2,793 research outputs found
Extracting fetal heart beats from maternal abdominal recordings: Selection of the optimal principal components
This study presents a systematic comparison of different approaches to the automated selection of the principal components (PC) which optimise the detection of maternal and fetal heart beats from non-invasive maternal abdominal recordings. A public database of 75 4-channel non-invasive maternal abdominal recordings was used for training the algorithm. Four methods were developed and assessed to determine the optimal PC: (1) power spectral distribution, (2) root mean square, (3) sample entropy, and (4) QRS template. The sensitivity of the performance of the algorithm to large-amplitude noise removal (by wavelet de-noising) and maternal beat cancellation methods were also assessed. The accuracy of maternal and fetal beat detection was assessed against reference annotations and quantified using the detection accuracy score F1 [2*PPV*Se / (PPV + Se)], sensitivity (Se), and positive predictive value (PPV). The best performing implementation was assessed on a test dataset of 100 recordings and the agreement between the computed and the reference fetal heart rate (fHR) and fetal RR (fRR) time series quantified. The best performance for detecting maternal beats (F1 99.3%, Se 99.0%, PPV 99.7%) was obtained when using the QRS template method to select the optimal maternal PC and applying wavelet de-noising. The best performance for detecting fetal beats (F1 89.8%, Se 89.3%, PPV 90.5%) was obtained when the optimal fetal PC was selected using the sample entropy method and utilising a fixed-length time window for the cancellation of the maternal beats. The performance on the test dataset was 142.7 beats2/min2 for fHR and 19.9 ms for fRR, ranking respectively 14 and 17 (out of 29) when compared to the other algorithms presented at the Physionet Challenge 2013
A Macroscopic Mathematical Model For Cell Migration Assays Using A Real-Time Cell Analysis
Experiments of cell migration and chemotaxis assays have been classically
performed in the so-called Boyden Chambers. A recent technology, xCELLigence
Real Time Cell Analysis, is now allowing to monitor the cell migration in real
time. This technology measures impedance changes caused by the gradual increase
of electrode surface occupation by cells during the course of time and provide
a Cell Index which is proportional to cellular morphology, spreading, ruffling
and adhesion quality as well as cell number. In this paper we propose a
macroscopic mathematical model, based on \emph{advection-reaction-diffusion}
partial differential equations, describing the cell migration assay using the
real-time technology. We carried out numerical simulations to compare simulated
model dynamics with data of observed biological experiments on three different
cell lines and in two experimental settings: absence of chemotactic signals
(basal migration) and presence of a chemoattractant. Overall we conclude that
our minimal mathematical model is able to describe the phenomenon in the real
time scale and numerical results show a good agreement with the experimental
evidences
Recurring patterns in stationary intervals of abdominal uterine electromyograms during gestation
Abdominal uterine electromyograms (uEMG) studies have focused on uterine contractions to describe the evolution of uterine activity and preterm birth (PTB) prediction. Stationary, non-contracting uEMG has not been studied. The aim of the study was to investigate the recurring patterns in stationary uEMG, their relationship with gestation age and PTB, and PTB predictivity. A public database of 300 (38 PTB) three-channel (S1-S3) uEMG recordings of 30 min, collected between 22 and 35 weeks' gestation, was used. Motion and labour contraction-free intervals in uEMG were identified as 5-min weak-sense stationarity intervals in 268 (34 PTB) recordings. Sample entropy (SampEn), percentage recurrence (PR), percentage determinism (PD), entropy (ER), and maximum length (L MAX) of recurrence were calculated and analysed according to the time to delivery and PTB. Random time series were generated by random shuffle (RS) of actual data. Recurrence was present in actual data (p<0.001) but not RS. In S3, PR (p<0.005), PD (p<0.01), ER (p<0.005), and L MAX (p<0.05) were higher, and SampEn lower (p<0.005) in PTB. Recurrence indices increased (all p<0.001) and SampEn decreased (p<0.01) with decreasing time to delivery, suggesting increasingly regular and recurring patterns with gestation progression. All indices predicted PTB with AUC≥0.62 (p<0.05). Recurring patterns in stationary non-contracting uEMG were associated with time to delivery but were relatively poor predictors of PTB
Advertising city. L'arte di svelare lo spazio urbano
La tesi indaga il ruolo della pubblicità outdoor nella città storica europea, un campo di “limite” inedito o poco esplorato, offrendo una nuova interpretazione della prassi ormai diffusa della sponsorizzazione dei beni monumentali da parte dei privati.
