20 results on '"SIMONI D"'
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2. A data-driven analysis of short and long laminar separation bubbles
- Author
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Dellacasagrande, M., primary, Lengani, D., additional, Simoni, D., additional, and Yarusevych, S., additional
- Published
- 2023
- Full Text
- View/download PDF
3. Effects of Ribbed Surfaces on Profile Losses of Low-Pressure Turbine Blades
- Author
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Dellacasagrande, M., primary, Lengani, D., additional, Simoni, D., additional, Ubaldi, M., additional, and Bertini, F., additional
- Published
- 2023
- Full Text
- View/download PDF
4. A data-driven optimal disturbance procedure for free-stream turbulence induced transition
- Author
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Dotto, A., primary, Barsi, D., additional, Lengani, D., additional, and Simoni, D., additional
- Published
- 2022
- Full Text
- View/download PDF
5. Effects of Upstream Wakes on the Boundary Layer Over a Low-Pressure Turbine Blade
- Author
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De Vincentiis, L., Ðurovic, K., Lengani, D., Simoni, D., Pralits, J., Henningson, D. S., and Hanifi, A.
- Subjects
Mechanical Engineering - Abstract
In the present work, the evolution of the boundary layer over a low-pressure turbine blade is studied using direct numerical simulations, with the aim of investigating the unsteady flow field induced by the rotor-stator interaction. The freestream flow is characterized by the high level of freestream turbulence and periodically impinging wakes. As in the experiments, the wakes are shed by moving bars modeling the rotor blades and placed upstream of the turbine blades. To include the presence of the wake without employing an ad-hoc model, we simulate both the moving bars and the stationary blades in their respective frames of reference and the coupling of the two domains is done through appropriate boundary conditions. The presence of the wake mainly affects the development of the boundary layer on the suction side of the blade. In particular, the flow separation in the rear part of the blade is suppressed. Moreover, the presence of the wake introduces alternating regions in the streamwise direction of high- and low-velocity fluctuations inside the boundary layer. These fluctuations are responsible for significant variations of the shear stress. The analysis of the velocity fields allows the characterization of the streaky structures forced in the boundary layer by turbulence carried by upstream wakes. The breakdown events are observed once positive streamwise velocity fluctuations reach the end of the blade. Both the fluctuations induced by the migration of the wake in the blade passage and the presence of the streaks contribute to high values of the disturbance velocity inside the boundary layer with respect to a steady inflow case. The amplification of the boundary layer disturbances associated with different spanwise wavenumbers has been computed. It was found that the migration of the wake in the blade passage stands for the most part of the perturbations with zero spanwise wavenumber. The non-zero wavenumbers are found to be amplified in the rear part of the blade at the boundary between the low- and high-speed regions associated with the wakes.
- Published
- 2022
6. Investigation on Strain and Stress Principal Axes in Unsteady DNS Turbine Data
- Author
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Lengani, D., additional, Simoni, D., additional, De Vincentiis, L., additional, Ðurović, K., additional, Pralits, J., additional, Henningson, D. S., additional, and Hanifi, A., additional
- Published
- 2022
- Full Text
- View/download PDF
7. Effects of Ribbed Surfaces on Profile Losses of Low-Pressure-Turbine Blades
- Author
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Dellacasagrande, M., additional, Lengani, D., additional, Simoni, D., additional, Ubaldi, M., additional, and Bertini, F., additional
- Published
- 2022
- Full Text
- View/download PDF
8. On the receptivity of low-pressure turbine blades to external disturbances
- Author
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Lengani, D., Simoni, D., Pralits, J. O., Durovic, Kristina, De Vincentiis, Luca, Henningson, Dan, Hanifi, Ardeshir, Lengani, D., Simoni, D., Pralits, J. O., Durovic, Kristina, De Vincentiis, Luca, Henningson, Dan, and Hanifi, Ardeshir
- Abstract
