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Pin-on-disc study of dry sliding behavior of Co-free HVOFcoated disc tested against different friction materials

Friction 2021年第5期9卷 1242-1258页

作者： Matteo FEDERICI Cinzia MENAPACE Alessandro MANCINI Giovanni STRAFFELINI stefano GIALANELLA Department of Industrial Engineering University of TrentoTrento 32122Italy Brembo S.p.A. StezzanoBergamo 24040Italy

The dry sliding behavior of three commercial friction materials(codenamed FM1,FM2,and FM3)tested against a Co‐free cermet coating produced by high‐velocity oxy‐fuel(HVOF)on gray cast‐iron discs is ***1 is a conventional low‐metallic friction material,FM2 is developed for using against HVOF‐coated discs,and FM3 is a Cu‐free friction material with a low content of abrasives and a relatively high concentration of steel *** the tribological evaluation,they are tested on a pin‐on‐disc(PoD)test rig against Co‐free HVOF‐coated discs,with particular attention to the running‐in stage,which is fundamental for the establishment of a friction layer between the two mating surfaces,i.e.,the pin and *** PoD tests are performed at room temperature(RT)and a high temperature(HT)of 300℃.At RT,all materials exhibit a long running‐in *** HT,no running‐in is observed in FM1 and FM2,whereas a shorter running‐in period,with respect to the RT case,is observed in FM3 followed by the attainment of a comparatively high coefficient of *** RT,the pin wear is mild in all cases but severe at ***3 shows the lowest wear rate at both ***,the coated disc shows no wear when sliding against the FM3 friction *** the results are interpreted considering the microstructural characteristics of the friction layers formed on the sliding *** findings of the present study provide insights into reducing wear in braking system components and hence reducing environmental particulate matter emissions from their wear,through the use of disc coatings.

关键词： friction materials sliding wear high‐velocity oxy‐fuel(HVOF)coatings pin‐on‐disc(PoD)testing

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molecular pathology of intraductal papillary mucinous neoplasms of the pancreas

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World Journal of Gastroenterology 2014年第29期20卷 10008-10023页

作者： Marina Paini stefano Crippa stefano Partelli Filippo Scopelliti Domenico Tamburrino Andrea Baldoni Massimo Falconi Department of Surgery University of Verona Division of Pancreatic Surgery Ospedali RiunitiUniversità Politecnica delle Marche Division of Pancreatic Surgery Casa di Cura Dott.Pederzoli37019 Peschiera del Garda (VR)Italy

Since the first description of intraductal papillary mucinous neoplasms(IPMNs)of the pancreas in the eighties,their identification has dramatically increased in the last decades,hand to hand with the improvements in diagnostic imaging and sampling techniques for the study of pancreatic ***,the heterogeneity of IPMNs and their malignant potential make difficult the management of these *** objective of this review is to identify the molecular characteristics of IPMNs in order to recognize potential markers for the discrimination of more aggressive IPMNs requiring surgical resection from benign IPMNs that could be *** briefly summarize recent research findings on the genetics and epigenetics of intraductal papillary mucinous neoplasms,identifying some genes,molecular mechanisms and cellular signaling pathways correlated to the pathogenesis of IPMNs and their progression to *** knowledge of molecular biology of IPMNs has impressively developed over the last few years.A great amount of genes functioning as oncogenes or tumor suppressor genes have been identified,in pancreatic juice or in blood or in the samples from the pancreatic resections,but further researches are required to use these informations for clinical intent,in order to better define the natural history of these diseases and to improve their management.

关键词： Intraductal papillary mucinous neoplasm Pancreas Pancreatic cancer Molecular pathology Oncogene Tumor suppressor gene Dysplasia Malignant transformation

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A layer-wise MITC9 finite element for the freevibration analysis of plates with piezo-patches

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International Journal of Smart and Nano Materials 2015年第2期6卷 85-104页

作者： Maria Cinefra stefano Valvano Erasmo Carrera Department of Mechanical and Aerospace Engineering Politecnico di TorinoTorinoItaly School of Aerospace Mechanical and Manufacturing Engineering CollegeRMIT UniversityMelbourneAustralia Department of Mathematics Faculty of ScienceKing Abdulaziz UniversityP.O.Box 80203Jeddah 21589Saudi Arabia

The present article considers the free-vibration analysis of plate structures with piezoelectric patches by means of a plate finite element with variable through-the-thickness layer-wise *** refined models used are derived from Carrera’s Unified Formulation(CUF)and they permit the vibration modes along the thickness to be accurately *** finite-element method is employed and the plate element implemented has nine nodes,and the mixed interpolation of tensorial component(MITC)method is used to contrast the membrane and shear locking *** related governing equations are derived from the principle of virtual displacement,extended to the analysis of electromechanical *** isotropic plate with piezoelectric patches is analyzed,with clamped-free boundary conditions and subjected to open-and short-circuit *** results,obtained with different theories,are compared with the higher-order type solutions given in the *** conclusion is reached that the plate element based on the CUF is more suitable and efficient compared to the classical models in the study of multilayered structures embedding piezo-patches.

