From Bio-waste to Bone Substitute: Synthesis of Biomimetic Hydroxyapatite and Its Use in Chitosan-based Composite Scaffold Preparation

Nanocomposite structure of the bone can be mimicked by chitosan/hydroxyapatite (CS/HAp) composite scaffold. Biological hydroxyapatite (HAp) contains various ions, which have a crucial role in bone growth. The aim of the present work was to synthesize biomimetic hydroxyapatite and prepare composite scaffolds based on chitosan, where HAp was synthesised from hen eggshells, seashells and cuttlefish bone. The powders were composed of nano-structured calcium deficient HAp and amorphous calcium phosphate (ACP). In the as-prepared powders, Sr2+, Mg2+ and Na+ ions were detected as a result of using biogenic precursor of Ca2+ ions. Highly porous CS/HAp structures have been prepared by freeze-gelation technique. The CS/HAp scaffolds have shown highly porous structure with very well interconnected pores and homogeneously dispersed HAp particles. The MTT assay of CS/HAp scaffolds has shown no toxicity, and the live/dead assay has confirmed good viability and proliferation of seeded cells. This work is licensed under a Creative Commons Attribution 4.0 International License

Sharpness of the phase transition and exponential decay of the subcritical cluster size for percolation on quasi-transitive graphs

We study homogeneous, independent percolation on general quasi-transitive graphs. We prove that in the disorder regime where all clusters are finite almost surely, in fact the expectation of the cluster size is finite. This extends a well-known theorem by Menshikov and Aizenman & Barsky to all quasi-transitive graphs. Moreover we deduce that in this disorder regime the cluster size distribution decays exponentially, extending a result of Aizenman & Newman. Our results apply to both edge and site percolation, as well as long range (edge) percolation. The proof is based on a modification of the Aizenman & Barsky method.Comment: Latex 2e; 25 pages (a4wide); small editorial corrections; one reference adde

GRAIN AND OIL YIELD INVESTIGATED SUNFLOWER HYBRIDS DEPENDING ON THE GROWING SEASON

U četverogodišnjim poljskim pokusima (od 2001.-2004.) u zapadnoj Slavoniji (Nova Gradiška) istraživan je utjecaj vremenskih prilika (godine) i hibrida suncokreta na prinos sjemena i ulja. U pokusu je istraživano pet hibrida suncokreta: PR63A90, Alzan, Aleksandra, Opera i Pixel. Dobiveni rezultati istraživanja pokazali su da na prinos sjemena i ulja značajan utjecaj imaju vremenske prilike (godina), hibrid i njihova interakcija. Najveći prinosi sjemena i ulja po hektaru ostvareni su u godini u kojoj je tijekom srpnja palo 65 mm, a tijekom kolovoza 48 mm oborina, a prosječna relativna vlaga zraka tijekom vegetacije bila je ispod 70%. Visoki sadržaj ulja u sjemenu ostvaren je u godini s dovoljno vlage u tlu tijekom faze sinteze ulja, višom srednjom dnevnom temperaturom (21,7oC) u fazi intenzivne sinteze ulja, a nižom (14,1oC) u fazi usporene sinteze ulja. Značajno najveći prinos sjemena (3901 kg/ha) i ulja (1688 kg/ha) ostvaren je u 2003. godini, dok je najveći sadržaj ulja (54,94% u s. t.) ostvaren u 2001. godini. Po prinosu sjemena i ulja po hektaru najrodniji hibridi bili su: PR63A90 i Aleksandra. Najveći sadržaj ulja u sjemenu (51,56% u s. t.) imao je hibrid Opera.In four-year field experiments (2001-2004) conducted in Western Slavonia (Nova Gradiška) influence of weather conditions (year) and sunflower hybrids on grain and oil yield was investigated. In the experiments five sunflower hybrids (PR63A90, Alzan, Aleksandra, Opera and Pixel) were investigated. Obtained results have indicated that weather conditions, hybrid and their interaction have significant influence on grain and oil yield. The highest grain and oil yield per hectare were obtained in the year with 65 mm precipitation in July, 48 mm in August and relative air humidity during the sunflower vegetation below 70%. High oil content in seed was obtained in the year with sufficient soil moisture during the oil synthesis, higher mean air daily temperature (21.70C) in the stage of intensive oil sythesis, and lower (14.10C) in the stage of slower oil synthesis. Significantly the highest grain (3901 kg/ha) and oil (1688 kg/ha) yield were obtained in 2003 year, while the highest oil content (54.94% in d. m.) was obtained in 2001 year. According to grain and oil yield, the most productive hybrids were: PR63A90 and Aleksandra whereas the highest oil content in seed (51.56% in d. m.) had Opera hybrid

