A preliminary study of local administration of dexamethasone after tooth extraction: Better preservation of residual alveolar ridge?

Background/Aim. It is important that the height of the edentulous alveolar ridge after tooth extraction remains at a reasonable acceptable level for as long as possible. The aim of this study was to report preliminary results of the clinical effect of local oral submucous administration of dexamethasone after tooth extractions in order to prepare alveolar supporting tissues for acceptance of removable dentures. Methods. In a total of 15 patients (11 partially and 4 completely edentulous) the quantity of 0.25 mL to 0.5 mL of dexamethasone was injected bucally and orally in the region of the tooth socket after complicated extractions. Results. Healing of extraction wounds was uneventful in all the patients, without pain or local inflammation. Conclusion. Dexamethasone can be locally applied to oral tissues to prevent post-extraction inflammation and extensive resorption of the residual alveolar ridge. The obtained results are promising for patients undergoing classic prosthodontic rehabilitation soon after tooth extraction, demonstrating that there are no adverse effects after local oral corticosteroids administration. [Projekat Ministarstva nauke Republike Srbije, br. 175021

Realism’s Understanding of Negative Numbers

Our topic is the understanding of the nature of negative numbers – the entities to which expressions such as ‘-1’ refer. Following Frege, we view positive whole numbers as providing the answer to the question „how many?“ In this light, how are we to view negative numbers? Both positive and negative numbers can be ordered through the relation of larger or smaller. It is then true of all negative numbers that they are entities which are (somehow) smaller than zero. For many, this has been understood as an ontological paradox: how can something be „less than nothing?“ Some propose to avoid the paradox by treating negative numbers as mere façons de parler. In this paper, we propose a more realist account, taking as our starting point the thesis that there is at least one familiar type of object, the magnitude of which can be expressed with negative numbers, namely, debt. How can the sense of an expression be ontologically paradoxical, yet the expression itself still plausibly refer to a social object such as a debt? Or, put differently, how is it possible to be, at the same time, a realist in financial theory and a nominalist in mathematical theory? The paper first shows that the paradox arises when the two distinct ways in which negative numbers are connected to real objects are run together. The first of the two refers to debt only, whereas the second could refer to debt, as well as to physical objects. Finally, we claim that a debt is at once a specifically social object and part of reality as described by physics

Migration of depleted uranium contamination through the soil

Military use of ammunition with depleted uranium at South Serbia, caused contamination of the environment. Surface soil and soil profile around projectile with depleted uranium were analyzed three years later by high resolution alpha/gamma spectrometry. It was found that activity levels in the soil layer next to the penetrator changes to 1% of initial value at 15 cm distance. This value is about double background uranium level of the soil at the Bratoselce location.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

The influence of electromagnetic field (2 mT, 50 Hz) on spontaneous bioelectrical activity of antennal lobe neurons of adult Morimus funereus (Insecta, Coleoptera)

