The role of surfactants in Jet break-up for inkjet printing

Surfactants are often present in fluids used in inkjet printing technology. There is therefore a need to develop a better understanding of the mechanisms underlying the surfactant transport and their effect on the drop formation and jet break-up, in the inkjet printing timescales, which are usually less than a microsecond. The effects of surfactants are modelled by introducing a surface tension force in the boundary condition at the free surface that depends upon the surfactant concentration, which in turn requires an additional equation for the surfactant transport at the surface. This transport equation is coupled with a surface tension isotherm, which captures the dependence of the surface tension on the surfactant concentration. The diffusion of the surfactants on the interface is relatively slow compared to new surface generation and the advection of surfactants by surface flows. As a consequence, surfactants become localised to the front of the ejected fluid with low concentration in the trailing ligament. This non-uniformity of the surfactants along the droplet interface gives rise to surface tension gradients and therefore strong Marangoni forces which have big impact on the jet break-up and drop behaviour. The strength of the surfactant is defined by how much the surface tension can be reduced depending on the concentration. Our results show that a stronger surfactant can prevent satellite formation for viscous fluids. This is a consequence of the effect the surfactants have on the thinning rate of the jet neck. We investigate the scaling laws for the jet break-up for different surfactant strengths and our results show that the break-off time of the neck increases with an increasing surfactant strength. All these results are validated with experiments. We use high-speed video experimental observations to capture the subtle changes to the jetting behaviour at the sub-millisecond timescale of the jet break-up. We also use our model for the surfactant distribution and the surface tension computation to study the effect of surfactants on the oscillation of the drop after break-off. The frequency and decay of these oscillations provide a method for measuring dynamic surface tension. We find an important effect of surfactants on the attenuation of oscillations of droplets, due to the rigidification of the surface. This requires careful interpretation of oscillation results in determining bulk viscosity and surface tension

Φλεγμονή και θρομβωτικά επεισόδια σε ασθενείς με κλασικά μυελοϋπερπλαστικά νοσήματα: Νεότερα δεδομένα και θεραπευτικές δυνατότητες

