Dolomitni agregati iz kamenoloma Čelina, Podsusedsko Dolje i Jarče polje podvrgnuti su ispitivanju na udarno habajuća opterećenja i zamrzavanje. Pri tome su korištene nenormirane i normirane metode ...prema HRN-u i ASTM-u. Posebna pažnja posvećena je određivanju koeficijenta Los Angeles (KLA), koeficijenta drobivosti (KD) i indeksa pregranulacije (lp) prije te nakon 25 i 50 ciklusa zamrzavanja. Dobivene vrijednosti, prikazane tebelarno i grafički, posljedica su strukturno-teksturnih i petrografskih značajki, geneze i različitih postgenetskih procesa, prije svega tektonike (mikroraspucanost i kataklaziranje) i rekristalizacije. Posebno je utvrđen utjecaj veličine, oblika i međusobne povezanosti kristala dolomita na udarno habajuća opterećenja te defekata u obliku savijanja, tlačnih sraslačkih lamela i kalavosti.
OBJECTIVE: The aim of this study was to determine the effect of the apical foramen diameter and different application methods of Mineral Trioxide Aggregate (MTA) on the fracture resistance of ...simulated immature teeth using a Universal Testing Machine.MATERIALS AND METHOD: Ninety extracted human teeth were used for the fracture resistance test. The apical foramen was prepared to a diameter of 1.0 mm or 1.4 mm to simulate the open apex of immature teeth. MTA was mixed according to manufacturer's recommendations and placed into the root canals with different apical foramen diameter by four different root filling techniques: retrograde, two-phased orthograde, and ortograde with or without internal matrix. Prepared roots were marked 2 mm below the cemento-enamel junction and embedded in transparent acrylic resin in cylinder moulds. Vertical force was applied along the long axis of the tooth at a speed of 5 mm/min, and the maximum resistance to fracture for each tooth was determined in Newton. A software package was used for the statistical analysis. The data were analyzed by using one-way ANOVA and post-hoc Tukey tests.RESULTS: A statistically significant difference could not be observed between the groups (p>0.05) whereas statistically significant differences were found between the test groups and the control groups (p<0.05).CONCLUSION: There was no significant difference between different vertical root filling techniques in increasing the fracture strength of the teeth. The diameter of the apical foramen did not have a significant effect on the fracture resistance.
AMAÇ: Bu çalışmada apikal foramen çapının ve farklı uygulama yöntemlerinin Mineral Trioksit Agregat’ın (MTA) simüle edilmiş immatür dişler üzerine olan kırılma dayanımına etkisinin Universal Test Cihazı kullanılarak belirlenmesi amaçlandı.GEREÇ VE YÖNTEM: Çalışmada 90 adet çekilmiş üst çene kesici insan dişi kullanıldı. Çalışmada, açık apekse sahip immatür dişleri simüle etmek amacıyla apikal foramen, çapı 1.0 veya 1.4 mm olacak şekilde hazırlandı. Üretici firmanın talimatları doğrultusunda karıştırılan MTA dört farklı yolla (retrograd, ortograd, 2 aşamalı ortograd ve internal matriks destekli ortograd yolla) farklı apikal foramen çapa sahip dişlerin kök kanallarının içine yerleştirildi. Negatif kontrol grubu olarak seçilmiş 5 adet diş hiçbir işlem yapılmadan deney süresine kadar salin solüsyonu içerisinde bekletildi. Pozitif kontrol grubu olarak preparasyonu yapılmış rastgele 5 adet diş seçildi; ancak kanal dolguları yapılmadı. Hazırlanan kökler silindir kalıplar kullanılarak mine-sement sınırının 2 mm apikalinden şeffaf akrilik rezin içerisine gömüldü. Örneklere, dişe dik gelecek şekilde, 5 mm/dk hızda dikey kuvvet uygulandı. Her bir örneğe uygulanan dikey kuvvetler karşısında dişlerin maksimum kırılma dirençleri Newton cinsinden belirlendi. Verilerin istatistiksel analizi bir software kullanılarak yapıldı. Elde edilen veriler tek yönlü ANOVA ve post-hoc Tukey testleri kullanılarak analiz edildi.BULGULAR: Deney gruplarının birbiri arasında istatistiksel olarak fark bulunmazken (p>0.05), pozitif ve negatif kontrol grupları ile aralarında istatistiksel fark bulundu (p<0.05).SONUÇ: Farklı yollarla yerleştirilen MTA’nın dikey kuvvetler karşısında dişlerin kırılma dayanımları üzerine anlamlı bir etkisi olmadığı saptandı.
