Authors:P. Jovin, L. Đukanović, Z. Jovanović, M. Vesković and J. Tošić
The seed maize hybrid ZP 677 was tested under irrigated conditions on the DPP Maglic estate in Backi Maglic during 2000 and 2001. Sowing the female component of the hybrid ZP 677 at an inter-row spacing of 70 cm resulted in both higher yield (4.55 t ha-1) and higher number of seeds per unit area (15,407,000) in comparison to sowing at an inter-row spacing of 35 cm, where the corresponding values were 4.39 t ha-1 and 14,667,000, respectively. At sowing densities of 71,425, 85,538 and 99,899 plants ha-1, yields of 4.46, 4.38 and 4.59 th ha-1 were recorded, while the number of seeds per unit area amounted to 14,670,000, 14,769,000 and 15,686,000, respectively. The 1000-seed weight decreased on average for all seed fractions at both inter-row spacings as the sowing density increased. Neither inter-row spacing nor sowing density affected the seed germination obtained with the standard test method, but germination in the cold test exhibited an insignificant increase with an increase in sowing density.
Authors:V. Živanović, S. Grujić, M. Tošić, N. Blagojević and J. Nikolić
The crystallization of K2O·TiO2·3GeO2 glass under non-isothermal condition was studied. In powdered glass with particle sizes less than 0.15 mm, surface crystallization
was dominant and an activation energy of crystal growth of Ea,s=327±50 kJ mol−1 was calculated. In the size range 0.15 to 0.45 mm, both surface and volume crystallization occurred. For particle sizes >0.45
mm, volume crystallization dominated with spherulitic morphology of the crystals growth and Ea,v=359±64 kJ mol−1 was calculated.
Authors:S Grujić, N Blagojević, M Tošić, V Živanović and B Božović
effect of replacing 20 mol% of GeO2 by TiO2
on the properties of potassium germanate glass was investigated. The structure
and devitrification behaviour of glasses were studied by Fourier transform
infrared spectroscopy (FTIR), differential thermal analysis (DTA) and X-ray
diffraction (XRD). It was observed that potassium titanium germanate has a
higher glass transition temperature and a higher thermal stability vs. crystallization.
The presence of two exothermic peaks on the DTA curve of potassium germanate
glass indicates the complex crystallization process. The XRD pattern of this
glass heated at the temperature of the first crystallization peak indicated
that the GeO2 and K2Ge7O15
were formed. Only the K2TiGe3O9
phase was identified, in a case when potassium titanium germanate glass was
heated at the temperature of the crystallization peak.
Authors:T. Vulić, Č. Oparnica, B. Djordjević, S. Kuzmanović, M. Sta rović, R. Ford and M. Tošić
Graft transmissibility of the plum sectorial resistance to Plum pox virus (PPV) was investigated. Sectorial resistance is the resistance which is manifested in a sector or portion of infected plant, where virus is not present. Sectorial resistance to PPV is exhibited in the crown or in primary shoots of the plum tree. Double budding method was applied. One bud was carrying sectorial resistance to PPV, while the other one was infected with the virus. Infection on shoots was evaluated by symptoms appearance and serological test for PPV presence.Among three plum cultivars the best results were obtained with cv. “Crvena ranka“. Sectorial resistance to PPV has been successfully transmitted by buds of “Crvena ranka“. Plum cv. “Čačanska rodna“ failed to transmit sectorial resistance. Plum cv. “Stanley“ was between those two above-mentioned plum cultivars.
Authors:Milica Jovanović, Branko Milošević, Olga Dulović, Mijomir Pelemiš, Goran Stevanović, Tanja Tošić, Branka Stošović and M.J. Zervos
The purpose of this study was to evaluate the molecular relatedness of clinical isolates of vancomycin-resistant enterococci (VRE) collected from patients of the Clinic for Infectious and Tropical Diseases in Belgrade. Among 40 isolates available for the investigation, 36 were identified as Enterococcus faecium, whereas 2 were Enterococcus faecalis and Enterococcus raffinosus, respectively. Pulsed-field gel electrophoresis (PFGE) typing revealed 21 strain types, comprising 7 clusters which contained at least two isolates and 14 unique PFGE patterns. Although we searched for pathogenicity factor genes (gelE, cylB, asa1, efaAfs, esp, cpd, cob) in representatives of all macro-restriction patterns, they have been confirmed in only one clone of E. faecalis. Genes esp and hyl, commonly found in E. faecium, were yilded in 10 macro-restriction patterns of this species, and their presence could not be ascribed to clonally related strains (p = 0.05). All VRE isolates were multiresistant and positive for vanA gene. Twenty strains of VRE and 6 clusters obtained from Intensive care unit (ICU) are proof of intensive transmission of these microorganisms at this department. The results of this study suggest wide genotypic variability among the clinical VRE isolates, but also intrahospital dissemination of some of them.