Hybrid Micro-Modeling Approach for the Analysis of the Cyclic Behavior of RC Frames

The present study is aimed at developing a hybrid approach to consider the effect of concrete cracking on the hysteretic response of RC frames. The mechanical behavior of the concrete is defined according to the smeared cracking approach, while discrete cracking surfaces are included in the geometrical model. The interface behavior of the discrete cracking surfaces is defined by the combination of contact and cohesive elements. The proposed approach is adopted in ABAQUS to simulate an experimental test on a double cantilever column for the calibration of the numerical model. Therefore, a test conducted on a RC portal and modeled numerically for the first time is simulated. Numerical and experimental results are compared in terms of hysteretic force-displacement behavior and cumulative dissipated energy, in order to assess the reliability of the proposed model in simulating the energy dissipation capacity of RC members subjected to lateral cyclic loading. The hybrid modeling approach proposed allows an accurate description of the stress distribution and a fairly satisfactory matching of the hysteretic behavior with a reasonable compromise in terms of computational effort

Brittle failure in RC masonry infilled frames:the role of infill overstrength

The interaction between an infill panel and a reinforced concrete (RC) column can lead to the brittle failure of the structural element. A novel combination of cutting-edge analytical modelling approaches for masonry infills and RC elements is employed to simulate five experimental tests (three infilled and two bare) characterized by brittle failure modes. The infill is modelled with a multi-strut idealisation, and the RC column is modelled using the recently developed PinchingLimitStateMaterial in OpenSees. The effects of the infill type (solid or hollow) and ductility characteristics of the RC elements on the optimal modelling parameters are investigated. The focus of this study is on the assumption of the overstrength ratio between the maximum and cracking strengths of the panel when brittle failure occurs. The preliminary assumption for this parameter is the widely accepted value of 1.3 suggested in the formulation by Panagiotakos and Fardis. This value is found to influence the shear failure simulation. To more accurately predict brittle failure, higher overstrength values of the infill are used in the numerical model to improve the matching between the numerical and experimental tests. These values are then compared with the approximate estimation of the overstrength ratio from a database of 98 experimental tests. The suggested estimation of the overstrength ratio is systematically greater than 1.3 and dependent on the infill type (i.e., 1.44 for hollow and 1.55 for solid infills). The proposed values can have a high impact on future code-compliant recommendations aimed at verifying the likelihood of the occurrence of brittle failure in columns due to their interaction with infill panels

Hybrid Micro-Modeling Approach for the Analysis of the Cyclic Behavior of RC Frames

The present study is aimed at developing a hybrid approach to consider the effect of concrete cracking on the hysteretic response of RC frames. The mechanical behavior of the concrete is defined according to the smeared cracking approach, while discrete cracking surfaces are included in the geometrical model. The interface behavior of the discrete cracking surfaces is defined by the combination of contact and cohesive elements. The proposed approach is adopted in ABAQUS to simulate an experimental test on a double cantilever column for the calibration of the numerical model. Therefore, a test conducted on a RC portal and modeled numerically for the first time is simulated. Numerical and experimental results are compared in terms of hysteretic force-displacement behavior and cumulative dissipated energy, in order to assess the reliability of the proposed model in simulating the energy dissipation capacity of RC members subjected to lateral cyclic loading. The hybrid modeling approach proposed allows an accurate description of the stress distribution and a fairly satisfactory matching of the hysteretic behavior with a reasonable compromise in terms of computational effort

Immunological backbone of uveal melanoma: is there a rationale for immunotherapy?

No standard treatment has been established for metastatic uveal melanoma (mUM). Immunotherapy is commonly used for this disease even though UM has not been included in phase III clinical trials with checkpoint inhibitors. Unfortunately, only a minority of patients obtain a clinical benefit with immunotherapy. The immunological features of mUM were reviewed in order to understand if immunotherapy could still play a role for this disease

Reduced long-term overall mortality in heart failure patients with prolonged QRS treated with CRT combined with ICD vs. heart failure patients with narrow QRS treated with ICD only

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Characterization of digital annular pulleys and their entheses: an ultrasonographic study with anatomical and histological correlations

Objectives: Digital annular pulleys (DAP) are important anatomical structures for finger function. The anatomy, histology, and imaging assessment of DAP, particularly at the level of their entheses is still not clearly defined. The advent of high-frequency ultrasound (US) transducers opened new perspectives in evaluating sub-millimeter scale structures, such as pulleys, paving the way for their global assessment. The study aimed at characterizing DAP from an anatomical, histological, and US perspective, focusing on the detection and complete description of pulley entheses. Methods: US assessment and gross anatomy dissection were conducted on 20 cadaveric hands to study DAP thickness and structure including enthesis identification. The results of the US and anatomical measurements were correlated. DAP entheses identified by US were characterized via histological analysis. DAP in 20 healthy controls (HC) were detected and measured by US. The A1, A2, and A4 DAP entheses were assessed using a new dynamic maneuver to better evaluate those structures. Results: 1200 DAP (400 cadaveric, 800 HC) were analyzed. The cadaveric study demonstrated strong correlation between anatomical and US measurement of DAP (r = 0.96). At histological level, DAP entheses at the volar plate, sesamoid bones, or phalangeal ridges contained fibrous and fibrocartilaginous tissue. The US assessment of A1, A2, and A4 DAP in HC allowed the identification of 718/720 (99.73%) entheses. Conclusion: US is an effective tool to detect and study DAP. DAP entheses reveal both fibrous and fibrocartilaginous characteristics. A newly described maneuver to optimize DAP enthesis visualization enhances their detection by US