Spoljašnja magnetna polja (MP) narušavaju ravnotežu bioloških sistema, čak i tokom kraćeg vremena izlaganja, što za posledicu ima poremećaje na različitim nivoima organizacije. Na ovaj način nastali poremaćaji akumuliraju se u organizmima, što je jedan od razloga za traženje objašnjenja bioloških efekata MP. S druge strane, veoma važna činjenica koja nas usmerava na što bolje razumevanje ove problematike je potreba za zaštitom ljudskog zdravlja zbog uvođenja novih tehnologija u svakodnevni život, industriju i medicinu, kao i zbog terapijske upotrebe MP. Pretpostavka je da se interakcija spoljašnjih MP i organizama dešava na svim nivoima organizacije, uključujući i nervni sistem. Stoga je cilj ovih istraživanja bio ispitivanje uticaja elektromagnetnog polja (2 mT, 50 Hz) različitih karakteristika (trajanje, talasni oblik) na spontanu bioelektričnu aktivnost neurona antenalnog lobusa adulta Morimus funereus. Aktivnost neurona (pozadinskih/neuronske populacije i najbližih registrujućoj elektrodi) je registrovana kroz nekoliko faza u kojima smo adulte izlagali sinusoidalnom ili kvadratnom MP različitog trajanja: 5, 10 i 15 min (MP-5, MP-10, MP-15, respektivno). Uticaj MP smo procenjivali na osnovu promena u neuronskoj aktivnosti, a procenjivali smo i (i)reverzibilnost promena između tripleta formiranih od određenih eksperimentalnih faza. U tripletima koji slede vremenski tok eksperimenta, a podrazumevaju delovanje MP određenog trajanja (MP-5, MP-10 i MP-15, respektivno), testirali smo i njihove međusobne razlike. Rezultati istraživanja su pokazali da primenjeno MP, bez obzira na dužinu izlaganja i talasni oblik, menja aktivnost neurona antenalnog lobusa. U sinusoidalnom MP, te promene su najizraženije nakon delovanja MP-15, a u kvadratnom MP, nakon delovanja MP-5. Pokazano je da je kontrolna aktivnosti pozadinskih neurona značajno promenjene nakon delovanja sinusoidalnog MP-5, kao i nakon delovanja MP-10, a značajno je manja nakon delovanja MP-15. S druge strane, sinusoidalno MP, bez obzira na dužinu izlaganja izaziva značajnu inhibiciju kontrolne aktivnosti najbližih neurona...External magnetic fields (MF) disturb the equilibrium of biological systems, even during short-term exposure, resulting in disturbances at different levels of organization. These changes accumulate in organisms, which is one of the reasons for testing biological effects of MF. On the other hand, the fact that modern man is exposed to increasing number of MF sources due to the use of new technologies in everyday life, industry, medicine, as well as therapeutic application of MF, makes this topic even more important, in terms of human health protection. It is assumed that the interaction between external MF and organisms takes place at all levels of organization, including the nervous system. Thus, the aim of this study was to investigate the influence of electromagnetic field (EMF) of different characteristics (exposure duration, waveform) on spontaneous bioelectrical activity of antennal lobe neurons of adult Morimus funereus. Neurons activity (background/neuronal population and those nearest to the recording electrode) was registered through several phases of exposure of adult longhorn beetles to sine wave or square wave MF of different exposure duration: 5, 10 and 15 minutes (MP-5, MP-10 and MP-15, respectively). Estimation of MF influence was based on registered changes of neuronal activity. (I)reversibility of such changes was tested through comparison the triplets formed by particular experimental phases. Changes in triplets that follow the time course of the experiment, with reference to MF influence of different exposure duration (MP-5, MP-10 and MP-15, respectively), were also tested. Results of this study showed that the applied MF, regardless of exposure duration and waveform, modifies the activity of antennal lobe neurons. In sine wave MF, the most prominent changes are recorded after MP-15, while in square wave MF such changes were recorded after MP-5. Control activity of the neuronal population was significantly changed both after MP-5 and MP-10, as well as significantly decreased after MP-15. Sine wave MF, regardless of exposure duration, significantly inhibits control activity of nearest neurons..

RICONOSCERSI NELLA SCRITTURA: IMPLICAZIONI INTERTESTUALI E METATESTUALI NEI ROMANZI LJUDI GOVORE DI RASTKO PETROVIĆ E CONVERSAZIONE IN SICILIA DI ELIO VITTORINI

In un approccio comparatistico, con gli strumenti analitici della semiotica interpretativa e della narratologia, si prendono in esame i punti in comune di due testi modernisti appartenenti rispettivamente alla letteratura serba e a quella italiana: Ljudi govore (1931) di Rastko Petrović e Conversazione in Sicilia di Elio Vittorini (1939). Si focalizzano procedimenti e implicazioni intertestuali e metatestuali delle due opere che ne confermano l’appartenenza alle poetiche del modernismo. Parole chiave: Rastko Petrović, Ljudi govore, Conversazione in Sicilia, Elio Vittorini, letteratura comparata, semiotica interpretativa, narratologia, narrative modernista

Freshwater jellyfish Craspedacusta sowerbyi Lankester, 1880 (Hydrozoa, Olindiidae): 50 years' observations in Serbia

