Unstructured discretisation of a non-local transition model for turbomachinery flows

Ferrero, Andrea,Larocca, Francesco,Bernaschek, Verena Techno-Press 2017 Advances in aircraft and spacecraft science Vol.4 No.5

The description of transitional flows by means of RANS equations is sometimes based on non-local approaches which require the computation of some boundary layer properties. In this work a non-local Laminar Kinetic Energy model is used to predict transitional and separated flows. Usually the non-local term of this model is evaluated along the grid lines of a structured mesh. An alternative approach, which does not rely on grid lines, is introduced in the present work. This new approach allows the use of fully unstructured meshes. Furthermore, it reduces the grid-dependence of the predicted results. The approach is employed to study the transitional flows in the T106c turbine cascade and around a NACA0021 airfoil by means of a discontinuous Galerkin method. The local nature of the discontinuous Galerkin reconstruction is exploited to implement an adaptive algorithm which automatically refines the mesh in the most significant regions.

The oval technique for nipple-areolar complex reconstruction

Vozza, Amalia,Larocca, Fabio,Ferraro, Giuseppe,Nicoletti, Giovanni Francesco,D'Andrea, Francesco Korean Society of Plastic and Reconstructive Surge 2019 Archives of Plastic Surgery Vol.46 No.2

Background Nipple-areolar complex (NAC) reconstruction is the final stage of breast reconstruction. Ideal reconstruction of the NAC requires symmetry in position, size, shape, texture, pigmentation, and permanent projection, and although many technical descriptions of NAC reconstruction exist in the medical literature, there is no gold standard technique. The technique devised by the authors is very versatile, with excellent results, and it enables 1-step reconstruction with optimal results in terms of shape and nipple projection. Methods Our technique consists of a combination of modified local flaps and a full-thickness skin graft. Patients were observed for 18 months to estimate the amount of retraction. This procedure was performed in 40 patients, four of them bilaterally. The duration of the follow-up was 30 months. Complications occurred in 10% of patients, and included infections (5%), ischemia (2.5%), and hematoma (2.5%). Results No cases of total nipple necrosis were reported. The NAC shape remained optimal in all cases, with a very small reduction of the vertical and horizontal diameters of the areola, which maintained its designed round shape well, and negligible retraction in the diameter and projection of the nipple. Conclusions The oval technique represents a major step forward, involving a combination of existing techniques, such as the C-V flap and the cutaneous graft, to achieve excellent results regarding areola shape and nipple projection, significantly reducing the cases of nipple ischemia. These results were substantially obtained through subcutaneous equatorial sutures, skin grafting, and flattening of the apexes of the flap.

The oval technique for nipple-areolar complex reconstruction

Amalia Vozza,Fabio Larocca,Giuseppe Ferraro,Giovanni Francesco Nicolett,Francesco D’Andrea 대한성형외과학회 2019 Archives of Plastic Surgery Vol.46 No.2

Background Nipple-areolar complex (NAC) reconstruction is the final stage of breast reconstruction. Ideal reconstruction of the NAC requires symmetry in position, size, shape, texture, pigmentation, and permanent projection, and although many technical descriptions of NAC reconstruction exist in the medical literature, there is no gold standard technique. The technique devised by the authors is very versatile, with excellent results, and it enables 1-step reconstruction with optimal results in terms of shape and nipple projection. Methods Our technique consists of a combination of modified local flaps and a full-thickness skin graft. Patients were observed for 18 months to estimate the amount of retraction. This procedure was performed in 40 patients, four of them bilaterally. The duration of the follow- up was 30 months. Complications occurred in 10% of patients, and included infections (5%), ischemia (2.5%), and hematoma (2.5%). Results No cases of total nipple necrosis were reported. The NAC shape remained optimal in all cases, with a very small reduction of the vertical and horizontal diameters of the areola, which maintained its designed round shape well, and negligible retraction in the diameter and projection of the nipple. Conclusions The oval technique represents a major step forward, involving a combination of existing techniques, such as the C-V flap and the cutaneous graft, to achieve excellent results regarding areola shape and nipple projection, significantly reducing the cases of nipple ischemia. These results were substantially obtained through subcutaneous equatorial sutures, skin grafting, and flattening of the apexes of the flap.