In the present work, the laminar-turbulent transition of the flow evolving around a low-pressure turbine blade has been investigated. Direct numerical simulations have been carried out for two different free stream turbulence intensity (FSTI) levels to investigate the role of free stream oscillations on the evolution of the blade boundary layer. Emphasis is placed on identifying the mechanisms driving the formation and breakup of coherent structures in the high FSTI case and how these processes are affected by the leading-edge receptivity and/or by the continuous forcing in the blade passage. Proper orthogonal decomposition (POD) has been adopted to provide a clear statistical representation of the shape of the structures. Extended POD projections provided temporal and spanwise correlations that allowed us to identify dominant temporal structures and spanwise wavelengths in the transition process. The extended POD analysis shows that the structures on the pressure side are not related to what happens at the leading edge. The results on the suction side show that the modes defining the leading edge and the passage bases correlate with coherent structures responsible for the transition. The most energetic mode of the passage basis is strongly related to the most amplified wavelength in the boundary layer and breakup events leading to transition. Modes with a smaller spanwise wavelength belong to the band predicted by optimal disturbance theory, they amplify with a smaller gain in the rear suction side, and they show the highest degree of correlation between the passage region and the rear suction side., QC 20220322
- Published
- 2022
- Full Text
- View/download PDF
9. Free-Stream Turbulence Induced Boundary-Layer Transition In Low-Pressure Turbines
- Author
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De Vincentiis, Luca, Durovic, Kristina, Lengani, D., Simoni, D., Pralits, J., Henningson, Dan S., Hanifi, Ardeshir, De Vincentiis, Luca, Durovic, Kristina, Lengani, D., Simoni, D., Pralits, J., Henningson, Dan S., and Hanifi, Ardeshir
- Abstract
In the present work the evolution of the boundary layer over a low-pressure turbine blade is studied by means of direct numerical simulations. The set-up of the simulations follows the experiments by [1], aiming to investigate the unsteady flow field induced by the rotor-stator interaction. The free-stream flow is characterized by high level of free-stream turbulence and periodically impinging wakes. As in the experiments, the wakes are shed by moving bars modeling the rotor blades and placed upstream of the turbine blades. To include the presence of the wake without employing an ad-hoc model, we simulate both the moving bars and the stationary blades in their respective frames of reference and the coupling of the two domains is done through appropriate boundary conditions. The presence of the wake mainly affects the development of the boundary layer on the suction side of the blade. In particular, the flow separation in the rear part of the blade is suppressed. Moreover, the presence of the wake introduces alternating regions in the streamwise direction of high- and low-velocity fluctuations inside the boundary layer. These fluctuations are responsible for significant variations of the shear stress. The analysis of the velocity fields allows the characterization of the streaky structures forced in the boundary layer by turbulence carried by upstream wakes. The breakdown events are observed once positive streamwise velocity fluctuations reach the end of the blade. Both the fluctuations induced by the migration of the wake in the blade passage and the presence of the streaks contribute to high values of the disturbance velocity inside the boundary layer with respect to a steady inflow case. The amplification of the boundary layer disturbances associated with different spanwise wavenumbers has been computed. It was found that the migration of the wake in the blade passage stands for the most part of the perturbations with zero spanwise wavenumber. The non-zero wavenum, QC 20230614
- Published
- 2022
- Full Text
- View/download PDF
10. Investigation on Strain and Stress Principal Axes in Unsteady DNS Turbine Data
- Author
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Lengani, D., Simoni, D., De Vincentiis, Luca, Durovic, Kristina, Pralits, J., Henningson, Dan S., Hanifi, Ardeshir, Lengani, D., Simoni, D., De Vincentiis, Luca, Durovic, Kristina, Pralits, J., Henningson, Dan S., and Hanifi, Ardeshir
- Abstract
