Conditions for dynamic balance of a rigid body with heavy foot

Opisan je model krutog tela i teškog stopala spojenih obrtnim zglobom u konstantnom gravitacionom polju. Kruto telo se kreće u vertikalnoj ravni, dok teško stopalo leži na ravnoj, vrlo hrapavoj horizontalnoj podlozi. Uslovi za dinamički balans ovog sistema matematički su izraženi koristeći metodu tačke nula momenta. Pokazuje se da oni određuju oblast u faznom prostoru u kojoj stanje sistema treba da bude da bi se dinamički balans sistema održao. Takođe se pogodnom simulacijom kretanja sistema u dinamičkom balansu pokazuje da ovi uslovi nisu dovoljni da sistem održi uspravan stav, već da su u vezi s njegovom upravljivošću. Ukratko se razmatra koji su neophodni uslovi da bi ovaj sistem u dinamičkom balansu zadržao uspravan stav.The model of a rigid body and heavy foot joined by the revolute joint in the constant gravitational field is described. The rigid body moves in the vertical plane, whereas the heavy foot lies on the flat, very rough horizontal support. Conditions for the dynamic balance of this system are mathematically expressed by using the ZMP method. It is shown that they determine an area in the phase space in which the state of the system should be in order that its dynamic balance is kept. It is also shown by appropriate simulations of motion of the system in the dynamic balance that these conditions are not sufficient for the system to keep its upright posture, but are in connection with its controllability. It is briefly discussed what are the necessary conditions for this system in dynamic balance to keep its upright posture

Conditions for dynamic balance of a rigid body with heavy foot

Opisan je model krutog tela i teškog stopala spojenih obrtnim zglobom u konstantnom gravitacionom polju. Kruto telo se kreće u vertikalnoj ravni, dok teško stopalo leži na ravnoj, vrlo hrapavoj horizontalnoj podlozi. Uslovi za dinamički balans ovog sistema matematički su izraženi koristeći metodu tačke nula momenta. Pokazuje se da oni određuju oblast u faznom prostoru u kojoj stanje sistema treba da bude da bi se dinamički balans sistema održao. Takođe se pogodnom simulacijom kretanja sistema u dinamičkom balansu pokazuje da ovi uslovi nisu dovoljni da sistem održi uspravan stav, već da su u vezi s njegovom upravljivošću. Ukratko se razmatra koji su neophodni uslovi da bi ovaj sistem u dinamičkom balansu zadržao uspravan stav.The model of a rigid body and heavy foot joined by the revolute joint in the constant gravitational field is described. The rigid body moves in the vertical plane, whereas the heavy foot lies on the flat, very rough horizontal support. Conditions for the dynamic balance of this system are mathematically expressed by using the ZMP method. It is shown that they determine an area in the phase space in which the state of the system should be in order that its dynamic balance is kept. It is also shown by appropriate simulations of motion of the system in the dynamic balance that these conditions are not sufficient for the system to keep its upright posture, but are in connection with its controllability. It is briefly discussed what are the necessary conditions for this system in dynamic balance to keep its upright posture

In-vitro ispitivanje karakteristika matičnosti ćelija poreklom od oralnog planocelularnog karcinoma

