| 1. |
- Maccioni, Lorenzo, et al.
(författare)
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Fluxes in a full-flooded lubricated Tapered Roller Bearing: Particle Image Velocimetry measurements and Computational Fluid Dynamics simulations
- 2023
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Ingår i: Tribology International. - 0301-679X. ; 188
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Tidskriftsartikel (refereegranskat)abstract
- The acquisition of complex fluxes inside a Tapered Roller Bearing (TRB) via Particle Image Velocimetry (PIV) is an experimental challenge. This can be successfully performed by exploiting a special test rig having the outer ring manufactured with sapphire. In the present paper, the velocity field in the region between cage, rollers and outer race have been captured via PIV in a fully flooded lubricated TRB. The experimental conditions have been reproduced numerically via Computational Fluid Dynamics (CFD). The comparison of PIV results with CFD ones showed excellent consistency. It has been observed that, in the target domain, the tangential velocity of the lubricant is greater than those of the cage. In addition, in the proximity of the edges of the rollers, squeezing effects due to high gradients of pressure have been recorded. The distribution of flow rates due to the pumping effect in different regions of the TRB have been estimated.
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| 2. |
- Maccioni, Lorenzo, et al.
(författare)
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Particle Image Velocimetry measurements inside a tapered roller bearing with an outer ring made of sapphire: Design and operation of an innovative test rig
- 2022
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Ingår i: Tribology International. - : Elsevier BV. - 0301-679X. ; 165
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Tidskriftsartikel (refereegranskat)abstract
- Experimental studies on rolling-element bearing lubrication represent an ambitious engineering challenge. In the present study, the design of a dedicated test rig to perform Particle Image Velocimetry (PIV) measurements on the lubricant inside a tapered roller bearing is presented. Through the usage of a sapphire outer ring, it has been possible to optically access the inside of a bearing without compromising its kinematics. PIV measurements allowed the reconstruction of the lubricant velocity field in the cavity between the cage and the outer ring at different rotational speeds. Results show that as the speed of rotation increases, bubbles due to aeration phenomena tend to appear and modify the behavior of the lubricant considerably.
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| 3. |
- Maccioni, Lorenzo, et al.
(författare)
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Study of the impact of aeration on the lubricant behavior in a tapered roller bearing: Innovative numerical modelling and validation via particle image velocimetry
- 2022
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Ingår i: Tribology International. - : Elsevier BV. - 0301-679X. ; 165
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Tidskriftsartikel (refereegranskat)abstract
- The air-lubricant interaction causes aeration which influences lubrication mechanisms in rolling-element-bearings. The goal of this paper is to develop a Computational Fluid Dynamics (CFD) model capable to take into consideration aeration. A new solver was implemented in the open-source environment OpenFOAM®. A dip lubricated tapered-roller-bearing was simulated with the new and a standard solver. The numerical predictions were compared with experimental data acquired on a dedicated test rig exploiting Particle Image Velocimetry (PIV). The comparison of the standard predictions and the experimental data for high shaft rotational speeds (higher level of aeration) shows discrepant results. On the other hand, the solver that takes aeration into account leads to results which are comparable to the experimental ones in all rotational ranges investigated via PIV.
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| 4. |
- Maccioni, Livia, et al.
(författare)
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Variants at chromosome 20 (ASIP locus) and melanoma risk
- 2013
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136. ; 132:1, s. 42-54
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Tidskriftsartikel (refereegranskat)abstract
- Agouti signaling protein (ASIP) locus on chromosome 20q11 is implicated, as shown by genome-wide association studies, in phenotype variation and melanoma risk. We genotyped 837 melanoma cases and 1,154 controls for 21 single nucleotide polymorphisms (SNPs) informative for 495 polymorphisms at the locus. Our data showed an increased risk of melanoma (odds ratio [OR] 1.27, 95% confidence interval [95% CI] 1.03-1.57) in carriers of the rs4911414 variant, located 120 kb upstream of ASIP. The main effect of rs4911414, as reported previously, was in tandem with a 10 kb adjacent polymorphism rs1015362; two constituted risk-associated haplotype/diplotype. Except for rs1015363, none of the 12 tagging SNPs, genotyped to cover 239.9 kb region with polymorphisms linked to rs4911414 and rs1015362, were associated with melanoma. Our data confirmed a previous association of melanoma risk (OR 1.82, 95% CI 1.37-2.41) with rs4911442, located in intron 5 of the nuclear receptor coactivator 6 (NCOA6) gene. The rs910871, one of the six variants, genotyped to cover NCOA6, showed an association with melanoma risk (OR 1.33, 95% CI 1.04-1.70). Both, rs4911442 and rs910871 were in moderate linkage with a, previously reported, risk-associated rs910873 polymorphism. A haplotype from the variants within NCOA6 showed an association with risk of melanoma (OR 1.49, 95% CI 1.17-1.88). Interaction between risk-associated polymorphisms and previously genotyped melanocortin receptor 1 (MC1R) variants, in our study, was not statistically significant. Nevertheless, the carriers of the variant alleles over the background of MC1R variants were at a higher risk than the carriers not enriched for MC1R variants. Our data confirmed the association of different variants at chromosome 20q11 with melanoma risk.
