sustainability analysis of friction stir welding of aa5754 sheets

Abstract The environmental impact of friction stir welding process vs. welding parameters was evaluated and analysed in detail. To this purpose, butt joints in AA5754 aluminum alloy sheets were obtained at different rotational and welding speeds. All input and output data, in terms of materials, energies and emissions, were collected and analyzed using a life cycle assessment software in order to evaluate the environmental impact index. Sound weld was used as functional unit and all energy and material flows were based on it. The results given by the life cycle assessment analysis has shown that the environmental impact of friction stir welding is strongly affected by rotational and welding speeds. The environmental impact was also related to the mechanical properties of joints, expressed as ultimate tensile strength and ultimate elongation

Environmental assessment of an automated impregnation process of carbon fiber tows

Abstract The aim of the present study is to assess the environmental loads of an automated impregnation process of carbon fiber tows with a thermoset epoxy resin. A streamlined Life Cycle Assessment (LCA), in the "gate-to-gate" form, has been carried out, following the ISO 14040/44 methodology. This study has been focused on the following environmental impact categories: global warming potential (GWP), cumulative energy demand (CED) and water consumption. A single linear meter of manufactured towpreg has been chosen as functional unit. Simapro v. 8.5 and Ecoinvent v. 3.5 have been used respectively as LCA software and Life Cycle Inventory database

A new holistic 3D non-invasive analysis of cellular distribution and motility on fibroinalginate microcarriers using light sheet fluorescent microscopy

Cell interaction with biomaterials is one of the keystones to developing medical devices for tissue engineering applications. Biomaterials are the scaffolds that give three-dimensional support to the cells, and are vectors that deliver the cells to the injured tissue requiring repair. Features of biomaterials can influence the behaviour of the cells and consequently the efficacy of the tissue-engineered product. The adhesion, distribution and motility of the seeded cells onto the scaffold represent key aspects, and must be evaluated in vitro during the product development, especially when the efficacy of a specific tissue-engineered product depends on viable and functional cell loading. In this work, we propose a non-invasive and non-destructive imaging analysis for investigating motility, viability and distribution of Mesenchymal Stem Cells (MSCs) on silk fibroin-based alginate microcarriers, to test the adhesion capacity of the fibroin coating onto alginate which is known to be unsuitable for cell adhesion. However, in depth characterization of the biomaterial is beyond the scope of this paper. Scaffold-loaded MSCs were stained with Calcein-AM and Ethidium homodimer-1 to detect live and dead cells, respectively, and counterstained with Hoechst to label cell nuclei. Time-lapse Light Sheet Fluorescent Microscopy (LSFM) was then used to produce three dimensional images of the entire cells-loaded fibroin/alginate microcarriers. In order to quantitatively track the cell motility over time, we also developed an open source user friendly software tool called Fluorescent Cell Tracker in Three-Dimensions (F-Tracker3D). Combining LSFM with F-Tracker3D we were able for the first time to assess the distribution and motility of stem cells in a non-invasive, non-destructive, quantitative, and three-dimensional analysis of the entire surface of the cell-loaded scaffold. We therefore propose this imaging technique as an innovative holistic tool for monitoring cell-biomaterial interactions, and as a tool for the design, fabrication and functionalization of a scaffold as a medical device

Nanocomposite Hydrogels with Self-Assembling Peptide-Functionalized Carbon Nanostructures

Carbon nanostructures (CNSs) are attractive components to attain nanocomposites, yet their hydrophobic nature and strong tendency to aggregate often limit their use in aqueous conditions and negatively impact their properties. In this work, carbon nanohorns (CNHs), multi-walled carbon nanotubes (CNTs), and graphene (G) are first oxidized, and then reacted to covalently anchor the self-assembling tripeptide L-Leu-D-Phe-D-Phe to improve their dispersibility in phosphate buffer, and favor the formation of hydrogels formed by the self-organizing L-Leu-D-Phe-D-Phe present in solution. The obtained nanocomposites are then characterized by transmission electron microscopy (TEM), oscillatory rheology, and conductivity measurements to gain useful insights as to the key factors that determine self-healing ability for the future design of this type of nanocomposites.Carbon nanostructures (CNS) morphology and functionalization effects are studied to attain nanocomposite and supramolecular hydrogels with a self-assembling tripeptide. The latter is covalently anchored onto carbon nanotubes and carbon nanohorns, and the resulting nanocomposite soft matter is characterized at the nanoscale and macroscale to rationalize the self-healing ability of the hydrogel, and the CNS influence on peptide fibrillation in aqueous buffer.imag