In the present work, high-fidelity direct numerical sim- ulation (DNS) data has been adopted in conjunction with an extensive post-processing to provide a detailed descrip- tion of the turbulence characteristics and its production within a low pressure turbine (LPT) cascade blade pas- sage operating with unsteady inflow. Proper orthogonal decomposition is used at first to provide the statistical rep- resentation of the flow structures that occur in the blade passage. Different inlet turbulent scales are isolated and a representation of the turbulence produced in the passage is also provided. Principal axes of the Reynolds stress and the strain tensors have been analyzed to provide further insight on the turbulence production. Since each spatial POD mode captures a quota of the Reynolds stress ten- sor, the POD modes are well suited to provide reduced order models (ROMs) that represent the different scales of turbulence. Namely, four different scales are defined, and the eigenvectors of the stress tensor for each reduced model are discussed. The discussion includes the compar- ison with the principal axis of the strain rate tensor. It is shown that the spatial locations where the eigen- vectors of the strain and stress tensors are aligned lead to the largest production of turbulent kinetic energy. The de- terministic periodic perturbations induced at the inlet by the unsteady incoming wakes lead to the largest produc- tion of turbulence in the passage region where the highest strain is detected and where the eigenvectors of the two tensors are aligned. In the suction side boundary layers, the highest production is related to the local maximum of the Reynolds shear stress due to the stochastic perturba- tions. The deterministic perturbations do not contribute to the production of turbulence in the suction side bound- ary layer, even though their induced stress is not negli- gible, because the eigenvector directions have a maximum misalignment., QC 20230614
- Published
- 2022
- Full Text
- View/download PDF
11. Effect of free-stream turbulence properties on different transition routes for a zero-pressure gradient boundary layer
- Author
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Dotto, A., primary, Barsi, D., additional, Lengani, D., additional, Simoni, D., additional, and Satta, F., additional
- Published
- 2022
- Full Text
- View/download PDF
12. On the receptivity of low-pressure turbine blades to external disturbances
- Author
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Lengani, D., primary, Simoni, D., additional, Pralits, J.O., additional, Đurović, K., additional, De Vincentiis, L., additional, Henningson, D.S., additional, and Hanifi, A., additional
- Published
- 2022
- Full Text
- View/download PDF
13. Identification of free-stream and boundary layer correlating events in free-stream turbulence-induced transition
- Author
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Verdoya, J., primary, Dellacasagrande, M., additional, Barsi, D., additional, Lengani, D., additional, and Simoni, D., additional
- Published
- 2022
- Full Text
- View/download PDF
14. Exploring the Materials and Condition of 20th-Century Dolls in Zoe Leonard’s Mouth Open, Teeth Showing 2000
- Author
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Judith Lee, Libby Ireland, Joyce H. Townsend, Bronwyn Ormsby, Angelica Bartoletti, Deborah Cane, Simoní Da Ros, Rose King, Isabella del Gaudio, and Katherine Curran
- Subjects
twentieth-century dolls ,plastic ,degradation ,conservation ,contemporary art ,Organic chemistry ,QD241-441 - Abstract
Systematic condition and analytical surveys were carried out on Zoe Leonard’s (b. 1961) Mouth Open, Teeth Showing 2000, an installation artwork in Tate’s collection consisting of 162 children’s dolls. The dolls were manufactured at various points within the 20th century and encompass several potentially problematic synthetic polymers found in modern and contemporary museum collections. To explore the doll materials and conservation condition, a multi-analytical approach was used to identify key synthetic polymer types and additives present, including portable and bench analytical techniques. Challenging degradation phenomena associated with different types of doll have been discussed and related to their material composition, which has helped our understanding of the conservation challenges inherent to this contemporary artwork.
- Published
- 2022
- Full Text
- View/download PDF
15. Low Rank Education of Cascade Loss Sensitivity to Unsteady Parameters by Proper Orthogonal Decomposition
- Author
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Lengani, D., Simoni, D., Yepmo, V., Ubaldi, M., Zunino, P., and Bertini, F.