Colmando una lacuna della letteratura esistente dove il ruolo della pubblicità nella pratica architettonica è generalmente studiato dal punto di vista delle grandi metropoli e solo raramente in relazione alla monumentalità della città storica, “Advertising city. L’arte di svelare lo spazio urbano” fornisce un contributo al tema pubblicità in ambito disciplinare affrontando la questione delle trasformazioni dello spazio urbano ad opera dello strumento pubblicitario.
La ricostruzione del quadro teorico-concettuale avviene ripercorrendo il mutuo scambio tra pubblicità -arte-architettura nella storia delle città attraverso la selezione, rilettura e sistematizzazione unitaria di esempi paradigmatici eterogenei, tratti dal campo pubblicitario, artistico e architettonico, che restituiscono un ampio e inedito quadro di riferimento sul rapporto “architettura-pubblicità ” e sul “potenziale dell’effimero” nella costruzione dell’urbano.
Alla pubblicità vengono riconosciute alcune potenzialità latenti che si fondano sulla tecnica comune a quella artistica, dello “straniamento”; a partire dalla condizione di “frattura” operata dall'affissione pubblicitaria nelle scene urbane viene esplorata la possibilità di rileggere il processo machiavellico di sponsorizzazione come strumento prefigurativo di nuovi assetti architettonici di spazi e parti di città .
Le sperimentazioni condotte a Napoli, Milano e Atene, casi emblematici nell’ambito delle città storiche europee, dei diversi approcci ai meccanismi e alle pratiche di sponsorizzazione messi in campo in relazione al rapporto Monumento-Pubblicità muovono alla costruzione dell’ipotesi della ricerca.
La logica sistemica di Monumentando Napoli, il mutuo legame arte pubblicità messo in scena da In Alto, arte sui ponteggi a Milano, la logica negazionista di Atene che annunciando il No del Kas alla sfilata di Gucci sull’Acropoli rilancia mediaticamente il Brand Partenone, evidenziano gli esiti di tecniche pubblicitarie efficaci dal punto di vista della disciplina architettonica. Dimostrando che attraverso le potenzialità mediatiche stranianti dell’effimero è possibile restituire visibilità a monumenti marginalizzati, creare nuove scenografie conferendo eccezionalità a ciò che appare ordinario, determinare associazioni inedite in spazi consolidati attraverso itinerari sottesi alle logiche mediatiche, alle strategie di marketing e visibilità , l’impacchettamento dei monumenti ad opera dei ponteggi, inevitabile conseguenza dell’organizzazione tecnica e pratica dei cantieri, viene riletto come “installazione” e come metodo di astrazione delle forme del monumento, che può mettere in luce lati inediti dell’oggetto occultato.
La tesi sovverte il punto di vista che tende a considerare l’effimero come orpello inquinante la purezza dell’architettura reinterpretandolo come potenziale strumento di sperimentazione di logiche compositive altre che, oltre al reperimento di fondi necessari per il restauro dei monumenti, consenta di rivelare significati e relazioni spaziali inedite di un patrimonio culturale che necessita di essere riscoperto e rivitalizzato. Come l’arte, la pubblicità viene ridefinita da un ruolo conoscitivo sperimentale in grado di manipolare e costruire sull’esistente effimere composizioni urbane finalizzate a ri-contestualizzare e ridefinire, in senso “rossiano”, un rinnovato ruolo attivo significante per il monumento marginalizzato e dimenticato.
