Histochemical observation and the analysis of biochemical bone regeneration markers in treatment of an osteoporotic rat bone with Ca/Co-HAp nanoparticles

One of the prerequisites for a good prosthetic rehabilitation is well preserved bone tissue. However, osteoporosis as a modern age disease often compromises a good dental treatment. Oral implantology offers a solution through the use of various biomaterials. Most researchers focus on the synthesis of the nanomaterials with magnetic and paramagnetic properties. The aim of this study is to examine the role of Ca / Co-HAp nanoparticles in the regeneration of the osteoporotic alveolar bone in experimental animals by analyzing the biochemical blood markers (ALP, Ca, Mg, and P) and through histochemical analysis. The research was carried out on female Westar rats, aged 6-8 weeks. The obtained results for the biochemical blood markers showed statistically significant rise. Histological analysis revealed high level reparatory skills of the biocomposite implanted in the bone defect as early as in the 6th week of the experiment as well as an increased alkaline phosphatase activity in the mineralized tissues. The implantation of the biomaterials facilitates osteogenesis, justifying their use in the accelerated regeneration treatment of the osteoporotic alveolar bone

Electrochemical Deposition of Al-Ti Alloys from Equimolar AlCl3 + NaCl Containing Electrochemically Dissolved Titanium

Al-Ti alloys were electrodeposited from equimolar chloroaluminate molten salts containing up to 0.1 M of titanium ions, which were added to the electrolyte by potentiostatic dissolution of metallic Ti. Titanium dissolution and titanium and aluminium deposition were investigated by linear sweep voltammetry and chronoamperometry at 200 and 300 °C. Working electrodes used were titanium and glassy carbon. The voltammograms on Ti obtained in the electrolyte without added Ti ions indicated titanium deposition and dissolution proceeding in three reversible steps: Ti4+ ⇄ Ti3+, Ti3+ ⇄ Ti2+ and Ti2+ ⇄ Ti. The voltammograms recorded with glassy carbon in the electrolyte containing added titanium ions did not always clearly register all of the three processes. However, peak currents, which were characteristics of Al, Ti and Al-Ti alloy deposition and dissolution, were evident in voltammograms on both working electrodes used. A constant potential electrodeposition regime was used to obtain deposits on the glassy carbon working electrode. The obtained deposits were characterized by SEM, energy-dispersive spectrometry and XRD. In the deposits on the glassy carbon electrode, the analysis identified an Al and AlTi3 alloy formed at 200 °C and an Al2Ti and Al3Ti alloy obtained at 300 °C

Testing the antimicrobial activity of hydroxyapatite nanoparticles in vitro

Antimicrobial materials based on hydroxyapatite are very attractive for wide application in medicine and stomatology. The goal of this work was to test antimicrobial activity of hydroxyapatite nanoparticles Co/Ca- hydroxyapatite and biphasic calcium phosphate/ poly (lactide-co-glycolide) composite biomaterial. Antimicrobial activity of the samples was tested using dilution method and disk diffusion. The results of antimicrobial tests were obtained by determining the reduction percentage the number of bacteria in physiological solution where bacteria cells were exposed to the samples. It can be concluded that synthesized HAp biomaterials have satisfactory antimicrobial activity against tested bacteria strains

A novel algorithm for dynamic student profile adaptation based on learning styles

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.E-learning recommendation systems are used to enhance student performance and knowledge by providing tailor- made services based on the students’ preferences and learning styles, which are typically stored in student profiles. For such systems to remain effective, the profiles need to be able to adapt and reflect the students’ changing behaviour. In this paper, we introduce new algorithms that are designed to track student learning behaviour patterns, capture their learning styles, and maintain dynamic student profiles within a recommendation system (RS). This paper also proposes a new method to extract features that characterise student behaviour to identify students’ learning styles with respect to the Felder-Silverman learning style model (FSLSM). In order to test the efficiency of the proposed algorithm, we present a series of experiments that use a dataset of real students to demonstrate how our proposed algorithm can effectively model a dynamic student profile and adapt to different student learning behaviour. The results revealed that the students could effectively increase their learning efficiency and quality for the courses when the learning styles are identified, and proper recommendations are made by using our method