Τα μυελοϋπερπλαστικά νεοπλάσματα ή μυελοϋπερπλαστικά νοσήματα (ΜΥΝ) αποτελούν ομάδα κλωνικών αιματολογικών νοσημάτων που χαρακτηρίζονται από υπερπλασία μίας ή περισσότερων κυτταρικών σειρών του μυελού των οστών. Τα κλασικά μυελοϋπερπλαστικά νοσήματα χαρακτηρίζονται από την απουσία της διαμετάθεσης t(9;22) και, ως εκ τούτου, του χρωμοσώματος Philadelphia, και περιλαμβάνουν την αληθή πολυκυτταραιμία (polycythemia vera, PV), την ιδιοπαθή θρομβοκυττάρωση (essential thrombocythemia, ET) και την πρωτοπαθή μυελοίνωση (primary myelofibrosis, PMF). Η κλασική μετάλλαξη JAK2V617F χαρακτηρίζει τη πλειοψηφία των ασθενών με PV, και μικρότερα ποσοστά των ασθενών με ΕΤ και PMF, με δευτερεύουσες τις μεταλλάξεις καλρετικουλίνης (CALR) και του υποδοχέα της θρομβοποιητίνης (MPL). Το βασικό χαρακτηριστικό της παθοφυσιολογίας των κλασικών ΜΥΝ είναι η υπέρμετρη ενεργοποίηση του JAK/ STAT μονοπατιού που οδηγεί σε ιδιαίτερα υψηλή παραγωγή κυτταροκινών, σε συνδυασμό με ενεργοποίηση και άλλων μονοπατιών μέσω επικοινωνίας αυτών (cross- talk). Η κλινική εικόνα των νοσημάτων χαρακτηρίζεται από συμπτωματολογία που σχετίζεται με τις διαταραχές της αιμοποίησης, τη σπληνομεγαλία, και, χαρακτηριστικά, από την εκδήλωση θρομβωτικών επεισοδίων στους ασθενείς τόσο πριν και κατά τη διάγνωση, όσο και κατά την περίοδο παρακολούθησης. Η παθοφυσιολογία και η βιολογική συμπεριφορά των νοσημάτων αποτελούν αντικείμενο εντατικής μελέτης στην έρευνα, με σημαντικά ευρήματα τα τελευταία 15 έτη σχετικά με τη διαταραχή της λειτουργίας των σηματοδοτικών μονοπατιών που σχετίζονται με τη συστηματική φλεγμονή, την κυτταρική επιβίωση, και την κυτταρική ανάπτυξη σε επίπεδο μυελού των οστών. Η φλεγμονή αναγνωρίζεται πλέον ως κεντρικός άξονας της παθοφυσιολογίας των ΜΥΝ και σχετίζεται με την εκδήλωση θρομβώσεων σε ένα πολυπαραγοντικό παθογενετικό μοντέλο ανοσοθρόμβωσης σε επίπεδο αγγείου, αιμοσφαιρίων και μηχανισμού της πήξης. Έτσι, παρότι η χρήση των JAK αναστολέων στη θεραπεία των ΜΥΝ έχει συντελέσει στη σημαντική βελτίωση της ποιότητας ζωής και της επιβίωσης των ασθενών, η επίπτωση των θρομβωτικών επεισοδίων αποτελεί ακόμη υπαρκτό παράγοντα θνητότητας και επιδείνωσης του επιπέδου ζωής, ακόμη και σε ασθενείς υπό θεραπεία. H προσθήκη νέων JAK και JAK/ FLT3 αναστολέων στις θεραπευτικές επιλογές και η αναζήτηση φαρμάκων με διαφορετικούς μηχανισμούς δράσης στοχεύει στη βέλτιστη αντιμετώπιση των ασθενών και την ελάττωση του αριθμού των θρομβωτικών επεισοδίων. Η βιβλιογραφική αυτή ανασκόπηση αποσκοπεί στην καταγραφή των σύγχρονων δεδομένων σχετικά με τους παθοφυσιολογικούς μηχανισμούς της θρόμβωσης σε συσχέτιση με τη φλεγμονή στα κλασικά μυελοϋπερπλαστικά νοσήματα, τους παράγοντες κινδύνου για θρόμβωση, καθώς και τους νέους πιθανούς θεραπευτικούς στόχους που αναδεικνύονται.Myeloproliferative neoplasms (MPN) are a group of clonal hematological diseases characterized by hyperproliferation of one or more hematologic cell lines. Classical myeloproliferative diseases share the feature of absence of translocation (9;22) and, therefore, the philadelphia chromosome, and include polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF). The typical mutation JAK2V617F is present in the majority of patients with PV as well as less patients with ET and PMF, while mutations of calreticulin (CALR) gene and thrombopoietin receptor (myeloproliferative leukemia virus- MPL) gene are also common mutations. The pathophysiology of classical MPNs is characterized by constant activation of the JAK/STAT pathway, which leads to a cytokine overproduction, combined with the activation of more signalling pathways through cross- talk. Clinical presentation includes symptoms due to abnormal hematopoiesis, splenomegaly, and, typically, episodes of arterial and venous thrombosis before diagnosis as well as during the follow- up period. Their pathophysiology and biologic behaviour are being studied intensively during the past fifteen years in the subjects of disruption of function of signalling pathways of inflammation, cell survival and cell growth in the bone marrow. Inflammation is currently recognized as a central axis in MPNs’ pathophysiology and correlates with thrombotic episodes, in a multivariate model of immunothrombosis concerning the blood cells and coagulation mechanisms. Thus, even though the use of JAK inhibitors in the treatment of myeloproliferative neoplasms has contributed to the improvement of patients’ quality of life and survival, the consequences of thromboses are still detrimental for mortality and wellbeing, even for patients under treatment. The addition of new JAK and JAK/FLT3 inhibitors to the therapeutic options and the investigation for novel therapeutic agents aim to improve treatment and decrease thrombotic episodes. This review is aiming to collect current data in the subjects of the pathophysiology of thrombosis in relation to inflammation in classical MPNs, the risk factors for thrombosis, and the novel prospective therapeutic targets that could be addressed

Στιγμιαία τιμή της τάσης έναρξης και της τάσης περαίωσης των μερικών εκκενώσεων στο συνδυασμό "Pertimax-λάδι μετασχηματιστών" υπό κρουστικές τάσεις ± 1,2/100μs εντός ανομοιογενούς πεδίου

