated in the primary tumor (SUVmax, SUVmean, MTV, TLG) and whole-body (WB_SUVmax, WB_MTV, and WB_TLG). Receiver operating characteristic (ROC) analysis was used to determine the capability to predict DFS and find the optimal threshold for each parameter. Ninety-five grade III breast cancer patients with different molecular types were retrieved from the databases of the University Hospital of Padua and the University Hospital of Ferrara (luminal A: 5; luminal B: 34; luminal B-HER2: 22; HER2-enriched: 7; triple-negative: 27). In luminal B patients, WB_MTV (AUC: 0.75; best cut-off: WB_MTV > 195.33; SS: 55.56%, SP: 100%; p = 0.002) and WB_TLG (AUC: 0.73; best cut-off: WB_TLG > 1066.21; SS: 55.56%, SP: 100%; p = 0.05) were the best predictors of DFS. In luminal B-HER2 patients, WB_SUVmax was the only predictor of DFS (AUC: 0.857; best cut-off: WB_SUVmax > 13.12; SS: 100%; SP: 71.43%; p < 0.001). No parameter significantly affected the prediction of DFS in patients with grade III triple-negative BC. Volume-based parameters, extracted from baseline F-18-FDG PET, seem promising in predicting recurrence in patients with grade III luminal B and luminal B- HER2 breast cancer undergoing NAC

    Inertial Sensors in Swimming: Detection of Stroke Phases through 3D Wrist Trajectory.

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    Monitoring the upper arm propulsion is a crucial task for swimmer performance. The swimmer indeed can produce displacement of the body by modulating the upper limb kinematics. The present study proposes an approach for automatically recognize all stroke phases through three-dimensional (3D) wrist\u2019s trajectory estimated using inertial devices. Inertial data of 14 national-level male swimmer were collected while they performed 25 m front-crawl trial at intensity range from 75% to 100% of their 25 m maximal velocity. The 3D coordinates of the wrist were computed using the inertial sensors orientation and considering the kinematic chain of the upper arm biomechanical model. An algorithm that automatically estimates the duration of entry, pull, push, and recovery phases result from the 3D wrist\u2019s trajectory was tested using the bi-dimensional (2D) video-based systems as temporal reference system. A very large correlation (r = 0.87), low bias (0.8%), and reasonable Root Mean Square error (2.9%) for the stroke phases duration were observed using inertial devices versus 2D video-based system methods. The 95% limits of agreement (LoA) for each stroke phase duration were always lower than 7.7% of cycle duration. The mean values of entry, pull, push and recovery phases duration in percentage of the complete cycle detected using 3D wrist\u2019s trajectory using inertial devices were 34.7 (\ub1 6.8)%, 22.4 (\ub1 5.8)%, 14.2 (\ub1 4.4)%, 28.4 (\ub1 4.5)%. The swimmer\u2019s velocity and arm coordination model do not affect the performance of the algorithm in stroke phases detection. The 3D wrist trajectory can be used for an accurate and complete identification of the stroke phases in front crawl using inertial sensors. Results indicated the inertial sensor device technology as a viable option for swimming arm-stroke phase assessment

    Therapeutic Radiometals: Global Trends Analysis of Scientific Literature (2008 -2018)

