Particle Suspensions in Complex Formulations

Particle suspensions are ubiquitous in nature and engineering/manufacturing applications. Suspensions exhibit complex rheological phenomena even in the simplest cases of monodisperse rigid spheres in Newtonian media. To complicate matters further, industrial formulations, toothpaste being a typical example, often involve particles that vary in size, surface morphology and porosity, suspended in non-Newtonian and viscoelastic solvent media. Such systems entail new particle and polymer dynamics which are poorly understood, introducing new challenges in manufacturing and product stability. Experimental evidence considering the combined effects of these parameters on suspension rheology is limited. The present study attempts to address this gap by examining two types of non- colloidal, commercial silica particles, commonly used in toothpaste formulations and differing in surface area, roughness and porosity, suspended in various non-aqueous Newtonian and non-Newtonian solvents. Their suspension rheology was investigated under steady state and oscillatory shear at different volume fractions and compared to that of relatively smooth glass sphere suspensions with a similar size distribution, used as a control system and investigated under the same experimental and solution conditions. Particle surface roughness and porosity increased suspension viscosity and induced non-Newtonian rheological phenomena at lower particle volume fractions in both the Newtonian and non-Newtonian suspending media. This was due to the increased particle specific surface area and effective volume fraction, as the solvent gets absorbed into the pores, leading to enhanced particle-particle or particle-solvent interactions. Glycerol and mineral oil were first used as the suspending medium to probe two mechanisms for suspension shear thinning: a friction driven and an adhesion driven respectively. Suspensions in glycerol exhibited shear thinning at __ ≥ 0.25 due to the elastic deformation of the surface asperities at increasing shear leading to a reduction in the friction coefficient. In contrast, suspensions in mineral oil showed pronounced shear thinning and elasticity at __ ≥ 0.02 due to particle agglomeration; this was due to the agglomerates breaking down upon increasing the shear rate. The use of an optical shearing technique enabled the monitoring of particle deagglomeration in situ which was quantified using image analysis and aggregation metrics. Based on these findings, tuning of suspension shear thinning was demonstrated by inhibiting particle agglomeration through particle surface chemistry modification. To explore the effects of solvent elasticity and shear thinning on suspension rheology and provide links with industrially relevant formulations, the same particles were studied in two non-Newtonian solvents: a viscoelastic Boger fluid and a shear thinning and weakly viscoelastic Xanthan gum solution. Elastic thickening was induced for certain suspensions in the Boger fluid. The shear thinning nature of the Xanthan gum solution seemed to suppress this phenomenon giving rise to strong shear thinning response, compared to the same suspensions in the corresponding Newtonian solvents, especially in the dilute concentration regime. The effect of temperature on suspension rheology was also investigated by heating the suspensions to 60oC, a typical temperature that solids are added in industrial manufacturing. Heating significantly decreased suspension viscosity and suppressed the shear thickening response. The suppression of the shear thickening response was either due to a decrease in the possibility of hydroclustering in the Newtonian solvents or the decrease in the flexibility of the polymer chains at elevated temperature, requiring higher stresses to show strain hardening. In contrast, suspension shear thinning was found to both increase and decrease with temperature. The thesis offers new insights in tuning suspension rheology through the particle surface morphology and chemistry as well as the physical and chemical properties of the suspending media. Suspension rheology is complex and thus, understanding the mechanisms governing it, will aid manufacturers in addressing challenges during industrial processing and developing guidelines for the design and optimization of formulations tailored to specific applications. This work forms part of an EPSRC funded research programme on addressing manufacturing challenges of Future Formulations and in particular, non-aqueous paste formulations. It also involves the collaboration with leading companies in the pharmaceutical and inkjet printing fields (GlaxoSmithKline, Xaar Plc)

Crisis as Emotional Labour in the News. Assessing the Trauma Frame During the Economic and the Pandemic Crisis