CSC) are accountable for tumour initiation, progression and metastasis. Until now, studies were focused exclusively on the characterization of these cell populations within the tumour itself, while tumour margins were neglected, although it is known that the histological and molecular status of tumour margins may play a significant role in the course of the disease. In the present study tumor and margin cell cultures obtained from patients with oral squamous cell carcinoma were used to determine the expression patterns in the course of time, of CSC-related markers (CD44, CD133, Oct-4, Sox2, Nanog), epithelial to mesenchymal transition (EMT)-related markers (Vimentin, αSMA, SLUG and SNAIL), and features, i.e. the clonal, proliferative and migratory potential of the two types of cells. The aims of the study were to isolate cells from oral squamous cell carcinomas and their respective margins, to characterize these cells using CSC/EMT markers, to assess their self-renewal, proliferation and migration potential and determine their chemoresistance. Cell cultures were obtained from 12 tissue specimens (6 tumors and 6 margins). Total RNA was extracted and gene expression analysis was done by real-time PCR. Flow cytometry, immunocytometry, immunohistochemistry, Raman micro-spectroscopy, sphere formation, cell proliferation, colony forming, scratch wound healing and MTT assays were conducted to fully characterize the two cell types. With minor differences, cells originating from both tumors and tumor margins showed the presence of stem cell markers CD133, Nanog, Sox2, CD44, and Oct-4, had the capacity to form spheroids and showed chemoresistance/sensitivity. All the studied EMT markers were expressed in both tumor and margin cells, without statistically significant difference (p>0.05). With few exceptions, for both EMT and CSC markers, the expression was higher in the 5th passage compared to the 1st, probably as the consequence of culture enrichment with CSC in the course of time...oviji podaci ukazuju na postojanje male subpopulacije kancerskih matičnih ćelija (KMĆ) koje su odgovorne za inicijaciju, progresiju i metastaziranje tumora. Do sada, su studije bile fokusirane isključivo na karakterizaciju ovih ćelijskih populacija unutar samog tumora, dok su margine tumora bile zanemarene, iako je poznato da histološki i molekularni status margina tumora može imati značajnu ulogu u toku bolesti. U ovoj studiji, primarne kulture ćelija tumora i margina dobijenih od pacijenata sa oralnim planocelularnim karcinomom su korišćene za ispitivanje ekspresije markera povezanih sa KMĆ (CD44, CD133, Oct-4, Sox2, Nanog), markera epitelno mezenhimske tranzicije (EMT) (E-kadherin, N-kadherin, Vimentin, ɑSMA, SLUG i SNAIL), a ispitivan je i klonalni, proliferativni i migracijski potencijal ova dva tipa ćelija. Stoga su ciljevi ove studije bili da se izoluju ćelije oralnog planocelularnog karcinoma i njegovih margina, uspostave primarne ćelijske kulture i ispitaju populacije ćelija sa karakteristikama kancerske matičnosti. Ćelijske kulture su dobijene iz 12 uzoraka tkiva (6 tumora i 6 margina). RNK je ekstrahovana i analiza ekspresije gena je urađena pomoću lančane reakcije polimeraze u realnom vremenu. Korišćene su i protočna citometrija, imunocitohemija, imunohistohemija, Raman mikro- spektroskopija, testovi formiranja sfera, ćelijske proliferacije, formiranja kolonija, migracije i MTT test citotoksičnosti, kako bi se u potpunosti okarakterisala ova dva tipa ćelija. Sa manjim odstupanjima, ćelije koje potiču od tumora i ćelije poreklom od margine pokazale su prisustvo markera matičnih ćelija CD133, Nanog, Sox2, CD44 i Oct-4, imale su sposobnost da formiraju sferoide i pokazale su hemorezistenciju. Takođe, svi ispitivani EMT markeri kao dodatni dokaz kancerske matičnosti, bili su eksprimirani u tumorskim i ćelijama margine, bez statistički značajne razlike (p> 0,05). Uz nekoliko izuzetaka, ekspresija EMT i KMĆ markera je bila viša u petoj pasaži u poređenju sa prvom, što bi moglo da se tumači obogaćenjem ćelijskih kultura subpopulacijom KMĆ tokom vremena..

Dosimetry audit in radiotherapy centers in Serbia in 2013

U radu su predstavljeni rezultati provere apsorbovanih doza u vodi za Co-60 i visokoenergetske snopove fotona na linearnim akceleratorima postignute u radioterapijskim ustanovama u Srbiji u sklopu Programa IAEA/WHO TLD postal dose quality audit. Program je sproveden u februaru 2013. godine preko koordinatora za Srbiju – SSDL INN Vinča, Laboratorija „Zaštita“. U Programu su učestvovali radioterapijski centri iz Beograda, Sremske Kamenice, Kragujevca, Niša i Kladova. Program ima za cilj da se prati i po potrebi vrši revizija dozimetrijskih procedura u radioterapiji za procenu pacijentnih doza.The purpose of this paper is to present the results of TLD absorbed doses in water for Co-60 and high-energy photon beams on linacs in radiotherapy centers in Serbia in the framework of the IAEA/WHO TLD Postal Dose Quality Audit Program. This program was carried out in February 2013, coordinated by SSDL INN Vinča Laboratory for Radiation Protection - country coordinator for Serbia. Radiotherapy centers from Belgrade, Sremska Kamenica, Kragujevac, Nis and Kladovo took part in this program. The aim of the program is to follow and, if needed, audit dosimetry procedures for estimation of patient dose in radiotherapy treatment.XXVII Simpozijum Društva za zaštitu od zračenja Srbije i Crne Gore, Tara, 12-14. oktobar 2011

Data driven model for prediction of rail traffic

The rail system, as a system with high capacity, the least air and water pollution, solvable noise and vibration emission problem and the least space usage, is competitive with other modes of transportation. In addition, European transport policy supports shift from road to rail and waterborne transport. It is expected that changes in rail traffic volume be followed by changes in certain economic parameters. On the other hand, changes in economy influence rail traffic volume. The aim of this paper is creation of the data driven models for prediction of rail traffic volume in different economic contexts, using world development indicators, defined by the World Bank, as input parameters

Analysis and optimization of underactuated finger for CMSysLab robotic hand

In this paper is presented mathematical analysis of 3-DOF underactuated robotic finger with linkage driven mechanism. The optimization procedure is described for obtaining optimal parameters of four bar mechanism. As results, the adaptability of the finger is improved and the grasping forces maximized within the working area limits