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    Background-aim: Academic journals have published a large number of papers in the therapeutic NM research field in the last 10 years. Despite this, a literature analysis has never been made before to point out the research interest in therapeutic radionuclides (RNs). For this reason, the present study has the aim to specifically analyze the research output on therapeutic radiometals from 2008 (January) to 2018 (October) with the aim to quantify and identify the global trend of scientific literature and emphasize the interdisciplinary nature of this research field. Methods: The data search has been targeted on conventional (I-131, Y-90, Lu-177, Re-188, Re-186, Sm-153, Sr-89, Er-186) and emergent (Cu-67, Sc-47, Ra-223, Ho-166, Tb-161, Tb-149, Pb-212/Bi-212, Ac225, Bi-213, At-211, Sn-117) RNs. Authors, starting from this time frame data, have been quantitatively first, and qualitatively after, analyzed and interpreted the scientific trend of this topic. Bibliometric data have been exported from Scopus database and elaborated with Excel. The number of article, article in press, note, short survey, review and letter, have been divided per year and RN with the aim to make perceptible the trend of the last decade. Data have been categorized also in terms of Journal Subject Areas in order to bring out the multidisciplinary nature of the research in this field. Finally, for each publication, authors country provenience have been extrapolated and elaborated to map the global researcher interest and involvement of human and financial resources. Results: A total of 12.717 publications have been analyzed. 81.3% of the publications regards conventional RNs while 18.7% regards emergent RNs. The most investigated therapeutic RNs are I-131, Y-90, Lu-177 among conventional, Ra-223, followed by Sn-117, Bi213 and Ac-225 among emergent RNs. From the analysis, it is evident the multidisciplinary contribution to this field but in particular, as expected, in the case of conventional RN most publications comes from preclinical and clinical fields while for the emergents the contribution is unbalanced for Physics, Engineering, Material Science fields mainly focused on emergent RNs production studies. From the geographical point of view we can see how almost half of the total works have been published by European in both conventional and Clin Transl Imaging (2019) 7 (Suppl 1):S1–S138 S127 123 emergent RNs categories. It is also evident the high collaboration grade between countries characteristics in line with the multidisciplinarity of this medical sector. Moreover, we extrapolated a countries top 20 for each category. On the podium for the conventional RNs are USA, Germany and China, while for emergent RNs are USA, Germany, United Kingdom. And much more. Conclusions: From this analysis arise that the success of NM has been intimately linked to the availability of new RNs and the radiopharmaceuticals field is constantly evolving thanks to the contribution of specialists coming from different disciplines and the collaboration between countries. In recent years the focus of the research shifted on the field of emergent therapeutic radioisotope production and application, such as Cu-67, Sc-47, for the interest in new treatment strategies such as the theranostics personalized approach. Alpha emitters, in particular Ra-223 and Ac-225 are also gaining attention in particular in USA and Germany. Instead, among conventional radionuclides the research on Lu-177 is constantly growing

    Extra virgin olive oil phenol extracts exert hypocholesterolemic effects through the modulation of the LDLR pathway: In vitro and cellular mechanism of action elucidation

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    This study was aimed at investigating the hypocholesterolemic effects of extra virgin olive oil (EVOO) phenols and the mechanisms behind the effect. Two phenolic extracts were prepared from EVOO of different cultivars and analyzed using the International Olive Council (IOC) official method for total phenols, a recently validated hydrolytic procedure for total hydroxytyrosol and tyrosol, and 1H-NMR analysis in order to assess their secoiridoid profiles. Both of the extracts inhibited in vitro the 3-hydroxy-3-methylglutaryl co-enzyme A reductase (HMGCoAR) activity in a dose-dependent manner. After the treatment of human hepatic HepG2 cells (25 µg/mL), they increased the low-density lipoprotein (LDL) receptor protein levels through the activation of the sterol regulatory element binding proteins (SREBP)-2 transcription factor, leading to a better ability of HepG2 cells to uptake extracellular LDL molecules with a final hypocholesterolemic effect. Moreover, both of the extracts regulated the intracellular HMGCoAR activity through the increase of its phosphorylation by the activation of AMP-activated protein kinase (AMPK)-pathways. Unlike pravastatin, they did not produce any unfavorable effect on proprotein convertase subtilisin/kexin 9 (PCSK9) protein level. Finally, the fact that extracts with different secoiridoid profiles induce practically the same biological effects suggests that the hydroxytyrosol and tyrosol derivatives may have similar roles in hypocholesterolemic activity

    Extra virgin olive oil phenol extracts exert hypocholesterolemic effects through the modulation of the LDLR pathway: In vitro and cellular mechanism of action elucidation