关键词： plate patches finite-element method piezoelectric materials mixed interpolated tensorial components Carrera’s Unified Formulation layer-wise

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Turbulence,aeration and bubble features of air-water flows in macro-and intermediate roughness conditions

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Water Science and Engineering 2011年第2期4卷 170-184页

作者： stefano PAGLIARA Thendiyath ROSHNI Iacopo CARNACINA Department of Civil Engineering University of Pisa

Free surface flows aeration potential causing the in macro- and intermediate flow characteristics to vary roughness conditions have a high with slopes and discharges. The underlying mechanism of two-phase flow characteristics in macro- and intermediate roughness conditions were analyzed in an experimental setup assembled at the Laboratory of Hydraulic Protection of the Territory （PITLAB） of the University of Pisa, Italy. Crushed angular rocks and hemispherical boulders were used to intensify the roughness of the bed. Flow rates per unit width ranging between 0.03 m^2/s and 0.09 m^2/s and slopes between 0.26 and 0.46 were tested over different arrangements of a rough bed. Analyses were mainly carried out in the inner flow region, which consists of both bubbly and intermediate flow regions. The findings revealed that the two-phase flow properties over the rough bed were much affected by rough bed arrangements. Turbulence features of two-phase flows over the rough bed were compared with those of the stepped chute data under similar flow conditions. Overall, the results highlight the flow features in the inner layers of the two-phase flow, showing that the maximum turbulence intensity decreases with the relative submergence, while the bubble frequency distribution is affected by the rough bed elements.

关键词： turbulent flow, aeration characteristics boulder macro- and intermediate roughness correlation analysis two-phase flow

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Model Adaptation Enriched with an Anisotropic Mesh Spacing for Nonlinear Equations: Application to Environmental and CFD Problems

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Numerical Mathematics(Theory,Methods and Applications) 2013年第3期6卷 447-478页

作者： stefano Micheletti Simona Perotto Filippo David MOX–Modeling and Scientific Computing Department of Mathematics"F.Brioschi"Politecnico of MilanoVia Bonardi 9I-20133 MilanoItaly STMicroelectronics Via Tolomeo 1I-20100 Cornaredo(MI)Italy

Goal of this paper is to suitably combine a model with an anisotropic mesh adaptation for the numerical simulation of nonlinear advection-diffusion-reaction systems and incompressible flows in ecological and environmental *** the reduced-basis method terminology,the proposed approach leads to a noticeable computational saving of the online phase with respect to the resolution of the reference model on nonadapted *** search of a suitable adapted model/mesh pair is to be meant,instead,in an offline fashion.

关键词： Model adaptation anisotropic mesh adaptation goal-oriented analysis advectiondiffusion-reaction systems Navier-Stokes equations finite elements

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APolygonal Discontinuous Galerkin Formulation for Contact Mechanics in Fluid-Structure Interaction Problems

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Communications in Computational Physics 2021年第6期30卷 1-33页

作者： stefano Zonca Paola FAntonietti Christian Vergara MOX Dipartimento di MatematicaPolitecnico di MilanoItaly LABS Dipartimento di ChimicaMateriali e Ingegneria Chimica“Giulio Natta”Politecnico di MilanoItaly

In this work,we propose a formulation based on the Polygonal Discontinuous Galerkin(PolyDG)method for contact mechanics that arises in fluid-structure interaction *** particular,we introduce a consistent penalization approach to treat the frictionless contact between immersed structures that undergo large *** key feature of the method is that the contact condition can be naturally embedded in the PolyDG formulation,allowing to easily support polygonal/polyhedral *** proposed approach introduced a fixed background mesh for the fluid problem overlapped by the structure grid that is able to move independently of the fluid *** assess the validity of the proposed approach,we report the results of several numerical experiments obtained in the case of contact between flexible structures immersed in a fluid.

关键词： Polygonal Discontinuous Galerkin method fluid-structure interaction contact mechanics

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Role of taxanes in pancreatic cancer

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World Journal of Gastroenterology 2012年第33期18卷 4457-4465页

作者： Carmen Belli stefano Cereda Michele Reni Department of Oncology San Raffaele Scientific Institute 20132 Milan Italy

Pancreatic cancer is one of the most deadly cancers and is characterized by a poor prognosis. Single agent gemcitabine, despite its limited activity and modest impact on disease outcome, is considered as the standard therapy in pancreatic cancer. Most of the combination regimens used in the treatment of this disease, also including the targeted agents, did not improve the outcome of patients. Also, taxanes have been tested as single agent and in combination chemotherapy, both in first line and as salvage chemotherapy, as another possible option for treating pancreatic cancer. The inclusion of taxanes in combination with gemcitabine as upfront therapy obtained promising results. Accordingly, taxanes, and above all, new generation taxanes, appear to be suitable candidates for further testing to assess their role against pancreatic cancer in various clinical settings.

