RESUMEN
Variable Angle Tow (VAT) laminates offer a promising alternative to classical straight-fiber composites in terms of design and performance. However, analyzing these structures can be more complex due to the introduction of new design variables. Carrera's unified formulation (CUF) has been successful in previous works for buckling, vibrational, and stress analysis of VAT plates. Typically, one-dimensional (1D) and two-dimensional (2D) CUF models are used, with a linear law describing the fiber orientation variation in the main plane of the structure. The objective of this article is to expand the CUF 2D plate finite elements family to perform free vibration analysis of composite laminated plate structures with curvilinear fibers. The primary contribution is the application of Reissner's mixed variational theorem (RMVT) to a CUF finite element model. The principle of virtual displacements (PVD) and RMVT are both used as variational statements for the study of monolayer and multilayer VAT plate dynamic behavior. The proposed approach is compared to Abaqus three-dimensional (3D) reference solutions, classical theories and literature results to investigate the effectiveness of the developed models. The results demonstrate that mixed theories provide the best approximation of the reference solution in all cases.
RESUMEN
Aims: This study aimed to evaluate the impacts of a pilot project concerning the closure of a Forensic Psychiatric Hospital (FPH) inspired by Human Development Theory and the Capability Approach. Background: The dismantlement of the FPH of Barcellona Pozzo di Gotto (Sicily Region in Italy) began in 2010 with the pilot project Luce é Libertà and ended in 2017. With the closure of six FPHs, Italy officially became the first country worldwide to close such institutions. After the closure of FPHs, some critical issues emerged, and the debate shifted to developing small-scale facilities and residences for the execution of security measures (RESM). However, few studies have provided results on the cohort of patients discharged from FPHs. Objective: Following are the objectives of this study: a) Assessing the effectiveness of the pilot project in terms of better functioning accordingly to the Classification of Functioning of Disability and Health (ICF) framework, social and labour insertion, health conditions, level of dangerousness to other, rate of readmission in forensic services, b) cost analysis, and c) describing how the CA has been applied and translated into methodological and administrative devices and concrete intervention strategies. Methods: A pre-post evaluation design was performed with a comparison between the intervention and the control group for the healthcare cost analysis. Data were collected from 2010 to 2019 at three points: T0) as a baseline, T1 and T2) for the follow-up. The instruments are a structured questionnaire, the Scale HoNOS Secure, 4 sub-scales of ICF (Activity and participation dimensions: sociality, culture, and knowledge, daily life, income, and work) (Cronbach's Alpha from 0.76 to 0.94), and n.20 interviews with key stakeholders and beneficiaries. Results: Main results include a) the discharge of 55 patients through the use of a person-centered approach and the Personal Capability Budget (PCB), b) the expansion of substantial freedom of choice and the improvement of ICF score (t-test Sig. <, 02), c) the reduction of the risk for others and themselves (Mean Diff. -2,15 Sig. .000), d) at T2 42% of beneficiaries achieved a job placement and 36% were living in one's own home, e) at T2 the need of security measures has reduced from the initial 70% to 6.8%, and f) reduction of the healthcare costs from the fourth year onwards. Conclusion: Indications emerge to support processes of deinstitutionalisation and capabilities expansion through innovative models, a person-centered approach supported by PCBs, social finance, and social impact investments.
RESUMEN
OBJECTIVE: The aim of this study was to develop and validate a decision support model using data mining algorithms, based on morphologic features derived from MRI images, to discriminate between complete responders (CR) and non-complete responders (NCR) patients after neoadjuvant chemoradiotherapy (CRT), in a population of patients with locally advanced rectal cancer (LARC). METHODS: Two populations were retrospectively enrolled: group A (65 patients) was used to train a data mining decision tree algorithm whereas group B (30 patients) was used to validate it. All patients underwent surgery; according to the histology evaluation, patients were divided in CR and NCR. Staging and restaging MRI examinations were retrospectively analysed and seven parameters were considered for data mining classification. Five different classification methods were tested and evaluated in terms of sensitivity, specificity, accuracy and AUC in order to identify the classification model able to achieve the best performance. The best classification algorithm was subsequently applied to group B for validation: sensitivity, specificity, positive and negative predictive value, accuracy and ROC curve were calculated. Inter and intra-reader agreement were calculated. RESULTS: Four features were selected for the development of the classification algorithm: MRI tumor regression grade (MR-TRG), staging volume (SV), tumor volume reduction rate (TVRR) and signal intensity reduction rate (SIRR). The decision tree J48 showed the highest efficiency: when applied to group B, all the CR and 18/21 NCR were correctly classified (sensitivity 85.71%, specificity 100%, PPV 100%, NPV 94.2%, accuracy 95.7%, AUC 0.833). Both inter- and intra-reader evaluation showed good agreement (κ > 0.6). CONCLUSIONS: The proposed decision support model may help in distinguishing between CR and NCR patients with LARC after CRT.