La tesi perviene all’individuazione di alcune categorie operative e tecniche architettoniche che aprono la strada a nuove sperimentazioni architettoniche (di lettura o costruzione) sulla città storica contemporanea, in grado di veicolare, attraverso il progetto, la condizione di straniamento prodotta dall’apparato effimero pubblicitario. “Quattro modi del comporre il nascondere per mostrare” vengono così definiti: “Il Monumento nobilitato: occultare per riscattare”, “Il Monumento sostituito: occultare per esporre”, “Il Monumento trasformato: s-montare per allestire”, “Il Monumento percorso: (1+2+3)xn volte”
Acute disseminated encephalomyelitis presenting as fever of unknown origin: case report
BACKGROUND: Fever of unknown origin (FUO) can be defined as a body temperature higher than 38.3°C on several occasions over more than 3 weeks, the diagnosis of which remains uncertain after 1 week of evaluation. Acute disseminated encephalomyelitis (ADEM) is an inflammatory demyelinating disease of the central nervous system with a wide range of clinical manifestations. The highest incidence of ADEM is observed during childhood and it usually occurs following a viral or bacterial infection or, more rarely, following a vaccination, or without a preceding cause. CASE PRESENTATION: Here, we describe an atypical case of ADEM that initially manifested as several weeks of FUO in a fifteen years old boy. CONCLUSIONS: This case report suggests a new possible syndromic association between ADEM and FUO, which should be considered in the clinical examination of patients with FUO, especially in the presence of also modest neurologic or neuropsychiatric symptoms
Acute Disseminated Encephalomyelitis Presenting as Fever of Unknown Origin: Case Report
Background: Fever of unknown origin (FUO) can be defined as a body temperature higher than 38.3°C on several occasions over more than 3 weeks, the diagnosis of which remains uncertain after 1 week of evaluation. Acute disseminated encephalomyelitis (ADEM) is an inflammatory demyelinating disease of the central nervous system (CNS) with a wide range of clinical manifestations. The highest incidence of ADEM is observed during childhood and it usually occurs following a viral or bacterial infection or, more rarely, following a vaccination, or without a preceding cause. Case presentation: Here, we describe an atypical case of ADEM that initially manifested as several weeks of FUO in a 15 years old boy. Conclusions: This case report suggests a new possible syndromic association between ADEM and FUO, which should be considered in the clinical examination of patients with FUO, especially in the presence of also modest neurologic or neuropsychiatric symptoms. 
Prevention of postoperative atrial fibrillation in open heart surgery patients by preoperative supplementation of n-3 polyunsaturated fatty acids: An updated meta-analysis
BackgroundSeveral randomized clinical trials evaluated whether preoperative supplementation of omega-3 (n-3) polyunsaturated fatty acids protects against postoperative atrial fibrillation after cardiac surgery, a condition associated with increased cardiac and cerebral mortality. However, their efficacy remains still controversial. An updated meta-analysis was performed to clarify if preoperative n-3 polyunsaturated fatty acid supplementation prevents postoperative atrial fibrillation in patients undergoing cardiac surgery.MethodsArticles were retrieved until November 2012 by screening electronic databases (PubMed, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials) and cross references. Two of us independently reviewed articles and agreed to select 8 randomized clinical trials. For each study, the incidence of atrial fibrillation in both the intervention and placebo groups was extracted to calculate odd ratio and 95% confidence intervals (CIs). Weighted study-specific estimates were combined using fixed (Mantel-Haenszel method) and random-effects (DerSimonian-Laird method) models.ResultsThis meta-analysis includes 2687 patients (1337 in the intervention group) who underwent cardiac surgery. Pooled analysis using fixed-effects models showed a significant reduction (average, 16%; 95% CI, 1%-29%) in postoperative atrial fibrillation by preoperative n-3 polyunsaturated fatty acids. There was a low heterogeneity among studies (PÂ =Â .07 and I2Â =Â 46%). By using a random-effects model, the reduction averaged 25% (odds ratio, 0.75; 95% CI, 0.57-1.00; PÂ =Â .05). When isolated coronary artery bypass graft surgery was only considered (7 studies), a significant protection averaging 34% was observed in a fixed model (odds ratio, 0.66; 95% CI, 0.50-0.87; PÂ =Â .003; I2Â =Â 26%, PÂ =Â .23).ConclusionsA preoperative supplementation of n-3 polyunsaturated fatty acids significantly prevents the occurrence of postoperative atrial fibrillation in patients undergoing cardiac surgery, in particular coronary artery bypass surgery
