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Unsteady Inflow Effects on the Wake Shed from a High-Lift LPT Blade Subjected to Boundary Layer Laminar Separation

Journal of Thermal Science 2012年第2期21卷 97-108页

作者： Francesca Satta marina ubaldi Pietro Zunino Università degli Studi di Genova

An experimental investigation on the near and far wake of a cascade of high-lift low-pressure turbine blades subjected to boundary layer separation over the suction side surface has been carried out, under steady and unsteady inflows. Two Reynolds number conditions, representative of take-off/landing and cruise operating conditions of the real engine, have been tested. The effect of upstream wake-boundary layer interaction on the wake shed from the profile has been investigated in a three-blade large-scale linear turbine cascade. The comparison between the wakes shed under steady and unsteady inflows has been performed through the analysis of mean velocity and Reynolds stress components measured at midspan of the central blade by means of a two-component crossed miniature hot-wire probe. The wake development has been analyzed in the region between 2% and 100% of the blade chord from the central blade trailing edge, aligned with the blade exit direction. Wake integral parameters, half-width and maximum velocity defects have been evaluated from the mean velocity distributions to quantify the modifications induced on the vane wake by the upstream wake. Moreover the thicknesses of the two wake shear layers have been considered separately in order to identify the effects of Reynolds number and incoming flow on the wake shape. The self-preserving state of the wake has been looked at, taking into account the different thicknesses of the two shear layers. The evaluation of the power density spectra of the velocity fluctuations allowed the study of the wake unsteady behavior, and the detection of the effects induced by the different operating conditions on the trailing edge vortex shedding.

关键词： Wake-wake unsteady interaction high-lift blade profiles low-pressure turbine blade wake.

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An Experimental Investigation of the Dissipation Mechanisms in the Suction Side Boundary Layer of a Turbine Blade

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Journal of Thermal Science 2008年第4期17卷 289-297页

作者： Francesca Satta Daniele Simoni marina ubaldi Pietro Zunino Dipartimento di Macchine Sistemi Energetici e Trasporti-Università di Genova

The present work is part of an extensive experimental activity carried out by the authors in recent years aimed at investigating the boundary layer transition phenomenon in turbine blades. The large scale of the cascade and the use of advanced LDV instrumentation and precision probe traversing mechanism resulted in high degree of spatial resolution and high accuracy of measurements. The main dissipation mechanism determining the profile losses in turbomachinery blades is the work of deformation of the mean motion within the boundary layer operated by both viscous and turbulent shear stresses. In the present paper, the local viscous and turbulent deformation works have been directly evaluated from the detailed measurements of boundary layer mean velocity and Reynolds shear stress. The results show the distributions and the relative importance of the viscous and turbulent contributions to the loss production, in relation with the boundary layer states occurring along the turbine profile.

关键词： Axial flow turbines Profile boundary layer Energy dissipation mechanism Boundary layer transition Laser Doppler measurements.

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Large Eddy Simulation of the By-pass Transition Process under Different Inlet Turbulence Conditions

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Journal of Thermal Science 2021年第6期30卷 2112-2121页

作者： BARSI Dario COSTA Carlo LENGANI Davide SIMONI Daniele ubaldi marina DIME-University of Genova Via Montallegro 11-16145 GenovaItaly

The transition process of the boundary layer developing over a flat plate with elevated inlet Free Stream Turbulence Intensity(FSTI)has been studied by means of Large Eddy Simulation(LES).To this purpose,four cases with different inflow disturbances have been tested varying the magnitude and the length scale of *** has been performed by using the finite-volume ANSYS Fluent *** computational domain,which was constituted by a rectangular domain with a zero thickness plate,was based on an ERCOFTAC test case in order to provide a validation with a well-known set of data by comparing the boundary layer integral parameters and mean and fluctuating streamwise velocity *** four cases were discussed within the paper by looking at classical statistical properties as well as advanced post-processing *** was shown that the decrease in the free stream turbulence level postpones the transition location,whereas the variation of the integral length scale has a very low influence on the distribution of the time-mean flow *** Orthogonal Decomposition(POD)has been applied to the instantaneous LES flow fields in order to provide a statistical representation of the structures responsible for transition and their response to free-stream turbulence intensity and length *** presence of vortical filaments parallel to the wall,typically referred as boundary layer streaks,is clearly identified;their characteristic dimensions and how they change as a function of FSTI properties were analyzed within the paper.