- Abstract
In this study, proper orthogonal decomposition (POD) has been applied to a large dataset describing the profile losses of low-pressure turbine (LPT) cascades, thus allowing (i) the identification of the most influencing parameters that affect the loss generation; (ii) the identification of the minimum number of requested conditions useful to educate a model with a reduced number of data. The dataset is constituted by the total pressure loss coefficient distributions in the pitchwise direction. The experiments have been conducted varying the flow Reynolds number, the reduced frequency, and the flow coefficient. Two cascades are considered: the first for tuning the procedure and identifying the number of really requested tests, and the second for the verification of the proposed model. They are characterized by the same axial chord but different pitch-to-chord ratio and different flow angles, hence two Zweifel numbers. The POD mode distributions indicate the spatial region where losses occur, the POD eigenvectors provide how such losses vary for different design conditions and the POD eigenvalues provide the rank of the approximation. Since the POD space shows an optimal basis describing the overall process with a low-rank representation (LRR), a smooth kernel is educated by means of least-squares method (LSM) on the POD eigenvectors. Particularly, only a subset of data (equal to the rank of the problem) has been used to generate the POD modes and related coefficients. Thanks to the LRR of the problem in the POD space, predictors are low-order polynomials of the independent variables (Re, f+, and ϕ). It will be shown that the smooth kernel adequately estimates the loss distribution in points that do not participate to the education. In addition, keeping the same steps for the education of the kernel on another cascade, loss distribution and magnitude are still well captured. Thus, the analysis show that the rank of the problem is much lower than the tested conditions, and consequently, a reduced number of tests are really necessary. This could be useful to reduce the number of hi-fidelity simulations or detailed experiments in the future, thus further contributing to optimize LPT blades.
- Published
- 2021
- Full Text
- View/download PDF
16. It's not all in your feet: Improving penalty kick performance with human-avatar interaction and machine learning.
- Author
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Bloechle JL, Audiffren J, Le Naour T, Alli A, Simoni D, Wüthrich G, and Bresciani JP
- Abstract
Penalty kicks are increasingly decisive in major international football competitions. Yet, over 30% of shootout kicks are missed. The outcome of the kick often relies on the ability of the penalty taker to exploit anticipatory movements of the goalkeeper to redirect the kick toward the open side of the goal. Unfortunately, this ability is difficult to train using classical methods. We used an augmented reality simulator displaying an holographic goalkeeper to test and train penalty kick performance with 13 young elite players. Machine learning algorithms were used to optimize the learning rate by maintaining an optimal level of training difficulty. Ten training sessions of 20 kicks reduced the redirection threshold by 120 ms, which constituted a 28% reduction with respect to the baseline threshold. Importantly, redirection threshold reduction was observed for all trained players, and all things being equal, it corresponded to an estimated 35% improvement of the success rate., Competing Interests: The authors declare no competing interests., (© 2024 The Author(s).)
- Published
- 2024
- Full Text
- View/download PDF
17. New insights into neuropathology and pathogenesis of autoimmune glial fibrillary acidic protein meningoencephalomyelitis.
- Author
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Guo Y, Endmayr V, Zekeridou A, McKeon A, Leypoldt F, Hess K, Kalinowska-Lyszczarz A, Klang A, Pakozdy A, Höftberger E, Hametner S, Haider C, De Simoni D, Peters S, Gelpi E, Röcken C, Oberndorfer S, Lassmann H, Lucchinetti CF, and Höftberger R
- Subjects
- Humans, Animals, Dogs, Glial Fibrillary Acidic Protein metabolism, Astrocytes pathology, Autoantibodies, Encephalomyelitis pathology, Autoimmune Diseases of the Nervous System cerebrospinal fluid, Autoimmune Diseases of the Nervous System therapy, Meningoencephalitis cerebrospinal fluid, Meningoencephalitis pathology
- Abstract
Anti-glial fibrillary acidic protein (GFAP) meningoencephalomyelitis (autoimmune GFAP astrocytopathy) is a new autoimmune central nervous system (CNS) disease diagnosable by the presence of anti-GFAP autoantibodies in the cerebrospinal fluid and presents as meningoencephalomyelitis in the majority of patients. Only few neuropathological reports are available and little is known about the pathogenic mechanisms. We performed a histopathological study of two autopsies and nine CNS biopsies of patients with anti-GFAP autoantibodies and found predominantly a lymphocytic and in one autopsy case a granulomatous inflammatory phenotype. Inflammatory infiltrates were composed of B and T cells, including tissue-resident memory T cells. Although obvious astrocytic damage was absent in the GFAP-staining, we found cytotoxic T cell-mediated reactions reflected by the presence of CD8
+ /perforin+ /granzyme A/B+ cells, polarized towards astrocytes. MHC-class-I was upregulated in reactive astrocytes of all biopsies and two autopsies but not in healthy controls. Importantly, we observed a prominent immunoreactivity of astrocytes with the complement factor C4d. Finally, we provided insight into an early phase of GFAP autoimmunity in an autopsy of a pug dog encephalitis that was characterized by marked meningoencephalitis with selective astrocytic damage with loss of GFAP and AQP4 in the lesions.Our histopathological findings indicate that a cytotoxic T cell-mediated immune reaction is present in GFAP autoimmunity. Complement C4d deposition on astrocytes could either represent the cause or consequence of astrocytic reactivity. Selective astrocytic damage is prominent in the early phase of GFAP autoimmunity in a canine autopsy case, but mild or absent in subacute and chronic stages in human disease, probably due to the high regeneration potential of astrocytes. The lymphocytic and granulomatous phenotypes might reflect different stages of lesion development or patient-specific modifications of the immune response. Future studies will be necessary to investigate possible implications of pathological subtypes for clinical disease course and therapeutic strategies., (© 2024. The Author(s).)- Published
- 2024
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18. New Synthetic Isoxazole Derivatives Acting as Potent Inducers of Fetal Hemoglobin in Erythroid Precursor Cells Isolated from β-Thalassemic Patients.
