Craniofacial changes in patients with skeletal class II treated with appliance with screws for mesial shift of the lower jaw

Uvod. Biološki najprihvatljivija metoda lečenja druge klase je modifikacija rasta funkcionalnim aparatima. Aparat sa zavrtnjem za mezijalno usmeravanje donje vilice (M blok) zahvaljujući svojoj konstrukciji ima osobine i funkcionalnog i aktivnog ortodontskog aparata. Cilj rada. Cilj istraživanja bio je utvrđivanje skeletnih i dentoalveolarnih promena, kao i promena na mekotkivnom profilu nakon terapije M blokom u poređenju sa Frankel-ovim regulatorom funkcije tip I i bionatorom po Balters-u tip I. Metode rada. Istraživanjem je obuhvaćeno 70 pacijenata podeljenih u 3 grupe prema vrsti korišćenog aparata (M blok, Frankel-ov regulator funkcije tip I, bionator po Balters-u tip I). Pre terapije svakom od pacijenata uzeta je anamneza i urađen klinički pregled. Pre početka, kao i na kraju terapije, urađen je ortopantomografski i profilni teleradiografski snimak i uzeti su otisci za studijske modele. Na kraju terapije analizirane su promene u položaju i razvijenosti kako gornje, tako i donje vilice, međuviličnih odnosa, promene na kranijalnoj bazi i mekotkivnom profilu lica, kao i promene u položaju sekutića iTMZ-a. Rezultati. Statistički značajne razlike dobijene su prilikom korišćenja M bloka u analizama razvijenosti i položaja gornje vilice i donje vilice, međuviličnih uglova, dužine prednje i zadnje kranijalne baze, pravca rasta lica, dužine prednje i zadnje visine lica, položaja gornje usne u odnosu na estetsku liniju i položaja gornjih i donjih sekutića i TMZ-a. Zaključak. M blok dovodi do preusmeravanja položaja gornje i donje vilice i korekcije II klase u I.Introduction. Biological most appropriate method of treatment class II is a modification of the growth with functional appliances. The machine screw in the mesial direction of the mandible (M block) due to design has features of both functional and active orthodontic appliances. Objective. The aim of the study was to evaluate the skeletal and dentoalveolar changes as well as changes in soft tissue profile after treatment with M block compared with Frankel's function regulator type I and Balters’ bionator type I. Methods. The study included 70 patients divided into 3 groups according to the type of device used (M block, Frankel's function regulator type I, Balters’ bionator type I). Before the therapy each patient's medical history was taken and the clinical examination was performed. At the beginning of the therapy orthopantomographic and profile cephalograph were shot and impressions were taken for study models. At the end of treatment, the changes in the position and development of both the upper and lower jaw, intermaxillary relationships, changes in the cranial base and soft tissue facial profile, as well as changes in the position of the incisors and TMJ. Results. Statistically significant differences were found when using the M block in the analysis of the development and position of the maxilla and mandible, intermaxillary angles, length of anterior and posterior cranial base, the direction of facial growth, length of anterior and posterior face height, the position of the upper lip in relation to the aesthetic line and position of the upper and lower incisors and TMJ. Conclusion. M block leads to redirection of the position of the upper and lower jaw and corrections of class II into class I

Oxidative stress is reduced in Wistar rats exposed to smoke from tobacco and treated with specific broad-band pulse electromagnetic fields

There have been a number of attempts to reduce the oxidative radical burden of tobacco. A recently patented technology, pulse electromagnetic technology, has been shown to induce differential action of treated tobacco products versus untreated products on the production of reactive oxygen species (ROS) in vivo. In a 90-day respiratory toxicity study, Wistar rats were exposed to cigarette smoke from processed and unprocessed tobacco and biomarkers of oxidative stress were compared with pathohistological analysis of rat lungs. Superoxide dismutase (SOD) activity was decreased in a dose-dependent manner to 81% in rats exposed to smoke from normal cigarettes compared to rats exposed to treated smoke or the control group. These results correspond to pathohistological analysis of rat lungs, in which those rats exposed to untreated smoke developed initial signs of emphysema, while rats exposed to treated smoke showed no pathology, as in the control group. The promise of inducing an improved health status in humans exposed to smoke from treated cigarettes merits further investigation

Influence of mechanical activation on MgO-TiO2 system

Poster presented at the 10th Conference of the Materials Research Society of Serbia - YUCOMAT 2008, Herceg Novi, Montenegro, September 8-12, 200

The tribological performance of hardfaced/ thermal sprayed coatings for increasing the wear resistance of ventilation mill working parts

During the coal pulverizing, the working parts of the ventilation mill are being worn by the sand particles. For this reason, the working parts are usually protected with materials resistant to wear (hardfaced/thermal sprayed coatings). The aim of this study was to evaluate the tribological performance of four different types of coatings as candidates for wear protection of the mill’s working parts. The coatings were produced by using the filler materials with the following nominal chemical composition: NiFeBSi-WC, NiCrBSiC, FeCrCTiSi, and FeCrNiCSiBMn, and by using the plasma arc welding and flame and electric arc spraying processes. The results showed that Ni-based coatings exhibited higher wear resistance than Fe-based coatings. The highest wear resistance showed coating produced by using the NiFeBSi-WC filler material and plasma transferred arc welding deposition process. The hardness was not the only characteristic that affected the wear resistance. In this context, the wear rate of NiFeBSi-WC coating was not in correlation with its hardness, in contrast to other coatings. The different wear performance of NiFeBSi-WC coating was attributed to the different type and morphological features of the reinforcing particles (WC)