RANS simulation of secondary flows in a low pressure turbine cascade: Influence of inlet boundary layer profile

Michele, Errante,Andrea, Ferrero,Francesco, Larocca Techno-Press 2022 Advances in aircraft and spacecraft science Vol.9 No.5

Secondary flows have a huge impact on losses generation in modern low pressure gas turbines (LPTs). At design point, the interaction of the blade profile with the end-wall boundary layer is responsible for up to 40% of total losses. Therefore, predicting accurately the end-wall flow field in a LPT is extremely important in the industrial design phase. Since the inlet boundary layer profile is one of the factors which most affects the evolution of secondary flows, the first main objective of the present work is to investigate the impact of two different inlet conditions on the end-wall flow field of the T106A, a well known LPT cascade. The first condition, labeled in the paper as C1, is represented by uniform conditions at the inlet plane and the second, C2, by a flow characterized by a defined inlet boundary layer profile. The code used for the simulations is based on the Discontinuous Galerkin (DG) formulation and solves the Reynolds-averaged Navier-Stokes (RANS) equations coupled with the Spalart Allmaras turbulence model. Secondly, this work aims at estimating the influence of viscosity and turbulence on the T106A end-wall flow field. In order to do so, RANS results are compared with those obtained from an inviscid simulation with a prescribed inlet total pressure profile, which mimics a boundary layer. A comparison between C1 and C2 results highlights an influence of secondary flows on the flow field up to a significant distance from the end-wall. In particular, the C2 end-wall flow field appears to be characterized by greater over turning and under turning angles and higher total pressure losses. Furthermore, the C2 simulated flow field shows good agreement with experimental and numerical data available in literature. The C2 and inviscid Euler computed flow fields, although globally comparable, present evident differences. The cascade passage simulated with inviscid flow is mainly dominated by a single large and homogeneous vortex structure, less stretched in the spanwise direction and closer to the end-wall than vortical structures computed by compressible flow simulation. It is reasonable, then, asserting that for the chosen test case a great part of the secondary flows details is strongly dependent on viscous phenomena and turbulence.

Characteristics of Cell Lines Established from Human Gastric Carcinoma

Park, J G,Oie, H K,LaRocca, R V,Johnson, B E,Bang, Y J,Kim, J P,Israel, M A,Gazdar, A F 한국유전학회 1988 Genes & Genomics Vol.10 No.4

Four gastric carcinoma cell lines were established from one primary and three metastatic tumors. All lines expressed human form of the 4 enzyme tested and were free of contamination with mycoplasma or murine viruses. Population doubling times ranged from 26-47 h. Cloning efficiency ranged from 1.9-27%. Three of 4 cultures displayed both adherent and floating subpopulations. Cell line, NCI-N87, grew as adherent monolayers. We examined for expression of DDC, an enzyme characteristic of NE cells. Relatively high levels of enzyme activity (>10units/㎎ protein; 1unit = 1nM CO2/m) was detected in 2 lines but all lines didn't show cytoplasmic dense core ("neurosecretory") granules, mRNA expression of chromogranin A, and didn't reacted with natural killer cell antigens, Leu-7 and NKH-1. Double minute chromosomes(DMs) were found in all 4 cell lines. Homogeneously staining regions(HSRs) were present in the minor subline of SNU-16. One line, SNU-16, has c-myc gene amplification. N-myc, L-myc, myb and EGF-R gene were not amplified. All of 4 lines expressed c-myc mRNA and erb B mRNA. N-myc, L-myc, v-sis, IGF-2 and GRP were not expressed. In this report we describe the establishment and characterization of 4 continuous cell lines derived from human primary and metastatic gastric carcinomas. However a modest number of gastric carcinoma lines have been described, our report describes three interesting or unique features, including expression and secretion of high concentration of 3 gastrointestinal cell associated antigens; high frequency of expression of the NE cell marker DDC; and possibly unique line with c-myc gene amplification and subline having HSRs at 4 separate chromosomal locations.

