Minimal invasive treatment of urethral strictures: An experimental study of the effect of Paclitaxel coated balloons in the wall of strictured rabbit’s urethra

Purpose: The aim of this study is the evaluation of the distribution of Paclitaxel (PTX) released by a coated balloon in the layers of rabbit’s urethra. Methods: 18 rabbits were included. A Laser Device was used for the stricture formation. After two weeks, dilation of the strictured urethra was performed by using Advance 35LP PTA balloons and Advance 18 PTX PTA balloons. The experimental models were divided into 3 groups. The group Α included two rabbits without any intervention except for the stenosis procedure. Group B compromised six rabbits that underwent dilation with Advance 35LP PTA balloons. Group C consisted of 10 rabbits to which dilation with both Advance 35LP PTA balloons and Advance 18 PTX PTA balloons was applied. Histological evaluation and Immunohistochemistry were performed on all specimens. Results: Inflammation, fibrosis and ruptures were detected in the specimens of the study. In specimens of Group C the decrease of inflammation and fibrosis rate was greater. Anti-PTX antibody was detected in the epithelium, lamina propria and smooth muscle layer of all specimens of urethras that have been harvested immediately and 1 day after the dilation with Advance 18 PTX PTA balloon and it was not observed in any layer of the urethral wall of the rest of the examined specimens of Group C. Conclusions: PTX’s enrichment was detected in the smooth muscle layer of all specimens that have been harvested immediately and 24h after the dilation with Advance 18 PTX PTA balloons. PTX may play an inhibitive role in the recurrence of the stenosis

Εισαγωγή του Polestar design στον χώρο των supercar

Η παρούσα διπλωματική εργασία πραγματεύεται την δημιουργία ενός Concept σχεδίου αυτοκινήτου Polestar, με σκοπό την εισαγωγή της σχεδιαστικής γλώσσας της εταιρίας στον χώρο των Supercar. Μέσω της χρήσης της μεθοδολογίας σχεδίασης οχημάτων, που τροποποιείται για της ανάγκες της εργασίας, αναδύεται η ανάγκη τμηματοποίησης της εργασίας σε δύο μέρη, το ερευνητικό σκέλος και το σκέλος της σχεδίασης. Στο πρώτο μέρος πραγματοποιείται έρευνα στην σχεδιαστική ιστορία της Polestar αλλά και της Volvo ως θυγατρικές εταιρίες, έπειτα ερευνώνται τα χαρακτηριστικά όπως αεροδυναμικά χαρακτηριστικά και οι επιδώσεις που πρέπει να φέρει ένα όχημα έτσι ώστε να θεωρείται Supercar και τέλος η μηχανολογική ανάλυση ηλεκτρικών οχημάτων με σκοπό την άντληση αναγκών χώρου και επιδόσεων ηλεκτρικών μερών. Στο δεύτερο μέρος, εξερευνώνται στο χαρτί σιλουέτες και χαρακτηριστικά ενώ με την χρήση του MidJourney AI πραγματοποιούνται μέσω νευρωνικού σχέδια για πιο Futuristic σχεδιαστικές ιδέες. Πλησιάζοντας στο τέλος της σχεδίασης 3 Concept παρουσιάζονται ως ολοκληρωμένες ιδέες και ένα από αυτά προχωράει στην επόμενη και τελευταία διαδικασία της 3D μοντελοποίησης με σκοπό την καλύτερη δυνατή αναπαράσταση του σχεδίου με σκοπό την βελτίωση και ομαλοποίησή του. Η ανάδυση και διόρθωση των προβληματικών περιοχών του σχεδίου πραγματοποιήθηκε μεσώ της χρήσης VR εξοπλισμού για την ακριβή απεικόνιση του μοντέλου σε πραγματικές διαστάσεις και φωτισμό που βοηθά στη μεθοδολογία σχεδίασης

Effects of Electric Vehicles on the aspects of a Microgrid with increased penetration of Distributed Generation units