Nomogram for predicting radiation maculopathy in patients treated with Ruthenium-106 plaque brachytherapy for uveal melanoma

Purpose: To develop a predictive model and nomogram for maculopathy occurrence at 3 years after106Ru/106Rh plaque brachytherapy in uveal melanoma. Material and methods: Clinical records of patients affected by choroidal melanoma and treated with106Ru/106Rh plaque from December 2006 to December 2014 were retrospectively reviewed. Inclusion criteria were: dome-shaped melanoma, distance to the fovea > 1.5 mm, tumor thickness > 2 mm, and follow-up > 4 months. The delivered dose to the tumor apex was 100 Gy. Primary endpoint of this investigation was the occurrence of radiation maculopathy at 3 years. Analyzed factors were as follows: gender, age, diabetes, tumor size (volume, area, largest basal diameter and apical height), type of plaque, distance to the fovea, presence of exudative detachment, drusen, orange pigment, radiation dose to the fovea and sclera. Univariate and multivariate Cox proportional hazards analyses were used to define the impact of baseline patient factors on the occurrence of maculopathy. Kaplan-Meier curves were used to estimate freedom from the occurrence of the maculopathy. The model performance was evaluated through internal validation using area under the ROC curve (AUC), and calibration with Gronnesby and Borgan tests. Results: One hundred ninety-seven patients were considered for the final analysis. Radiation-related maculopathy at 3 years was observed in 41 patients. The proposed nomogram can predict maculopathy at 3 years with an AUC of 0.75. Distance to fovea appeared to be the main prognostic factor of the predictive model (hazard ratio of 0.83 [0.76-0.90], p < 0.01). Diabetes (hazard radio of 2.92 [1.38-6.20], p < 0.01), and tumor volume (hazard radio of 21.6 [1.66-281.14], p = 0.02) were significantly predictive for maculopathy occurrence. The calibration showed no statistical difference between actual and predicted maculopathy (p = 1). Conclusions: Our predictive model, together with its nomogram, could be a useful tool to predict the occurrence of radiation maculopathy at 3 years after the treatment

The Pediatric Choroidal and Ciliary Body Melanoma Study A Survey by the European Ophthalmic Oncology Group

Purpose: To collect comprehensive data on choroidal and ciliary body melanoma (CCBM) in children and to validate hypotheses regarding pediatric CCBM: children younger than 18 years, males, and those without ciliary body involvement (CBI) have more favorable survival prognosis than young adults 18 to 24 years of age, females, and those with CBI. Design: Retrospective, multicenter observational study. Participants: Two hundred ninety-nine patients from 24 ocular oncology centers, of whom 114 were children (median age, 15.1 years; range, 2.7-17.9 years) and 185 were young adults. Methods: Data were entered through a secure website and were reviewed centrally. Survival was analyzed using Kaplan-Meier analysis and Cox proportional hazards regression. Main Outcome Measures: Proportion of females, tumor-node-metastasis (TNM) stage, cell type, and melanoma-related mortality. Results: Cumulative frequency of having CCBM diagnosed increased steadily by 0.8% per year of age between 5 and 10 years of age and, after a 6-year transition period, by 8.8% per year from age 17 years onward. Of children and young adults, 57% and 63% were female, respectively, which exceeded the expected 51% among young adults. Cell type, known for 35% of tumors, and TNM stage (I in 22% and 21%, II in 49% and 52%, III in 30% and 28%, respectively) were comparable for children and young adults. Melanoma-related survival was 97% and 90% at 5 years and 92% and 80% at 10 years for children compared with young adults, respectively (P = 0.013). Males tended to have a more favorable survival than females among children (100% vs. 85% at 10 years; P = 0.058). Increasing TNM stage was associated with poorer survival (stages I, II, and III: 100% vs. 86% vs. 76%, respectively; P = 0.0011). By multivariate analysis, being a young adult (adjusted hazard rate [HR], 2.57), a higher TNM stage (HR, 2.88 and 8.38 for stages II and III, respectively), and female gender (HR, 2.38) independently predicted less favorable survival. Ciliary body involvement and cell type were not associated with survival. Conclusions: This study confirms that children with CCBM have a more favorable survival than young adults 18 to 25 years of age, adjusting for TNM stage and gender. The association between gender and survival varies between age groups. (C) 2016 by the American Academy of Ophthalmology.Peer reviewe