关键词： by-pass transition Large Eddy Simulation(LES) Proper Orthogonal Decomposition(POD) boundary layer streaks

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Experimental Analysis of the Aerodynamic Performance of an Innovative Low Pressure Turbine Rotor

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Journal of Thermal Science 2016年第1期25卷 22-31页

作者： Infantino Daniele Satta Francesca Simoni Daniele ubaldi marina Zunino Pietro Bertini Francesco DIME-Universita degli Studi di Genova Via MontaUegro 11-16145 GenovaItaly Avio Aero Viale I Maggio 56I-10040 Rivalta(TO)-Italy

In the present work the aerodynamic performances of an innovative rotor blade row have been experimentally investigated. Measurements have been carried out in a large scale low speed single stage cold flow facility at a Reynolds number typical of aeroengine cruise, under nominal and off-design conditions. The time-mean blade aerodynamic loadings have been measured at three radial positions along the blade height through a pressure transducer installed inside the hollow shaft, by delivering the signal to the stationary frame with a slip ring. The time mean aerodynamic flow fields upstream and downstream of the rotor have been measured by means of a five-hole probe to investigate the losses associated with the rotor. The investigations in the single stage research turbine allow the reproduction of both wake-boundary layer interaction as well as vortex-vortex interaction. The detail of the present results clearly highlights the strong dissipative effects induced by the blade tip vortex and by the momentum defect as well as the turbulence production, which is generated during the migration of the stator wake in the rotor passage. Phase-locked hot-wire investigations have been also performed to analyze the time-varying flow during the wake passing period. In particular the interaction between stator and rotor structures has been investigated also under off-design conditions to further explain the mechanisms contributing to the loss generation for the different conditions.

关键词： Low Pressure Turbine Single Stage Research Turbine Rotor Aerodynamic Loading Hot-wire Anemometry

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Colorectal cancer and dormant metastases:Put to sleep or destroy?

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World Journal of Gastrointestinal Oncology 2024年第6期16卷 2304-2317页

作者： marina A Senchukova Department of Oncology Orenburg State Medical UniversityOrenburg 460000Russia

After reading the review by An et al“Biological factors driving colorectal cancer metastasis”,which covers the problem of the metastasis of colorectal cancer(CRC),I had a desire to discuss with readers one of the exciting problems associated with dormant *** deaths from CRCs are caused by metastases,which can be detected both at diagnosis of the primary tumor and several years or even decades after *** is because tumor cells that enter the bloodstream can be destroyed by the immune system,cause metastatic growth,or remain dormant for a long *** tumor cells may not manifest themselves throughout a person’s life or,after some time and under appropriate conditions,may give rise to the growth of *** this editorial,we will discuss the most important features of dormant metastases and the mechanisms of premetastatic niche formation,as well as factors that contribute to the activation of dormant metastases in *** will pay special attention to the possible mechanisms involved in the formation of circulating tumor cell complexes and the choice of therapeutic strategies that promote the dormancy or destruction of tumor cells in CRCs.