This study focuses on the way(s) that the economic and the pandemic crisis were covered by media outlets and aims to research whether journalists’ own feelings and experiences of covering both these traumatic events were depicted in their news articles. Drawing on Semetko and Valkenburg’s (2000) set of five generic frames this study focuses on Greece, a country that has been severely hit by both these crises and brings together theories about journalism as emotional labour that defy the prevailing notion of the distant and neutral observers. Moving one step further, this study argues that journalists convey their source’s emotions, but in some cases, they also reveal their own feelings through their news articles. Findings suggest that apart from the already documented frames, (i.e., attribution of responsibility, conflict, human interest, economic consequences, and morality), journalists used the trauma frame, a notion we use to refer to news articles that essentially reflect and reveal journalists’ own emotions. This finding refutes the traditional understanding of quality journalistic discourse as one stripped of emotional expression and opens new pathways for research

The Accessible Underwater Cultural Heritage Sites (AUCHS) as a sustainable tourism development opportunity in the Mediterranean Region

This article is about the multi-dimensional value of the Accessible Underwater Cultural Heritage Sites (AUCHS) for coastal areas and islands in the Mediterranean Region, especially as an opportunity for sustainable blue growth. It is an attempt to underline the need for the broad promotion of Underwater Cultural Heritage (UCH) and to highlight the contribution of innovative technologies for direct and indirect accessibility to underwater cultural heritage remains. The paper further demonstrates how the AUCHS can become niches of touristic development for an area whilst offering multifaceted socioeconomic benefits to the local communities

Effects of prenatal exposure to endocrine disruptors in mice behavior and brain neurochemistry

Οι ενδοκρινικές διαταρακτικές ενώσεις (EDCs) είναι ουσίες που μπορούν να διαταράξουν την ομαλή λειτουργία ενδογενών ορμονών με κάθε τρόπο. Πρόσφατα, η μελέτη SELMA μιας κοόρτης εγκύων γυναικών έδειξε ότι πολλές από τις γνωστές EDCs είναι παρούσες στο αίμα και στα ούρα αυτών των γυναικών και μπορούν δυνητικά να βλάψουν τους απογόνους τους σε πολλαπλά επίπεδα, συμπεριλαμβανομένης της νευρωνικής τους ανάπτυξης. Στα πλαίσια του EDC-MixRisk, αποσαφηνίστηκαν τα μείγματα EDCs που σχετίζονται με νευροαναπτυξιακές βλάβες στα παιδιά της μελέτης SELMA. Στην παρούσα μελέτη, εκθέσαμε έγκυους θηλυκούς μυς σε διαφορετικές δόσεις ενός μείγματος ενδοκρινικών διαταρακτών κατά τη διάρκεια της κύησης. Έπειτα, ερευνήσαμε τις επιδράσεις αυτού του μείγματος σε συγκεκριμένες πτυχές της συμπεριφοράς και του μοτίβο έκφρασης γονιδίων σχετιζόμενων με αποκρίσεις στο στρες στους ενήλικους αρσενικούς απογόνους. Δείξαμε ότι έκθεση σε υψηλές –σε σχέση με την ανθρώπινη έκθεση- δόσεις αυτού του μείγματος επάγουν υπερκινητικότητα κι αυξάνουν στρατηγικές ενεργού διαχείρισης στους ενήλικους αρσενικούς μυς, μέσω απορρύθμισης του άξονα Υποθαλάμου-Υπόφυσης-Επινεφριδίων. Αυτά τα αποτελέσματα καταδεικνύουν μια συσχέτιση με ανάλογους φαινοτύπους ασθενών με νευροαναπτυξιακές διαταραχές κι αποτελούν πηγή έμπνευσης για περαιτέρω έρευνα και πρόληψη των επιδράσεων νευροενδοκρινικών διαταρακτών.Endocrine disrupting compounds (EDCs) are substances that can disturb the normal function of endogenous hormones in any manner. Recently, SELMA study of a pregnant women cohort showed that many of the known EDCs are present in the urine and the sera of these women and can potentially harm their offspring in multiple levels, including in their neuronal development. In the frame of EDC-MixRisk, the mixtures of EDCs associated with neurodevelopmental impairment in children of the SELMA study were defined. In the present study, we exposed pregnant mice dams to different doses of a mixture of endocrine disruptors during gestation. Then, in their adult male offspring we investigated the effects of this mixture on certain aspects of behavior and expression pattern of genes related to stress responses. We showed that exposure to high –relevant to human exposure-doses of this mixture of compounds induces hyperactivity and increases active coping in adult male mice, through deregulation of the Hypothalamus-Pituitary-Adrenals axis. These results indicate an association with equivalent phenotypes in patients with neurodevelopmental disorders and are influential for further investigation and prevention of the effects of EDCs