Partial replacement of soybean meal with pumpkin seed cake in lamb diets: Effects on carcass traits, haemato-chemical parameters and fatty acids in meat

The composition of lamb diets has an effect on production traits and meat quality, especially fatty acid proportions. Recently, in organic farming, soybean meal has frequently been replaced with feedstuffs that are rich in protein. The aim of the present study was to determine the effects of partial replacement of soybean meal with pumpkin seed cake on carcass traits, biochemical parameters and fatty acids of lamb meat produced in organic farming. The research was carried out on 70-day-old lambs of the Merinolandschaf breed. Thirty-six lambs were grouped by gender, and allotted to three treatment groups, which were given one of the three diets: control diet with no pumpkin seed cake; a diet in which 10% of soybean meal was replaced with 10% pumpkin seed cake; and a diet in which 15% of soybean meal was replaced with 15% pumpkin seed cake. The experimental feeding period was 30 days. Hay and water were provided ad libitum. Differential blood tests and haematological parameters were determined, and the concentrations of minerals and biochemical parameters, and enzyme activity were ascertained in blood serum. Carcass traits and lamb meat colour did not differ among dietary treatments. Significant differences were observed in the concentrations of some biochemical parameters, which indicated good energy and protein balance, and changes in fat metabolism that did not impair antioxidant status. Compared with the control, the concentration of linoleic acid (C18:2 n-6) was higher in diets containing 10% and 15% of pumpkin seed cake replacements. The results indicated that partial replacement of soybean meal with 10% or 15% of pumpkin seed cake could be implemented in lamb feeding in organic farming without major changes in carcass traits, haemato-chemical parameters and the fatty acid profile in meat.Keywords: Blood parameters, meat quality, Merinolandschaf lambs, organic farmin

REPRODUCTIVE PARAMETERS OF THOROUGHBRED MARES IN CROATIA

For the purpose of gaining better cognition on Thoroughbred breeding in Croatia, reproductive parameters of 87 Thoroughbred mares were analyzed. An average age of the first covering and foaling were 5.9 and 6.6 years, respectively. The average gestation length was 341.1 days and the most frequent foaling period (20.2% of foalings) was recorded between 336 to 340 days of gestation. Prolonged gestation period (p<0.05) was determined in colts. The gestation length was the longest in January (344.4 days) and the shortest in July (324.0 days). Between the gestation length and the age of the mare no significant correlation was found. There was a trend of foaling rate decreasing in mares older than 11 years. The highest number of successively registered foalings with 10 live born foals was observed on 2 individual samples. The greatest number of foalings occurred in April (30.9%), whilst there was no foaling in October. The genders were 50.6% male and 49.4% female foals. The incidence of abortions was 7.3%. Although indicators point to the breeding strategy heading towards the right direction, by educating the owners and with frequent veterinary supervision, especially for twin reduction, the reproductive performance could be enhanced

