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Search Results: 1 - 10 of 272539 matches for " Staj?i? Aleksandar P. "
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Hybrid Nd-Fe-B/barium ferrite magnetic materials with epoxy matrix
StajiAleksandar P.,Staji?-Tro?i? Jasna T.,Gruji? Aleksandar S.,Stijepovi? Mirko Z.
Hemijska Industrija , 2012, DOI: 10.2298/hemind111104098s
Abstract: Lately a great attention has been paid to the research of bonded hybrid composites with improved dynamic mechanical capacities capable of replacing bonded Nd-Fe-B magnetic materials, by using the cheaper (ferrite) materials instead of the Nd-Fe-B powder while retaining the satisfying values of the maximal magnetic energy. The objective of this study is to assess how different contents of Nd-Fe-B and/or barium ferrite particles can affect morphological, dynamic mechanical and magnetic properties of bonded composite materials. The interactions between employed magnetic powders and the interactions between magnetic powders and polymer binder are considered. For the examination of the magnetic behaviour, a vibrating sample magnetometer (VSM) is used. Different shapes and sizes of the obtained hysteresis loops are used for comparison and prediction of the polymer bonded materials properties. The homogeneous distribution of the magnetic particles in the polymer matrix is validated using the scanning electron microscope (SEM). The elastic and damping behaviour examined by the dynamic mechanical analysis (DMA) show improved properties for hybrid composite materials.
Complex odontoma associated with an impacted molar
Stojanovi? Dragana,StajiAleksandar,?oli? Snje?ana
Stomatolo?ki Glasnik Srbije , 2007, DOI: 10.2298/sgs0703195s
Abstract: Odontomas are the most common odontogenic tumors. They are usually asymptomatic and could be detected accidentally after an X-ray examination of the jaw. The most frequent location of odontomas is maxillary front. The case reported here is a complex odontoma found in the left mandible, associated with an impacted third molar of a 14-year-old girl. Under local anesthesia, both the impacted third molar and odontoma were surgically extracted. Histopathological examination confirmed the diagnosis of complex odontoma.
Evidence that ampicillin and streptomycin can suppress autotomic behavior in rats
Krsljak Elena S.,Staji? Z.
Acta Veterinaria , 2004, DOI: 10.2298/avb0403145k
Abstract: Autotomy is a phenomenon of deafferentation of the rat limb by transection of the sciatic and saphenous nerves, inducing an automutilation of the limb as a response to painful stimuli generated from the amputation neuroma. Autotomy has been proposed as an experimental model for neuralgia pain. The present study was designed to investigate the influence of streptomycin, ampicillin and chloramphenicol applied either in the vicinity of the nerve stump or intramuscularly. The course of autotomy was followed during 8 weeks using the scoring system of Wall et al. (1979). It was shown that streptomycin and ampicillin can suppress autotomy when applied topically whereas systemic use of the investigated antibiotics was efficient only when streptomycin was injected.
Prof. Dr. Sinisa Radojevic: Anatomist, surgeon, doyen and great friend of the Faculty of medicine in Novi Sad
Dragani? Vera P.,Le?iAleksandar,Mihalj Marija,Polzovi? Agneza
Medicinski Pregled , 2004, DOI: 10.2298/mpns0410505d
Abstract: Prof. Dr. Sinisa Radojevic was born in 1895 in Kragujevac. While still a boy, he participated in World War I and was awarded the Albanian Certificate of Service. He graduated from Grammar School and a School of Medicine and specialized Surgery in Bordeaux. He remained a Francophile his entire life, and published numerous scientific papers in France. He was a member of the French Academy of Medicine. After School of Medicine was founded in Belgrade, he returned to Serbia and began working at the Anatomy Institute of School of Medicine, Belgrade. At the time when School of Medicine was founded in Novi Sad, he took part in foundation of the Institute of Anatomy, holding the post of Institute Manager until he retired. With a huge enthusiasm, professor Radojevic had a leading role in organization of the Institute. He worked with and educated junior associates, who provided the Institute with extraordinary expert and scientific reputation. Professor Radojevic was an extraordinary figure, an exceptional anatomist and erudite, but primarily a warm and kind man of a true European orientation.
Time trend and clinical pattern of extrapulmonary tuberculosis in Serbia, 1993-2007
Pe?ut Dragica P.,Bulaji? Milica V.,Le?iAleksandar R.