Μελέτη της επίδρασης νέων αναστολέων της φωσφορυλίωσης της πρωτεΐνης tau στο μονοπάτι Wnt σηματοδότησης

Το μονοπάτι Wnt σηματοδότησης το οποίο ενεργοποιείται από προσδέτες Wnt σε διαμεμβρανικούς υποδοχείς της κυτταρικής επιφάνειας εμπλέκεται σε πληθώρα διεργασιών, όπως στη νευροπροστασία. Κατά την εξέλιξη της νόσου Alzheimer’s έχει παρατηρηθεί απενεργοποίηση του μονοπατιού αυτού εξαιτίας της πρόσδεσης του αναστολέα Dickkopf-1 (Dkk1) στους υποδοχείς της κυτταρικής επιφάνειας, που αποτρέπει τη σύνδεση με το προσδέτη Wnt, οδηγώντας στην ενεργοποίηση της GSK3β και την φωσφορυλίωση της πρωτεΐνης tau, του κύριου συστατικού των νευροϊνιδιακών δεματίων που εμπλέκονται στην νόσο Alzheimer. Έχει βρεθεί ότι μια μικρή ένωση, η γαλλοκυανίνη, είναι ικανή να αναιρέσει τη δράση του Dkk1, ωστόσο το γεγονός ότι θα πρέπει να χορηγηθεί σε υψηλές συγκεντρώσεις για να επιτύχει τη δράση της, την καθιστά ακατάλληλη ως πιθανή θεραπευτική εφαρμογή. Στην παρούσα, εργασία, έχει επιχειρηθεί η αναστολή της επίδρασης του Dkk1 στο μονοπάτι Wnt σηματοδότησης με συν-επώαση νευρικών κυττάρων ποντικού με θρεπτικό εμπλουτισμένο με Dkk1 κι ανάλογα της γαλλοκυανίνης που έχουν προκύψει από εισαγωγή διαφορετικών υποκαταστατών στο μόριό της. Αρχικά, με τη χρήση της δοκιμασίας κυτταροτοξικότητας διαπιστώθηκε ότι τα ανάλογα της γαλλοκυανίνης δεν είναι νευροτοξικά. Επίσης, με την τεχνική της ανοσοαποτύπωσης κατά Western ελέγχθηκε κατά πόσο τα ανάλογα της γαλλοκυανίνης δρούν ως αγωνιστές ή ανταγωνιστές της σηματοδότησης wnt. Βρέθηκε ότι οι περισσότερες από τις ουσίες που εξετάστηκαν δεν έιχαν δράση αγωνιστή ή ανταγωνιστή. Σε επόμενο βήμα, εξετάζουμε την επίδραση διαφορετικών συγκεντρώσεων των εν λόγω ουσιών στα νευρικά κύτταρα ποντικού παρουσία Dkk1. Ως μελλοντικός στόχος τίθεται η μελέτη της επίδρασης των αναλόγων παρουσία Dkk1 αλλά και του ανταγωνιστικού προσδέτη Wnt-3a που συνδέεται με τους υποδοχείς κι ενεργοποιεί το μονοπάτι.The Wnt signaling pathway, which is activated by binding of Wnt ligands to transmembrane cell surface receptors, is involved in a plurality of processes, such as neuroprotection. During the development of Alzheimer’s disease, deactivation of that pathway has been observed due to the binding of the Dickkopf-1 inhibitor (Dkk1) to the transmembrane receptors, preventing the association of the Wnt ligand and leading to activation of GSK3β and phosphorylation of tau protein, the main component of neurofibrillary tangles which are involved in Alzheimer’s disease. It has been shown that a small compound, gallocyanine, is capable of reversing the effect of Dkk1, although the fact that it is successful in high concentrations makes it unsuitable as a potential therapeutic application. In this project, we attempt the inhibition of the effect of Dkk1 on Wnt signaling pathway by co-incubating mouse nerve cells with nutrient medium enriched with Dkk1 and analogs of gallocyanine, which have been produced through introduction of different substituents into the molecule. Firstly, using the cytotoxicity assay, we found that the analogs of gallocyanine are not neurotoxic. In addition, using the technique of Western immunoblotting we checked whether the analogs of gallocyanine act as agonists or antagonists of Wnt signaling. We found that most of them act neither as an agonist nor as an antagonist. To continue, we examine the effect of the analogs of various concentrations on the Wnt signaling pathway in the presence of Dkk1. A prospective target is to study the effect of the substances in the presence of both Dkk1 and Wnt-3a ligand, which binds to the receptors and activates the pathway