Rendgen-kefalometrijska analiza pozicije kondila nakon bimaksilarne osteotomije mandibularnog prognatizma

Background/Aim. Postoperative condylar position is a substantial concern in surgical correction of mandibular prognathism. Orthognathic surgery may change condylar position and this is considered a contributing factor for early skeletal relapse and the induction of temporomandibular disorders. The purpose of this study was to evaluate changes in condylar position, and to correlate angular skeletal measurements following bimaxillary surgery. Methods. On profile teleradiographs of 21 patients with mandibular angular and linear parametres, the changes in condylar position, were measured during preoperative orthodontic treatment and 6 months after the surgical treatment. Results. A statistically significant difference in values between the groups was found. The most distal point on the head of condyle point (DI) moved backward for 1.38 mm (p = 0.02), and the point of center of collum mandibulae point (DC) moved backward for 1.52 mm (p = 0.007). The amount of upward movement of the point DI was 1.62 mm (p = 0.04). Conclusion. In the patients with mandibular prognathism, the condyles tend to migrate upward and forward six months after bimaxillary surgery.Uvod/Cilj. Postoperativna pozicija kondila je značajna za hiruršku korekciju mandibularnog prognatizma. Ortognatska hirurgija može da promeni poziciju kondila, a to može biti jedan od faktora koji doprinosi ranom skeletnom recidivu i pojavi temporomandibularnih disfunkcija. Zbog toga je cilj ove studije bio da proceni promene pozicije kondila kao i da ne korelišu promene pozicije kondila sa angularnim skeletnim promenama nakon bimaksilarne hirurgije. Metode. Na telerendgenskim snimcima 21 bolesnika sa mandibularnim prognatizmom mereni su angularni i linearni parametri koji opisuju promene u položaju kondila, pre ortodontske pripreme i šest meseci nakon hirurške korekcije. Rezultati. Ustanovljena je statistička značajnost razlika u vrednosti parametara između grupa. Tačka DI - najdistalnija tačka na glavi kondila, pomerila se unazad 1,38 mm (p = 0,02), a tačka DC - tačka koja označava centar collum mandibulae, pomerila se, takođe, unazad za 1,52 mm (p = 0,007). Vrednost pomeranja tačke DI naviše bila je 1,62 mm (p = 0,04). Zaključak. Kod bolesnika sa mandibularnim prognatizmom, kondili su težili da migriraju unapred i naviše šest meseci nakon bimaksilarne operacije

Build-Up PMMA Plate Effect on Calibration of TLD Reader

The routine monitoring of the occupationally exposed individuals constitutes an integral part of radiation protection program implemented at the Vinca Institute of Nuclear Sciences (INNV). The Individual monitoring service (IMS) at the INNV, accredited according to quality standard EN ISO/IEC 17025, is using Harshaw 6600 Plus automatic reader and thermoluminescent dosimeters (TLD) from two manufacturers (Harshaw, RadPro international GmbH). Working procedures are implemented according to Technical Recommendations for Monitoring Individuals Occupationally Exposed to External Radiation, RP 160 (European Commission, 2009). Among general consideration, RP 160 is suggesting that routine calibration of dosimetry system should be performed taking into consideration secondary charged particle equilibrium. As TLD system in use at IMS INNV comprises of TLD reader and of TLD cards, this consideration should be applied in both cases: when the reader and the TLD cards are being calibrated. During reader calibration, secondary charged particle equilibrium can be ensured using build-up PMMA plate of certain thickness placed in front of dosimeters. In this paper, influence of the build-up plate on reader calibration is being analyzed. This influence is observed through changes in reader calibration factor (RCF). RCF values obtained during reader calibration procedure with and without 2 mm thick build-up plate are presented. Exposures of whole body TLDs placed on slab phantom were done with Cs-137 radiation source located at Secondary Standard Dosimetry Laboratory (SSDL) at INNV. TLDs from both manufacturers had 2 detectors for measuring the dose equivalent at the depths of 10 mm and 0.07 mm. TLD reader was calibrated to measure effective dose in terms of Hp(10) and local skin dose in terms of Hp(0.07). RCF values for detectors measuring Hp(10), from both manufacturers, when irradiated without the plate were around 5% higher than RCF values obtained when irradiations were done with the plate. Values of RCFs for detectors measuring Hp(0.07) were around 1% higher when the plate had not been used. As RCF value is inversely proportional to measured dose, reader calibration without build-up plate, in terms of Hp(10), would lead to underestimated dose values. The observed RCF deviation of Hp(0.07) detector is regarded as consequence of exposure conditions uncertainties. In conclusion, if a constant geometry and constant operational conditions of TLDs are achieved, the only part of the TLD system that is not stable for a long time period is the TLD reader. To avoid inaccurate results, RCF should be orderly checked and reader calibration should be done according to widely accepted standards, currently in effect.3rd International Conference on Radiation and Applications in Various Fields of Research (RAD), Jun 08-12, 2015, Budva, Montenegr