Detailed and relevant limnological investigations of Serbian waters were initiated in 1958 and have continued to the present. During the period 1971-2008 we monitored biological elements as a part of working studies/projects, including the distribution of the freshwater jellyfish Craspedacusta sowerbyi Lankester, 1880. We observed over 500 sampling sites in running and standing waters. Specimens of this hydro-medusa were found in five of them. Throughout the period of investigation, only the medusae stages were observed. Our purpose in this paper was to provide data of the records and distribution of this limnomedusa during the period 1958-2008 in inland waters of Serbia. These observations should contribute to knowledge on the limnofauna not only of the Balkan Peninsula but Europe as a whole.Opsežna i značajna limnološka istraživanja voda u Srbiji otpočela su 1958. godine i nastavljena do danas. Tokom celog istraživačkog perioda nađena je slatkovodna meduza Craspedacusta sowerbyi Lankester, 1880 na pet lokaliteta (bara na Velikoj Moravi kod Ćuprije, Savsko jezero kod Beograda, jezero Velika Peščara kod Zrenjanina, jezero Miloševo kod Jagodine i jezero Šumarice kod Kragujevca). Predstavljeni rezultati su doprinos dosadašnjih saznanja o nalazima i distribuciji ove vrste u Srbiji, kao i poznavanju limnofaune Balkanskog poluostrva i Evrope.Projekat ministarstva br. 14302

Primena metode atomske apsorpcione spektrofotometrije (AAS) za određivanje sadržaja teških metala u fosfogipsu

Phosphogypsum is formed as a by-product in the process of 'green' phosphoric acid production. This is done in the so called 'wet process' by the action of sulphuric acid on raw phosphate at low temperature ( lt 100 °C). Despite the same molecular formula and marked similarity with natural gypsum, phosphogypsum contains more than 50 impurities, and this is directly connected with the type of phosphate used in the production cycle. The aim of this paper was to consider the possibility of using phosphogypsum for amelioration of solonetz soil, bearing in mind its content of heavy metals, which are rather toxic for human organism and which can be transferred from soil to various plants used in human nutrition. On the other hand, there are very few data in the literature about the determination of heavy metals in phosphogypsum. The content of heavy metals in phosphogypsum was determined by atomic absorption spectrophotometry because this method has broad application in ana­lytical practice due to its high sensitivity, selectivity and precision. The results of the investigation indicate the following average content of heavy metals (in ppm): Fe-785, Pb-45, Zn-45, Cd-7, Mn-8, Co-10, Ni-20 and Cu-17. For the investigation of the effect of phosphogypsum on solonetz soil the following points were taken into consideration: maximum recommended dose of phosphogypsum (7 t/ha) for the amelioration of solonetz soil and the weight of soil layer (from 0 to 20 cm) having an area of 1 ha. The results obtained indicate that the amounts of heavy metals that are introduced into the soil with 7 t/ha of phosphogypsum are in the range from 0.035 to 0.8% of their maximum permissible content for arable soils. This means that only long-term application of phosphogypsum would introduce significant amounts of these elements into the soil.Procesom dobijanja 'zelene' fosforne kiseline tzv. 'mokrim postupkom', dejstvom sumporne kiseline na sirovi fosfat na niskoj temperaturi ( lt 100 °C) kao nus-proizvod nastaje - fosfogips (sa faktorom 5:1, u odnosu na H3PO4). Uprkos istoj molekulskoj formuli i izraženoj sličnosti sa prirodnim gipsom, fosfogips sadrži preko 50 vrsta nečistoća, što je u direktnoj vezi sa vrstom fosfata koji je korišćen u proizvodnom ciklusu. Cilj rada bio je razmatranje mogućnosti primene fosfogipsa za melioraciju soloneca, sa aspekta sadržaja teških metala, koji su izuzetno toksični i kumulativni za čovekov organizam, a iz zemljišta prelaze u biljke, kojima se čovek hrani. Sa druge strane, u literaturi se nalaze veoma oskudni podaci o ispitivanju sadržaja teških metala u fosfogipsu. Sadržaj teških metala u fosfogipsu određivan je metodom atomske apsorpcione spektrofotometrije (AAS), budući da je to metoda koja je našla veliku primenu u praksi usled visoke osetljivosti, selektivnosti i preciznosti. Rezultati ispitivanja su pokazali sledeći sadržaj teških metala (u ppm): Fe-785, Pb-45, Zn-45, Cd-7, Mn-8, Co-10, Ni-20, Cu-17. Za ispitivanje uticaja primene fosfogipsa za melioraciju soloneca, uzeta je u obzir preporučena maksimalna norma za gipsovanje soloneca od 7 t/ha zemljišta i težina sloja debljine od 0 do 20 cm a površine 1 ha. Dobijeni rezultati su pokazali da se preporučenom maksimalnom normom za gipsovanje soloneca fosfogipsom unosi po 1 ha zemljišta od 0,035 do 0,8% od maksimalno dozvoljenog sadržaja teških metala - MDK vrednosti, što znači da bi tek višegodišnjom upotrebom fosfogipsa došlo do unošenja značajnijih količina ovih elemenata u zemljište. Kako se proces melioracije soloneca najčešće vrši u intervalu od 5 do 6 godina, unošenje teških metala bilo bi u zanemarljivoj količini i bez uticaja na životnu sredinu