TP53 drives abscopal effect by secretion of senescence-associated molecular signals in non small cell lung cancer

Background Recent developments in abscopal effect strongly support the use of radiotherapy for the treatment of metastatic disease. However, deeper understanding of the molecular mechanisms underlying the abscopal effect are required to best benefit a larger proportion of patients with metastasis. Several groups including ours, reported the involvement of wild-type (wt) p53 in radiation-induced abscopal effects, however very little is known on the role of wtp53 dependent molecular mechanisms. Methods We investigated through in vivo and in vitro approaches how wtp53 orchestrates radiation-induced abscopal effects. Wtp53 bearing (A549) and p53-null (H1299) NSCLC lines were xenotransplanted in nude mice, and cultured in 2D monolayers and 3D tumor spheroids. Extracellular vesicles (EVs) were isolated from medium cell culture by ultracentrifugation protocol followed by Nanoparticle Tracking Analysis. Gene expression was evaluated by RT-Real Time, digital qRT-PCR, and dot blot technique. Protein levels were determined by immunohistochemistry, confocal anlysis, western blot techniques, and immunoassay. Results We demonstrated that single high-dose irradiation (20 Gy) induces significant tumor growth inhibition in contralateral non-irradiated (NIR) A549 xenograft tumors but not in NIR p53-null H1299 or p53-silenced A549 (A549sh/p53) xenografts. We further demonstrates that irradiation of A549 cells in vitro induces a senescence-associated secretory phenotype (SASP) producing extracellular vesicles (EVs) expressing CD63 and carrying DNA:RNA hybrids and LINE-1 retrotransposon. IR-A549 EVs also hamper the colony-forming capability of recipient NIR A549 cells, induce senescent phenotype, nuclear expression of DNA:RNA hybrids, and M1 macrophage polarization. Conclusions In our models, we demonstrate that high radiation dose in wtp53 tumors induce the onset of SASP and secretion of CD63+ EVs loaded with DNA:RNA hybrids and LINE-1 retrotransposons that convey senescence messages out of the irradiation field triggering abscopal effect in NIR tumors

Prognostic value of three-dimensional electroanatomic voltage mapping in patients with arrhythmias of right ventricular origin

