1,857 research outputs found
A unifying view for performance measures in multi-class prediction
In the last few years, many different performance measures have been
introduced to overcome the weakness of the most natural metric, the Accuracy.
Among them, Matthews Correlation Coefficient has recently gained popularity
among researchers not only in machine learning but also in several application
fields such as bioinformatics. Nonetheless, further novel functions are being
proposed in literature. We show that Confusion Entropy, a recently introduced
classifier performance measure for multi-class problems, has a strong
(monotone) relation with the multi-class generalization of a classical metric,
the Matthews Correlation Coefficient. Computational evidence in support of the
claim is provided, together with an outline of the theoretical explanation
Heart, lung and vessels... but brain and hands too! The case for a novel journal in the cardiovascular scholarly arena
Diagnostic accuracy of myocardial perfusion imaging with czt technology. Systemic review and meta-analysis of comparison with invasive coronary angiography
OBJECTIVES:
This study sought to summarize the evidence on stress myocardial perfusion imaging (MPI) using cadmium-zinc-telluride (CZT) technology for the diagnosis of obstructive coronary artery disease (CAD). The CZT cameras are newly introduced, and comparative data with the conventional Anger technology (Anger-MPI) are lacking.
BACKGROUND:
The diagnostic accuracy of Anger-MPI for detection of angiographically significant CAD is well established; however, less evidence is available on the diagnostic accuracy of CZT-MPI.
METHODS:
Clinical studies comparing CZT-MPI and invasive coronary angiography were systematically searched and abstracted. Calculations of diagnostic accuracy, including sensitivity, specificity, likelihood ratios, and diagnostic odds ratio, were obtained with fixed and random effects, reporting point estimates and 95% confidence intervals.
RESULTS:
Based on our search, a total of 16 studies (N = 2,092) were included. The sensitivity of CZT-MPI was 0.84 (95% confidence interval [CI]: 0.78 to 0.89), whereas the specificity of 0.69 (95% CI: 0.62 to 0.76) was significantly reduced. The positive likelihood ratio was 2.73 (95% CI: 2.21 to 3.39), the negative likelihood ratio was 0.24 (95% CI: 0.17 to 0.31), and the diagnostic odds ratio was 11.93 (95% CI: 7.84 to 17.42). At subgroup and meta-regression analyses, the diagnostic accuracy between D-SPECT and Discovery cameras was similar (p = 0.711) and not impacted upon by smaller sample size studies (p = 0.573).
CONCLUSIONS:
CZT-MPI has satisfactory sensitivity for angiographically significant CAD, but its suboptimal specificity warrants further development and research
Impact of electronic alternatives to tobacco cigarettes on indoor air particular matter levels
An aerosol study was carried out in a test room measuring particulate matter (PM) with
an aerodynamic diameter smaller than 10, 4, 2.5 and 1 m (PM10, PM4, PM2.5, PM1) before and
during the use of electronic alternatives to tobacco cigarettes (EATC) IQOS®, GLO®, JUUL®, with
dierent kinds of sticks/pods, as well as during the smoking of a conventional tobacco cigarette.
The aerosol was mainly in the PM1 size range (>95%). All studied EATCs caused lower indoor PM1
concentrations than conventional tobacco cigarettes. Nevertheless, they determined a worsening of
indoor-PM1 concentration that ranged from very mild for JUUL®—depending on the pod used—to
considerably severe for IQOS® and GLO®. Median values ranged from 11.00 (Iqos3 and Juul2) to
337.5 g m3 (Iqos4). The high variability of particle loadings was attributed both to the type of
stick/pod used and to the dierent way of smoking of volunteers who smoked/vaped during the
experiments. Moreover, during vaping IQOS® and GLO® indoor PM1 concentrations reach levels
by far higher than outdoor concentrations that range from 14 to 21 g m3, especially during the
exhalation of the smoke. From these results emerge an urgent need of a legislative regulation limiting
the use of such devices in public places
Monitoring of minimal residual disease in leukemia, advantages and pitfalls.
