rotordynamic analysis of a centrifugal pump for automotive applications

Abstract A proper design of a high speed rotating machinery cannot be performed without a deep understanding of the rotor-dynamic aspects involved. The main purpose of the present work is to show how different methodologies can be adopted and integrated, in both preliminary and detailed design phases. The study focused on the dynamic analysis of a centrifugal pump for automotive applications, called purge pump, whose role is to take the air and gasoline vapor mix from the canister to the intake manifold of combustion chambers, in order to reduce emissions. It is quite small and rotates at a constant relatively high speed. The dynamic models were developed using commercial software widely used in companies and in the academic environment. First, an analytical model was devised with all the components assumed as rigid, except the supports. Then a 1-D Finite Element model of the shaft was created with lumped masses and finally a full flexible multibody model for transient analysis, which requires much more computational time with respect to all the other approaches but provides more information, was developed,. In addition to unbalance, localized defects in the pump ball bearings as source of vibration for the pump were investigated. In particular, a detailed 3-D model of faulty ball bearing was set up using a rigid multibody commercial code in order to simulate a localized defect and to evaluate the dynamic load produced. The presented set of methodologies can be a useful tool to understand the critical aspects of the design, as well as to predict the dynamic response and to suggest suitable modifications for a better rotor-dynamic behavior of the whole system reducing vibrations and consequently acoustic noise and improving structural reliability

Continuous glucose monitoring in patients with type 2 diabetes on hemodialysis

Diabetic kidney disease is the leading cause of end-stage kidney disease in high-income countries. The strict control of glycemic oscillations is the principal therapeutic target, but this could be hard to achieve in uremic patients due to their unpredictable insulin sensitivity. Currently, the evaluation of the glycemic profile relies on serum markers (glycated hemoglobin HbA1c, glycated albumin, and fructosamine), capillary glucose blood control (self-monitoring of blood glucose), and interstitial glucose control (continue glucose monitoring). We conducted a systematic review of published articles on continue glucose monitoring in hemodialysis patients with type 2 diabetes, which included 12 major articles. Four studies found significant fluctuations in glucose levels during hemodialysis sessions. All studies reported a higher mean amplitude of glucose variations on the hemodialysis day. Three studies agreed that continue glucose monitoring is better than glycated hemoglobin in detecting these abnormalities. Moreover, continue glucose monitoring was more accurate and perceived as easier to use by patients and their caregivers. In patients with type 2 diabetes on hemodialysis, glucose levels show different variation patterns than the patients on hemodialysis without diabetes. Considering manageability, accuracy, and cost-effectiveness, continue glucose monitoring could be the ideal diagnostic tool for the patient with diabetes on hemodialysis

Hematopoietic Stem Cells in Type 1 Diabetes

Despite the increasing knowledge of pathophysiological mechanisms underlying the onset of type 1 diabetes (T1D), the quest for therapeutic options capable of delaying/reverting the diseases is still ongoing. Among all strategies currently tested in T1D, the use of hematopoietic stem cell (HSC)-based approaches and of teplizumab, showed the most encouraging results. Few clinical trials have already demonstrated the beneficial effects of HSCs in T1D, while the durability of the effect is yet to be established. Investigators are also trying to understand whether the use of selected and better-characterized HSCs subsets may provide more benefits with less risks. Interestingly, ex vivo manipulated HSCs showed promising results in murine models and the recent introduction of the humanized mouse models accelerated the translational potentials of such studies and their final road to clinic. Indeed, immunomodulatory as well as trafficking abilities can be enhanced in genetically modulated HSCs and genetically engineered HSCs may be viewed as a novel "biologic" therapy, to be further tested and explored in T1D and in other autoimmune/immune-related disorders

Anti-diabetic drugs and weight loss in patients with type 2 diabetes

Introduction: Obesity is frequently a comorbidity of type 2 diabetes. Even modest weight loss can significantly improve glucose homeostasis and lessen cardiometabolic risk factors in patients with type 2 diabetes, but life-style-based weight loss strategies are not long-term effective. There is an increasing need to consider pharma-cological approaches to assist weight loss in the so called diabesity syndrome. Aim of this review is to analyze the weight-loss effect of non-insulin glucose lowering drugs in patients with type 2 diabetes. Material and methods: A systematic analysis of the literature on the effect of non-insulin glucose lowering drugs on weight loss in patients with type 2 diabetes was performed. For each class of drugs, the following parameters were analyzed: kilograms lost on average, effect on body mass index and body composition. Results: Our results suggested that anti-diabetic drugs can be stratified into 3 groups based on their efficacy in weight loss: metformin, acarbose, empagliflozin and exenatide resulted in a in a mild weight loss (less than 3.2% of initial weight); canagliflozin, ertugliflozin, dapagliflozin and dulaglutide induces a moderate weight loss (between 3.2% and 5%); liraglutide, semaglutide and tirzepatide resulted in a strong weight loss (greater than 5%). Conclusions: This study shows that new anti-diabetic drugs, particularly GLP1-RA and Tirzepatide, are the most effective in inducing weight loss in patients with type 2 diabetes. Interestingly, exenatide appears to be the only GLP1-RA that induces a mild weight loss