Rational design and synthesis of compounds based on aroylacrylic acid amid scaffold that exert anticholinesterase, antitubuline and antiproliferative activity.

U ovoj tezi su opisane različite strukturne modifikacije aroilakrilnih kiselina, zasnovane na relativno jednostavnim sintetičkim procedurama. Biološka aktivnost dobijenih novih jedinjenja (sa oznakama 1a-29a, 1b-38b, 151c, 152c i 156c) je ispitana prema nekoliko bioloških meta relevantnih za maligna oboljenja i Alchajmerovu bolest.Dizajnirana je i sintetizovana kongenerna serija dvadeset i devet amida (E)-4-aril-4-okso-2-butenskih kiselina, u nameri da se ispita njihova antiproliferativna aktivnost i mogući mehanizam dejstva. Antiproliferativna aktivnost je ispitana prema tri ćelijske linije humanih tumora (HeLa, FemX, K562). Jedinjenja su ispoljavala antiproliferativnu aktivnost u niskim mikromolarnim ili submikromolarnim koncentracijama. Najjače dejstvo su pokazala alkil-supstituisana jedinjenja na aroil-delu molekula. Četrnaest jedinjenja je inhibiralo polimerizaciju tubulina u koncentracijama nižim od 20 μM. Jedinjenje sa najvećom jačinom antitubulinskog dejstva je derivat sa nesupstituisanim aroil-fenil- i nesupstituisanim fenilamidnim prstenom, 1a, sa IC50=2,9 μM. Testirana je i akutna toksičnost in vivo, na albino miševima (NMRI Hann). LD50 za fluoro-derivat 23a iznosila je 45 mg/kg. Ovo ukazuje na značajnu toksičnost amida aroilakrilnih kiselina (1a-29a). Analiza ćelijskog ciklusa, urađena na K562 ćelijama, pokazala je da derivati 1a, 2a i 23a izazivaju porast broja ćelija u G2/M fazi, međutim, inhibicija polimerizacije tubulina nije jedini mehanizam dejstva ovih jedinjenja. Uprkos tome, jedinjenja 1a-29a predstavljaju dobre vodeće strukture za dizajn nove klase antitubulinskih agenasa.Amidi aroilakrilnih kiselina su dalje modifikovani Majklovom adicijom odabranih sekundarnih cikličnih amina na aktiviranu dvostruku vezu, u nameri da se dobiju jedinjenja koja bi ispoljavala inhibicionu aktivnost prema enzimima iz grupe holinesteraza. Dizajnirana je i sintetizovana kongenerna serija od trideset i osam 4-aril-4-okso-2-(N-aril/cikloalkil)butanamida. Strukturne varijacije su obuhvatile cikloalkilamino-grupu na položaju C2 butanskog fragmenta, kao i grupu vezanu za amidni azot molekula. Dvanaest jedinjenja, uglavnom piperidinskih i imidazolskih derivata, inhibiralo je acetilholinesterazu(AChE) u niskom mikromolarnom opsegu. Ova jedinjenja nisu bila aktivna prema butirilholinesterazi (BChE). Nekoliko N-metilpiperazinskih derivata je inhibiralo BChE u niskom mikromolarnom ili submikromolarnom opsegu koncentracija. Ova jedinjenja su bila neaktivna prema AChE. Prema tome, priroda cikloalkilamino-grupe na položaju C2 određuje selektivnost prema jednom, odnosno drugom enzimu. Najaktivniji inhibitor AChE ispoljava mešoviti tip inhibicije, što ukazuje na vezivanje i za slobodan enzim i za enzim-supstrat kompleks. Detaljna doking studija, urađena za sedam jedinjenja sa najvećom jačinom inhibicionog dejstva prema AChE, ukazala je na mogućnost formiranja vodonične veze između amidne -NH- grupe inhibitora i –OH grupe bočnog ostatka Tyr 124. Simulacija molekulske dinamike kompleksa AChE sa jedinjenjem (S)-18, duga 5 ns, pokazala je da je ova interakcija tokom vremena najstabilnija. Ovo je verovatno najjača interakcija između inhibitora i enzima.U nameri da se dizajniraju dualni heterodimerni reverzibilni inhibitori AChE, sprovedena je 3D-QSAR studija, zasnovana na deskriptorima koji su nezavisni od međusobnog prostornog svrstavanja molekula, na setu od 110 dualnih reverzibilnih inhibitora AChE. Izvedena su tri modela, koristeći konformacije molekula dobijene na osnovu sledećih kriterijuma: (i) konformacije minimalne energije, (ii) konformacije najsličnije sa konformacijom liganda kokristalisanog sa AChE i (iii) konformacije dobijene dokingom jedinjenja u šupljinu aktivnog mesta AChE. Sva tri modela imala su dobre statističke parametre i prediktivnost, nezavisno od toga koji je tip