PRODUCTION POTENTIAL OF ENDANGERED BREEDS OF SHEEP IN CROATIA AND MONTENEGRO

Cilj je ovoga rada bio utvrditi proizvodni potencijal i veličinu populacije ugroženih pasmina ovaca u Republici Hrvatskoj i Crnoj Gori. U Republici Hrvatskoj se uzgaja 9 izvornih pasmina ovaca od kojih je samo jedna visoko ugrožena (dubrovačka ruda: 702 grla), a 5 su potencijalno ugrožene (cigaja, rapska ovca, creska ovca, istarska ovca i krčka ovca). Najveću tjelesnu masu i veličinu legla ima cigaja (74,64 kg i 1,21), a najmanju krčka ovca (35,44 kg i 1,06). Najviše mlijeka u laktaciji proizvedu istarska ovca i cigaja, a najmanje creska ovca i rapska ovca. Završni dnevni prirast i prosječni dnevni prirast muške janjadi u field uvjetima bili su najveći u cigaje (307 g i 35,77 kg), a najmanji u janjadi krčke ovce. U Crnoj Gori se uzgaja 6 izvornih pasmina ovaca. Zetska žuja je najmalobrojnija pasmina ovaca u Crnoj Gori i ima status kritično ugrožene pasmine (oko 150 grla), dok su pivska pramenka, sora i ljaba potencijalno ugrožene pasmine. Najbolje proizvodne rezultate (mliječnost) imaju pivska i bardoka (106,8 i 110 kg), a najlošije zetska žuja (49,6 kg). Proizvodni potencijal ugroženih pasmina ovaca u obje zemlje ukazuje na opravdanost značaj¬nijih ulaganja u širenje njihovih uzgoja, što će pridonijeti i podizanju profitabilnosti uzgoja kao i povećanju interesa za navedene pasmine ovaca.The aim of the present study was to determine the production potential and the size of the population of endangered sheep breeds in Croatia and Montenegro. In the Republic of Croatia 9 native breeds of sheep are reared, of which only 1 is highly endangered (Dubrovnik ruda: 702 animals), and 5 are potentially endangered (Tsigai, Rab sheep, Cres sheep, Istrian sheep and Krk sheep). Tsigai has the highest body weight and litter size (74.64 kg and 1.21) and the lowest Krk sheep (35.44 kg and 1.06). Istrian sheep and Tsigai have the highest amount of milk and Cres sheep and Rab sheep the lowest. The final daily gain and average daily gain of male lambs in field conditions were the best in Tsigai (307 g 35.77 kg) and the poorest in lambs of Krk sheep. In Montenegro, 6 native breeds of sheep are reared. Zetska zuja is the smallest breed of sheep in Montenegro and has the status of a critically endangered breed (about 150 animals), while Pivska pramenka, Sora and Ljaba are potentially endangered breeds. Pivska pramenka and Bardoka have the highest productive performance (milk production; 106.8 and 110 kg), and Zetska zuja the lowest (49.6 kg). Production potential of endangered breeds of sheep in both countries indicates the justification of significant investment in the expansion of their breeding, which will contribute to increasing the profitability of farming as well as increasing interest in the breed of sheep

DETERMINATION OF CALCIUM CONTENT IN DIETARY SUPPLEMENTS

Calcium is a macro element that is very important for the human body: its content and circulation in the body is large, it serves as the electrolyte, it has a building role and participates in the process of metabolism. The European Union, the World Health Organization (WHO) and the Ministry of Food and Drug (Food and Drug Administration, FDA) gave the RDA (Recommended Dietary Allowances,) for this macro element. The absorption and bioavailability of the calcium may vary depending on a number of factors, and because all of the foregoing it is consumed by means of different supplements. The aim of this study was to determine the content of calcium in the various diet products using the volumetric analytical method of analysis. Supplements that were analyzed are divided into two groups. The first group consists supplements in which the calcium is present in the form of different chemical compounds, and the second group consists of supplements of a number of different manufacturers in which the calcium is in the form of calcium carbonate. Calcium content, obtained by applying the method above, which ranged from 95.11% to 99.80% compared to the theoretical value. Results were analyzed using the t-test, while not producing a statistically significant difference