- Author
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Zuccato C, Cosenza LC, Tupini C, Finotti A, Sacchetti G, Simoni D, Gambari R, and Lampronti I
- Subjects
- Humans, Erythroid Precursor Cells, Biological Assay, Hydroxyurea pharmacology, Isoxazoles, Fetal Hemoglobin genetics, beta-Thalassemia drug therapy
- Abstract
Induction of fetal hemoglobin (HbF) is highly beneficial for patients carrying β-thalassemia, and novel HbF inducers are highly needed. Here, we describe a new class of promising HbF inducers characterized by an isoxazole chemical skeleton and obtained through modification of two natural molecules, geldanamycin and radicicol. After preliminary biological assays based on benzidine staining and RT-qPCR conducted on human erythroleukemic K562 cells, we employed erythroid precursors cells (ErPCs) isolated from β-thalassemic patients. ErPCs weretreated with appropriate concentrations of isoxazole derivatives. The accumulation of globin mRNAs was studied by RT-qPCR, and hemoglobin production by HPLC. We demonstrated the high efficacy of isozaxoles in inducing HbF. Most of these derivatives displayed an activity similar to that observed using known HbF inducers, such as hydroxyurea (HU) or rapamycin; some of the analyzed compounds were able to induce HbF with more efficiency than HU. All the compounds were active in reducing the excess of free α-globin in treated ErPCs. All the compounds displayed a lack of genotoxicity. These novel isoxazoles deserve further pre-clinical study aimed at verifying whether they are suitable for the development of therapeutic protocols for β-thalassemia.
- Published
- 2023
- Full Text
- View/download PDF
19. Italian guidance on Dementia Day Care Centres: A position paper.
- Author
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Mossello E, Baccini M, Caramelli F, Biagini CA, Cester A, De Vreese LP, Darvo G, Vampini C, Gotti M, Fabbo A, Marengoni A, Cavallini MC, Gori G, Chattat R, Marini M, Ceron D, Lanzoni A, Pizziolo P, Mati A, Zilli I, Cantini C, Caleri V, Tonon E, Simoni D, Mecocci P, Ungar A, and Masotti G
- Subjects
- Humans, Aged, Day Care, Medical, Syndrome, Caregivers psychology, Dementia therapy, Dementia psychology, COVID-19 prevention & control
- Abstract
Dementia Day Care Centres (DDCCs) are defined as services providing care and rehabilitation to people with dementia associated with behavioural and psychological symptoms (BPSD) in a semi-residential setting. According to available evidence, DDCCs may decrease BPSD, depressive symptoms and caregiver burden. The present position paper reports a consensus of Italian experts of different disciplines regarding DDCCs and includes recommendations about architectural features, requirements of personnel, psychosocial interventions, management of psychoactive drug treatment, prevention and care of geriatric syndromes, and support to family caregivers. DDCCs architectural features should follow specific criteria and address specific needs of people with dementia, supporting independence, safety, and comfort. Staffing should be adequate in size and competence and should be able to implement psychosocial interventions, especially focused on BPSD. Individualized care plan should include prevention and treatment of geriatric syndromes, a targeted vaccination plan for infectious diseases including COVID-19, and adjustment of psychotropic drug treatment, all in cooperation with the general practitioner. Informal caregivers should be involved in the focus of intervention, with the aim of reducing assistance burden and promoting the adaptation to the ever-changing relationship with the patient., (© 2023. The Author(s).)