RANS simulation of secondary flows in a low pressure turbine cascade: Influence of inlet boundary layer profile

Michele, Errante,Andrea, Ferrero,Francesco, Larocca Techno-Press 2022 Advances in aircraft and spacecraft science Vol.9 No.5

Secondary flows have a huge impact on losses generation in modern low pressure gas turbines (LPTs). At design point, the interaction of the blade profile with the end-wall boundary layer is responsible for up to 40% of total losses. Therefore, predicting accurately the end-wall flow field in a LPT is extremely important in the industrial design phase. Since the inlet boundary layer profile is one of the factors which most affects the evolution of secondary flows, the first main objective of the present work is to investigate the impact of two different inlet conditions on the end-wall flow field of the T106A, a well known LPT cascade. The first condition, labeled in the paper as C1, is represented by uniform conditions at the inlet plane and the second, C2, by a flow characterized by a defined inlet boundary layer profile. The code used for the simulations is based on the Discontinuous Galerkin (DG) formulation and solves the Reynolds-averaged Navier-Stokes (RANS) equations coupled with the Spalart Allmaras turbulence model. Secondly, this work aims at estimating the influence of viscosity and turbulence on the T106A end-wall flow field. In order to do so, RANS results are compared with those obtained from an inviscid simulation with a prescribed inlet total pressure profile, which mimics a boundary layer. A comparison between C1 and C2 results highlights an influence of secondary flows on the flow field up to a significant distance from the end-wall. In particular, the C2 end-wall flow field appears to be characterized by greater over turning and under turning angles and higher total pressure losses. Furthermore, the C2 simulated flow field shows good agreement with experimental and numerical data available in literature. The C2 and inviscid Euler computed flow fields, although globally comparable, present evident differences. The cascade passage simulated with inviscid flow is mainly dominated by a single large and homogeneous vortex structure, less stretched in the spanwise direction and closer to the end-wall than vortical structures computed by compressible flow simulation. It is reasonable, then, asserting that for the chosen test case a great part of the secondary flows details is strongly dependent on viscous phenomena and turbulence.

Turbomachinery design by a swarm-based optimization method coupled with a CFD solver

Ampellio, Enrico,Bertini, Francesco,Ferrero, Andrea,Larocca, Francesco,Vassio, Luca Techno-Press 2016 Advances in aircraft and spacecraft science Vol.3 No.2

Multi-Disciplinary Optimization (MDO) is widely used to handle the advanced design in several engineering applications. Such applications are commonly simulation-based, in order to capture the physics of the phenomena under study. This framework demands fast optimization algorithms as well as trustworthy numerical analyses, and a synergic integration between the two is required to obtain an efficient design process. In order to meet these needs, an adaptive Computational Fluid Dynamics (CFD) solver and a fast optimization algorithm have been developed and combined by the authors. The CFD solver is based on a high-order discontinuous Galerkin discretization while the optimization algorithm is a high-performance version of the Artificial Bee Colony method. In this work, they are used to address a typical aero-mechanical problem encountered in turbomachinery design. Interesting achievements in the considered test case are illustrated, highlighting the potential applicability of the proposed approach to other engineering problems.

Reynolds stress correction by data assimilation methods with physical constraints

Thomas Philibert,Andrea Ferrero,Angelo Iollo,Francesco Larocca Techno-Press 2023 Advances in aircraft and spacecraft science Vol.10 No.6

Reynolds-averaged Navier-Stokes (RANS) models are extensively employed in industrial settings for the purpose of simulating intricate fluid flows. However, these models are subject to certain limitations. Notably, disparities persist in the Reynolds stresses when comparing the RANS model with high-fidelity data obtained from Direct Numerical Simulation (DNS) or experimental measurements. In this work we propose an approach to mitigate these discrepancies while retaining the favorable attributes of the Menter Shear Stress Transport (SST) model, such as its significantly lower computational expense compared to DNS simulations. This strategy entails incorporating an explicit algebraic model and employing a neural network to correct the turbulent characteristic time. The imposition of realizability constraints is investigated through the introduction of penalization terms. The assimilated Reynolds stress model demonstrates good predictive performance in both in-sample and out-of-sample flow configurations. This suggests that the model can effectively capture the turbulent characteristics of the flow and produce physically realistic predictions.

