103 research outputs found
Pukotine na valjkastom ležaju
Bearings are among the most important components of electromotors, pumps, compressors and other processing equipment. After 30 years of work some non-destructive and metallographic examinations were carried out on a single-row cylindrical roller-bearing. A non-destructive liquid-penetrant testing revealed crack indications on an inner ring groove. When a sample of the roller-bearing outer ring was cut out for metallographic examination, new cracks were discovered that were not detected by the non-destructive testing. However, with the examination of the non-failed bearing it is possible to obtain useful information that can help us to decide how much of the remaining population of bearings with the same geometry and loading should be examined.Ležajevi su veoma znaÄajne komponente elektromotora, crpki, kompresora i ostale procesne opreme. Na jednorednom valjkastom cilindriÄnom ležaju, koji je bio u pogonu 30 godina bile su izvedene kontrole bez razaranja i metalografska kontrola. Sa metodom tekuÄih pentranata su se otkrile indikacije pukotina u žlijebu unutraÅ”njeg prstena. Kada je bio iz vanjskog prstena uzet uzorak za metalografsko ispitivanje otkrivene su bile nove pukotine, koje nisu bile detektirane kontrolom bez razaranja. Sa ispitivanjem ležaja koji nije otkazao tako je moguÄe dobiti korisne informacije, koje nam mogu pomoÄi o odluci koliki Äe biti broj ispitanih ležajeva izmeÄu ostale populacije s jednakom geometrijom i optereÄenjem
Registration of buldings in real-estate register
The goal of the diploma paper was to present the participants the process regarding the real- estate registration, namely from the recording a building in land register, recording a bulding into property register to recording a building into a cadastre. The diploma paper presents the problem- solving during the period of last ten years, which has brought along many changes to the newly developed real-estate register. Simultaneously the real-estate registers have also been change and suplemented. New changes always cause to solve past problems and at the same time open door for new problems and knowledge. The result of the diploma paper is shown in the awareness of real-estate owners and their trustees, and finally in the legislation, which should in case of owners' inactivity tend to the currency of land survey register
Photogrammetric capture and data processing for generating a 3D model of a traffic accident scene
Photogrammetry is a science, used in many different areas. In this thesis, its application in documentation of traffic accidents is presented, where a 3D model of the scene is generated from photos. The working process includes surveying measurements, taking photos of the calibration field and the traffic accident scene, photogrammetric measurements and generation of a 3D model. The first part introduces the theory about this area and presents the experience about this work in Slovenia and around the world. Briefly is presented also the use of terrestrial laser scanning, by means of examples. The thesis is mostly about the presentation and description of field work and phases for creating the final three-dimensional model of a traffic accident scene. There is also a detailed description of work, done in the PhotoModeler program, which I used in my practical example
Alternativni modeli ispitivanja toksiÄnosti ksenobiotika
The alternatives to whole-animal testing include endpoint assays, cell and tissue cultures, use of tissue slices, toxicokinetic modelling, and structure-activity relationships and databases. The use of in vitro systems (subcellular fractions, cell lines, primary cell cultures, tissue slices, organ cultures, etc.) as research tools in toxicology is widespread. In the past few years, the apoptosis phenomena were followed by very precise intracellular changes where, through programmed cell death, a cell can be removed from a population. The in vitro systems are ideally suited for investigations of the molecular, cellular and physiological mechanisms of chemically induced toxicity, which cannot readily be studied in vivo for known target organ and target species toxicity studies and for answering specific questions about toxic effects. The main justification for