97 σ.Η διερεύνηση της ηλεκτρονικής συμπεριφοράς, τα φαινόμενα γήρανσης και διάσπασης των ηλεκτρομονωτικών υλικών εντός μονωτικού ελαίου υπό την επίδραση υψηλών τάσεων έχουν αποτελέσει αντικείμενο μελέτης εξαιτίας της ευρείας χρήσης τους στη βιομηχανία. Η εργασία αυτή αφορά σε μετρήσεις που έγιναν στον συνδυασμό «Pertimax-λάδι μετασχηματιστών» υπό κρουστική τάση ±1,2/100 μs εντός ανομοιογενούς πεδίου και διαρθρώνεται σε τέσσερα μέρη. Στο πρώτο εισαγωγικό μέρος, η θεωρία του οποίου αναφέρεται κυρίως στο βιβλίο του Καθηγητή Ε.Μ.Π. Περικλή Μπούρκα: “Εφαρμογές Κτιριακών – Βιομηχανικών Μελετών και Εγκαταστάσεων”, περιγράφονται οι βασικές ιδιότητες των βιομηχανικών ηλεκτρομονωτικών υλικών, τα κριτήρια αξιολόγησης τους και οι κατηγορίες διάκρισης των μονωτικών υλικών ανάλογα με τη φυσική τους κατάσταση. Στη συνέχεια, εξετάζονται στα είδη καταπόνησης και τα είδη διάτρησης που αυτά υφίστανται. Τέλος στο ίδιο κεφάλαιο αναπτύσσονται οι δύο βασικές θεωρίες για την ερμηνεία του φαινομένου της γήρανσης και διάσπασης: η μακροσκοπική θεωρία και η κβαντομηχανική θεωρία, οι οποίες αποτελούν και το βασικό εργαλείο επεξεργασίας των μετρήσεων για την εξαγωγή συμπερασμάτων. Στο δεύτερο μέρος γίνεται αναφορά στο σκοπό της παρούσας διπλωματικής εργασίας. Περιγράφεται η διαδικασία που ακολουθήθηκε για την πραγματοποίηση των μετρήσεων και ο καθορισμός των μετρούμενων μεγεθών. Παρατίθενται χρήσιμοι ορισμοί για σημαντικά ηλεκτρικά μεγέθη και μαθηματικές σχέσεις με τις οποίες θα αξιολογήσουμε τα μονωτικά υλικά. Στο τρίτο μέρος παρατίθενται πίνακες που αναφέρονται στα αποτελέσματα των μετρήσεων. Οι πίνακες αυτοί περιλαμβάνουν τόσο τα απευθείας μετρούμενα μεγέθη (επιβαλλόμενη τάση και φορτία έναρξης και περαίωσης), όσο και αυτά που υπολογίσαμε για την αξιολόγηση των υλικών (π.χ. κινητικότητα, ένταση πεδίου, ειδική αγωγιμότητα κα). Οι πίνακες συνοδεύονται από τις γραφικές παραστάσεις των κριτηρίων αξιολόγησης ως προς την επιβαλλόμενη τάση uk και την ένταση του ηλεκτρικού πεδίου Εk. Ακολουθεί, η μαθηματική προσέγγιση των γραφικών παραστάσεων. Έτσι γίνεται αντιληπτή οπτικά και θεωρητικά η μεταξύ τους σχέση και παρατηρούμε την εξέλιξη φαινομένων με την αύξηση της επιβαλλόμενης τάσης ή της πεδιακής έντασης. Η διπλωματική εργασία κλείνει, στο τέταρτο μέρος, με τα συμπεράσματα που προκύπτουν από τις μετρήσεις. Τα συμπεράσματα αυτά απορρέουν από τη μελέτη, την επεξεργασία και παρατήρηση μέσω του θεωρητικών εργαλείων, της στατιστικής ανάλυσης και των γραφικών παραστάσεων των υπολογιζόμενων μεγεθών και των φαινομένων που λαμβάνουν χώρα κατά τη διεξαγωγή της πειραματικής διαδικασίας.The examination of the electronic attribute, the ageing and the degradation of electrical insulation material within insulating oil, has been extensively investigated due to their excessive use in the industrial sector This thesis analyses the results of measurements which have been held in conjunction «Pertimax-oil transformers» applying impulse voltage ± 1,2 / 100 μs in a heterogeneous field. The first introductory part, describes the main properties of industrial electrical insulation materials, their evaluation criteria and their division according to their physical condition. Additionally, this study presents the types of strain and perforation. Finally, in the same chapter, the macroscopic theory and the quantum mechanics theory are presented. The methodology of these two theories is used for the interpretation of the results. The theory of this first part is based on the book “Application of Building – Industrial Research and Installation” by P. Mpourkas, Professor in the National Technical University of Athens. The second part refers to the purpose of this thesis, describes the procedure of the measurements and defines the measured magnitude and the mathematical fractions used for the results. In the third part, the results of the measurements and the calculated magnitude are presented in tables. All these are illustrated in diagrams as a function to the implicated voltage uk and the intensity of the electric field Ek. Moreover, these diagrams are approached by a mathematical perspective Finally, the fourth part is the conclusion of this study. The measurements are analyzed according to the theoretical tools of statistics analysis, the graphs and the phenomena that took place during the experimental procedure. At this point, I would like to thank my supervisor Professor for appointing this thesis to me, and for his invaluable support and contribution during its implementation. This thesis analyses the results of measurements which have been held in conjunction «Pertimax-oil transformers» applying impulse voltage ± 1,2 / 100 ms in a heterogeneous field.Ευαγγελία Π. Αντωνοπούλο