Structural characterization of mechanically activated MgO-TiO2 system

In this article the influence of ball miling process on structure of MgO-TiO2 system was investigated. The mixtures of MgO-TiO2 powders were mechanically activated in a planetary ball mill for the time period from 0 to 120 minutes. The influence of mechanical activation on the lattice vibrational spectra was studied by Raman spectroscopy at room temperature. Structural investigations have been performed on produced powders. Nitrogen adsorption method was used to determine the BET specific surface area and pore size distribution. Unusual results have been obtained: specific surface area continuously decreased up to 40 minutes of activation and increased after that, reaching its minimun value of 5.5 m2/g. The Raman spectra of activated powders have shown that anatase modes have been decreasing in intensity and broadening as the time of activation extended. Also, the additional modes attributed to TiO2 II, srilankite and rutile phases started to appear as a consequence of activation

The Influence of Mechanical Activation on Sintering Process of BaCO3-SrCO3-TiO2 System

In this article the influence of mechanical activation on sintering process of barium-strontiumtitanate ceramics has been investigated. Both non-activated and mixtures treated in planetary ball mill for 5, 10, 20, 40, 80 and 120 minutes were sintered at 1100-1400 °C for 2 hours in air atmosphere. The influence of mechanical activation on phase composition and crystal structure has been analyzed by XRD, while the effect of activation and sintering process on microstructure was investigated by scanning electron microscopy. It has been established that temperature of 1100 °C was to low to induce final sintering stage for the system. Electrical measurements have been conducted for the densest ceramics sintered at 1400 °C for 2 hours

Microstructure evolution and sintering kinetics of ZnO

The aim of this work was to analyse the kinetics and microstructure evolution of ZnO sintering process. ZnO powder was isothermally sintered (15, 30, 60, 90 and 120 min) in the temperature range from 8000C to 12000C. The values of Lenel parameter were calculated and used for the analysis of the densification and mass transport processes. Using scanning electron microscopy the analysis of the microstructure evolution and dependence of the average grain size with temperature and time of sintering was obtained. The results of this research could enable development of a new phenomenological equations in the analyses of ZnO-based materials sintering kinetics

Torrential floods and town and country planning in Serbia

Torrential floods are the most frequent natural catastrophic events in Serbia, causing the loss of human lives and huge material damage, both in urban and rural areas. The analysis of the intra-annual distribution of maximal discharges aided in noticing that torrential floods have a seasonal character. The erosion and torrent control works (ETCWs) in Serbia began at the end of the 19th century. Effective protection from torrential floods encompasses biotechnical works on the slopes in the watershed and technical works on the torrent beds, within a precisely defined administrative and spatial framework in order to achieve maximal safety for people and their property. Cooperation to overcome the conflicts between the sectors of the water resources management, forestry, agriculture, energetics, environmental protection and local economic development groups is indispensable at the following levels: policy, spatial planning, practice, investments and education. The lowest and most effective level is through the Plans for Announcement of Erosive Regions (PAERs) and the Plans for Protection from Torrential Floods (PPTFs), with Hazard Zones (HZs) and Threatened Areas (TAs) mapping on the basis of the hydrologic, hydraulic and spatial analysis of the factors that are important for the formation of torrential floods. Solutions defined through PAERs and PPTFs have to be integrated into Spatial Plans at local and regional levels

Analysis of early-stage sintering mechanisms of mechanically activated BaTiO3

Prah barijum-titanata je mehanički aktiviran u planetarnom mlinu sa kuglicama 60 i 120 minuta. Neizotermsko sinterovanje neaktiviranog i aktiviranih uzoraka proučeno je u dilatometru u temperaturskom intervalu od sobne do 1380oS sa tri različite brzine zagrevanja (10, 20 i 30oS/min). Mehanizmi ranih stadijuma sinterovanja su analizirani za sva tri tipa uzoraka i uočene su značajne razlike između neaktiviranih i mehanički aktiviranih uzoraka.Barium-titanate powder was mechanically activated in a planetary-ball mill for 60 and 120 minutes. Non-isothermal sintering of non-activated and activated powder samples was investigated using a dilatometer in the temperature interval from room to 1380oC with three different heating rates (10, 20 and 30oC/min). Early-stage sintering mechanisms for all three types of samples were analyzed, showing significant differences between the non-activated and mechanically activated samples

Structural and Electrical Properties of Sintered Barium-Zinc-Titanate Ceramics

The aim of this work was an investigation of structural and electrical properties of sintered barium-zinc-titanate ceramics. Mixtures of BaCO3, ZnO and TiO2 were mechanically activated in a planetary ball mill up to 80 minutes and sintered isothermally in air for 120 minutes at 1300°C. The phase composition in the BaCO3-ZnO-TiO2 system after milling and sintering was analyzed using the XRD method. The existence of pure barium-zinc-titanate has been registered. Microstructure analyses were performed using SEM. The results of electric resistivity, capacitance and loss tangent of the sintered samples were correlated with the XRD and SEM results.\ud PACS numbers: 81.20.Wk, 81.20.Ev, 61.05.C-, 84.37.+