developing in vitro toxicity tests is that they will make toxicology a more scientifically based practice. It is increasingly apparent that the development and incorporation of stepwise testing strategies, combining experimental data from a range of alternative methods (physicochemical techniques, quantitative structure-activity relationships - QSAR, metabolic and kinetic modelling and in vitro tests), provide the most advanced way to predict toxicity, reducing at the same time the number of laboratory animals used for testing.Alternativni sustavi ispitivanja toksiÄnosti na životinjama obuhvaÄaju postupke koji ukljuÄuju stanice i kulture, uporabu dijelova tkiva, toksikokinetiÄko modeliranje, kao i odnose aktivnosti prema strukturi ksenobiotika. Uporaba in vitro sustava (staniÄnih frakcija, staniÄnih linija, primarnih staniÄnih kultura, dijelova tkiva, kulture organa itd.) ima Å”iroku primjenu u toksikoloÅ”kim istraživanjima. U posljednjih nekoliko godina fenomen apoptoze može se pratiti prema vrlo preciznim unutarstaniÄnim promjenama te utvrÄena programirana smrt stanice iskoristiti u uklanjanju takvih stanica iz populacije. In vitro sustavi idealno se rabe u istraživanjima molekularnih, staniÄnih i fizioloÅ”kih mehanizama toksiÄnosti izazvanih kemikalijama, dok in vivo studije toksiÄnosti ne mogu dati te odgovore. Glavna potvrda razvoja i praÄenja toksiÄnosti spojeva u in vitro testovima jest znanstvena utemeljenost toksikologije. Razvoj i uvoÄenje strategija testiranja koje primjenjuju kombinaciju eksperimentalnih podataka iz niza alternativnih metoda (fizikalno-kemijske tehnike, QSAR tehnike, metaboliÄko i kinetiÄko modeliranje) omoguÄuje najefikasniju procjenu toksiÄnosti, kao i istodobno smanjenje broja laboratorijskih životinja potrebnih u postupcima testiranja toksiÄnosti spojeva
Molekularni mehanizmi i morfoloŔka obilježja autofagije
Autofagija je evolucijski dobro oÄuvan kataboliÄki proces koji se dogaÄa u svim eukariotskim stanicama, a u kojem stanica razgradnjom oÅ”teÄenih makromolekula i organela, izmeÄu ostalog, osigurava hranjive tvari i energiju za održavanje vitalnih funkcija. Radi održavanja homeostaze, autofagija se na bazalnoj razini odvija neprestano u gotovo svim stanicama. RazliÄiti fizioloÅ”ki podražaji (oÅ”teÄenja organela, nakupljanja proteinskih agregata, hipoksija, oksidacijski stres, upala i dr.) induciraju proces autofagije. Ipak, dokazano je da su nedostatak nutrijenata i energetski stres najsnažniji regulatori procesa autofagije. Pokretanjem autofagije stanice se ābraneā recikliranjem hranjivih sastojaka i/ili razgradnjom oÅ”teÄenih organela. Uslijed prekomjerne eliminacije organela i citoplazmatskog sadržaja, prekomjerne mitofagije (selektivne razgradnje mitohondrija) i posljediÄnog nedostatka energije, aktivacija autofagije može rezultirati i staniÄnom smrÄu (tzv. staniÄna smrt ovisna o autofagiji). Istraživanja su ukazala na važnost autofagije u oÄuvanju zdravlja kod bakterijskih i virusnih infekcija, karcinoma, neurodegenerativnih, metaboliÄkih i upalnih bolesti. Pojam autofagije najÄeÅ”Äe se odnosi na najviÅ”e istražen oblik autofagije - makroautofagiju. Osim o tom obliku autofagije, u ovom preglednom radu dan je uvid u mehanizme i obilježja mikroautofagije i autofagije posredovane Å”aperonom (CMA)
Opstati ili umrijeti ā regulacija staniÄne smrti
StaniÄno umiranje je temeljni bioloÅ”ki proces, koji je u fizioloÅ”kom smislu embrionalnoga razvoja i obnove tkiva, te kao patoloÅ”ki odgovor na ozljedu
stanica i infekciju patogenima, ukljuÄen u mehanizme koji kontroliraju razvoj, homeostazu i imunoloÅ”ku regulaciju viÅ”estaniÄnih organizama.
Stanice mogu umrijeti sluÄajnom (bioloÅ”ki nekontrolirani procesi) ili reguliranom (genetski kontrolirani molekularni procesi) staniÄnom smrÄu.
StaniÄna smrt odvija se razliÄitim mehanizmima koji dovode do pojave razliÄitih morfoloÅ”kih promjena u stanicama zahvaÄenim tim procesima.
Nedavna otkriÄa u tom podruÄju i detekcija sve veÄeg broja novih oblika regulirane staniÄne smrti, rezultirala su novom sustavnom klasifikacijom
i nomenklaturom razliÄitih tipova staniÄne smrti. U ovom preglednom radu dan je uvid u sustav klasifikacije, mehanizme i obilježja glavnih tipova
staniÄne smrti: nekroze, apoptoze i autofagije
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