Asunto(s)
Terapia Neoadyuvante , Neoplasias del Recto , Algoritmos , Quimioradioterapia , Humanos , Imagen por Resonancia Magnética , Neoplasias del Recto/tratamiento farmacológico , Neoplasias del Recto/terapia , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
The main goal of this work is to automatically segment colorectal tumors in 3D T2-weighted (T2w) MRI with reasonable accuracy. For such a purpose, a novel deep learning-based algorithm suited for volumetric colorectal tumor segmentation is proposed. The proposed CNN architecture, based on densely connected neural network, contains multiscale dense interconnectivity between layers of fine and coarse scales, thus leveraging multiscale contextual information in the network to get better flow of information throughout the network. Additionally, the 3D level-set algorithm was incorporated as a postprocessing task to refine contours of the network predicted segmentation. The method was assessed on T2-weighted 3D MRI of 43 patients diagnosed with locally advanced colorectal tumor (cT3/T4). Cross validation was performed in 100 rounds by partitioning the dataset into 30 volumes for training and 13 for testing. Three performance metrics were computed to assess the similarity between predicted segmentation and the ground truth (i.e., manual segmentation by an expert radiologist/oncologist), including Dice similarity coefficient (DSC), recall rate (RR), and average surface distance (ASD). The above performance metrics were computed in terms of mean and standard deviation (mean ± standard deviation). The DSC, RR, and ASD were 0.8406 ± 0.0191, 0.8513 ± 0.0201, and 2.6407 ± 2.7975 before postprocessing, and these performance metrics became 0.8585 ± 0.0184, 0.8719 ± 0.0195, and 2.5401 ± 2.402 after postprocessing, respectively. We compared our proposed method to other existing volumetric medical image segmentation baseline methods (particularly 3D U-net and DenseVoxNet) in our segmentation tasks. The experimental results reveal that the proposed method has achieved better performance in colorectal tumor segmentation in volumetric MRI than the other baseline techniques.
Asunto(s)
Neoplasias Colorrectales/diagnóstico por imagen , Imagenología Tridimensional , Imagen por Resonancia Magnética , Redes Neurales de la Computación , Algoritmos , Medios de Contraste , Aprendizaje Profundo , Reacciones Falso Positivas , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Intestino Grueso/diagnóstico por imagenRESUMEN
The main goal of this work was to assess the performance of different initializations of matrix factorization algorithms for an accurate identification of muscle synergies. Currently, nonnegative matrix factorization (NNMF) is the most commonly used method to identify muscle synergies. However, it has been shown that NNMF performance might be affected by different kinds of initialization. The present study aims at optimizing the traditional NNMF initialization for data with partial or complete temporal dependencies. For this purpose, three different initializations are used: random, SVD-based, and sparse. NNMF was used to identify muscle synergies from simulated data as well as from experimental surface EMG signals. Simulated data were generated from synthetic independent and dependent synergy vectors (i.e., shared muscle components), whose activation coefficients were corrupted by simulating controlled degrees of correlation. Similarly, EMG data were artificially modified, making the extracted activation coefficients temporally dependent. By measuring the quality of identification of the original synergies underlying the data, it was possible to compare the performance of different initialization techniques. Simulation results demonstrate that sparse initialization performs significantly better than all other kinds of initialization in reconstructing muscle synergies, regardless of the correlation level in the data.
RESUMEN
PURPOSE: Haralick features Texture analysis is a recent oncologic imaging biomarker used to assess quantitatively the heterogeneity within a tumor. The aim of this study is to evaluate which Haralick's features are the most feasible in predicting tumor response to neoadjuvant chemoradiotherapy (CRT) in colorectal cancer. MATERIALS AND METHODS: After MRI and histological assessment, eight patients were enrolled and divided into two groups based on response to neoadjuvant CRT in complete responders (CR) and non-responders (NR). Oblique Axial T2-weighted MRI sequences before CRT were analyzed by two radiologists in consensus drawing a ROI around the tumor. 14 over 192 Haralick's features were extrapolated from normalized gray-level co-occurrence matrix in four different directions. A dedicated statistical analysis was performed to evaluate distribution of the extracted Haralick's features computing mean and standard deviation. RESULTS: Pretreatment MRI examination showed significant value (p < 0.05) of 5 over 14 computed Haralick texture. In particular, the significant features are the following: concerning energy, contrast, correlation, entropy and inverse difference moment. CONCLUSIONS: Five Haralick's features showed significant relevance in the prediction of response to therapy in colorectal cancer and might be used as additional imaging biomarker in the oncologic management of colorectal patients.