Numerical and experimental analysis of the sedimentation of spherical colloidal suspensions under centrifugal force

Understanding the sedimentation behaviour of colloidal suspensions is crucial in determining their stability. Since sedimentation rates are often very slow, centrifugation is used to expedite sedimentation experiments. The effect of centrifugal acceleration on sedimentation behaviour is not fully understood. Furthermore, in sedimentation models, interparticle interactions are usually omitted by using the hard-sphere assumption. This work proposes a one-dimensional model for sedimentation using an effective maximum volume fraction, with an extension for sedimentation under centrifugal force. A numerical implementation of the model using an adaptive finite difference solver is described. Experiments with silica suspensions are carried out using an analytical centrifuge. The model is shown to be a good fit with experimental data for 480 nm spherical silica, with the effects of centrifugation at 705 rpm studied. A conversion of data to Earth gravity conditions is proposed, which is shown to recover Earth gravity sedimentation rates well. This work suggests that the effective maximum volume fraction accurately captures interparticle interactions and provides insights into the effect of centrifugation on sedimentation

Comparing oil based ointment versus standard practice for the treatment of moderate burns in Greece: a trial based cost effectiveness evaluation

<p>Abstract</p> <p>Background</p> <p>The local treatment of burn wounds has long been a subject of debate. The objective of this study was to compare the cost and the effectiveness of Moist Exposed Burn Ointment -MEBO versus a combination of <it>povidone iodine </it>plus <it>bepanthenol </it>cream for partial thickness burns.</p> <p>Methods</p> <p>The study was carried out in the Burn Center of a state hospital in Athens, Greece. 211 patients needing conservative therapy were prospectively selected according to the depth of the burn wound. The treatment was allocated according to the Stratified Randomization Design. The outcomes measured were mean cost of in-hospital stay, rate of complications, time of 50% wound healing, pain scores, in hospital stay diminution. We have adopted a societal perspective.</p> <p>Results</p> <p>In the total groups MEBO presented lower cost, (although not significantly different: p = 0.10) and better effectiveness. The data suggest that MEBO is the dominant therapy for superficial partial burn wound with significantly lower costs and significantly higher effectiveness due to a lesser time of recovery and consequently lower time of hospitalization and follow-up. MEBO presented similar percentages of complications with the comparator, lower pain levels and smaller time of no healthy appearance of the burn limits for superficial partial thickness burns.</p> <p>Conclusions</p> <p>The data suggested that topical application of MEBO may be considered for further investigation as a potential first-line treatment modality for superficial partial thickness burns.</p> <p>Trial registration</p> <p>The trial has been registered on the International Standard Randomised Controlled Trial Number Register (ISRCTN) and given the registration number <a href="http://www.controlled-trials.com/ISRCTN74058791">ISRCTN74058791</a>.</p

Inflammatory Myofibroblastic Tumor of the Breast

Inflammatory myofibroblastic tumors (IMTs) of the breast represent extremely rare lesions. Due to the scarcity of reports, their natural history, recurrence, and metastatic potential remain poorly defined. We report on a case of a primary breast IMT in a postmenopausal female patient treated successfully with breast conserving surgery and review the literature pertaining to this rare entity