Endocardial voltage mapping (EVM) by CARTO system offers the potential to accurately identify the presence, location and extent of right ventricular (RV) low-voltage regions (i.e. electroanatomic scars) which may represent the substrate of life-threatening right ventricular tachyarrhythmias. This study prospectively evaluated the prognostic value of RV electroanatomic scars in a cohort of patients presenting clinically with arrhythmias of RV origin. Methods The study population comprised 109 consecutive patients (73 men and 36 women; mean age 36±14 years) with a left bundle branch block pattern ventricular arrhythmia, of which 21 with ventricular tachycardia (VT), 64 with non sustained VT, frequent and/or repetitive premature ventricular beats were detectable in 24 patients. All patients underwent detailed clinical evaluation and high density RV EVM by sampling multiregional RV bipolar electrograms (197±23 sampled points) to identify RV electroanatomic scars (defined as low-amplitude areas with bipolar electrogram <0,5 mV). Results Electroanatomic scars were found in 54 patients (49%), affecting 20,4±13,0% (range 2,6% to 49,8%) of the RV free wall. The presence of electroanatomic scar significantly correlated with a positive family history (P<0,001), late potentials on SAECG (P<0,001), and RV dilatation/dysfunction (P<0,001). During the follow-up, mean period of 49±13 months, 25 of 109 patients (23%) experienced malignant arrhythmic events such as sudden death in 2, cardiac arrest due to ventricular fibrillation in 4, appropriate ICD intervention in 7, and unstable VT leading to syncope in 12. Unexplained syncope (P<0,001) and electroanatomic scar (P<0,001) were significantly associated with the arrhythmic events. Among patients with an abnormal RV EVM, those who experienced arrhythmic events during follow-up had a significantly greater percentage of electroanatomic scar (27,4±10,5% versus 16,0±12,3%, p<0,001). After adjustment for age, family history, VT, and RV dilatation/dysfunction, unexplained syncope (OR=15,9, 95%CI=4,1-61,8; P<0,001) and RV electroanatomic scars (OR=9,28, 95% CI=2,0-42,7; P=0,004) remained independent predictors of malignant arrhythmic outcome. Conclusions Electroanatomic scars were found in approximately half of patients with significant arrhythmias of right ventricular origin. There was a significant correlation between electroanatomic scar extent and incidence of arrhythmic events during follow-up. Electroanatomic scar, unlike RV dilatation/dysfunction, was an independent predictor of malignant arrhythmic outcome.La mappa elettroanatomica di voltaggio con sistema CARTO permette di identificare e caratterizzare (presenza, sede ed estensione) aree di miocardio ventricolare caratterizzate da basso voltaggio elettrico, cosiddette “cicatrici elettroanatomiche”, che rappresentano un possibile substrato per tachiaritmie ventricolari pericolose per la vita. Questo studio si propone di valutare prospetticamente il valore prognostico della presenza di cicatrici elettroanatomiche in una popolazione di pazienti con aritmie ad origine dal ventricolo destro. Metodi La popolazione studiata era costituita da 109 pazienti (73 maschi e 36 femmine, età media 36±14 anni) giunti consecutivamente alla nostra osservazione per la comparsa di aritmie ventricolari con aspetto tipo blocco di branca sinistra, che includevano tachicardia ventricolare sostenuta in 21, tachicardia ventricolare non sostenuta in 64 e battiti ventricolari prematuri frequenti e/o ripetitivi in 24 pazienti. Tutti i pazienti sono stati sottoposti ad una dettagliata valutazione clinica e alla mappa elettroanatomica di voltaggio del ventricolo destro eseguita registrando elettrogrammi bipolari multiregionali (197±23 punti) allo scopo di identificare la presenza di cicatrici elettroanatomiche (definite come aree con voltaggio elettrico inferiore a 0,5 mV). Risultati La presenza di cicatrici elettroanatomiche è stata documentata in 54 pazienti (49%). L’estensione della cicatrice elettroanatomica, espressa come area percentuale di parete libera del ventricolo destro con voltaggio elettrico inferiore a 0,5mV, variava da 2,6% a 49,8% (media 20,4±13,0%). La presenza di cicatrice elettroanatomica risultava associata in maniera statisticamente significativa con storia familiare positiva (P<0,001), dimostrazione di potenziali tardivi al SAECG (P<0,001) e presenza di dilatazione/disfunzione del ventricolo destro (P<0,001). Durante un follow-up di 49±13 mesi, 25 pazienti (23%) hanno presentato eventi aritmici maligni, quali morte improvvisa (2 pazienti), arresto cardiaco da fibrillazione ventricolare (4 pazienti), intervento appropriato dell’ICD (7 pazienti) e sincope secondaria a tachicardia ventricolare (12 pazienti). All’analisi univariata le uniche variabili cliniche-elettrofisiologiche predittive di eventi aritmici nel follow-up risultavano una storia positiva per sincope aritmica (P<0,001) e la presenza di cicatrice elettroanatomica (P<0,001). Nei pazienti con un mappa elettroanatomica di voltaggio anormale, la comparsa di eventi aritmici durante il follow-up si associava ad un’estensione della cicatrice elettroanatomica significativamente superiore (27,4±10,5% verso a 16,0±12,3%, P<0,001). All’analisi multivariata, la sincope inspiegata (OR=15,9, IC 95%=4,1-61,8; P<0,001) e la presenza di cicatrice elettroanatomica (OR=9,28, IC 95%=2,0-42,7; P=0,004) rimanevano predittori indipendenti di rischio aritmico, dopo correzione dei dati per età, storia familiare, presenza di tachicardia ventricolare e dilatazione/disfunzione del ventricolo destro. Conclusioni La presenza di cicatrici elettroanatomiche veniva documentata in circa metà dei pazienti con aritmie ad origine dal ventricolo destro. I pazienti con cicatrice elettroanatomica presentavano più spesso storia familiare positiva, potenziali tardivi e dilatazione/disfunzione del ventricolo destro. L’estensione della cicatrice elettroanatomica correlava con l’incidenza di eventi aritmici durante il follow-up. La presenza di cicatrice elettroanatomica, a differenza della dilatazione/disfunzione del ventricolo destro, costituiva un marker predittivo indipendente di rischio aritmico

