Methods for Clearance Influence Analysis in Planar and Spatial Mechanisms

This doctoral dissertation presents a new method to asses the influence of clearancein the kinematic pairs on the configuration of planar and spatial mechanisms. The subject has been widely investigated in both past and present scientific literature, and is approached in different ways: a static/kinetostatic way, which looks for the clearance take-up due to the external loads on the mechanism; a probabilistic way, which expresses clearance-due displacements using probability density functions; a dynamic way, which evaluates dynamic effects like the actual forces in the pairs caused by impacts, or the consequent vibrations. This dissertation presents a new method to approach the problem of clearance. The problem is studied from a purely kinematic perspective. With reference to a given mechanism configuration, the pose (position and orientation) error of the mechanism link of interest is expressed as a vector function of the degrees of freedom introduced in each pair by clearance: the presence of clearance in a kinematic pair, in facts, causes the actual pair to have more degrees of freedom than the theoretical clearance-free one. The clearance-due degrees of freedom are bounded by the pair geometry. A proper modelling of clearance-affected pairs allows expressing such bounding through analytical functions. It is then possible to study the problem as a maximization problem, where a continuous function (the pose error of the link of interest) subject to some constraints (the analytical functions bounding clearance- due degrees of freedom) has to be maximize. Revolute, prismatic, cylindrical, and spherical clearance-affected pairs have been analytically modelled; with reference to mechanisms involving such pairs, the solution to the maximization problem has been obtained in a closed form.

Strategie formulative per la veicolazione nasale di farmaci

Microparticelle a base di complessi polielettrolitici di Chitosano/Pectina per il rilascio nasale di Tacrina cloridrato. Lo scopo di questo studio è stata la ricerca di nuove formulazioni solide per la somministrazione nasale di Tacrina cloridrato allo scopo di ridurre l’eccessivo effetto di primo passaggio epatico ed aumentarne la biodisponibilità a livello del Sistema Nervoso Centrale. La Tacrina è stata incapsulata in microparticelle mucoadesive a base di complessi elettrolitici di chitosano e pectina. Le microparticelle sono state preparate mediante due diversi approcci tecnologici (spray-drying e spray-drying/liofilizzazione) e analizzate in termini di caratteristiche dimensionali, morfologiche e chimico-fisiche. Nanoparticelle di Chitosano reticolate con Sodio Cromoglicato per il trattamento della rinite allergica. Il Sodio Cromoglicato è uno dei farmaci utilizzati per il trattamento della rinite allergica. Come noto, la clearance mucociliare provoca una rapida rimozione dei farmaci in soluzione dalla cavità nasale, aumentando così il numero di somministrazioni giornaliere e, di conseguenza, riducendo la compliance del paziente. Per ovviare a tale problema, si è pensato di includere il sodio cromoglicato in nanoparticelle di chitosano, un polimero capace di aderire alla mucosa nasale, prolungare il contatto della formulazione con il sito di applicazione e ridurre il numero di somministrazioni giornaliere. Le nanoparticelle ottenute sono state caratterizzate in termini di dimensioni, resa, efficienza di incapsulazione e caricamento del farmaco, potenziale zeta e caratteristiche mucoadesive. Analisi quantitativa di Budesonide amorfa tramite calorimetria a scansione differenziale. È stato sviluppato un nuovo metodo quantitativo allo stato solido basato sulla Calorimetria a Scansione Differenziale (DSC) in grado di quantificare in modo selettivo e accurato la quantità di Budesonide amorfa presente in una miscela solida. Durante lo sviluppo del metodo sono stati affrontati problemi relativi alla convalida di metodi analitici su campioni solidi quali la miscelazione di polveri solide per la preparazione di miscele standard e il calcolo della precisione.

Omission of axillary clearance in patients with early breast cancer and positive sentinel node biopsy treated with conservative surgery: application of the ACOSOG Z011 trial in clinical practice

Background: Axillary lymph node dissection (ALND) in presence of sentinel lymph node (SLN) metastases has been the standard in breast cancer (BC) patients for many years. Today, after the publication of the ACOSOG Z0011 trial, ALND is a procedure restricted to a dwindling group of patients with a clearly metastatic axilla. Material and methods: This was a prospective observational trial involving two Italian Breast Units: Policlinico di Sant’Orsola and San Raffaele hospital. Objective was to evaluate that the omission of ALND in patients with cT1-2 cN0 BC undergoing breast conserving surgery (BCS) and histological finding of metastases in 1 or 2 SLN is not associated with a worse prognostic outcome. Primary endpoint was overall survival (OS). Secondary endpoints were disease free survival (DFS) and locoregional recurrence. All BC patients treated between the 1st of November 2020 and 31st of July 2023 with cT1-2 cN0 BC, preoperative negative axillary ultrasound and 1 or 2 metastatic SLN treated with sentinel node biopsy (SLNB) alone entered the study. Results: 795 cT1-2 cN0 BC patients underwent BCS and SLNB. Ninety patients were included. Median age was 60 (52-68) years. Seventy-five patients (83%) had T1 tumor and 15 (17%) T2. Median tumor size was 16 mm (11-19). The median SLN removed was 2 (1-3). Eighty-one patients had 1 positive SLN (90%), while 9 had 2 SLN metastasis (10%). 39 (43%) micrometastases were identified and 51 macrometastasis (57%). All patients underwent radiotherapy. Seventeen (19%) performed adjuvant chemotherapy. Two received immunotherapy with trastuzumab and pertuzumab. Endocrine therapy was given to 84 (93%). At a median follow-up of 19 months (IQR 13-23) OS and DFS were 100%. No loco-regional recurrence was seen. Conclusion: The preliminary results of our study confirm that omitting ALND in patients meeting Z011 criteria is oncologically safe and should be the standard of care.