关键词： Circulating tumor cells Colorectal cancer Disseminated tumor cells Dormant metastases Metastases Premetastatic niche

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Synthetic lethality by PARP inhibitors: new mechanism uncovered based on unresolved transcription-replication conflicts

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Signal Transduction and Targeted Therapy 2024年第8期9卷 3163-3164页

作者： marina Kolesnichenko Claus Scheidereit Department of Hepatology and Gastroenterology Charite-Universitatsmedizin BerlinBerlinGermany Laboratory for Signal Transduction in Tumor Cells Max Delbruck Center for Molecular Medicine in the Helmholtz Association(MDC)BerlinGermany

In a landmark study recently published in Nature,Petropoulous et *** that synthetic lethality of poly(ADP-ribose)polymerase(PARP)inhibitors in cells with defective homologous recombination repair(HR)results predominantly from transcription replication conflicts(TRC)and not,as previously proposed,from PARP trapping on DNA(Fig.1).The article unveils a new mechanism behind synthetic lethality of PARP inhibitors with relevance for cancer therapy.

关键词： al. PARP mechanism

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The bumpy road of purinergic inhibitors to clinical application in immune-mediated diseases

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Neural Regeneration Research 2024年第6期19卷 1206-1211页

作者： Matihias T.Wyss Christine Heuer marina Herwerth Institute of Pharmacology and Toxicology University of Zurich Neuroscience Center Zurich (ZNZ) University of Zurich and ETH Zurich 3. Neurology Department University Hospital of Zurich

Purinergic signaling plays important roles throughout the body in the regulation of organ functions during and following the disruption of homeostasis. This is also reflected by the widespread expression of two families of purinergic receptors(P1 and P2) with numerous subtypes. In the last few decades, there has been increasing evidence that purinergic signaling plays an important role in the regulation of immune functions. Mainly, signals mediated by P2 receptors have been shown to contribute to immune system-mediated pathologies. Thus, interference with P2 receptors may be a promising strategy for the modulation of immune responses. Although only a few clinical studies have been conducted in isolated entities with limited success, preclinical work suggests that the use of P2 receptor inhibitors may bear some promise in various autoimmune diseases. Despite the association of P2 receptors with several disorders from this field, the use of P2 receptor antagonists in clinical therapy is still very scarce. In this narrative review, we briefly review the involvement of the purinergic system in immunological responses and clinical studies on the effect of purinergic inhibition on autoimmune processes. We then open the aperture a bit and show some preclinical studies demonstrating a potential effect of purinergic blockade on autoimmune events. Using suramin, a non-specific purinergic inhibitor, as an example, we further show that off-target effects could be responsible for observed effects in immunological settings, which may have interesting implications. Overall, we believe that it is worthwhile to further investigate this hitherto underexplored area.

关键词： autoimmune diseases neurological disorders purinergic system P2 receptor inhibitors suramin

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Colon and rectal cancer:An emergent public health problem

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World Journal of Gastroenterology 2024年第7期30卷 644-651页

作者： marina Pinheiro David Nascimento Moreira Michele Ghidini LAQV REQUIMTEDepartment of ChemistryFaculty of PharmacyUniversity of Porto4050-313 PortoPortugal Unidade de Saúde Pública Unidade Local de Saúde Barcelos/EsposendeBarcelinhos 4755-069BragaPortugal Medical Oncology Unit Fondazione IRCCS Ca’Granda Ospedale Maggiore PoliclinicoMilan 20122Italy

Colorectal cancer ranks third globally,with a high mortality *** the United States,and different countries in Europe,organized population screenings exist and include people between 50 and 74 years of *** screenings have allowed an early diagnosis and consequently an improvement in health *** and rectal cancer(CRC)is a disease of particular interest due to the high global burden associated with it and the role attributed to prevention and early diagnosis in reducing morbidity and *** study is a review of CRC pathology and includes the most recent scientific evidence regarding this pathology,as well as a diagnosis of the epidemiological situation of ***,the recommendation from a public health perspective will be discussed in detail taking into account the context and the most current recommendations.