Vojnosanitetski Pregled , 2012, DOI: 10.2298/vsp1203227p
Abstract: Background/Aim. Increased incidence of extrapulmonary tuberculosis (XPTB) is reported worldwide. Serbia is a country in socio-economic transition period with lowmiddle HIV prevalence and intermediate-to-low tuberculosis (TB) incidence rate, 100% directly observed treatment (DOT) coverage, and mandatory BCG vaccination at birth. The aim of the study was to examine the incidence trend and clinical features of XPTB in Serbia during a 15-year period. Methods. This retrospective observational study included XPTB cases diagnosed in the period between 1st January 1993 and 31st Decembre 2007, according to the reports of the National Referral Institute of Lung Diseases and Tuberculosis in Belgrade and Central Tuberculosis Register. Population estimates with extrapolations were based on 1991 and 2002 census data. Results. While the overall TB incidence rate showed a slight, not significant decreasing trend (p = 0.535), a significant increase was found for XPTB (y = 1.7996 + 0.089x; R2 = 0.4141; p = 0.01). A total of 2,858 XPTB cases (newly diagnosed and 10% relapses) gave an average age specific incidence rate of 2.51/100,000 population (95% confidence interval, SD = 0.6182) with 8.9% annual increase. The male-to-female ratio was 0.54. Lymph nodes were most frequently affected site (48.5%) followed by genitourinary (20.5%), pleural (12%), and osseo-arthicular (10.3%) TB. Treatment outcome was successful in 88.29% of patients (cured and completed), 3.64% died, 5.18% interrupted, 0.57% displaced, and 2.3% unknown. Conclusion. Increasing trend of XPTB incidence rate may be a result of increased morbidity due to still present risk factors, possible higher detection rate in Serbia and better notification. A high coverage of newborns with BCG vaccination at birth might contribute to a decreased number and rare XPTB cases in children.
Activity of antioxidative defense enzymes in the blood of patients with liver echinococcosis
Lili? Aleksandar,Den?i? Sr?an,Pavlovi? Sla?an Z.,Blagojevi? Du?ko P.
Vojnosanitetski Pregled , 2007, DOI: 10.2298/vsp0704235l
Abstract: Background/Aim. Chronic echinococcocal disease is the parasite human disease caused by the penetration of larval (asexual) stages of the canine tapeworm (Echinococcus granulosus) in the liver of humans. After the penetration of the parasite, the host organism react by activating complement- depending immune response. The aim of this study was to elucidate the influence of larval form of Echinococcus granulosus in the liver on the activity of antioxidative defense enzymes in the blood of patients before and after the surgical intervention. Methods. We investigated the activity of antioxidative defense enzymes: copper/zinc containing superoxide dismutase (CuZn SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR) and glutathione-S-transferase (GST) in the blood of patients before and after the surgical intervention in respect to the controls, clinically healthy persons. Results. Our results showed that the activity of the GSH-Px was significantly decreased in the plasma of the patients with echinocococal disease before the surgery in respect to the controls. The activity of GST was significantly higher in the blood of the patients after the surgery in comparison to the controls. Conclusion. Chronic liver echinoccocal disease caused significant changes of some antioxidative defense enzymes, first of all Se-dependent enzyme GSH-Px, which could be a suitabile biomarker in the biochemical evaluation of the disease. This work represents a first comprehensive study of the activity of antioxidative defense enzymes in cronic liver echinococcocosis in the patients before and after the surgical intervention in respect to the clinically healthy persons.
Interdependence between oscillations and transients of delayed fluorescence induction processes in the thylakoid membrane of the intact maize leaf: Responses to effects of increased temperatures and drought
Radenovi? ?edomir N.,Markovi? Ksenija P.,Radoj?iAleksandar R.,An?elkovi? Violeta B.