konformacija upotrebljen. Modeli su ukazali na važnost protonovanog piridinskog azota takrinskog fragmenta jedinjenja za inhibiciono dejstvo prema AChE. Takođe su intearkcije donora i akaceptora vodoničnih veza prepoznate kao veoma važne. Na ovo ukazuje prisustvo varijabli koje su povezane sa protonovanim piridinskim azotom i sa dve amino-grupe linkera. Polja molekulskih interakcija (MIF) izračunata za šupljinu aktivnog mesta AChE upotrebom N1= (piridinski azot) i DRY (hidrofobna) GRID proba omogućili su da se pronađe veza između aminokiselinskih ostataka u aktivnom mestu AChE i varijabli koje imaju visok pozitivan uticaj na modele. Spoljašnja prediktivnost modela je testirana na setu od 40 inhibitora AChE, od kojih je većina bila stukturno nesrodna sa jedinjenjima iz osnovnog seta, na osnovu koga je model izveden. Aktivnost nekih jedinjenja je određena na različitom enzimskom izvoru (mAChE). Nađeno je da spoljašnja prediktivnost modela jako zavisi od konformacija jedinjenja koje su upotebljene za izvođenje modela. Model zasnovan nakonformacijama jedinjenja dobijenih dokingom je imao superiornu prediktivnu moć u odnosu na ostala dva modela, što ukazuje na važnost upotrebe konformacija jedinjenja koje su dobijene u odnosu na geometrijska ograničenja vezivnog mesta AChE. Dizajnirano je nekoliko dualnih, heterodimernih inhibitora AChE zasnovanih na strukturi takrina i amida aroilakrilnih kiselina in silico, i njihova aktivnost je procenjena upotrebom modela izvedenog iz konformacija dobijenih dokingom. Tri jedinjenja su sintetisana i eksperimentalno je određena njihova aktivnost. Jedinjenja su aktivna u nanomolarnim koncentracijama, što je u saglasnosti sa aktivnošću procenjenom na osnovu modela.In this thesis, various structural modifications of benzoylacrylic acid scaffold, achieved through relatively simple synthetic procedures were done. The resulting novel compounds were tested toward biological targets relevant for cancer and Alzheimers disease.We designed and synthesized various aroylacrylic acid amides, aiming to test their antiproliferative activity and to possibly inferr their principal mechanism of action. Antiproliferative activity of twenty-nine (E)-4-aryl-4-oxo-2-butenoic acid amides against three human tumor cell lines (HeLa, FemX, and K562) was tested. Compounds showed antiproliferative activity in one-digit micromolar to submicromolar concentrations. The most potent derivatives toward all cell lines tested, bear alkyl substitutents on the aroyl moiety of the molecules. Fourteen compounds showed tubulin assembly inhibition at concentrations < 20 μM. The most potent inhibitor of tubulin assembly was compound 1a, with unsubstituted aroyl and phenylamido rings, with IC50 = 2.9 μM. Compound 23a had an LD50 in vivo of 45 mg/kg in albino mice (NMRI Hann), as obtained by oral administration. Cell cycle analysis on K562 cells showed that the compounds 1a, 2a and 23a cause accumulation of the cells in G2/M phase, but inhibition of microtubule polymerization is not the principal mode of action of compounds. Nevertheless, they may be useful leads for the design of a new class of antitubulin agents.Further, we modified aroylacrylic acids amides by Michaels addition of suitably chosen secondary cyclic amines on the activated double bond, with aim to obtain compounds which inhibit cholinesterase enzymes. Congeneric set of thirty-eight 4-aryl-4-oxo-2-(N-aryl/cycloalkyl)butyramides has been designed, synthesized and evaluated for acetyl- and butyrylcholinesterase inhibitory activity. Structural variations included cycloalkylamino group attached to C2 position of butanoyl moiety, and the variation of amido moiety of molecules. Twelve compounds, mostly piperidino and imidazolo derivatives, inhibited AChE in low micromolar range, and were inactive toward BChE. Several N-methylpiperazino derivatives showed inhibition of BChE in low micromolar or submicromolar concentrations, and wereinactive toward AChE. Therefore, the nature of the