Immunogenicity and safety of SARS-CoV-2 mRNA vaccines in a cohort of patients with type 1 diabetes

Patients with type 1 diabetes (T1D) may develop severe outcomes during COVID-19 disease, but their ability to generate an immune response against the SARS-CoV-2 messenger RNA (mRNA) vaccines remains to be established. Here we evaluated the safety, immunogenicity and glycometabolic effects of the SARS-CoV-2 mRNA vaccines in patients with T1D. A total of 375 patients, 326 with T1D and 49 non-diabetics, who received two doses of the SARS-CoV-2 mRNA vaccines (mRNA-1273, BNT162b2) between March and April 2021 at the ASST FBF-Sacco Milan, Italy, were included in this monocentric observational study (NCT04905823). Local and systemic adverse events were reported in both groups after SARS-CoV-2 mRNA vaccination without statistical differences between them. While both T1D patients and non-diabetic subjects exhibited a parallel increase in anti-SARS-CoV-2S titers after vaccination, the vast majority of T1D patients (70% and 78% respectively) did not show any increase in the SARS-CoV-2-specific cytotoxic response as compared to the robust increased observed in all non-diabetic subjects. A reduced secretion of the T cell-related cytokines IL-2 and TNF-alpha in vaccinated patients with T1D was also observed. No glycometabolic alterations were evident in patients with T1D using continuous glucose monitoring during follow-up. Administration of the SARS-CoV-2 mRNA vaccine is associated with an impaired cellular SARS-CoV-2-specific cytotoxic immune response in T1D patients

Analisi rotordinamica di una pompa centrifuga per impiego nel settore Automotive

La presente tesi si focalizza su aspetti di rotordinamica riguardanti un nuovo prodotto di Pierburg Pump Technology: la Purge Pump. Essa è una pompa centrifuga atta a condurre la miscela di aria e vapori di benzina dal canister al collettore di alimentazione delle camere di combustione, inserendosi all'interno di un sistema ausiliario nato per ottemperare a normative antinquinamento. L'elevata velocità di rotazione e l'inerzia polare della girante hanno reso indispensabile l'applicazione dei concetti propri della dinamica dei rotori per descrivere correttamente il comportamento vibratorio della linea d'asse: partendo da un modello analitico a corpi rigidi, si è passato ad un modello monodimensionale a elementi finiti dell'albero rotante sino ad arrivare alla costruzione in Ansys di un multibody con tutti i componenti flessibili. Nella parte finale del lavoro si è simulato, mediante il software MSC Adams, un cuscinetto della Purge Pump allo scopo di stimare il carico dinamico dovuto alla presenza di un difetto localizzato sulla ralla esterna, il quale rappresenta una delle sorgenti di vibrazione per la pompa. Tutti gli approcci e i modelli implementati sono stati infine sfruttati come strumenti di analisi per valutare l'effetto sulla risposta dinamica di una soluzione alternativa di montaggio dei cuscinetti; questa consiste nel ricavare su ciascun anello esterno due gole circonferenziali in cui si inseriscono degli O-rings in materiale elastomerico che, interponendosi tra anelli esterni e corpo pompa, conferiscono molta più cedevolezza ai supporti del sistema rotante

Valutazione dell'atresia della tricuspide mediante ecocardiografia. II. Analisi della funzionalità ventricolare sinistra.

