Modelling headed stud shear connectors of steel-concrete pushout tests with PCHCS and concrete topping

Lucas Mognon Santiago Prates,Felipe Piana Vendramell Ferreira,Alexandre Rossi,Carlos Humberto Martins 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.46 No.4

The use of precast hollow-core slabs (PCHCS) in civil construction has been increasing due to the speed of execution and reduction in the weight of flooring systems. However, in the literature there are no studies that present a finite element model (FEM) to predict the load-slip relationship behavior of pushout tests, considering headed stud shear connector and PCHCS placed at the upper flange of the downstand steel profile. Thus, the present paper aims to develop a FEM, which is based on tests to fill this gap. For this task, geometrical non-linear analyses are carried out in the ABAQUS software. The FEM is calibrated by sensitivity analyses, considering different types of analysis, the friction coefficient at the steel-concrete interface, as well as the constitutive model of the headed stud shear connector. Subsequently, a parametric study is performed to assess the influence of the number of connector lines, type of filling and height of the PCHCS. The results are compared with analytical models that predict the headed stud resistance. In total, 158 finite element models are processed. It was concluded that the dynamic implicit analysis (quasi-static) showed better convergence of the equilibrium trajectory when compared to the static analysis, such as arc-length method. The friction coefficient value of 0.5 was indicated to predict the load-slip relationship behavior of all models investigated. The headed stud shear connector rupture was verified for the constitutive model capable of representing the fracture in the stress-strain relationship. Regarding the number of connector lines, there was an average increase of 108% in the resistance of the structure for models with two lines of connectors compared to the use of only one. The type of filling of the hollow core slab that presented the best results was the partial filling. Finally, the greater the height of the PCHCS, the greater the resistance of the headed stud.

Is percutaneous destruction of a solitary liver colorectal metastasis as effective as a resection?

Ugo Marchese,Heloise Seux,Jonathan Garnier,Jacques Ewald,Gilles Piana,Bernard Lelong,Cecile De Chaisemartin,Helene Meillat,Jean-Robert Delpero,Olivier Turrini 한국간담췌외과학회 2021 Annals of hepato-biliary-pancreatic surgery Vol.25 No.2

Backgrounds/Aims: Surgical resection remains the gold standard in the treatment of colorectal liver metastasis. However, when a patient presents with a deep solitary colorectal liver metastasis (S-CLM), the balance between the hepatic volume sacrificed and the S-CLM volume is sometimes clearly unappropriated. Thus, alternatives to surgery, such as operative and percutaneous radiofrequency ablation (RFA) and microwave ablation (MWA), have been developed. This study aimed to identify the prognostic factors affecting survival of patients with S-CLM who undergo curative-intent liver resection or local destruction (RFA or MWA). Methods: We retrospectively identified 211 patients with synchronous or metachronous S-CLM who underwent either surgical resection (n=182) or local destruction (RFA or MWA; n=29) according to the S-CLM size, location, and surrounding Glissonian structures. Results: Patients who underwent RFA or MWA had S-CLM of a smaller size than those who underwent resection (mean 19.7 vs. 37.3 mm, p<.01). The 1-, 3-, and 5-year overall survival (OS) rates were 97.4%, 84.9%, and 74.9%, respectively. The 1-, 3-, and 5-year disease-free survival (DFS) rates were 77.9%, 47%, and 38.9%, respectively. S-CLM located in the left liver (p=.04), S-CLM KRAS mutation (p<.01), and extra-hepatic recurrence (p<.01) were identified as independent poor risk factors for overall survival (OS); the OS and DFS were comparable in patients with surgical procedure or percutaneous MWA. Conclusions: In eligible S-CLM cases, percutaneous MWA seems to be as oncologically efficient as surgical resection and should be include in the decision-tree for treatment strategies.