Approaches to Handling Temporal Data in Object-Oriented Databases

Temporal databases are an active and fast growing research area. Although many temporal extensions of the relational data model have been proposed, there is no comparable amount of work in the context of object-oriented data models. Moreover, few of the proposed models have been implemented. This report discusses how the temporal data model developed for T Chimera [4] has been implemented on top of the Ode OODBMS [1]. In particular, two different approaches to handle temporal data are investigated. The first approach relies on the Ode versioning mechanism [2]; the second one is based on the allocation of special structures for storing temporal data. The main contribution of this work is to show how time can be effectively introduced in a conventional object-oriented context. 1 Introduction Conventional database systems do not offer the possibility of dealing with time-varying data. The content of a database represents a snapshot of the reality in that only the current data values ar..

Semi-quantitative monitoring of confluence of adherent mesenchymal stromal cells on calcium-phosphate granules by using widefield microscopy images

The analysis of cell confluence and proliferation is essential to design biomaterials and scaffolds to use as bone substitutes in clinical applications. Accordingly, several approaches have been proposed in the literature to estimate the area of the scaffold covered by cells. Nevertheless, most of the approaches rely on sophisticated equipment not employed for routine analyses, while the rest of them usually do not provide significant statistics about the cell distribution. This research aims at studying confluence and proliferation of mesenchymal stromal cells (MSC) adherent on OSPROLIFE®, a commercial biomaterial in the form of granules. In particular, we propose a Computer Vision approach that can routinely be employed to monitor the surface of the single granules covered by cells because only a standard widefield fluorescent microscope is required. In order to acquire significant statistics data, we analyse wide-area images built by using MicroMos v2.0, an updated version of a previously published software specific for stitching brightfield and phase-contrast images manually acquired via a widefield microscope. In particular, MicroMos v2.0 permits to build accurate ‘‘mosaics’’ of fluorescent images, after correcting vignetting and photo-bleaching effects, providing a consistent representation of a sample region containing numerous granules. Then, our method allows to make automatically a statistically significant estimate of the percentage of the area of the single granules covered by cells. Finally, by analysing hundreds of granules at different time intervals we also obtained reliable data regarding cell proliferation, confirming that not only MSC adhere onto the OSPROLIFE® granules, but even proliferate over time