The term 'minimal residual disease' (MRD) defines the level of disease detectable in patients in clinical remission during therapy, below the detection limit of conventional methods. Very sensitive methods can be used, able to identify one leukemic cell out of 10,000 normal lymphocytes. In vivo measurements of leukemia cytoreduction reflect the combined effect of clinical and biological variables, thus providing direct information on the effectiveness of treatment in each patient. Thus, these methods can potentially be used for tailoring treatment and personalize the cure. Although MRD studies are becoming an integral part of the modern management of patients with leukemia, several parameters are critical for the application and interpretation of MRD studies, including therapeutic context, timing of sampling, target genes and sensitivity of the polymerase chain reaction (PCR) assay, inter-laboratory standardization (particularly relevant in multicenter studies), selection of patients, retrospective or prospective nature of the study. Methodologies and pitfalls as well as results of clinical uses of MRD will be reviewed in this article by selecting significant examples of its clinical impact in the management of patients with leukemia
Generation of fully non-stationary random processes consistent with target seismic accelerograms
Abstract In this paper, a method for generating samples of a fully non-stationary zero-mean Gaussian process, having a target acceleration time-history as one of its own samples, is presented. The proposed method requires the following steps: i) divide the time axis of the target accelerogram in contiguous time intervals in which a uniformly modulated process is introduced as the product of a deterministic modulating function per a stationary zero-mean Gaussian sub-process, whose power spectral density (PSD) function is filtered by two Butterworth filters; ii) estimate, in the various time intervals, the parameters of modulating functions by least-square fitting the expected energy of the proposed model to the energy of the target accelerogram; iii) estimate the parameters of the PSD function of the stationary sub-process, once the occurrences of maxima and of zero-level up-crossings of the target accelerogram, in the various intervals, are counted; iv) obtain the evolutionary spectral representation of the fully non-stationary process by adding the various contribution evaluated in the various intervals
Padronização de metodologia baseada em HPLC e detecção eletroquímica para determinação do potencial de redução plasmático de pacientes com doença renal crônica
Resumo: Há um esforço mundial no sentido de validar biomarcadores de estresse oxidativo e os potenciais de redução dos pares tióis/dissulfetos, principalmente o par cisteína/cistina, tem sido amplamente estudado com este fim. Por este motivo, padronizar um método para avaliar se o estado redox extracelular de fato pode ser empregado para quantificar clinicamente o estresse oxidativo poderia facilitar o entendimento do papel do estresse oxidativo em estudos clínicos. Com este objetivo, es e estudo se propôs a padronizar um método baseado em cromatografia líquida de alto desempenho (HPLC) e detecção coulométrica e utilizá-lo para avaliar o estado redox plasmático do par cisteína/cistina durante a progressão da doença renal crônica, já que a doença renal crônica é uma patologia intimamente relacionada com
o estresse oxidativo e necessita de um estudo mais abrangente e sistemático parase determinar quantitativamente o estresse oxidativo durante a sua progressão. Foram padronizados aspectos da cromatografia, detecção coulométrica, precipitação de proteínas, quantificação da cisteína e cistina, coleta e armazenamento do plasma. Foi utilizado plasma coletado de pacientes renais e doadores saudáveis, num total de 43 pessoas, para a análise do potencial de redução do par cisteína/cistina durante a progressão da doença renal. Os resultados demonstraram uma tendência de aumento do potencial de redução a partir do estágio da doença renal e um aumento mais significativo no grupo de pacientes em estágio 5 em diálise, sugerindo um maior estresse oxidativo nesses estágios onde a uremia sabidamente se revela mais presente. oncluiu-se a partir desses dados que o método foi padronizado com sucesso, entretanto, será necessário um número maior de indivíduos estudados para resultados estatisticamente mais relevantes no que diz respeito ao estresse oxidativo na progressão renal
Perinatal depression and patterns of attachment: a critical risk factor?
Background. This study aims to verify if the presence and severity of perinatal depression are related to any particular pattern of attachment. Methods. The study started with a screening of a sample of 453 women in their third trimester of pregnancy, who were administered a survey data form, the Edinburgh Postnatal Depression Scale (EPDS) and the Experience in Close Relationship (ECR). A clinical group of subjects with perinatal depression (PND, 89 subjects) was selected and compared with a control group (C), regarding psychopathological variables and attachment patterns. Results. The ECR showed a prevalence of “Fearful-Avoidant” attachment style in PND group (29.2% versus 1.1%, < 0.001); additionally, the EPDS average score increases with the increasing of ECR dimensions (Avoidance and Anxiety). Conclusion. The severity of depression increases proportionally to attachment disorganization; therefore, we consider attachment as both an important risk factor as well as a focus for early psychotherapeutic intervention
Serum and supplement optimization for EU GMP-compliance in cardiospheres cell culture
Cardiac progenitor cells (CPCs) isolated as cardiospheres (CSs) and CS-derived cells (CDCs) are a promising tool for cardiac cell therapy in heart failure patients, having CDCs already been used in a phase I/II clinical trial. Culture standardization according to Good Manufacturing Practices (GMPs) is a mandatory step for clinical translation. One of the main issues raised is the use of xenogenic additives (e.g. FBS, foetal bovine serum) in cell culture media, which carries the risk of contamination with infectious viral/prion agents, and the possible induction of immunizing effects in the final recipient. In this study, B27 supplement and sera requirements to comply with European GMPs were investigated in CSs and CDCs cultures, in terms of process yield/efficiency and final cell product gene expression levels, as well as phenotype. B27- free CS cultures produced a significantly reduced yield and a 10-fold drop in c-kit expression levels versus B27+ media. Moreover, autologous human serum (aHS) and two different commercially available GMP AB HSs were compared with standard research-grade FBS. CPCs from all HSs explants had reduced growth rate, assumed a senescent-like morphology with time in culture, and/or displayed a significant shift towards the endothelial phenotype. Among three different GMP gamma-irradiated FBSs (giFBSs) tested, two provided unsatisfactory cell yields, while one performed optimally, in terms of CPCs yield/phenotype. In conclusion, the use of HSs for the isolation and expansion of CSs/CDCs has to be excluded because of altered proliferation and/or commitment, while media supplemented with B27 and the selected giFBS allows successful EU GMP-complying CPCs culture
Non-synchronous earthquake motion in bridges design
The study aims to further develop, with respect to previous findings, and validate structural design criteria which account for the effects of earthquakes spatial variability. In past works [Nuti, C. and Vanzi. I. (2004) & (2005); Carnevale, L. et al. (2010)] the two simplest forms of this problem were dealt with: differential displacements between two points belonging to the soil or to two single degree of freedom structures. Existing codes appear indeed improvable on this aspect. For the differential displacements of two points on the ground, these results are generalized with different response spectra and validated using (indeed a small set of) real recordings. For the experimental validation, the first obtained results point towards an acceptable agreement of model vs. experimental results [Tropeano, G. et al. (2011)]. In any case, results indicate that the design codes can be improved on this topic, both for the two points (e.g. simply supported decks) and the multiple points (e.g. continuous decks on multiple piers) cases
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