Conjunct Agreement and Gender in South Slavic: From Theory to Experiments to Theory

Agreement with coordinated subjects in Slavic languages has recently seen a rapid increase in theoretical and experimental approaches, contributing to a wider theoretical discussion on the locus of agreement in grammar (cf. Marušič, Nevins, and Saksida 2007; Bošković 2009; Marušič, Nevins, and Badecker 2015). This paper revisits the theoretical predictions proposed for conjunction agreement in a group of South Slavic languages, with a special focus on gender agreement. The paper is based on two experiments involving speakers of Bosnian/Croatian/Serbian (BCS) and Slovenian (Sln). Experiment 1 is an elicited production experiment investigating preverbal-conjunct agreement, while Experiment 2 investigates postverbal-conjunct agreement. The data provide experimental evidence discriminating between syntax proper and distributed-agreement models in terms of their ability to account for preverbal highest-conjunct agreement and present a theoretical mechanism for the distinction between default agreement (which has a fixed number and gender, independent of the value of each conjunct) and resolved agreement (which computes number and gender based on the values of each conjunct and must resolve potential conflicts). Focusing on the variability in the gender-agreement ratio across nine combinations, the experimental results for BCS and Sln morphosyntax challenge the notion of gender markedness that is generally posited for South Slavic languages

Uticaj masti u obroku na masne kiseline u serumskim fosfolipidima i gojaznost životinja

Dietary fat and its relation to obesity has been a controversial issue for many years. Experimental data shows that most, though not all animals, which consume a high fat diet, will become obese. However, the effect of fatty acids on animal obesity has not been studied in detail. In order to evaluate the effects of low versus high fat diet on serum phospholipids fatty acids composition a 4-wk study was conducted on male Wister rats. The rats were fed low-fat (10% energy) and high-fat (46% energy) foods containing constant proportions of fatty acids. Control group C was fed a standard laboratory diet (polyunsaturated/ saturated (P/S) fatty ratio 1.3), group M was fed a standard laboratory diet supplemented with margarine (P/S ratio 0.95), and the diet of the SL group was additionally supplemented with a sunflower oil-lard (1:1) mixture (P/S ratio 1.3). All lipid supplemented hyperenergetic diets caused an increase in the average daily energy intake. Both the final and the daily body weight gain were significantly higher in M and SL groups than in group C. Additionally, serum triglyceride levels, LDL-cholesterol and total cholesterol were also significantly higher in M and SL groups when compared to the control group. Serum phospholipids fatty acids varied in response to total dietary fat. A significant decrease in saturated fatty acids (SFA) content (16:0 and 18:0) and an increase in monounsaturated fatty acid (MUFA) content (18:1, n-9) was found in the M group when compared to both C and SL groups. In the SL group, SFA content (18:0) was higher and MUFA content (18:1, n-9) was lower than in group C. Polyunsaturated fatty acids (PUFA) content showed an increase in both experimental groups. The PUFA/SFA ratio was higher in the M group than in the C and SL groups. Our study suggests that the amount of dietary fat has a greater influence on obesity than the effects of the type of fat consumed. However, depending on the type of fat present in the diet the differences were observed in the composition of serum PL fatty acid suggesting that both total fat and individual fatty acids have to be considered when reaching conclusions about the effect of dietary fat and obesity in animals.Uticaj masnih kiselina u ishrani i njihov efekat na pojavu gojaznosti kod životinja je kontraverzno pitanje već dugi niz godina. Uticaj pojedinačnih masnih kiselina na pojavu gojaznosti kod životinja nije do sada detaljnije proučavan. Sa ciljem da se ispita efekat dijeta sa niskim ili visokim sadržajem masti na pojavu gojaznosti, izvršena su istraživanja na Wister pacovima u trajanju od 4 nedelje. Pacovi su hranjeni eksperimentalnim dijetama koje su sadržale standardan, nizak (10%) ili visok (46%) energetski unos poreklom od masti. Grupa kontrolnih životinja (C) je hranjena standardnom laboratorijskom dijetom (odnos polizasićenih/ zasićenih masnih kiselina/PUFA, P/S 1.3), grupa M sa standardnom dijetom sa dodatkom margarina (P/S 0.95) i grupa SL sa dijetom kojoj je dodata mešavina 1:1 suncokretovog ulja i masti (odnos P/S 1.3). Obe dijete (M i SL) su uzrokovale povećanje u prosečnom dnevnom energetskom unosu. U grupi M i SL, registrovano je značajno povećanje u telesnoj težini kontinuirano tokom eksperimenta. Nivo serumskih triglicerida, LDL kao i ukupnog holesterola su bili značajnije povećani u M i SL grupi u poređenju sa kontrolom. Promene u profilu serumskih masnih kiselina fosfolipida su zavisile od sastava masti u eksperimentalnoj dijeti. Kod eksperimentalnih životinja grupe M primećeno je značajno smanjene serumskih zasićenih masnih kiselina (SFA, 16:0 i 18:0) kao i porast monozasićenih masnih kiselina (MUFA, 18:1, n-9) u poređenju sa SL i C grupom. Odnos PUFA/ SFA je bio veći u M u odnosu na SL i C grupu. Rezultati naših istraživanja ukazuju da količina masti u ishrani životinja ima veći uticaj na porast telesne mase nego vrsta prisutne masnoće. Promene u sastavu serumskih masnih kiselina fosfolipida u odnosu na tip masti u eksperimentalnim dijetama ukazuju na ulogu pojedinačnih masnih kiselina u procesu nastajanja gojaznosti kod životinja i te mehanizme treba dalje istraživati