Σκοπός της παρούσας εργασίας είναι η μελέτη ενός δικτύου χαμηλής τάσης 17 ζυγών. Πιο συγκεκριμένα, αυτό το δίκτυο περιλαμβάνει μια πληθώρα μονάδων διεσπαρμένης παραγωγής, όπως μια μικροτουρμπίνα, μια κυψέλη καυσίμου, μια ανεμογεννήτρια, δύο σειρές φωτοβολταϊκών και δύο ενεργειακούς διανομείς με μια μονάδα συμπαραγωγής ηλεκτρισμού-θερμότητας και ένα boiler ο καθένας. Αρχικά το δίκτυο μελετήθηκε ως προς τέσσερα διαφορετικά σενάρια λειτουργίας (χωρίς διεσπαρμένη παραγωγή, ανεξάρτητη λειτουργία μονάδων DG χωρίς CHPs, ανεξάρτητη λειτουργία μονάδων DG με CHPs και μικροδίκτυο). Σε κάθε προσομοίωση παρατηρούσαμε κάποια σημαντικά χαρακτηριστικά του δικτύου, όπως το κόστος, την έγχυση ισχύος από το ανάντη δίκτυο, την παραγωγή της μικροτουρμπίνας, της κυψέλης καυσίμου, του CHP και του boiler, τις απώλειες, τα προβλήματα στις τάσεις και τις υπερφορτίσεις των γραμμών. Έγιναν πολλές προσομοιώσεις με δύο διαφορετικές οριακές τιμές συστήματος, μια υψηλή (2008) και μια πιο χαμηλή (2009). Επίσης στις προσομοιώσεις άλλαζε και το επίπεδο διείσδυσης των ΑΠΕ (ανεμογεννήτριες, φωτοβολταϊκά) με σταθερό βήμα κάθε φορά. Όλες αυτές οι αρχικές προσομοιώσεις έγιναν με την ευρέως διαδεδομένη μέθοδο Lagrange, μέσω της συνάρτησης fmincon της Matlab. Στη συνέχεια, μόνο για λειτουργία του δικτύου ως μικροδίκτυο, που είναι και το πιο ενδιαφέρον σενάριο, έγινε βελτιστοποίηση του ετήσιου κόστους λειτουργίας του με χρήση μετευριστικής μεθόδου αυτή τη φορά, και πιο συγκεκριμένα του αρμονικού αλγορίθμου αναζήτησης. Έγιναν διάφορες δοκιμές προκειμένου να ευρεθούν οι καταλληλότερες τιμές των παραμέτρων της μεθόδου, η αποτελεσματικότητα της οποίας συγκρίνεται με τη μέθοδο Lagrange και τις τιμές κόστους που πήραμε κατά τις πρώτες προσομοιώσεις. Όλα όμως τα αποτελέσματα προέκυπταν με την προσομοίωση ενός ντετερμινιστικού μοντέλου, το οποίο δεν ανταποκρίνεται σε πραγματικές εφαρμογές, καθώς τόσο η ζήτηση φορτίου όσο και η παραγωγή των ΑΠΕ θεωρούνται τυχαίες μεταβλητές. Έτσι ακολούθησε και η οικονομική βελτιστοποίηση του μικροδικτύου με χρήση ενός στοχαστικού μοντέλου. Ακόμα, μελετήθηκε στοχαστικά και το CHP των δύο ενεργειακών διανομέων του υπό μελέτη δικτύου και με χρήση της μεθόδου Gram-Charlier βρέθηκε η συνάρτηση πυκνότητας πιθανότητας (PDF) της ηλεκτρικής ισχύος που παράγει το CHP κάθε εποχή του έτους. Τέλος, υπεισήλθαν και τα ηλεκτρικά οχήματα στο μικροδίκτυο, τα οποία μελετήθηκαν μόνο ως αποθηκευτικές διατάξεις (μπαταρίες), δηλαδή σα μια επιπλέον ζήτηση φορτίου. Έγινε εκτενής μελέτη της επίδρασής τους στο κόστος λειτουργίας του μικροδικτύου, στην καμπύλη ζήτησης φορτίου και στην διείσδυση των ΑΠΕ.The purpose of this diploma thesis is to study a 17-bus low-voltage power grid. More specifically, this power grid includes a variety of distributed generation units, such as a micro-turbine, a fuel cell, a wind turbine, photovoltaics and two energy distributors each one consisting of a unit of CHP and a boiler. Initially, four different operation scenarios were studied (without DG units, independent operation of the DG units without the presence of the CHPs, independent operation of the DG units with the presence of the CHPs and Microgrid). In each simulation, observations were made on some important features of the grid, such as its operational cost, the power injection from the upstream grid, the micro-turbine’s production, the fuel cell’s production, CHPs’ and boilers’ production, losses, problems on voltages and lines’ overcharges. Numerous simulations were completed with two different system marginal prices , a relatively high (that of the year 2008) and a relatively low (that of the year 2009). Also, another feature changing in simulations was the penetration level of renewable energy resources (wind turbines, photovoltaics) with a determined step each time. All these first simulations were carried out with the well-known method of Lagrange, using the function fmincon of Matlab. Moreover, only for the Microgrid scenario (which is the most interesting scenario to study), we carried out the optimization of the annual operating cost, using a met-heuristic method this time called Harmony Search algorithm (HS). There were several tests to determine the appropriate parameters of the method, the effectiveness of which is compared with the Lagrange method, and the cost values that were determined in those first simulations mentioned above. However, all the results were produced with the use of a deterministic simulation model, which does not correspond to real applications, due to the fact that both the load demand and the production of renewable energy resources are random variables. As a result, an economic optimization of the Microgrid using a stochastic model followed. Also, a stochastic study of the CHPs of the two energy distributors (HUBs) was completed, and by using the Gram-Charlier method we found the probability density function (PDF) of the electrical power produced by the CHPs in every season of the year. Finally, electrical vehicles (plug-in EVs) were introduced in the Microgrid and they were studied only as storage devices (whenever the grid could charge them through a selection algorithm) during the night hours. An extensive study of their effects on the cost of the Microgrid was conducted, along with their effects on the load demand curve and the penetration of the renewable resources as well.Κωνσταντίνος Δ. Παγώνη