Pacienţii cu leucemie acută dezvoltă anomalii ale hemostazei care determină apariţia de complicaţii hemoragipare şi chiar trombotice. Patogeneza acestor complicaţii este complexă si multifactorială. ...Deoarece trombocitele şi microparticulele trombocitare reprezintă elemente cheie în cadrul proceselor de hemostază si tromboză, am încercat să evidenţiem rolul lor în predicţia complicaţiilor hemoragice şi trombotice. Grupurile studiate au inclus 24 de pacienţi cu leucemie acută şi 16 voluntari sănătoşi. Evaluarea agregării plachetare s-a realizat prin agregometrie prin impedanţa în sânge integral, iar pentru determinarea microparticulelor trombocitare s-a utilizat citometria în flux. Opt pacienţi au dezvoltat complicaţii hemoragipare, care au fost asociate cu agregabilitate trombocitară diminuată la internare. Evenimentele trombotice majore au complicat evoluţia a 5 pacienţi şi au fost precedate de agregare trombocitară crescută la 3 cazuri şi nivel crescut de microparticule trombocitare la 2 cazuri. Rezultatele noastre evidenţiaza faptul că agregometria plachetară în sânge integral poate fi un instrument valoros în special în identificarea hiperreactivitaţii plachetare şi în predicţia evenimentelor trombotice. Un nivel crescut de microparticule trombocitare poate, de asemenea, să anticipeze apariţia trombozei. Aceste ipoteze necesită evaluare si confirmare pe un număr mai mare de pacienţi.
Cette thèse présente l'étude de la dynamique d'un atome ou d'une molécule en interaction avec un agrégat en vue d'étudier comment un petit système (l'atome, la molécule) échange de l'énergie ...électronique, cinétique et vibrationnelle avec un système possédant de très nombreux degrés de liberté (l'agrégat).Le premier système est l'étude, expérimentale et théorique, de la dynamique en temps réel d'un atome de baryum déposé sur agrégat d'argon (BaArn). L'atome de baryum est excité dans des niveaux de Rydberg, il en résulte une dynamique extrêmement riche entre le chromophore et l'agrégat. L'interprétation théorique a nécessité la conception d'une méthode de dynamique originale, permettant de traiter à la fois le grand nombre d'états excités mis en jeu, couplés à de nombreux degrés de libertés atomiques. La mise en commun des informations théoriques et expérimentales a permis d'établir l'ensemble du chemin réactionnel ayant lieu au cours de cette dynamique.Le deuxième système concerne l'étude par fluorescence de la photo-dissociation de Ca2 déposé sur agrégat d'hélium ou sur agrégat mixte hélium-argon (Ca2Hen ou Ca2ArmHen). Ces résultats sont comparés à ceux obtenu sur agrégat d'argon pur (Ca2Hen). Les différences entre ces trois types de solvant montrent que les interactions sont différentes suivant que le solvant est ``quantique'' (l'hélium) ou ``classique'' (l'argon). Plusieurs canaux réactionnels ont été mis en évidence selon que l'atome de calcium excité qui résulte de la photo-dissociation est libre ou reste solvaté par de l'hélium et/ou de l'argon. Les rapports de branchement entre ces différents canaux ont également été mesurés.
The dynamics of the interaction of an atom or a molecule with a large cluster has been studied in this manuscript in view of characterising the exchange of electronic vibrational and kinetic energy between a small system with another having a large number of degrees of freedom, the cluster.We have first studied experimentally and theoretically, the real time dynamicsof a barium atom deposited on argon clusters , (BaArn). The Ba atom was excited in high Rydberg states. A rich dynamics ensues between the chromophore an the cluster. For the theoretical interpretation a new method has been developed. It its designed to take into account the large number of electronically accessed states and their coupling with the numerous nuclear degrees of freedom of the atomic movements. The combination of the experimental and theoretical informations has allowed the characterisation of a reaction path for these dynamics. The second system studied is the photodissociation of the Ca2 molecule deposited on helium clusters pure or doped with argon (Ca2Hen or Ca2ArmHen), fluorescence emission. A comparison is also made with the Ca2Hen system. Important differences appear depending upon the nature of the solvating medium be it quantal (helium) or classical (argon). Several reaction channels have been characterised and measured for the formation of the resulting calcium atom in helium or argon solvating media.