3D direct-write printing of water soluble micromoulds for high-resolution rapid prototyping

Direct-write printing has contributed tremendously to additive manufacturing; in particular extrusion based printing where it has extended the range of materials for 3D printing and thus enabled use across many more sectors. The printing inks for direct-write printing however, need careful synthesis and invariably undergo extensive preparation before being able to print. Hence, new ink synthesis efforts are required every time a new material is to be printed; this is particularly challenging for low storage modulus (G’) materials like silicones, especially at higher resolutions (under 10 µm). Here we report the development of a precise (< 10 µm) 3D printable polymer, with which we 3D print micromoulds which are filled with standard silicones like polydimethylsiloxane (PDMS) and left to cure at room temperature. The proof of concept is demonstrated using a simple water soluble polymer as the mould material. The approach enables micrometre scale silicone structures to be prototyped with ease, away from the cleanroom

Zato što je političko znanje bitno: utjecaj deliberacije na mišljenje mladih građana

This paper addresses the importance of “knowledge” and “access to information” in the formation of young citizens’ opinion through deliberative procedures. The research presented in this paper is grounded in the theoretical framework of deliberative democracy as a democratic model and procedure that allows participants to be engaged in a rational and open dialogue before deciding on a particular issue. Our research draws empirically upon a deliberative event that took place in October 2014 at the Western Macedonia University of Applied Sciences in Greece. The topic of deliberation was “Political Public Opinion Polls.” The results of this study are commensurate with the dominant thesis in the relevant literature, which underlines that the deliberative procedure enriches the knowledge of citizens and thus enables them to participate effectively in the decision making process.Ovaj rad bavi se važnošću „znanja“ i „pristupa informacijama“ u formiranju mišljenja mladih građana o pojedinim temama kroz deliberativne procedure. Deliberativna demokracija, kao demokratski model i demokratska procedura koja dopušta sudionicima uključivanje u racionalan i otvoren dijalog prije odlučivanja o određenoj temi, teorijski je okvir na kojem se temelji istraživanje predstavljeno u ovom radu. Empirijski dio našeg rada temelji se na deliberativnom događaju koji se odvio u listopadu 2014. na instituciji za visoko obrazovanje Western Macedonia University of Applied Sciences u Grčkoj. Tema deliberacije bila je „Anketna istraživanja javnog mnijenja o politici“. Rezultati ovog istraživanja potvrđuju tezu iz relevantne literature koja naglašava kako deliberativne procedure obogaćuju znanje građana i tako im omogućavaju da učinkovito sudjeluju u procesu donošenja odluka