关键词： Colon and rectal neoplasia Colon and rectal tumor Mortality Morbidity

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Periodontitis:An often-neglected complication of diabetes

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World Journal of Diabetes 2024年第3期15卷 318-325页

作者： marina G Kudiyirickal Joseph M Pappachan Primary Care Dental Practice The Smile ClinicPreston PR16PZUnited Kingdom Department of Endocrinology and Metabolism Lancashire Teaching Hospitals NHS TrustPreston PR29HTUnited Kingdom Faculty of Science Manchester Metropolitan UniversityManchester M156BHUnited Kingdom Faculty of Biology Medicine and HealthThe University of ManchesterManchester M139PLUnited Kingdom

The bidirectional association between type 2 diabetes mellitus(T2DM)and periodontitis is now well established,resulting in periodontal disease being considered as the 6th major complication of diabetes mellitus(DM)after cardiovascular disease,eye disease,neuropathy,nephropathy,and peripheral vascular *** can worsen the virulence and invasiveness of pathogenic oral microbial flora aggravating the local inflammation and infection in those with periodontal *** the other hand,the chemical and immunological mediators released into the circulation as part of periodontal inflammation worsen the systemic insulin resistance with worsening of *** if undiagnosed or left untreated can also result in eventual tooth loss.A study by Xu et al in the World Journal of Diabetes examined the predictive factors associated with periodontitis in Chinese patients with *** prevalence of periodontitis was found to be 75.7%in this *** on logistic regression analysis,the predictive factors for higher risk were low tooth brushing frequency[odds ratio(OR)=4.3],high triglycerides(TG;OR=3.31),high total cholesterol(TC;OR=2.87),higher glycated hemoglobin(HbA1c;OR=2.55),and higher age(OR=1.05)while higher education level was protective(OR=0.53).However,the most influential variables were HbA1c followed by age,TC,TG,low education level,brushing frequency,and sex on the random forest model(this model showed higher sensitivity for predicting the risk).A good understanding of the predictors for periodontitis in T2DM patients is important in prevention,early detection of susceptible patients,and intervention to improve periodontal health and enable long-term glycaemic control as observed by Xu et al.

关键词： Diabetes mellitus Periodontitis Predictive factors Cardiovascular disease Glycaemic control

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Immune signature of small bowel adenocarcinoma and the role of tumor microenvironment

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World Journal of Gastroenterology 2024年第8期30卷 794-798页

作者： Grigorios Christodoulidis marina Nektaria Kouliou Konstantinos Eleftherios Koumarelas Department of General Surgery University Hospital of LarissaLarissa 41110Greece

In this editorial we comment on the article published“Clinical significance of programmed cell death-ligand expression in small bowel adenocarcinoma is determined by the tumor microenvironment”.Small bowel adenocarcinoma(SBA)is a rare gastrointestinal neoplasm and despite the small intestine's significant surface area,SBA accounts for less than 3%of such *** detection is challenging and the reason arises from its asymptomatic nature,often leading to late-stage discovery and poor *** involves platinum-based chemotherapy with a 5-fluorouracil combination,but the lack of effective chemotherapy contributes to a generally poor *** are linked to genetic disorders and risk factors,including chronic inflammatory *** unique characteristics of the small bowel,such as rapid cell renewal and an active immune system,contributes to the rarity of these tumors as well as the high intratumoral infiltration of immune cells is associated with a favorable *** cell death-ligand 1(PD-L1)expression varies across different cancers,with potential discrepancies in its prognostic *** instability(MSI)in SBA is associated with a high tumor mutational burden,affecting the prognosis and response to *** presence of PD-L1 and programmed cell death 1,along with tumor-infiltrating lymphocytes,plays a crucial role in the complex microenvironment of SBA and contributes to a more favorable prognosis,especially in the context of high MSI *** tumor-infiltrating lymphocytes are identified as independent prognostic indicators and the association between MSI status and a favorable prognosis,emphasizes the importance of evaluating the immune status of tumors for treatment decisions.

关键词： Programmed cell death 1 Programmed cell death-ligand 1 Programmed death ligand Small bowel adenocarcinoma Tumor infiltrating lymphocytes Tumor microenvironment Microsatellite instability

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