BASI MOLECOLARI E CELLULARI DELLA VITA

Prefazione La biologia è … un campo dalle possibilità illimitate, dal quale ci dobbiamo attendere le più sorprendenti delucidazioni; non possiamo quindi indovinare quali risposte essa potrà dare … ai problemi che le abbiamo posto. Forse queste risposte saranno tali da far crollare tutto l’artificioso edificio delle nostre ipotesi. (Sigmund Freud) La Biologia ha compiuto passi da gigante nel tempo intercorso tra la predizione di Freud e i nostri giorni. Nonostante ciò, il suo insegnamento a livello universitario, relativamente a molti corsi di laurea nei quali non costituisce materia fondante, vive un momento di grande incertezza. Infatti, le riforme degli ordinamenti con la suddivisione dei corsi di laurea in triennali e specialistici prima e magistrali poi, e l’introduzione dei corsi di laurea professionalizzanti hanno costretto molte facoltà a rivedere profondamente e radicalmente le loro offerte formative. Nella maggior parte dei casi, è proposto un numero eccessivo di insegnamenti da impartire in poche ore e con contenuti disciplinari ancora non ben definiti, con l’idea che la laurea triennale debba avere la capacità di preparare gli studenti ad affacciarsi al mondo del lavoro. L’organizzazione degli insegnamenti in moduli integrati, cioè insiemi di attività caratterizzati da una certa coerenza, pur essendo guidata dall’obiettivo condivisibile di impartire una preparazione di ampio respiro, ha rappresentato una fonte di problemi nell’identificazione dei programmi didattici relativi a ogni disciplina. Ciò richiede ancora, in molti casi, un’azione sensibilizzata alla selezione degli argomenti da trattare in ogni modulo e all’integrazione con le discipline affini. In questo contesto e in quanto impegnati in attività didattica in questi corsi, abbiamo sentito la necessità di tarare accuratamente l’insegnamento della Biologia, che copre un insieme enorme di argomenti, per adattarlo alle nuove esigenze. “Basi molecolari e cellulari della vita” è frutto di uno sforzo critico che ha permesso di rivedere i contenuti fondamentali della Biologia, indirizzandoli in modo specifico alla formazione di base delle figure destinate ad operare in molti casi in un ambiente clinico e al diretto contatto con i pazienti. Nella sua struttura, il volume è adatto a coprire la preparazione per le professioni sanitarie, quali ad es. quelle infermieristiche e riabilitative, le professioni tecnico-sanitarie, le professioni sanitarie tecniche della prevenzione, ma è stato formulato anche con l’obiettivo di soddisfare le esigenze degli studenti dei corsi di laurea triennale in scienze motorie. Gli argomenti trattati guidano gli studenti, indipendentemente dalla preparazione acquisita con gli studi secondari, alla comprensione degli indispensabili argomenti di base della struttura e delle funzioni delle macromolecole, della logica costruttiva delle strutture biologiche e dei diversi livelli di organizzazione della materia vivente. Sono poi trattate la struttura e l’organizzazione funzionale delle cellule procarioti, con le caratteristiche dei domini Archea e Bacteria, e di quelle eucarioti, fino ai virus, responsabili di diverse malattie nelle piante negli animali e nell’uomo. Particolare risalto è dato ovviamente alla biologia della cellula eucariote, con una panoramica essenziale dei principi unitari che ne assicurano il bilancio energetico, e dei meccanismi alla base dell’espressione dell’informazione genetica. Sono quindi descritti i sistemi di membrana, le interazioni delle cellule con l’ambiente che le circonda, il ciclo cellulare e le divisioni delle cellule somatiche e germinali, la riproduzione sessuata e asessuata con cenni dei processi cellulari che guidano lo sviluppo iniziale dell’embrione di mammifero e umano, ed è dato particolare rilievo agli aspetti strutturali e fisiologici delle cellule muscolari striate e lisce e dell’apparato muscolare scheletrico/cardiaco. Sono infine trattati gli argomenti della genetica, con la struttura dei genomi procarioti ed eucarioti, la trasmissione, le mutazioni e l’evoluzione dell’informazione genetica, compresi i meccanismi, più recentemente identificati, delle modificazioni epigenetiche. Il testo così strutturato, sintetico ma esauriente, potrà soddisfare le esigenze di un’ampia fascia di studenti indipendentemente dal corso di studio prescelto. Con questo volume, tutti gli studenti saranno in grado di comprendere i principi biologici di base e il linguaggio appropriato, entrambi necessari allo studio dei corsi successivi, ma anche di identificare le aree di interesse, selezionare le fonti di informazione scientifica e interpretarne i dati, costruendosi un bagaglio culturale necessario sia alla formazione limitata al corso di laurea triennale, che all’eventuale proseguimento degli studi in corsi di laurea magistrale o di formazione post-laurea. Ringraziamo sentitamente il Dott. Piccin per la fiducia e l’incoraggiamento profusi nella realizzazione del manuale; la Sig.ra Barbara Cariali e il Sig. Marco Marzola per aver dato veste grafica al volume. Saremo inoltre molto grati a tutti coloro che vogliano segnalarci ogni errore, inesattezza o svista che, nonostante i nostri sforzi, il manuale possa contenere

Deep Learning for Automatic Vision-Based Recognition of Industrial Surface Defects: A Survey

Automatic vision-based inspection systems have played a key role in product quality assessment for decades through the segmentation, detection, and classification of defects. Historically, machine learning frameworks, based on hand-crafted feature extraction, selection, and validation, counted on a combined approach of parameterized image processing algorithms and explicated human knowledge. The outstanding performance of deep learning (DL) for vision systems, in automatically discovering a feature representation suitable for the corresponding task, has exponentially increased the number of scientific articles and commercial products aiming at industrial quality assessment. In such a context, this article reviews more than 220 relevant articles from the related literature published until February 2023, covering the recent consolidation and advances in the field of fully-automatic DL-based surface defects inspection systems, deployed in various industrial applications. The analyzed papers have been classified according to a bi-dimensional taxonomy, that considers both the specific defect recognition task and the employed learning paradigm. The dependency on large and high-quality labeled datasets and the different neural architectures employed to achieve an overall perception of both well-visible and subtle defects, through the supervision of fine or/and coarse data annotations have been assessed. The results of our analysis highlight a growing research interest in defect representation power enrichment, especially by transferring pre-trained layers to an optimized network and by explaining the network decisions to suggest trustworthy retention or rejection of the products being evaluated