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome (APECED) due to AIRET16M mutation in a consanguineous Greek girl

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome (APECED) or autoimmune polyendocrine syndrome type 1 (APS-1) is a rare autosomal recessive disease caused by mutations of the AutoImmune REgulator (AIRE) gene, an important mediator of tolerance to self-antigens. It is characterized by two out of three major components: chronic mucocutaneous candidiasis, hypoparathyroidism and Addison's disease. We present an 11-year-old girl suffering from recurrent episodes of mucocutaneous candidiasis and onychomycosis from 1 to 6years of age, and transient alopecia at the age of 4years. Hypoparathyroidism and dental enamel hypoplasia were diagnosed at 8years. Autoantibodies to thyroid and adrenal glands were not detected and all other endocrine functions have remained normal. Genetic analysis revealed that the patient was homozygous for the mutation T16M in exon 1 of the AIRE gene (p.T16M, c.47C>T). This is the first APECED case reported for carrying this mutation in homozygous form. Parents were third cousins and heterozygous carriers of this mutatio

Digital Technologies for the Sustainable Development of the Accessible Underwater Cultural Heritage Sites

In recent years, the development in digital technologies such as Augmented Reality (AR) and Virtual Reality (VR) has evolved rapidly. These technologies are currently in the process of creating driving change in the Cultural and Creative Industries (CCIs), representing innovative means to share information, facilitating access and increasing the value and public awareness on Cultural and Natural Heritage. This is particularly relevant for underwater environments, where the most interesting cultural and naturalistic sites are accessible only to scuba divers, or not accessible at all, due to depth and/or environmental constraints. In addition, in underwater sites, guided diving tours are carried out by professionals that usually describe the area to be visited during the predive briefings; such step is needed due to the impossibility of underwater verbal communication without dedicated equipment, a practice very rarely adopted for recreational diving. So, these difficulties make it almost impossible to replicate under the sea, the guided tour approach that is usually offered in on-land museums. Considering such limitations, several technological applications are emerging to increase the accessibility underwater and enrich users' experience both for divers and nondivers. This work aims to identify the potential of underwater sites (either cultural or natural) to support the development of sustainable tourism (economic, environmental, cultural and social) in the Mediterranean. Moreover, it focuses on supplying local/regional authorities and stakeholders with a multidisciplinary plan for managing Underwater Museums and Knowledge Centres, by promoting innovation in the diving industry and improving users'/tourists' experience through value-added services and cutting-edge technologies

Use of transabdominal ultrasound-guided transjugular portal vein puncture on radiation dose in transjugular intrahepatic portosystemic shunt formation

PURPOSE:Transjugular intrahepatic portosystemic shunt (TIPS) creation is used to treat portal hypertension complications. Often the most challenging and time-consuming step in the procedure is the portal vein (PV) puncture. TIPS procedures are associated with prolonged fluoroscopy time and high patient radiation exposures. We measured the impact of transabdominal ultrasound guidance for PV puncture on duration of fluoroscopy time and dose.METHODS:We retrospectively analyzed the radiation dose for all TIPS performed over a four-year period with transabdominal ultrasound guidance for PV puncture (n=212, with 210 performed successfully and data available for 206); fluoroscopy time, dose area product (DAP) and skin dose were recorded.RESULTS:Mean fluoroscopy time was 12 min 9 s (SD, ±14 min 38 s), mean DAP was 40.3±73.1 Gy·cm2, and mean skin dose was 404.3±464.8 mGy.CONCLUSION:Our results demonstrate that ultrasound-guided PV puncture results in low fluoroscopy times and radiation doses, which are markedly lower than the only published dose reference levels