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| 5. |
- Maccioni, Livia, et al.
(författare)
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Variants at the 9p21 locus and melanoma risk
- 2013
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Ingår i: BMC Cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Background: The influence of variants at the 9p21 locus on melanoma risk has been reported through investigation of CDKN2A variants through candidate gene approach as well as by genome wide association studies (GWAS). Methods: In the present study we genotyped, 25 SNPs that tag 273 variants on chromosome 9p21 in 837 melanoma cases and 1154 controls from Spain. Ten SNPs were selected based on previous associations, reported in GWAS, with either melanocytic nevi or melanoma risk or both. The other 15 SNPs were selected to fine map the CDKN2A gene region. Results: All the 10 variants selected from the GWAS showed statistically significant association with melanoma risk. Statistically significant association with melanoma risk was also observed for the carriers of the variant T-allele of rs3088440 (540 C>T) at the 3' UTR of CDKN2A gene with an OR 1.52 (95% CI 1.14-2.04). Interaction analysis between risk associated polymorphisms and previously genotyped MC1R variants, in the present study, did not show any statistically significant association. Statistical significant association was observed for the interaction between phototypes and the rs10811629 (located in intron 5 of MTAP). The strongest association was observed between the homozygous carrier of the A-allele and phototype II with an OR of 15.93 (95% CI 5.34-47.54). Conclusions: Our data confirmed the association of different variants at chromosome 9p21 with melanoma risk and we also found an association of a variant with skin phototypes.
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| 6. |
- Mazzarone, Tessa, et al.
(författare)
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Predicting In-Hospital Acute Heart Failure Worsening in the Oldest Old : Insights from Point-of-Care Ultrasound
- 2023
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Ingår i: Journal of Clinical Medicine. - 2077-0383. ; 12:23
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Tidskriftsartikel (refereegranskat)abstract
- The decompensation trajectory check is a basic step to assess the clinical course and to plan future therapy in hospitalized patients with acute decompensated heart failure (ADHF). Due to the atypical presentation and clinical complexity, trajectory checks can be challenging in older patients with acute HF. Point-of-care ultrasound (POCUS) has proved to be helpful in the clinical decision-making of patients with dyspnea; however, to date, no study has attempted to verify its role in predicting determinants of ADHF in-hospital worsening. In this single-center, cross-sectional study, we consecutively enrolled patients aged 75 or older hospitalized with ADHF in a tertiary care hospital. All of the patients underwent a complete clinical examination, blood tests, and POCUS, including Lung Ultrasound and Focused Cardiac Ultrasound. Out of 184 patients hospitalized with ADHF, 60 experienced ADHF in-hospital worsening. By multivariable logistic analysis, total Pleural Effusion Score (PEFs) [aO.R.: 1.15 (CI95% 1.02-1.33), p = 0.043] and IVC collapsibility [aO.R.: 0.90 (CI95% 0.83-0.95), p = 0.039] emerged as independent predictors of acute HF worsening after extensive adjustment for potential confounders. In conclusion, POCUS holds promise for enhancing risk assessment, tailoring diuretic treatment, and optimizing discharge timing for older patients with ADHF.
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| 7. |
- Scarlata, Simone, et al.
(författare)
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Advancing healthcare through thoracic ultrasound research in older patients
- 2023
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Ingår i: Aging Clinical and Experimental Research. - 1594-0667 .- 1720-8319. ; 35:12, s. 2887-2901
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Forskningsöversikt (refereegranskat)abstract
- This paper reports the proceedings of a meeting convened by the Research Group on Thoracic Ultrasound in Older People of the Italian Society of Gerontology and Geriatrics, to discuss the current state-of-the-art of clinical research in the field of geriatric thoracic ultrasound and identify unmet research needs and potential areas of development. In the last decade, point-of-care thoracic ultrasound has entered clinical practice for diagnosis and management of several respiratory illnesses, such as bacterial and viral pneumonia, pleural effusion, acute heart failure, and pneumothorax, especially in the emergency–urgency setting. Very few studies, however, have been specifically focused on older patients with frailty and multi-morbidity, who frequently exhibit complex clinical pictures needing multidimensional evaluation. At the present state of knowledge, there is still uncertainty on the best requirements of ultrasound equipment, methodology of examination, and reporting needed to optimize the advantages of thoracic ultrasound implementation in the care of geriatric patients. Other issues regard differential diagnosis between bacterial and aspiration pneumonia, objective grading of interstitial syndrome severity, quantification and monitoring of pleural effusions and solid pleural lesions, significance of ultrasonographic assessment of post-COVID-19 sequelae, and prognostic value of assessment of diaphragmatic thickness and motility. Finally, application of remote ultrasound diagnostics in the community and nursing home setting is still poorly investigated by the current literature. Overall, the presence of several open questions on geriatric applications of thoracic ultrasound represents a strong call to implement clinical research in this field.
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