Effect of endodontic sealer on postoperative pain: a network meta-analysis

Monteiro Cynthia Maria Chaves,Martins Ana Cristina Rodrigues,Reis Alessandra,de Geus Juliana Larocca 대한치과보존학회 2023 Restorative Dentistry & Endodontics Vol.48 No.1

This systematic review and network meta-analysis aimed to answer the following focused research question: “Does the type of endodontic sealer affect the postoperative pain in patients who received endodontic treatment?” Different databases and grey literature were surveyed. Only one randomized controlled trial were included. The risk of bias in the studies was evaluated by using the Cochrane Collaboration’s tool. A random-effects meta-analysis was conducted to compare the risk and intensity of postoperative pain. The quality of the body of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation approach. Out of 11,601 studies, 15 remained for qualitative analyses and 12 for meta-analysis. Seven studies were classified at high risk of bias, and 8 studies raised some concerns. No significant differences between the endodontic materials were observed in the direct comparisons, both in risk and in intensity of postoperative pain (pairwise comparisons with 2 studies: I2 = 0%; p > 0.05 and 8 studies: I2 = 23%; p > 0.05, respectively). The certainty of the evidence was graded as low or moderate. There was no difference in the risk and intensity of postoperative pain after filling with different endodontic sealers. Further systematic reviews should be conducted.

Matricellular Protein CCN5 Reverses Established Cardiac Fibrosis

Jeong, Dongtak,Lee, Min-Ah,Li, Yan,Yang, Dong Kwon,Kho, Changwon,Oh, Jae Gyun,Hong, Gyeongdeok,Lee, Ahyoung,Song, Min Ho,LaRocca, Thomas J.,Chen, Jiqiu,Liang, Lifan,Mitsuyama, Shinichi,D'Escamard, Val American College of Cardiology 2016 Journal of the American College of Cardiology Vol.67 No.13

<P><B>Abstract</B></P><P><B>Background</B></P><P>Cardiac fibrosis (CF) is associated with increased ventricular stiffness and diastolic dysfunction and is an independent predictor of long-term clinical outcomes of patients with heart failure (HF). We previously showed that the matricellular CCN5 protein is cardioprotective via its ability to inhibit CF and preserve cardiac contractility.</P><P><B>Objectives</B></P><P>This study examined the role of CCN5 in human heart failure and tested whether CCN5 can reverse established CF in an experimental model of HF induced by pressure overload.</P><P><B>Methods</B></P><P>Human hearts were obtained from patients with end-stage heart failure. Extensive CF was induced by applying transverse aortic constriction for 8 weeks, which was followed by adeno-associated virus-mediated transfer of CCN5 to the heart. Eight weeks following gene transfer, cellular and molecular effects were examined.</P><P><B>Results</B></P><P>Expression of CCN5 was significantly decreased in failing hearts from patients with end-stage heart failure compared to nonfailing hearts. Trichrome staining and myofibroblast content measurements revealed that the established CF had been reversed by CCN5 gene transfer. Anti-CF effects of CCN5 were associated with inhibition of the transforming growth factor beta signaling pathway. CCN5 significantly inhibited endothelial-mesenchymal transition and fibroblast-to-myofibroblast transdifferentiation, which are 2 critical processes for CF progression, both in vivo and in vitro. In addition, CCN5 induced apoptosis in myofibroblasts, but not in cardiomyocytes or fibroblasts, both in vivo and in vitro. CCN5 provoked the intrinsic apoptotic pathway specifically in myofibroblasts, which may have been due the ability of CCN5 to inhibit the activity of NFκB, an antiapoptotic molecule.</P><P><B>Conclusions</B></P><P>CCN5 can reverse established CF by inhibiting the generation of and enhancing apoptosis of myofibroblasts in the myocardium. CCN5 may provide a novel platform for the development of targeted anti-CF therapies.</P>