Formal techniques in the safety analysis of software components of a new dialysis machine
The paper is concerned with the practical use of formal techniques to contribute to the risk analysis of a new neonatal dialysis machine. The described formal analysis focuses on the controller component of the software implementation. The controller drives the dialysis cycle and deals with error management. The logic was analysed using model checking techniques and the source code was analysed formally, checking type correctness conditions, use of pointers and shared memory. The analysis provided evidence of the verification of risk control measures relating to the software component. The productive dialogue between the developers of the device, who had no experience or knowledge of formal methods, and the analyst using the formal analysis tools, provided a basis for the development of rationale for the effectiveness of the evidence. (C) 2019 Elsevier B.V. All rights reserved.This work has been funded by: EPSRC research grants EP/G059063/1 and EP/J008133/1: CHI+MED (Computer -Human Interaction for Medical Devices); and NanoSTIMA (ref. NORTE-01-0145-FEDER-000016) financed by the North Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, and through the European Regional Development Fund (ERDF). Leo Freitas would like to acknowledge EPSRC Trams2 project for financial support, Andrew Sims for providing access to the dialyser, which was used as our case study and Aleksandrs Baklanovs for doing some of the source analysis as part of an undergraduate project
What is the role of locoregional anesthesia in breast surgery? A systematic literature review focused on pain intensity, opioid consumption, adverse events, and patient satisfaction
Breast surgery in the United States is common. Pain affects up to 50% of women undergoing breast surgery and can interfere with postoperative outcomes. General anesthesia is the conventional, most frequently used anaesthetic technique. Various locoregional anesthetic techniques are also used for breast surgeries. A systematic review of the use of locoregional anesthesia for postoperative pain in breast surgery is needed to clarify its role in pain management
Cost Minimization Analysis of Radiofrequency Compared to Laser Thermal Ablation in Patients with Hepatocellular Carcinoma
BACKGROUND: Over the last decade of years, minimally invasive techniques have been developed for the treatment of hepatocellular carcinoma and liver metastases. We sought to investigate the health costs associated with the management of patients with hepatocellular carcinoma treated with radiofrequency vs laser thermal ablation and their clinical outcomes.METHODS: We performed a retrospective analysis of the ablations performed in two referral centers in southern Italy, from 2009 to 2013. Resource use was valued by year 2017 official prices, in €. Direct healthcare costs (drugs, visits, tests and hospitalizations) of different ablation techniques were compared. Total costs were analyzed from Italian NHS perspective.RESULTS: A total of 140 patients were identified. Baseline demographics and clinical outcomes of interest did not differ between the two groups. Patients treated with laser thermal ablation resulted in an expected annually cost savings of 258.9 € per patient, in one-year follow-up healthcare costs compared with radiofrequency. The largest components of annual medical expenditures were attributable to drugs, regardless of the type of ablative technique.CONCLUSIONS: The ablation using either laser thermal ablation or radiofrequency is equally effective. Laser thermal ablation would carry disposable cost savings as compared to radiofrequency. The costs associated with management of patients with hepatocellular carcinoma, treated with laser thermal ablation were lower than those treated with radiofrequency ablation
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