Zbornik Matice Srpske za Prirodne Nauke , 2010, DOI: 10.2298/zmspn1018007r
Abstract: Standard induction processes of delayed fluorescence (DF) of chlorophyll (induction signals) occur when an intact leaf segment of maize inbreds and hybrids is kept in the phosphoroscope darkroom for more than 15 minutes (t > 15 min), and at the same time the leaf is illuminated with the intermittent white light. Resolved induction processes of DF chlorophyll into transients: A, B, C, D and E occur when the intact leaf segment of maize inbreds and hybrids is kept in the phosphoroscope darkroom for a significantly shorter period (500 s > t > 30 s), with the time rate t of 30 s, prior to its illumination with the intermittent white light. Induction transients: A, B, C, D and E are characterized with the time of their generation: tA = 31±6 ms (A), tB = 5 ± 0,5 s (B), tC = 15±5 s (C), tD = 360±20 s (D) and tE = 670±35 s (E), dynamics of changes in transients intensities (IA, IB, IC, ID and IE) and mechanisms of their generation. The induction processes of chlorophyll DF of the intact leaf of maize inbreds and hybrids resolved into transients: A, B, C, D and E are accompanied by the occurrence and different levels of activation energy (Ea, kJ mol-1) that correspond to critical temperatures ranging from 28 to 33°C. The generation mechanisms of induction transients A, B, C, D and E classify them into two groups. Transients A and B are of a physical character, while the transients: C, D, and E are of a chemical character. It is shown that the generation of the induction transients: B, C, D and E simultaneously follows establishing of the oscillations of induction processes of the DF chlorophyll. Oscillating of induction processes of DF chlorophyll is explained by the ion (K+, Na+, H+, Cl-) transport mechanism across the thylakoid membrane of the intact leaf of maize inbreds and hybrids grown under conditions of air drought, increased temperatures and water deficiency in the medium.
Chemical composition and antioxidant activity of berry fruits
Staji? Sla?ana M.,Tepi? Aleksandra N.,?ilas Sonja M.,?umi? Zdravko M.
Acta Periodica Technologica , 2012, DOI: 10.2298/apt1243093s
Abstract: The main chemical composition, contents of total phenolic (TPh), total flavonoid (TF), and total monomeric anthocyianin (TMA), as well as the antioxidant activity of two raspberry cultivars (Meeker and Willamette), two blackberry cultivars ( a anska bestrna and Thornfree) and wild bilberry were studied. The raspberry cultivars had the highest total solids among fruits investigated. Bilberry fruits had the highest sugar-to-acid ratio. Blackberry fruits were richer in crude fibers (cellulose) in comparison to raspberry and bilberry fruits. The content of pectic substances was highest in the bilberry. Also, bilberry had a highest content of TPh (808.12 mg GAE/100 g FW), TF (716.31 mg RE/100 g FW) and TMA (447.83 mg CGE/100 g FW). The antioxidant activity was evaluated spectrophotometrically, using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity assay. The DPPH free radical scavenging activity, expressed as the EC50 value (in mg of fresh weight of berry fruit per ml of the reaction mixture), of bilberry (0.3157 ± 0.0145 mg/ml) was the highest. These results also showed that the antioxidant value of 100 g FW bilberry, raspberry - Willamette, raspberry - Meeker, blackberry - a anska bestrna and blackberry - Thornfree is equivalent to 576.50 mg, 282.74 mg, 191.58 mg, 222.28 mg and 272.01 mg of vitamin C, respectively. There was a significant positive correlation between the antioxidant activities and content of total phenolics (RTPh 2=0.9627), flavonoids (RTF 2=0.9598) and anthocyanins (RTMA 2=0.9496) in berry fruits. [Projekat Ministarstva nauke Republike Srbije, br. TR 31044]
Low-temperature tension properties of glass-epoxy composite materials
Puti? Slavi?a S.,Stamenovi? Marina R.,Baj?eta Branislav B.,Staji? Predrag S.
Acta Periodica Technologica , 2005, DOI: 10.2298/apt0536123p
Abstract: The aim of this paper was to present the determination of tensile strength Rm and modulus of elasticity Et of glass-epoxy composites at two different temperatures (at room temperature t=20°C, and at t =—50°C). Standard mechanical testing was carried out on glass woven-epoxy composite material with different structures (two specific weights of reinforcement, 210 g/m2 and 550 g/m2) and orientations (0°/90° and ±45°). Micromechanical analysis of failure was performed on a stereo microscope and SEM in order to determine real models and mechanisms of crack.
Investigation method of torsional properties and damages of glass/epoxy composite pipes
Puti? Slavi?a S.,Stamenovi? Marina R.,Staji? Predrag S.,Baj?eta Branislav B.
Acta Periodica Technologica , 2006, DOI: 10.2298/apt0637097p
Abstract: Pipes made of composites glass fiber/epoxy resin are predominantly used in the chemical industry, construction, infrastructure and war technique. The pipes made for this purpose are in their use exposed to static and dynamic loading. Depending on the purpose, the pipes, especially those in complex structures, can be loaded by torsion. In that case, exceeding allowed tensions can cause damages such as cracking the fibers and matrix delamination. These damages can lead to the appearance of cracks on the pipes and in many cases to complete breakage of the pipe. Because of this, it is very important to evaluate composite pipes exposed to torsion and find out in which way the construction is weakened, what actually is the main goal of this paper.
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