L'étude de cette thèse est focalisée sur la compréhension des caractéristiques du transport dans des systèmes granulaires cœur - coquille (cobalt - cobalt oxyde). Nous avons étudié le comportement ...magnétique et de transport de notre système granulaire ferromagnétique/antiferromagnétique. Les agrégats de cobalt de 4 nm sont fabriqués par une source à pulvérisation magnétron et condensation en phase vapeur. Lorsque les agrégats sont oxydés pendant le dépôt ils adoptent une géométrie en cœur – coquille avec un cœur icosaédrique et une coquille CoO de structure cfc. Après le dépôt, les agrégats sont caractérisés par différentes méthodes. In situ, elles sont caractérisées en fonction de la quantité déposée par le spectromètre à temps vol. Ex situ, elles sont analysées par le SQUID (mesure magnétique) et par les mesures de transport. Plusieurs caractéristiques de nos échantillons ont été mises en évidence lors de l'analyse magnétique. Trois propriétés magnétiques nous intéressent principalement. La première est le couplage d'échange F/AF, étudié sur l'ensemble des agrégats de cobalt avec différents pourcentages d'oxydation (entre 33% de CoO et 95% de CoO). Nous avons constaté que l'effet maximum est obtenu pour l'échantillon le plus oxydé à cause de l'augmentation de la coquille d'oxyde. La deuxième propriété magnétique concerne la présence d'un superparamagnétisme modifié par l'interaction d'échange entre le cœur et la coquille. La troisième est l'effet de traînage qui se manifeste le plus souvent par une diminution du décalage d'échange et du champ coercitif après plusieurs mesures successives. Ce phénomène est dû à une instabilité de la configuration magnétique obtenue lors du refroidissement sous champ mais il est cependant difficile d'identifier l'origine exacte. Les propriétés de transport de notre système sont mises en évidence par l'étude de la résistivité, de la magnétorésistance et de la résistance du Hall en fonction de la température et du champ magnétique appliqué. La variation de la résistivité avec la température présente un minimum et qu'elle varie très peu avec la température. Ce comportent est typique des systèmes transitoires, se situant entre le régime métallique et le régime isolant. La faible magnétorésistance varie très peu avec la température. Son amplitude ne dépasse pas 0.1% dans tous les alliages granulaires mesurés. Le système étudié est caractérisé par une résistivité de Hall extraordinaire positive à toutes les températures de mesure.
This study is focused on understanding the transport properties of granular systems core - shell with emphasis on cobalt - cobalt oxide materials. We studied the magnetic and transport behavior of our granular system ferromagnetic/ antiferromagnetic. The cobalt clusters of 4 nm are obtained by a magnetron sputtering source and vapor phase condensation. The clusters oxidized during deposition adopt a core – shell geometry with icosahedra core and a fcc structure of CoO shell. After deposition, the clusters are characterized by different methods. In situ, they are characterized in terms of the amount of matter deposited by time flight spectrometer. Ex situ, they are analyzed by the SQUID (magnetic measurement) and transport measurements. Several characteristics of our samples have been identified during the magnetic analyses. Three magnetic properties are mainly interest. The first is the exchange bias F/AF, studied on the cobalt clusters with different oxidation percentages (between 33%CoO and 95% of CoO). We found that the maximum effect is obtained for the the oxidized samples due to the increased oxide shell size. The second magnetic property is the presence of superparamagnetism modified by the exchange interaction between the core and the shell. The third is the training effect shown often by a decrease in the exchange bias and coercive field after several successive measurements. This might be attributed to the instability of the magnetic configuration obtained upon cooling under a field, but it is difficult to identify the exact origin. The transport properties of our system are underlined by the study of the resistivity, magnetoresistance and Hall resistance as a function of temperature and applied magnetic field. The variation of resistivity with temperature shows a minimum. In the same time this variation is small as a function of the temperature. This behavior is associated with the transition systems which are found between the metallic and insulator regime. The variation of the magnetoresistance with temperature is small. Its amplitude does not exceed 0.1% in all granular alloys measured. The studied system is characterized by a positive extraordinary Hall resistivity at all temperatures of measurement.
Nicolae Ceaușescu, Chivu Stoica și Ilie Verdeț fac o vizită de lucru la Uzinele 23 August, în Fabrica de mașini unelte București, la Uzinele Grivița Roșie și la Întreprinderea Textilă Dacia. Nicolae ...Ceaușescu recomandă folosirea rațională a spațiilor de lucru, atingerea nivelului producției mai devreme. Colectivele își exprimă dorința fermă de a transpune în viață directivele conducerii de partid și de stat.
În comuna Scânteia, raionul Slobozia, a început recoltatul ogoarelor; În București are loc faza a III-a a concursului brutarilor. Lichstein Adolf din Oradea și brigada sa prepară specialități. Maxim ...Petre execută colaci cu lapte, pâine dietetică, pâine cu
Imagini din URSS de la construcția hidrocentralei de pe Angara; În Anglia au loc demonstrații de solidaritate cu poporul cubanez în fața ambasadei SUA; În Japonia are loc o demonstrație împotriva ...trupelor americane. Imagini cu baza aviatică de la Yokota;
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