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    This study was aimed at investigating the hypocholesterolemic effects of extra virgin olive oil (EVOO) phenols and the mechanisms behind the effect. Two phenolic extracts were prepared from EVOO of different cultivars and analyzed using the International Olive Council (IOC) official method for total phenols, a recently validated hydrolytic procedure for total hydroxytyrosol and tyrosol, and1 H-NMR analysis in order to assess their secoiridoid profiles. Both of the extracts inhibited in vitro the 3-hydroxy-3-methylglutaryl co-enzyme A reductase (HMGCoAR) activity in a dose-dependent manner. After the treatment of human hepatic HepG2 cells (25 µg/mL), they increased the low-density lipoprotein (LDL) receptor protein levels through the activation of the sterol regulatory element binding proteins (SREBP)-2 transcription factor, leading to a better ability of HepG2 cells to uptake extracellular LDL molecules with a final hypocholesterolemic effect. Moreover, both of the extracts regulated the intracellular HMGCoAR activity through the increase of its phosphorylation by the activation of AMP-activated protein kinase (AMPK)-pathways. Unlike pravastatin, they did not produce any unfavorable effect on proprotein convertase subtilisin/kexin 9 (PCSK9) protein level. Finally, the fact that extracts with different secoiridoid profiles induce practically the same biological effects suggests that the hydroxytyrosol and tyrosol derivatives may have similar roles in hypocholesterolemic activity

    Acute effects of a high volume vs. High intensity bench press protocol on electromechanical delay and muscle morphology in recreationally trained women

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    The purpose of the present investigation was to compare the acute responses on muscle architecture, electromechanical delay (EMD) and performance following a high volume (HV: 5 sets of 10 reps at 70% of 1 repetition maximum (1RM)) and a high intensity (HI: 5 sets of 3 reps at 90% of 1RM) bench press protocol in women. Eleven recreationally trained women (age = 23.3 ± 1.8 y; body weight = 59.7 ± 6.0 kg; height = 164.0 ± 6.3 cm) performed each protocol in a counterbalanced randomized order. Muscle thickness of pectoral (PEC MT) and triceps muscles (TR MT) were collected prior to and 15 min post each trial. In addition, EMD of pectoral (PEC EMD) and triceps (TR EMD) muscles were calculated during isometric bench press maximum force tests performed at the same timepoints (IBPF). Significantly greater increases in PEC MT (p < 0.001) and TR MT (p < 0.001) were detected following HV compared to HI. PEC EMD showed a significantly greater increase following HV compared to HI (p = 0.039). Results of the present study indicate that the HV bench press protocol results in greater acute morphological and neuromuscular changes compared to a HI protocol in women. Evaluations of muscle morphology and electromechanical delay appear more sensitive to fatigue than maximum isometric force assessments

    Analisi della suscettibilitĂ  da frana a scala di bacino (Bacino del Fiume Arno, Toscana-Umbria, Italia)

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    In questa nota vengono presentati i metodi applicati e i risultati ottenuti in una recente analisi della pericolosità da frana, condotta sul territorio del Bacino del Fiume Arno nell’ambito di una convenzione tra l’Autorità di Bacino e il Dipartimento di Scienze della Terra dell’Università di Firenze (2002-2005). Tutti i dati acquisiti, confluiti in una banca dati GIS, sono stati sintetizzati in carte tematiche e in una carta inventario delle frane. La sovrapposizione dei fattori predisponenti selezionati (pendenza, litologia, uso del suolo, curvatura di profilo e area drenata) ha permesso di definire le unità elementari per il trattamento statistico (Unità Territoriali Omogenee: UTO). La valutazione della pericolosità è stata estesa alle aree prive di movimenti franosi utilizzando metodi statistici multivariati implementati in Reti Neurali Artificiali. L’area di studio è stata suddivisa in cinque Macroaree morfologicamente e geologicamente omogenee: per ogni Macroarea, i predittori neurali sono stati addestrati su un opportuno sottoinsieme di dati, applicando poi i migliori all’intero data-set al fine di generare valori previsti dell’indice di suscettibilità per ogni UTO. Infine, i valori di uscita sono stati riclassificati in differenti livelli di pericolosità in base a criteri di soglia e validati per confronto con l’inventario. Una percentuale di area in frana compresa tra l’81 e il 96% risulta correttamente classificata dalla previsione nelle varie Macroare
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