Twenty-five patients with tricuspid atresia, ranging in age between 2 months and 23 years, previously morphologically studied, were assessed by M-mode echocardiography with regard to left ventricular function. Fifteen of them underwent palliative cardiac surgery (systemic-pulmonary anastomosis). Thirty normal subjects, same age and sex, were selected as controls. Patients with tricuspid atresia had a significant increase of left ventricular dimensions and mass and significant decrease of shortening fraction and ejection fraction. The left ventricular pre-ejection/ejection ratio (LPEP/LVET) was significantly higher in patients with tricuspid atresia compared to normals. In patients without surgical shunt there was no significant correlation between Qp/Qs determined by oximetry and the end-diastolic dimension and left ventricular function parameters. In patients with surgical shunt a significant correlation was found between ejection fraction, shortening fraction, systolic time intervals and Qp/Qs. Qp/Qs significantly correlated with end-diastolic dimension. Shortening fraction and ejection fraction were higher in patients with satisfactory systemic saturation, while left ventricular mass was increased in patients with longstanding surgical shunt. These data suggest that patients with tricuspid atresia, with or without surgical shunt, may present with a decreased left ventricular function, early detectable by echocardiography

Valutazione dell'atresia della tricuspide mediante ecocardiografia.I. Analisi morfologica.

Twenty-five patients with tricuspid atresia, ranging in age between 3 months and 23 years, were studied by M-mode and two-dimensional (2D) echocardiography. In all of them diagnosis was confirmed by cardiac catheterization and angiocardiography and in most of them at surgery or autopsy. Some anatomical specimens of tricuspid atresia were analyzed in order to be correlated with corresponding two-dimensional pictures. Contrast 2D echocardiography was performed in 12 of 25 patients. M-mode scanning right atrium-left ventricle showed a rudimentary echo coming from the atretic valve but didn't show its relations with the membranous portion of ventricular septum. 2D echocardiography in (two chambers) or (four chambers) view was particularly useful to distinguish tricuspid atresia from other hypoplastic right heart syndromes with functioning tricuspid valve. Peripheral contrast injection enhances diagnostic capability of 2D echocardiography, especially for the assessment of right ventricular dimensions, differentiation between atretic and imperforate valve and evaluation of ventricular septal defect

Positive impact of short-term gait rehabilitation in Parkinson patients: a combined approach based on statistics and machine learning

Parkinson's disease is the second most common neurodegenerative disorder in the world. Assumed that gait dysfunctions represent a major motor symptom for the pathology, gait analysis can provide clinicians quantitative information about the rehabilitation outcome of patients. In this scenario, wearable inertial systems for gait analysis can be a valid tool to assess the functional recovery of patients in an automatic and quantitative way, helping clinicians in decision making. Aim of the study is to evaluate the impact of the short-term rehabilitation on gait and balance of patients with Parkinson's disease. A cohort of 12 patients with Idiopathic Parkinson's disease performed a gait analysis session instrumented by a wearable inertial system for gait analysis: Opal System, by APDM Inc., with spatial and temporal parameters being analyzed through a statistic and machine learning approach. Six out of fourteen motion parameters exhibited a statistically significant difference between the measurements at admission and at discharge of the patients, while the machine learning analysis confirmed the separability of the two phases in terms of Accuracy and Area under the Receiving Operating Characteristic Curve. The rehabilitation treatment especially improved the motion parameters related to the gait. The study shows the positive impact on the gait of a short-term rehabilitation in patients with Parkinson's disease and the feasibility of the wearable inertial devices, that are increasingly spreading in clinical practice, to quantitatively assess the gait improvement

A new glucose monitoring system for the intermittent monitoring of interstitial glucose values in patients with diabetes mellitus

Objectives Glucose monitoring in diabetes is changing overtime with a constant development of new devices for continuous glucose monitoring (CGM). Aim of this observational, prospective study was to evaluate the clinical performance of a novel intermittently scanned CGM system, the Glunovo Flash in a cohort of patients with type 1 diabetes. Methods A total of 45 patients with T1D followed at the Endocrinology Unit of the ASST-FBF-Sacco (Milan) were enrolled. All patients were habitual CGM users and were asked to wear simultaneously the Glunovo Flash system and their habitual CGM device for 14 days. A comparison of CGM glucose metrics was performed. Patients’ opinions on the new device were also collected. Results Thirty-five patients completed the study period of two weeks (7 habitual real time CGM users, 28 habitual inter- mittently scanned CGM users). Mean Time In Range resulted significantly higher with the novel studied sensor respect to intermittently scanned CGM comparator. No differences were found considering other glucose metrics. A positive correlation was found between the Time In Range recorded by Glunovo Flash and intermittently scanned CGM comparators as well as for Time Above Range, Glucose Management Indicator, Time Below Range and Coefficient of Variation. No correlations were found between glucose metrics recorded by Glunovo Flash and real time CGM comparators. Patients reported a posi- tive experience of use with the new sensor but some elements appeared improvable. Conclusions The CGM device Glunovo Flash for patients with diabetes shows similar performance to other intermittently scanned CGM systems