Besnilo - epizootiološka situacija na teritoriji Srbije i zemalja u okruženju od 2006. do 2012. godine

Rabies is a disease that occurs both in animals and people, with relatively long period of incubation, intense clinical course and fatal ending. Majority of cases of illnes and death in people are caused by the standard rabies virus. According to books of regulations on suppression and eradiction of rabies from 1988. and 2009., each suspected rabies has to be laboratory confirmed. From 2006. to 2012. within the passive surveilance, 3549 samples of brain tissue were examined for the presence of rabies virus. The virus was confirmed in 923 samples by using the method of direct imunofluorescence. From 2006. to 2012. there were diagnosed 192, 160, 233, 181, 104, 43 and 10 positive cases, respectively. For the purpose of rabies eradiction at the territory of the Republic of Serbia, a regional project of oral vaccination of foxes against rabies has been implemented since 2010.Within monitoring of the effectiveness of oral vaccination against rabies which was carried out at the end of 2011. and at the beginning of 2012., there were examined 1385 samples, out of which 11 reacted positively. The virus was dominantly present in the fox population. During 2008. and 2009., a relatively large number of rabid cats was registered, what indicates a transmission of rabies from the fox to the cat population. The incidence of rabies at the territory of Serbia significantly differs from one epizootic area to another. Northern parts of the country (Sombor and Subotica epizootic regions) have more favorable situation with only two cases of rabies for the last 7 years. In the period until 2010., in Pozarevac, Novi Sad, Jagodina, Pancevo, Belgrade and Nis epizootic region, a gradual decline in number of positive cases was noticed. International project for oral vaccination of foxes against rabies which has been implemented at the territory of the Republic of Serbia and neighboring countries, influenced a significant reduction of registered rabies cases.Besnilo je bolest životinja i ljudi koja se odlikuje relativno dugim inkubacionim periodom i dramatičnim kliničkim tokom, koji se uvek završava smrtnim ishodom. Najveći broj slučajeva oboljenja i smrti ljudi potiče od infekcije klasičnim virusom besnila. Prema pravilnicima koji se bave suzbijanjem i iskorenjivanjem besnila iz 1988. i 2009. godine obavezna je laboratorijska potvrda svake klinički opravdane sumnje na besnilo. Od 2006. do 2012. godine u okviru pasivnog nadzora pregledano je 3549 uzoraka moždanog tkiva na prisustvo virusa besnila. Metodom direktne imunofluorescencije virus je dokazan u 923 uzoraka. Po godinama, od 2006. do 2012. godine dijagnostikovano je 192, 160, 233, 181, 104, 43 i 10 pozitivnih slučajeva. U cilju iskorenjivanja besnila na teritoriji Republike Srbije od 2010. godine se sprovodi regionalni projekat oralne vakcinacije lisica protiv besnila. U okviru monitoringa efikasnosti oralne vakcinacije lisica protiv besnila koji je sprovođen krajem 2011. i početkom 2012. godine ispitano je 1385 uzoraka od čega je 11 reagovalo pozitivno. Virus je dominantno prisutan u populaciji lisica. Tokom 2008. i 2009. godine dijagnostikavan je relativno veliki broj besnih mačaka, što ukazuje na prenos virusa iz populacije lisica u populaciju mačaka. Incidencija besnila na teritoriji Srbije se značajno razlikuje od jednog do drugog epizootiološkog područja. Severni delovi zemlje (somborsko i subotičko epizotiološko područje) imaju povoljniju epizootiološku situaciju (samo dva slučaja besnila u proteklih 7 godina). U periodu do 2010. godine na požarevačkom, novosadskom, jagodinskom, pančevačkom, beogradskom i niškom epizootiološkom području se uočava postepeni pad broja pozitivnih slučajeva. Međunarodni projekat oralne vakcinacije lisica protiv besnila koji se sprovodi na teritoriji Republike Srbije i okolnih zemalja uticao je na to da se broj prijavljenih slučajeva besnila u Srbiji drastično smanji