Does recombinant human erythropoietin accelerate correction of post-ulcer-bleeding anaemia? A pilot study

AIM: Anaemia caused by acute upper gastrointestinal bleeding is treated with blood transfusion or iron, but patients usually face a two-month recovery period from post-haemorrhage anaemia. This prospective, randomised, open, pilot study was designed to investigate whether recombinant human erythropoietin (Epoetin) therapy accelerate haematocrit increase in the post-bleeding recovery period. METHODS: We studied hospitalised patients admitted because of acute ulcer bleeding or haemorrhagic gastritis, who had a haematocrit of 27-33% and did not receive blood transfusions. One day after the endoscopic confirmation of cessation of bleeding, they were randomised either to erythropoietin (20 000 IU Epoetin alfa subcutaneously, on days 0, 4 and 6) plus iron (100 mg im, on days 1-6, (G(1)) or iron only (G(2)). Haematocrit was measured on days 0, 6, 14, 30, 45, and 60, respectively. RESULTS: One patient from G1 and two from G2 were lost to follow-up. Therefore, 14 and 13 patients from G1 and G2 respectively were analysed. Demographic characteristics, serum iron, ferritin, total iron binding capacity, reticulocytes, and haematocrit were not significantly different at entry to the study. Median reticulocyte counts were significantly different between groups on day six (G(1): 4.0, 3.0-6.4 vs G(2): 3.5, 2.1-4.4%, P=0.03) and median haematocrit on day fourteen [G(1): 35.9, 30.7-41.0 vs G(2): 32.5, 29.5-37.0% (median, range), P=0.04]. CONCLUSION: Erythropoietin administration significantly accelerates correction of anemia after acute ulcer bleeding. The haematocrit gain is equivalent to one unit of transfused blood two weeks after the bleeding episode

Estimating Stream Bank and Bed Erosion and Deposition with Innovative and Traditional Methods

Understanding the contributions of stream bank and bed erosion will allow us to implement the most effective management practices. The objective of this study was to assess different methods to measure bank and bed erosion at different scales, specifically the watershed, reach and plot. Innovative and traditional methods were utilized. At the watershed scale, indices based on free satellite images were used. For the reach scale, indices were used, but the images with higher accuracy were purchased and captured by unmanned aerial vehicles (UAVs). At the plot scale, erosion pins, cross-sections and laser scanning were applied. The watershed scale analysis showcased “hot spots”. These “hot spots” were reaches vulnerable to erosion and deposition. The indices of the purchased images were applied to these “hot spots” and allowed us to narrow the length of the reaches where UAV flights took place. These flight images located where erosion and deposition occurred. Finally, at the plot scale, laser scanning provided more detailed and accurate data at a greater scale compared to the traditional methods. The implementation of these methods allows us to find the areas vulnerable to erosion and deposition. These are the areas where nature-based solutions should be implemented to effectively mitigate erosion problems

Predicting the Outcome of Patients with Severe COVID-19 with Simple Inflammatory Biomarkers: The Utility of Novel Combined Scores—Results from a European Tertiary/Referral Centre

Background: The clinical significance of combinations of inflammatory biomarkers in severe COVID-19 infection is yet to be proved. Although several studies have evaluated the prognostic value of biomarkers in patients with COVID-19, there are limited data regarding the value of the combination scores that could take full advantage of the prognostic value of several biomarkers and that could account for the heterogeneity of patients with severe COVID-19. We investigated the prognostic value of combination scores of admission values of inflammatory biomarkers in adults with severe COVID-19. Methods: Adults admitted to the Department of Respiratory Medicine of the UHL with severe COVID-19 (April-September 2021, NCT05145751) were included. Demographics, medical history, laboratory tests and outcome (high-flow nasal cannula (HFNC), admission to Intensive Care Unit (ICU) or death) were recorded. The optimal cut-off points of on admission values of C-reactive protein (CRP), CRP to lymphocyte ratio (CLR), lymphocyte to neutrophil ratio (LNR) and derived variation of neutrophil to lymphocyte ratio (dv-NLR (neutrophil/white blood count-lymphocyte)) for the predetermined outcome were defined. Based on the cut-off of CRP, LNR, dv-NLR and CLR, which were found to be predictors for HFNC, 3 scores were defined: CRP and LNR (C-CRP #1), CRP and dv-NLR (C-CRP #2), CRP and CLR (C-CRP #3). Likewise, based on the cut-off of CRP and CLR, which were found to be predictors for death, the score of CRP and CLR (C-CRP #3*) was defined. The combination scores were then classified as: 2 points (both biomarkers elevated); 1 point (one biomarker elevated) and 0 points (normal values). None of the biomarkers was predictive for the ICU admission, so no further analysis was performed. Binomial logistic regression analysis was used to establish the predictive role for each biomarker. Results: One hundred and fifteen patients (60% males, mean age 57.7 years) were included. Thirty-seven (32.2%) patients required HFNC, nine (7.8%) died and eight (7%) were admitted to ICU, respectively. As far as HFNC is concerned, the cut-off point was 3.2 for CRP, 0.231 for LNR, 0.90 for dv-NLR and 0.004 for CLR. Two points of C-CRP #1 and 2 points of C-CRP #3 predicted HFNC with a probability as high as 0.625 (p = 0.005) and 0.561 (p p = 0.0038) in severe COVID-19. Conclusions: The combination scores of CRP and inflammatory biomarkers, based on admission values, are promising predictors for respiratory support using HFNC and for mortality in patients suffering from severe COVID-19 infection

Bladder Cancer during Pregnancy: A Review of the Literature

Bladder malignancy represents the fourth most common cancer in men and the eighth in women in the western world. Women under 75 years of age have a risk of 0.5–1% of developing bladder cancer. The diagnosis usually occurs between 65 and 70 years of age, whereas the mortality rate for women varies from 0.5 to 4 per 100,000 every year. Nulliparous women present a greater risk than women who have given birth. The risk is further decreased when parity increases. Theoretically, hormonal changes occurring during pregnancy play a protective role. Smoking and occupational exposure to specific chemicals are the most common risk factors of bladder cancer. Other risk factors such as chronic urinary tract inflammation, cyclophosphamide, radiotherapy, and familial correlation have been reported. The aim of this review is to highlight a rare combination, which is the co-existence of bladder malignancy and pregnancy. We present thirteen different cases of women who were diagnosed with malignant bladder tumors during their pregnancy. A review of the literature was conducted, focusing on the unspecific symptoms, possible diagnostic tools, and suitable treatment modalities. The management of bladder cancer in pregnancy is a challenging process. The fragile balance between the possible complications of pregnancy and maternal health is yet to be discussed