Income convergence between Southeast Europe and the European Union

Ovaj rad analizira prosječnu bruto per capita dohodovnu konvergenciju osam zemalja Jugoistočne Evrope (JIE) prema prosjeku EU-a. Cilj je utvrditi koji faktori doprinose konvergenciji zemalja JIE regije kao i opisati kretanje konvergencije u periodu 2000.-2018. godine, s posebnom pozornošću na dva pod perioda, prije i nakon Svjetske ekonomke krize. Koristimo pri tome kombinaciju parametarskih i neparametarskih metoda i linearne panel regresije fiksnih efekata s robusnim standardnim greškama. Rezultati sugeriraju da je konvergencija bila podstaknuta procesom EU integracija, obrazovnim nivoom stanovništva, investicijama (stranim, domaćim i javnim), kreditnom ekspanzijom u privatnom sektoru, kao i rastom javnih rashoda. S druge strane, ekonomska kriza, nezaposlenost i inflacija bili su glavni faktori koji su utjecali na divergenciju procesa. Zaključujemo na kraju i da je post-tranzicijski model rasta dominantan u regiji SEE, temeljen na stranim direktnim investicijama, nedovoljan, i da su domaće privatne investicije kritično-nedostajući faktor brže dohodovne konvergencije.This paper investigates the average gross per capita income convergence of eight Southeast European economies towards the EU average. Our goal is to analyse which factors have driven that convergence in the SEE region and describe convergence paths in the 2000-2018 period, concerning two sub-periods, before and after the economic crisis. We use a combination of parametric and nonparametric methods and a fixed effects linear panel regression with robust standard errors. Results suggest that the EU integration process drove convergence, education level, investment (FDI, private domestic and public investments), and private sector lending, as well as by government expenditures. Economic crisis, unemployment, and inflation were the main factors which have influenced the divergence process. We also concluded that the post-transition growth model dominant in the SEE region, based on an FDI inflow, has not sufficient for income convergence in this region. Private domestic investments are a critical missing factor for faster income convergence

Build-Up PMMA Plate Effect on Calibration of TLD Reader

The routine monitoring of the occupationally exposed individuals constitutes an integral part of radiation protection program implemented at the Vinca Institute of Nuclear Sciences (INNV). The Individual monitoring service (IMS) at the INNV, accredited according to quality standard EN ISO/IEC 17025, is using Harshaw 6600 Plus automatic reader and thermoluminescent dosimeters (TLD) from two manufacturers (Harshaw, RadPro international GmbH). Working procedures are implemented according to Technical Recommendations for Monitoring Individuals Occupationally Exposed to External Radiation, RP 160 (European Commission, 2009). Among general consideration, RP 160 is suggesting that routine calibration of dosimetry system should be performed taking into consideration secondary charged particle equilibrium. As TLD system in use at IMS INNV comprises of TLD reader and of TLD cards, this consideration should be applied in both cases: when the reader and the TLD cards are being calibrated. During reader calibration, secondary charged particle equilibrium can be ensured using build-up PMMA plate of certain thickness placed in front of dosimeters. In this paper, influence of the build-up plate on reader calibration is being analyzed. This influence is observed through changes in reader calibration factor (RCF). RCF values obtained during reader calibration procedure with and without 2 mm thick build-up plate are presented. Exposures of whole body TLDs placed on slab phantom were done with Cs-137 radiation source located at Secondary Standard Dosimetry Laboratory (SSDL) at INNV. TLDs from both manufacturers had 2 detectors for measuring the dose equivalent at the depths of 10 mm and 0.07 mm. TLD reader was calibrated to measure effective dose in terms of Hp(10) and local skin dose in terms of Hp(0.07). RCF values for detectors measuring Hp(10), from both manufacturers, when irradiated without the plate were around 5% higher than RCF values obtained when irradiations were done with the plate. Values of RCFs for detectors measuring Hp(0.07) were around 1% higher when the plate had not been used. As RCF value is inversely proportional to measured dose, reader calibration without build-up plate, in terms of Hp(10), would lead to underestimated dose values. The observed RCF deviation of Hp(0.07) detector is regarded as consequence of exposure conditions uncertainties. In conclusion, if a constant geometry and constant operational conditions of TLDs are achieved, the only part of the TLD system that is not stable for a long time period is the TLD reader. To avoid inaccurate results, RCF should be orderly checked and reader calibration should be done according to widely accepted standards, currently in effect.3rd International Conference on Radiation and Applications in Various Fields of Research (RAD), Jun 08-12, 2015, Budva, Montenegr