Electrodeposition of Aluminium-Vanadium Alloys from Chloroaluminate Based Molten Salt Containing Vanadium Ions

The Al-V alloys were synthetized by potentiostatic electrodeposition onto a glassy carbon electrode from equimolar AlCl3 + NaCl bath containing vanadium ions at 200 °C. The alloy deposits were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. The deposits were identified as Al3V and AlV3 alloys. It was found that intermetallic alloys were synthetized during aluminium underpotential deposition onto vanadium metal that was previously deposited on the glassy carbon electrode by diffusion-controlled overpotential deposition. Alloys were the result of solid-state interdiffusion between the initially deposited vanadium and the subsequently deposited aluminium. As a source to secure a constant concentration of vanadium in the electrolyte during deposition, vanadium anodic dissolution, and VCl3 melt addition were studied. The effect of vanadium ion concentration in the electrolyte on the composition and the surface morphology of the obtained deposits was investigated. The results indicate that controlled vanadium and aluminium codeposition could be a further step to the successful development of an advanced technology for Al3V and AlV3 alloy synthesis

Influence of Rare Earth Oxide Concentration on Electrochemical Co-Deposition of Nd and Pr from NdF3-PrF3-LiF Based Melts

The impact of rare earth oxide (REO) concentration on the deposition process and selective recovery of the metal being deposited from a molten fluoride salt system was investigated by applying deposition of Nd and Pr and varying the concentration of REO added to the electrolyte. A ternary phase diagram for the liquidus temperature of the NdF3-PrF3-LiF system was constructed to better predict the optimal electrolyte constitution. Cyclic voltammetry was used to record three redox signals, reflecting the processes involving Nd(III)/Nd and Pr(III)/Pr transformations. A two-step red/ox process for Nd(III) ions and a single-step red/ox process for Pr(III) ions were confirmed by square-wave voltammetry. The cyclic voltammetry results indicated the possibility of neodymium and praseodymium co-deposition. In order to sustain higher co-deposition rates on the cathode and to avoid increased production of PFC greenhouse gases on the anode, a low-overpotential deposition technique was used for Nd and Pr electrodeposition from the electrolyte with varying Nd2O3 and Pr6O11 concentrations. Co-deposited neodymium and praseodymium metals were characterized by electron probe microanalysis (EPMA) and X-ray diffraction (XRD) analysis. After electrodeposition, concentration profiles of neodymium and praseodymium were recorded, starting from the cathode surface towards the electrolyte bulk. The working temperature of 1050 °C of the molten fluoride salt basic electrolyte, in line with the constructed phase diagram, was validated by improved co-deposition and led to a more effective deposition process