Subgingival pathogens in chronic periodontitis patients affected by type 2 diabetes mellitus: a retrospective case-control study

Montevecchi, Marco,Valeriani, Leoluca,Gatto, Maria Rosaria,D'Alessandro, Giovanni,Piana, Gabriela Korean Academy of Periodontology 2021 Journal of Periodontal & Implant Science Vol.51 No.-

Purpose: The aim of this study was to compare the prevalence and bacterial load of 6 main periodontal pathogens between pairs of periodontal patients with and without type 2 diabetes mellitus. Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans genotypes were also investigated. Methods: Twenty patients affected by chronic periodontitis and type 2 diabetes were retrospectively selected and matched to 20 patients without diabetes on the basis of the degree and severity of periodontal disease. Microbiological data of subgingival biofilms were analysed and compared for the examined pathogens: A. actinomycetemcomitans, P. gingivalis, Prevotella intermedia, Treponema denticola, Fusobacterium nucleatum, and Tannerella forsythia. Results: The pairs were balanced in terms of demographic and clinical parameters, except for bleeding on probing and suppuration. In the microbiological test sites (4 for each patient), the mean probing pocket depth was 6.34±1.63 mm in patients with diabetes and 6.41±1.78 mm in patients without diabetes. No significant difference between pairs in the prevalence of P. gingivalis or the distribution of its genotypes was recorded. Patients with diabetes had a significantly greater amount of total bacterial load, P. gingivalis, T. denticola, T. forsythia, and F. nucleatum (P<0.05). Moreover, patients with diabetes had a higher number of sites with a greater cell count than patients without diabetes. When compared to the total bacterial load, only T. forsythia maintained its relative load in patients with diabetes (P=0.001). Conclusions: This retrospective matched study supports the hypothesis that microbiological differences exist among periodontal patients with and without diabetes mellitus.

Subgingival pathogens in chronic periodontitis patients affected by type 2 diabetes mellitus: a retrospective case-control study

Marco Montevecchi,Leoluca Valeriani,Maria Rosaria Gatto,Giovanni D'Alessandro,Gabriela Piana 대한치주과학회 2021 Journal of Periodontal & Implant Science Vol.51 No.6

Purpose: The aim of this study was to compare the prevalence and bacterial load of 6 main periodontal pathogens between pairs of periodontal patients with and without type 2 diabetes mellitus. Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans genotypes were also investigated. Methods: Twenty patients affected by chronic periodontitis and type 2 diabetes were retrospectively selected and matched to 20 patients without diabetes on the basis of the degree and severity of periodontal disease. Microbiological data of subgingival biofilms were analysed and compared for the examined pathogens: A. actinomycetemcomitans, P. gingivalis, Prevotella intermedia, Treponema denticola, Fusobacterium nucleatum, and Tannerella forsythia. Results: The pairs were balanced in terms of demographic and clinical parameters, except for bleeding on probing and suppuration. In the microbiological test sites (4 for each patient), the mean probing pocket depth was 6.34±1.63 mm in patients with diabetes and 6.41±1.78 mm in patients without diabetes. No significant difference between pairs in the prevalence of P. gingivalis or the distribution of its genotypes was recorded. Patients with diabetes had a significantly greater amount of total bacterial load, P. gingivalis, T. denticola, T. forsythia, and F. nucleatum (P<0.05). Moreover, patients with diabetes had a higher number of sites with a greater cell count than patients without diabetes. When compared to the total bacterial load, only T. forsythia maintained its relative load in patients with diabetes (P=0.001). Conclusions: This retrospective matched study supports the hypothesis that microbiological differences exist among periodontal patients with and without diabetes mellitus. Trial Registration: ClinicalTrials.gov Identifier: NCT03786133

Antimutagenic Effect of Aqueous Extract from Agaricus brasiliensis on Culture of Human Lymphocytes

Paula H. Gameiro,Jose´ S. Nascimento,Beatriz H.G. Rocha,Clause F.B. Piana,Raquel A. Santos,Catarina S. Takahashi 한국식품영양과학회 2013 Journal of medicinal food Vol.16 No.2

The mushroom Agaricus brasiliensis (sun mushroom), native from the southeast of Brazil, is well known by its medicinal properties that include effects on diabetes, cholesterol levels, and osteoporosis. The antimutagenic effects of A. brasiliensis has been investigated recently and revealed some controversial results depending on the temperature by which the A. brasiliensis tea is obtained. In the present study, we evaluated the effect of the A. brasiliensis extract prepared in two different temperatures, 4°C and 25°C, on the doxorubicin-induced DNA strand breaks and chromosomal aberrations (CAs) in human lymphocytes. The results demonstrated that A. brasiliensis was able to reduce the DXR-induced DNA damage in both temperatures; however, the CA test was more sensitive to demonstrate a better reduction when the cells were treated with an extract obtained at 25°C. A. brasiliensis extract obtained in different temperatures exhibited antigenotoxic and anticlastogenic effects in human lymphocytes.