关键词： Pancreatic cancer Advanced disease Metastatic disease Chemotherapy Taxanes Drug combinations Radiotherapy ABI-007

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Sustained neuronal viability by paracrine factors: new opportunities for endothelial progenitor cell secretome

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Neural Regeneration Research 2021年第7期16卷 1429-1430页

作者： stefano Di Santo Hans Rudolf Widmer Department of Neurosurgery Neurocenter and Regenerative Neuroscience ClusterUniversity Hospital BernSwitzerland University of BernInselspitalSwitzerland

Despite the big progresses in the field of regenerative medicine, the loss of neurons remains essentially an unresolved *** the different approaches under investigation, there are great expectations on stem and progen... 详细信息

关键词： progenitor strategies. spite

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Optimal Precursors Triggering the Kuroshio Extension State Transition Obtained by the Conditional Nonlinear Optimal Perturbation Approach

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Advances in Atmospheric Sciences 2017年第6期34卷 685-699页

作者： Xing ZHANG Mu MU Qiang WANG stefano PIERINI Key Laboratory of Ocean Circulation and Waves Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China University of Chinese Academy of Sciences Beijing 100049 China Institute of Atmospheric Sciences Fudan University Shanghai 200433 China Function Laboratory for Ocean Dynamics and Climate Qingdao National Laboratory for Marine Science and Technology Qingdao 266237 China Department of Science and Technology Parthenope University of Naples Naples 80143 Italy

In this study, the initial perturbations that are the easiest to trigger the Kuroshio Extension （KE） transition connecting a basic weak jet state and a strong, fairly stable meandering state, are investigated using a reduced-gravity shallow water ocean model and the CNOP （Conditional Nonlinear Optimal Perturbation） approach. This kind of initial perturbation is called an optimal precursor （OPR）. The spatial structures and evolutionary processes of the OPRs are analyzed in detail. The results show that most of the OPRs are in the form of negative sea surface height （SSH） anomalies mainly located in a narrow band region south of the KE jet, in basic agreement with altimetric observations. These negative SSH anomalies reduce the merid- ional SSH gradient within the KE, thus weakening the strength of the jet. The KE jet then becomes more convoluted, with a high-frequency and large-amplitude variability corresponding to a high eddy kinetic energy level; this gradually strengthens the KE jet through an inverse energy cascade. Eventually, the KE reaches a high-energy state characterized by two well defined and fairly stable anticyclonic meanders. Moreover, sensitivity experiments indicate that the spatial structures of the OPRs are not sensitive to the model parameters and to the optimization times used in the analysis.

关键词： Kuroshio Extension states transition CNOP approach optimal precursor ocean modeling

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Hepatocellular carcinoma in nonalcoholic fatty liver: Role of environmental and genetic factors

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World Journal of Gastroenterology 2014年第36期20卷 12945-12955页

作者： Paola Dongiovanni stefano Romeo Luca Valenti Internal Medicine 1B Fondazione IRCCS Ca’ Granda Ospedale Policlinico 20122 Milano Italy Department of Pathophysiology and Transplantation Università degli Studi di Milano 20122 Milano Italy Wallenberg Laboratory Department of Molecular and Clinical Medicine University of Gothenburg 40530 Gothenburg Sweden Clinical Nutrition Unit Department of Medical and Surgical Sciences University Magna Graecia 88100 Catan-zaro Italy

Hepatocellular carcinoma(HCC) is the fourth cause of cancer related mortality, and its incidence is rapidly increasing. Viral hepatitis, alcohol abuse, and exposure to hepatotoxins are major risk factors, but nonalcoholic fatty liver disease(NAFLD) associated with obesity, insulin resistance, and type 2 diabetes, is an increasingly recognized trigger, especially in developed countries. Older age, severity of insulin resistance and diabetes, and iron overload have been reported to predispose to HCC in this context. Remarkably, HCCs have been reported in non-cirrhotic livers in a higher proportion of cases in NAFLD patients than in other etiologies. Inherited factors have also been implicated to explain the different individual susceptibility to develop HCC, and their role seems magnified in fatty liver, where only a minority of affected subjects progresses to cancer. In particular, the common I148 M variant of the PNPLA3 gene influencing hepatic lipid metabolism influences HCC risk independently of its effect on the progression of liver fibrosis. Recently, rare loss-of-function mutations in Apolipoprotein B resulting in very low density lipoproteins hepatic retention and in Telomerase reverse transcriptase influencing cellular senescence have also been linked to HCC in NAFLD. Indeed, hepatic stellate cells senescence has been suggested to bridge tissue aging with alterations of the intestinal microbiota in the pathogenesis of obesity-related HCC. A deeper understanding of the mechanisms mediating hepatic carcinogenesis during insulin resistance, and the identification of its genetic determinants will hopefully provide new diagnostic and therapeutic tools.

关键词： Nonalcoholic fatty liver disease Steatosis Hepatocellular carcinoma Cirrhosis Fibrogenesis Liver disease Genetics Single nucleotide polymorphism Patatin-like phospholipase domain-containing 3

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