cycloalkylamino moiety governs the AChE/BChE selectivity profile of the compounds. The most active AChE inhibitor showed mixed-type inhibition, indicating binding to the free enzyme and to the enzyme-substrate complex. Thorough docking calculations of the seven most potent AChE inhibitors from the set, showed that the hydrogen bond can be formed between amide -NH- moiety of compounds and -OH group of Tyr 124. The 5 ns of productive, unconstrained, molecular dynamic simulation of the AChE-compound (S)-18 complex showed that this interaction is the most persistent. This is, probably, the major anchoring point for the binding.In intention to design dual heterodimeric, reversible, AChE inhibitors, the 3D-QSAR analysis, based on alignment independent descriptors (GRIND-2), was performed on the set of 110 structurally diverse, dual binding AChE reversible inhibitors. Three models were built, based on different conformations. Conformatiomns were generated following criteria: (i) minimum energy conformations, (ii) conformation most similar to the co-crystallized ligand conformation, and (iii) docked conformation. We found that regardless on conformation used, all the three models had good statistics and predictivity. The models revealed the importance of protonated pyridine nitrogen of tacrine moiety for anti AChE activity, and recognized HBA and HBD interactions as highly important for the potency. This was revealed by the variables associated with protonated pyridinum nitrogen, and the two amino groups of the linker. Molecular interaction fields (MIF) calculated with the N1= (pyridinium nitrogen) and the DRY (hydrophobic) GRID probes in the AChE active site, enabled us to establish the relationship between aminoacid residues within AChE active site and the variables having high impact on models. External predictive power of the models was tested on the set of 40 AChE reversible inhibitors, most of them structurally different from the training set. Some of those compounds were tested on the different enzyme source. We found that external predictivity was highly sensitive on conformations used. Model based on docked conformations had superior predictive ability, emphasizing the need for the employment of conformations built by taking into account geometrical restrictions of AChE active site gorge. Several dual, heterodimeric AChE inhibitors, comprising tacrine and aroylacrylic acid amides molecular fragments were designed in silico, and their activity was estimated using model based on docked conformations of compounds. Three compounds were synthesized, and their anti-AChE activity wasdetermined. The experimentally obtained nanomolar anti-AChE activity of compounds appered in a good agreement with the activity estimated from the model

Energy efficiency of residential buildings in Serbia

In this paper, presented is the stale-of-the-art of energy Efficiency of residential buildings in Serbia. Special attention is paid to energy efficiency in already existing buildings. The average energy consumption in residential buildings in Serbia is over 150 kWhm(-2) per year, while in developed European countries it is about 50 kWm(-2) per year. In this paper examined is the contribution of ventilation losses, through the windows of low quality, regardless whether they are poorly made, or made from bad materials, or with no adeguate glass. Besides ventilation losses, which are of major importance in our buildings, special attention is paid to transmission losses, which are conseguence of the quality and energy efficiency of the facade. All of the above statements are proved by measurements obtained on a representative building of the Block 34 in New Belgrade, built in the eighties of the last century. In addition to measurements performed the calculation of energy consumption for heating during winter has been made. The results of two different methods of calculation of energy consumption for heating are compared with the values obtained by measuring