- Published
- 2023
- Full Text
- View/download PDF
20. Anti-Neuronal IgG4 Autoimmune Diseases and IgG4-Related Diseases May Not Be Part of the Same Spectrum: A Comparative Study.
- Author
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Endmayr V, Tunc C, Ergin L, De Rosa A, Weng R, Wagner L, Yu TY, Fichtenbaum A, Perkmann T, Haslacher H, Kozakowski N, Schwaiger C, Ricken G, Hametner S, Klotz S, Dutra LA, Lechner C, de Simoni D, Poppert KN, Müller GJ, Pirker S, Pirker W, Angelovski A, Valach M, Maestri M, Guida M, Ricciardi R, Frommlet F, Sieghart D, Pinter M, Kircher K, Artacker G, Höftberger R, and Koneczny I
- Subjects
- Autoantibodies immunology, Autoantigens immunology, Female, Humans, Male, Neurons immunology, Neurons pathology, Immunoglobulin G4-Related Disease immunology, Immunoglobulin G4-Related Disease pathology
- Abstract
Background: IgG4 is associated with two emerging groups of rare diseases: 1) IgG4 autoimmune diseases (IgG4-AID) and 2) IgG4-related diseases (IgG4-RLD). Anti-neuronal IgG4-AID include MuSK myasthenia gravis, LGI1- and Caspr2-encephalitis and autoimmune nodo-/paranodopathies (CNTN1/Caspr1 or NF155 antibodies). IgG4-RLD is a multiorgan disease hallmarked by tissue-destructive fibrotic lesions with lymphocyte and IgG4 plasma cell infiltrates and increased serum IgG4 concentrations. It is unclear whether IgG4-AID and IgG4-RLD share relevant clinical and immunopathological features., Methods: We collected and analyzed clinical, serological, and histopathological data in 50 patients with anti-neuronal IgG4-AID and 19 patients with IgG4-RLD., Results: A significantly higher proportion of IgG4-RLD patients had serum IgG4 elevation when compared to IgG4-AID patients (52.63% vs. 16%, p = .004). Moreover, those IgG4-AID patients with elevated IgG4 did not meet the diagnostic criteria of IgG4-RLD, and their autoantibody titers did not correlate with their serum IgG4 concentrations. In addition, patients with IgG4-RLD were negative for anti-neuronal/neuromuscular autoantibodies and among these patients, men showed a significantly higher propensity for IgG4 elevation, when compared to women ( p = .005). Last, a kidney biopsy from a patient with autoimmune paranodopathy due to CNTN1/Caspr1-complex IgG4 autoantibodies and concomitant nephrotic syndrome did not show fibrosis or IgG4
+ plasma cells, which are diagnostic hallmarks of IgG4-RLD., Conclusion: Our observations suggest that anti-neuronal IgG4-AID and IgG4-RLD are most likely distinct disease entities., Competing Interests: LD received a grant from Fleury Laboratory for the Brazilian Autoimmune Encephalitis Project without personal compensation. CL served as a consultant for Roche. K-NP received a travel grant from Merck. RH reports speakers’ honoraria from Novartis and Biogen. The Medical University of Vienna (Austria; employer of Dr. Höftberger) receives payment for antibody assays and for antibody validation experiments organized by Euroimmun (Lübeck, Germany). The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Endmayr, Tunc, Ergin, De Rosa, Weng, Wagner, Yu, Fichtenbaum, Perkmann, Haslacher, Kozakowski, Schwaiger, Ricken, Hametner, Klotz, Dutra, Lechner, de Simoni, Poppert, Müller, Pirker, Pirker, Angelovski, Valach, Maestri, Guida, Ricciardi, Frommlet, Sieghart, Pinter, Kircher, Artacker, Höftberger and Koneczny.)- Published
- 2022
- Full Text
- View/download PDF
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