MAPKs and HSPs’ Activation of a Natural Daphnia magna Population in a Man-Perturbed Lake: Implications of Ecological Significance

Natural and anthropogenic pressures in inland waters induce molecular response mechanisms in organisms as a defense against such multiple stressors. We studied, for the first time, the expression of the stress proteins, heat shock proteins (HSP) and mitogen-activated proteins kinase (MAPK), in a Daphnia magna natural population as a response to environmental changes in a heavily modified water body (Lake Koronia, Northern Greece). In parallel, the water physicochemical parameters, nutrients’ concentration and phytoplankton abundance were measured. Our results showed fluctuations of the proteins’ levels (HSP70, HSP90, phospho-p38 MAPK, phospho-p44/42 MAPK) providing evidence of their expression in situ. HSP70 showed an increasing tendency while for HSP90, no tendency was recorded. The MAPKs’ members followed a reverse pattern compared to each other. The differential expression of HSP and MAPK members indicates that D. magna in Lake Koronia experienced stressors such as increasing temperature, salinity and increased nutrient concentrations, high pH values and variations in phytoplankton abundance that triggered their activation. These in situ findings suggest that HSP and MAPK expression patterns have the potential to be used as biomarkers of stress factors in D. magna, for effective biomonitoring and setting ecological restoration targets

MAPKs and HSPs’ Activation of a Natural <em>Daphnia magna</em> Population in a Man-Perturbed Lake: Implications of Ecological Significance

Natural and anthropogenic pressures in inland waters induce molecular response mechanisms in organisms as a defense against such multiple stressors. We studied, for the first time, the expression of the stress proteins, heat shock proteins (HSP) and mitogen-activated proteins kinase (MAPK), in a Daphnia magna natural population as a response to environmental changes in a heavily modified water body (Lake Koronia, Northern Greece). In parallel, the water physicochemical parameters, nutrients’ concentration and phytoplankton abundance were measured. Our results showed fluctuations of the proteins’ levels (HSP70, HSP90, phospho-p38 MAPK, phospho-p44/42 MAPK) providing evidence of their expression in situ. HSP70 showed an increasing tendency while for HSP90, no tendency was recorded. The MAPKs’ members followed a reverse pattern compared to each other. The differential expression of HSP and MAPK members indicates that D. magna in Lake Koronia experienced stressors such as increasing temperature, salinity and increased nutrient concentrations, high pH values and variations in phytoplankton abundance that triggered their activation. These in situ findings suggest that HSP and MAPK expression patterns have the potential to be used as biomarkers of stress factors in D. magna, for effective biomonitoring and setting ecological restoration targets

Multidrug resistance to antimicrobials as a predominant factor influencing patient survival

The impact of multidrug resistance to antimicrobials was assessed in a cohort of 243 patients with microbiologically documented infections by a variety of susceptible and multidrug-resistant (MDR) species. Multidrug resistance was defined as resistance to more than two antimicrobial agents of different chemical structure. Cox regression analysis was performed to define differences and the significance of any predisposing factors. Overall survival of patients infected by susceptible isolates was prolonged compared with patients infected by MDR isolates (P = 0.013). Mortality rates of infections caused by susceptible and MDR isolates were 4.87% and 16.15%, respectively (P = 0.013); the higher mortality rate for MDR isolates was more pronounced for infections by Klebsiella pneumoniae and Pseudomonas aeruginosa. Mean (+/- standard error (S.E.)) survival of patients infected by susceptible and MDR isolates in patients without signs of severe sepsis was 28 days and 27.29 +/- 0.35 days, respectively (P = not significant). Mean (S.E.) survival of patients with severe sepsis caused by susceptible and MDR isolates was 7.70 +/- 4.62 days and 10.45 +/- 2.18 days, respectively (P = 0.048). Diabetes mellitus type 2, the presence of severe sepsis and any underlying malignancy were the most important risk factors affecting survival. It is concluded that infections by MDR isolates were accompanied by higher mortality rates and decreased survival compared with infections by susceptible isolates. Diabetes mellitus type 2 and underlying malignancies were significant co-morbid conditions, whereas survival after infection by susceptible isolates was particularly decreased in the event of severe sepsis. (c) 2006 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved