Browsing 2. Ερευνητικές δημοσιεύσεις | Research publications by Issue Date
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- ItemOpen AccessAir flow characteristics in an industrial wood pallet drying kiln
Τμήμα Μηχανολόγων και Αεροναυπηγών Μηχαν. (Δημοσ. Π.Π. σε συνέδρια)(2010-07-21T09:52:17Z) Tzempelikos, Dimitrios; Filios, Andronikos; Margaris, Dionisios; Τζεμπελίκος, Δημήτριος; Φίλιος, Ανδρόνικος; Μάργαρης, ΔιονύσιοςThe improvement and optimization of air-distribution systems in drying kilns contributes to the preservation of the quality, safety and shelf life of perishable products. The present study reports on the numerical solution of airflow within a two dimensional drying kiln enclosure loaded with wooden pallets. The performance of air flow field is examined with and without supply of wooden pallets. Different arrangements of the supplied wooden pallets are investigated as well as the use of a screen in order to improve the airflow filed. The steady state RANS equations that formulate the flow problem are solved along with a turbulence model that is the standard k-εor the rng k-ε. The effect of the turbulence modeling is distinguished through direct comparisons of the derived airflow patterns. The results obtained show the presence of stagnant zones inside the pallets columns and above of them and the presence of recirculation regions in different zones of the drying kiln with the two turbulence models.
- ItemOpen AccessPhagocytic ability of neutrophils and monocytes in neonates.
Τμήμα Ιατρικής (Δημοσ. Π.Π. σε περιοδικά)(2011-10-26) Φίλιας, Αθανάσιος; Θεοδώρου, Γεώργιος; Μουζοπούλου, Σοφία; Βαρβαρίγου, Αναστασία; Μανταγός, Στέφανος; Καρακάντζα, Μαρίνα; Filias, Athanasios; Theodorou, Georgios; Mouzopoulou, Sofia; Varvarigou, Anastasia; Mantagos, Stephanos; Karakantza, Marina-
- ItemOpen AccessAllergic inflammation does not impact chemical-induced carcinogenesis in the lungs of mice
Τμήμα Ιατρικής (Δημοσ. Π.Π. σε περιοδικά)(2011-12-02) Doris, Konstantinos; Karabela, Sophia P; Kairi, Chrysoula; Simoes, Davina CM; Roussos, Charis; Zakynthinos, Spyros G; Kalomenidis, Ioannis; Blackwell, Timothy S; Stathopoulos, Georgios T; Doris, Κωνσταντίνος; Καράμπελα, Σοφία Π; Καΐρη, Χρυσούλα; Simoes, Davina CM; Ρούσσος, Χάρης; Ζακυνθινός, Σπύρος Γ; Καλομενίδης, Ιωάννης; Blackwell, Timothy S; Σταθόπουλος, Γεώργιος ΤAlthough the relationship between allergic inflammation and lung carcinogenesis is not clearly defined, several reports suggest an increased incidence of lung cancer in patients with asthma. We aimed at determining the functional impact of allergic inflammation on chemical carcinogenesis in the lungs of mice. Methods Balb/c mice received single-dose urethane (1 g/kg at day 0) and two-stage ovalbumin during tumor initiation (sensitization: days -14 and 0; challenge: daily at days 6-12), tumor progression (sensitization: days 70 and 84; challenge: daily at days 90-96), or chronically (sensitization: days -14 and 0; challenge: daily at days 6-12 and thrice weekly thereafter). In addition, interleukin (IL)-5 deficient and wild-type C57BL/6 mice received ten weekly urethane injections. All mice were sacrificed after four months. Primary end-points were number, size, and histology of lung tumors. Secondary end-points were inflammatory cells and mediators in the airspace compartment. Results Ovalbumin provoked acute allergic inflammation and chronic remodeling of murine airways, evident by airspace eosinophilia, IL-5 up-regulation, and airspace enlargement. Urethane resulted in formation of atypical alveolar hyperplasias, adenomas, and adenocarcinomas in mouse lungs. Ovalbumin-induced allergic inflammation during tumor initiation, progression, or continuously did not impact the number, size, or histologic distribution of urethane-induced pulmonary neoplastic lesions. In addition, genetic deficiency in IL-5 had no effect on urethane-induced lung tumorigenesis. Conclusions Allergic inflammation does not impact chemical-induced carcinogenesis of the airways. These findings suggest that not all types of airway inflammation influence lung carcinogenesis and cast doubt on the idea of a mechanistic link between asthma and lung cancer.
- ItemOpen AccessSpecific effects of bortezomib against experimental malignant pleural effusion: a preclinical study
Τμήμα Ιατρικής (Δημοσ. Π.Π. σε περιοδικά)(2011-12-02) Psallidas, Ioannis; Karabela, Sophia P; Moschos, Charalampos; Sherrill, Taylor P; Kollintza, Androniki; Magkouta, Sophia; Theodoropoulou, Panagiota; Roussos, Charis; Blackwell, Timothy S; Kalomenidis, Ioannis; Stathopoulos, Georgios T; Ψαλλίδας, Ιωάννης; Καράμπελα, Σοφία Π; Μόσχος, Χαράλαμπος; Sherrill, Taylor P; Κολλίντζα, Ανδρονίκη; Μαγκούτα, Σοφία; Θεοδωροπούλου, Παναγιώτα; Ρούσσος, Χάρης; Blackwell, Timothy S; Καλομενίδης, Ιωάννης; Σταθόπουλος, Γεώργιος Τ-
- ItemOpen AccessBrucellosis presenting as piriformis myositis: a case report
Τμήμα Ιατρικής (Δημοσ. Π.Π. σε περιοδικά)(2011-12-02) Kraniotis, Pantelis; Marangos, Markos; Lekkou, Alexandra; Romanos, Odysseas; Solomou, Ekaterini; Κρανιώτης, Παντελής; Μαραγκός, Μάρκος; Λέκκου, Αλεξάνδρα; Ρωμανός, Οδυσσέας; Σολωμού, ΑικατερίνηMyositis is a rare bacterial muscle infection. Involvement of the piriformis muscle has been rarely reported in the literature. In this report we describe a case of piriformis myositis due to Brucella melitensis, which to the best of our knowledge is the first such case presented in the literature.
- ItemOpen AccessQuintus Horatius Flaccus, Serm.1.3.63-8 & Epod.3 : δύσπεπτο χιούμορ
Τμήμα Φιλολογίας (Δημοσ. Π.Π. σε συνέδρια)(2011-12-08) Βαρτζιώτη, Όλγα; Vartzioti, OlgaΟ Οράτιος στη Σάτιρα 1.3.63-8 & τον Ίαμβο 3 χρησιμοποιεί όρους που αναδεικνύουν το δύσπεπτο χιούμορ στις συναναστροφές (amicitia)με κικερώνειο πνεύμα. Η ορολογία αυτή συνδέεται και με πλατωνικές και αριστοτελικές απόψεις για τη φύση του γέλιου και τη σχέση του με τις αισθήσεις.
- ItemOpen AccessScanned images resolution improvement using neural networks
Τμήμα Φυσικής (Δημοσ. Π.Π. σε περιοδικά)(2011-12-08) Panagiotopoulou, Antigoni; Anastassopoulos, Vassilis; Παναγιωτοπούλου, Αντιγόνη; Αναστασόπουλος, ΒασίλειοςA novel method of improving the spatial resolution of scanned images, by means of neural networks, is presented in this paper. Images of different resolution, originating from scanner, successively train a neural network, which learns to improve resolution from 25 to 50 pixels-per-inch (ppi), then from 100 to 200 ppi and finally, from 50 to 100 ppi. Thus, the network is provided with consistent knowledge regarding the point spread function (PSF) of the scanner, whilst it gains the generalization ability to reconstruct finer resolution images unfamiliar to it. The novelty of the proposed image-resolution-enhancement technique lies in the successive training of the neural structure with images of increasing resolution. Comparisons with the image scanned at 400 ppi demonstrate the superiority of our method to conventional interpolation techniques.
- ItemOpen AccessRegularized super-resolution image reconstruction employing robust error norms
Τμήμα Φυσικής (Δημοσ. Π.Π. σε περιοδικά)(2011-12-08) Panagiotopoulou, Antigoni; Anastassopoulos, Vassilis; Παναγιωτοπούλου, Αντιγόνη; Αναστασόπουλος, ΒασίλειοςA high-resolution image is reconstructed from a sequence of subpixel shifted, aliased low-resolution frames, by means of stochastic regularized super-resolution (SR) image reconstruction. The Tukey (T), Lorentzian (L), and Huber (H) cost functions are employed for the data-fidelity term. The performance of the particular error norms, in SR image reconstruction, is presented. Actually, their employment in SR recon-struction is preceded by dilating and scaling their influence functions to make them as similar as possible. Thus, the direct comparison of these norms in rejecting outliers takes place. The bilateral total variation (BTV) regularization is incorporated as a priori knowledge about the solution. The outliers effect is significantly reduced, and the high-frequency edge structures of the reconstructed image are preserved. The proposed TTV, LTV, and HTV methods are directly compared with a former SR method that employs the L1-norm in the data-fidelity term for synthesized and real sequences of frames. In the simulated experiments, noiseless frames as well as frames corrupted by salt-and-pepper noise are employed. Experimental results verify the robust statistics theory. Thus, the Tukey method performs best, while the L1-norm technique performs inferiorly to the proposed techniques.
- ItemOpen AccessSuper-resolution reconstruction of thermal infrared images
Τμήμα Φυσικής (Δημοσ. Π.Π. σε συνέδρια)(2011-12-08) Panagiotopoulou, Antigoni; Anastassopoulos, Vassilis; Παναγιωτοπούλου, Αντιγόνη; Αναστασόπουλος, ΒασίλειοςIn this paper a high-resolution (HR) thermal infrared image is reconstructed from a sequence of subpixel shifted, aliased low-resolution (LR) frames, by means of a stochastic regularized super-resolution (SR) method. The Huber (H) cost function is employed to measure the difference between the projected estimate of the HR image and each LR frame. The bilateral Total Variation (TV) regularization is incorporated as a priori knowledge about the solution. The proposed HTV super-resolution approach that employs the Huber norm in combination with the bilateral TV regularization exhibits superior performance to former SR method. Thus the effect of outliers is significantly reduced and the high-frequency edge structures of the reconstructed HR thermal infrared image are preserved. The proposed technique is also tested on frames that are corrupted by Gaussian noise and proves superior when compared to existing regularized SR method.
- ItemOpen AccessSuper-resolution image reconstruction techniques: Trade-offs between the data-fidelity and regularization terms
Τμήμα Φυσικής (Δημοσ. Π.Π. σε περιοδικά)Stochastic regularized methods are quite advantageous in Super-Resolution (SR) image reconstruction problems. In the particular techniques the SR problem is formulated by means of two terms, the data-fidelity term and the regularization term. The present work examines the effect of each one of these terms on the SR reconstruction result with respect to the presence or absence of noise in the Low-Resolution (LR) frames. Experimentation is carried out with the widely employed L2, L1, Huber and Lorentzian estimators for the data-fidelity term. The Tikhonov and Bilateral (B) Total Variation (TV) techniques are employed for the regularization term. The extracted conclusions can, in practice, help to select an effective SR method for a given sequence of LR frames. Thus, in case that the potential methods present common data-fidelity or regularization term, and frames are noiseless, the method which employs the most robust regularization or data-fidelity term should be used. Otherwise, experimental conclusions regarding performance ranking vary with the presence of noise in frames, the noise model as well as the difference in robustness of efficiency between the rival terms. Estimators employed for the data-fidelity term or regularizations stand for the rival terms.
- ItemOpen AccessSpeaker distance detection using a single microphone
Τμήμα Ηλεκτρολ. Μηχαν. και Τεχνολ. Υπολογ. (Δημοσ. Π.Π. σε περιοδικά)(2011-12-08) Georganti, Eleftheria; May, Tobias; van de Par, Steven; Harma, Aki; Mourjopoulos, John; Γεωργαντή, Ελευθερία; May, Tobias; van de Par, Steven; Harma, Aki; Μουτζόπουλος, ΓιάννηςA method to detect the distance of a speaker from a single microphone in a room environment is proposed. Several features, related to statistical parameters of speech source excitation signals, are introduced and are shown to depend on the distance between source and receiver. Those features are used to train a pattern recognizer for distance detection. The method is tested using a database of speech recordings in four rooms with different acoustical properties. Performance is shown to be independent of the signal gain and level, but depends on the reverberation time and the characteristics of the room. Overall, the system performs well especially for close distances and for rooms with low reverberation time and it appears to be robust to small distance mismatches. Finally, a listening test is conducted in order to compare the results of the proposed method to the performance of human listeners.
- ItemOpen AccessInterpolation in multispectral data using neural networks
Τμήμα Φυσικής (Δημοσ. Π.Π. σε συνέδρια)(2011-12-08) Tsagaris, Vassilis; Panagiotopoulou, Antigoni; Anastassopoulos, Vassilis; Τσαγκάρης, Βασίλειος; Παναγιωτοπούλου, Αντιγόνη; Αναστασόπουλος, ΒασίλειοςA novel procedure which aims in increasing the spatial resolution of multispectral data and simultaneously creates a high quality RGB fused representation is proposed in this paper. For this purpose, neural networks are employed and a successive training procedure is applied in order to incorporate in the network structure knowledge about recovering lost frequencies and thus giving fine resolution output color images. MERIS multispectral data are employed to demonstrate the performance of the proposed method.
- ItemOpen AccessSuper-resolution image reconstruction employing Kriging interpolation technique
Τμήμα Φυσικής (Δημοσ. Π.Π. σε συνέδρια)In this paper a high-resolution (HR) image is reconstructed from a sequence of subpixel shifted, aliased low-resolution (LR) frames by means of a novel nonuniform interpolation super-resolution (SR) method. A gradient-based algorithm estimates the horizontal and vertical shifts for each frame. Then, the uniformly spaced sampling points of the HR image are produced by means of Kriging interpolation. Wiener filtering is employed to deal with the restoration problem. The novelty of the proposed nonuniform interpolation approach to SR image reconstruction lies in the employment of Kriging interpolation technique. Comparisons with the original image demonstrate the superiority of our method to a conventional nonuniform interpolation one of SR image reconstruction.
- ItemOpen AccessBaseline cerebral oximetry values in cardiac and vascular surgery patients: a prospective observational study
Τμήμα Ιατρικής (Δημοσ. Π.Π. σε περιοδικά)(2012-01-10) Baikoussis, Nikolaos G; Karanikolas, Menelaos; Siminelakis, Stavros; Matsagas, Miltiadis; Papadopoulos, Georgios; Μπαϊκούσσης, Νικόλαος; Καρανικόλας, Μενέλαος; Συμινελάκης, Σταύρος; Ματσάγκας, Μιλτιάδης; Παπαδόπουλος, Γεώργιος100 cardiac surgery patients and 57 carotid surgery patients enrolled. Compared to cardiac surgery, carotid endarterectomy patients were older (71.05 ± 8.69 vs. 65.72 ± 11.04, P < 0.001), with higher baseline INVOS (P < 0.007) and greater stroke frequency (P < 0.002). Diabetes and high cholesterol were more common in cardiac surgery patients. Right side INVOS values were strongly correlated with left-side values in carotid (r = 0.772, P < 0.0001) and cardiac surgery patients (r = 0.697, P < 0.0001). Diabetes and high cholesterol were associated with significantly (P < 0.001) lower INVOS and smoking was associated with higher INVOS values in carotid, but not in cardiac surgery patients. Age, sex, CVA history, Hypertension, CAD, Asthma, carotid stenosis side and surgery side were not related to INVOS. Multivariate analysis showed that diabetes is strongly associated with lower baseline INVOS values bilaterally (P < 0.001) and explained 36.4% of observed baseline INVOS variability in carotid (but not cardiac) surgery.
- ItemOpen AccessThe reported thoracic injuries in Homer's Iliad
Τμήμα Ιατρικής (Δημοσ. Π.Π. σε περιοδικά)(2012-01-10) Αποστολάκης, Ευστράτιος; Αποστολάκη, Γεωργία; Αποστολάκη, Μαίρη; Χόρτη, Μαρία; Apostolakis, Efstratios; Apostolaki, Georgia; Apostolaki, Mary; Chorti, MariaHomer's Iliad is considered to be a prominent and representative work of the tradition of the ancient Greek epic poetry. In this poem Homer presents the battles which took place during the last year of the 10-year lasting Trojan War between Achaeans and Trojans. We wanted to examine the chest wounds, especially those which are described in detail, according to their localization, severity and mortality. Finally, there are reported 54 consecutive thoracic injuries in the Iliad. The mostly used weapons were the spear (63%), the stones (7.4%), the arrow (5.5%) and the sword (5.5%). We divided the injuries according to their severity in mild (those which did not cause serious injury to the victim), medium (those which cause the victim to abandon the battlefield), and severe (those which cause death of the victim). According to this classification, the reported injuries were mild in 11.11%, medium in 18.52%, and severe in the last 70.37% of the reported cases. In other words, 89% of the injuries belong to the medium or severe category of thoracic injury. As far as the mortality of the injuries is concerned, 38 out of 54 thoracic injuries include death, which makes the mortality percentage reach 70.37%. Concerning the "allocation of the roles", the Achaean were in 68% perpetrators and the Trojans in only 32%. In terms of gravity, out of 38 mortal injuries 30 involve a Trojan (78.95%) and the remaining 8 an Achaean (21.05%). The excellent and detailed description of the injuries by Homer, as well as of the symptoms, may reveal a man with knowledge of anatomy and medicine who cared for the injured warriors in the battlefield.
- ItemOpen AccessFolk intuitions, science-fiction and philosophy
Τμήμα Επιστημών της Εκπαίδευσης και της Αγωγής στην Προσχολική Ηλικία (Δημοσ. Π.Π. σε περιοδικά)(2012-01-10) Gasparatou, Renia; Γασπαράτου, ΡένιαSome experimental philosophers imply that philosophers should endorse folk intuitions and even use them to advance philosophical theses. In this paper I will try to contrast experimental appeals to intuition with J. L. Austin’s, whom some experimentalists cite as a precursor of their method. I will suggest that Austin evokes ordinary intuitions in order to dismantle philosophical quests. He even suggests (a) that the appeal to ordinary intuitions of the folk can hardly prescribe answers to extraordinary circumstances and (b) that philosophical quests themselves are extraordinary. Therefore, the appeal to folk intuitions cannot prescribe answers to philosophical problems. It can only dissolve philosophical quests; yet, the dismantling of philosophy hardly accords with the experimentalists’ agenda.
- ItemOpen AccessPharmacologic prophylaxis for atrial fibrillation following cardiac surgery: a systematic review
Τμήμα Ιατρικής (Δημοσ. Π.Π. σε περιοδικά)(2012-01-10) Κόνιαρη, Ιωάννα; Αποστολάκης, Ευστράτιος; Ρογκάκου, Χριστίνα; Μπαϊκούσης, Νικόλαος; Δουγένης, Δημήτριος; Koniari, Ioanna; Apostolakis, Efstratios; Rogkakou, Christina; Baikoussis, Nikolaos G; Dougenis, DimitriosAtrial Fibrillation (AF) is the most common arrhythmia occurring after cardiac surgery. Its incidence varies depending on type of surgery. Postoperative AF may cause hemodynamic deterioration, predispose to stroke and increase mortality. Effective treatment for prophylaxis of postoperative AF is vital as reduces hospitalization and overall morbidity. Beta - blockers, have been proved to prevent effectively atrial fibrillation following cardiac surgery and should be routinely used if there are no contraindications. Sotalol may be more effective than standard b-blockers for the prevention of AF without causing an excess of side effects. Amiodarone is useful when beta-blocker therapy is not possible or as additional prophylaxis in high risk patients. Other agents such as magnesium, calcium channels blocker or non-antiarrhythmic drugs as glycose-insulin - potassium, non-steroidal anti-inflammatory drugs, corticosteroids, N-acetylcysteine and statins have been studied as alternative treatment for postoperative AF prophylaxis.
- ItemOpen AccessIntravenous levosimendan-norepinephrine combination during off-pump coronary artery bypass grafting in a hemodialysis patient with severe myocardial dysfunction
Τμήμα Ιατρικής (Δημοσ. Π.Π. σε περιοδικά)(2012-01-10) Papadopoulos, Georgios; Baikoussis, Nikolaos G; Tzimas, Petros; Siminelakis, Stavros N; Karanikolas, Menelaos; Παπαδόπουλος, Γεώργιος; Μπαϊκούσσης, Νικόλαος; Τζίμας, Πέτρος; Συμινελάκης, Σταύρος; Καρανικόλας, ΜενέλαοςThis the case of a 63 year-old man with end-stage renal disease (on chronic hemodialysis), unstable angina and significantly impaired myocardial contractility with low left ventricular ejection fraction, who underwent off-pump one vessel coronary bypass surgery. Combined continuous levosimendan and norepinephrine infusion (at 0.07 μg/kg/min and 0.05 μg/kg/min respectively) started immediately after anesthesia induction and continued for 24 hours. The levosimendan/norepinephrine combination helped maintain an appropriate hemodynamic profile, thereby contributing to uneventful completion of surgery and postoperative hemodynamic stability. Although levosimendan is considered contraindicated in ESRD patients, this case report suggests that combined perioperative levosimendan/norepinephrine administration can be useful in carefully selected hemodialysis patients with impaired myocardial contractility and ongoing myocardial ischemia, who undergo off-pump myocardial revascularization surgery.
- ItemOpen AccessEducation as initiation to a “Form of life”: Conceptual investigation and education theory
Τμήμα Επιστημών της Εκπαίδευσης και της Αγωγής στην Προσχολική Ηλικία (Δημοσ. Π.Π. σε περιοδικά)(2012-01-11) Gasparatou, Renia; Γασπαράτου, ΡένιαAccording to L. Wittgenstein and Wittgensteinians, there is a set of intuitions, propositions and practices that forms the community’s bounds of sense. In this paper I discuss how fruitful this idea can be for education theory. I argue that, although the idea of an existing everyday framework can help explain how education works, any efforts to defend our current worldview as binding of our understanding boils down to conservatism. Following this view, comes the assertion that many problems posed today by philosophers and scientists are bogus and should be dismissed on the ground that they question our ordinary framework. Hence prescribing an even stronger version of conservatism that promotes quietism over intellectual challenge.
- ItemOpen AccessΜελέτη της ποιότητας ανθρώπινων γνάθων με φασματοσκοπία Raman
Τμήμα Φαρμακευτικής (Δημοσ. Π.Π. σε συνέδρια)(2012-03-08) Κοντογιάννης, Χρίστος; Όρκουλα, Μαλβίνα; Παντελιού, Σοφία; Κουβαριτάκη, Σοφία; Βαρδάκη, Μάρθα; Kontoyannis, Christos; Orkoula, Malvina; Panteliou, Sophia; Kouvaritaki, Sophia; Vardaki, MarthaΗ «ποιότητα» του οστού είναι ένας σύνθετος όρος που εξαρτάται από πολλούς παράγοντες όπως η πυκνότητα, οι μηχανικές ιδιότητες, η χημική σύσταση, η αρχιτεκτονική του οστού, σε μακροσκοπικό και μικροσκοπικό επίπεδο. Στην περίπτωση των γνάθων, η εκτίμηση της ποιότητας είναι μια απαραίτητη πληροφορία πχ. πριν από επεμβάσεις για προσθήκη εμφυτεύματος. Η παράμετρος στην οποία συχνότερα γίνεται αναφορά για να δίνεται μια εικόνα της κατάστασης του οστού, είναι η πυκνότητά του (Bone Mineral Density – BMD). Αυτή μετράται κλινικά με τεχνικές μη-επεμβατικές που όμως χρησιμοποιούν ακτινοβολία-Χ. Ένα ακόμη μειονέκτημά τους είναι η απόκρισή τους μόνο στο ανόργανο συστατικό του οστού (βιοαπατίτης) χωρίς να λαμβάνουν υπόψη τους το οργανικό (κυρίως κολλαγόνο τύπου Ι), το οποίο όμως και αυτό υφίσταται φθορά είτε λόγω γήρανσης του οστού είτε λόγω κάποιας ασθένειας. Στην παρούσα εργασία, ανθρώπινες γνάθοι μελετήθηκαν με Φασματοσκοπία Raman, μια τεχνική που δίνει πληροφορίες για τη χημική σύσταση του εξεταζόμενου δείγματος. Φάσματα Raman καταγράφηκαν από διάφορα σημεία των γνάθων. Μέτρηση των εμβαδών των κορυφών που αποδίδονται στον βιοαπατίτη και στο κολλαγόνο έδωσαν πληροφορίες για τη διαφοροποίηση της ποιότητας του οστού από σημείο σε σημείο της γνάθου. Από τη «χαρτογράφηση» των ιστών και τη σύγκριση μεταξύ τους προέκυψαν συμπεράσματα για τη δομή των γνάθων.