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Self-compacting concrete (SCC) is undoubtedly a promising ecological cement matrix composite of new generation. However, it is not easy to achieve the required combination of properties in fresh SCC mixes. SCC is also particularly sensitive to any changes in the laboratory and at the job site. Choice of constituents for SCC, especially cement and superplasticiser which are able to collaborate in the correct way, has a significant effect on SCC performance. In this investigation considered in qualitative way, four cements, varying in physical and chemical properties and phase composition were used to check their compatibility with a new generation superplasticiser, taking into account the properties of fresh and hardened self-compacting concretes. Results revealed some differences although it is impossible to answer definitely which cement performs with the superplasticiser in the best way.
The cheetah (Acinonyx jubatus) is one of highly endangered species because of low biodiversity, loss of habitat in the wild and reproductive problems in zoos, partially of male origin. The 11-year-old cheetah had no offspring in the past. Semen was collected by electroejaculation. The procedure was performed under general anesthesia using 3.5 mg of xylasine and 5.7 mg of ketamine per kg of body weight. An endorectal electrode was used and electrical stimuli were applied until ejaculation, which occurred as the result of 6 impulses. The 1 ml of semen collected was of olive colour, milky consistency and cat odour. The semen was evaluated microscopically as semi-dense. The progressive movement was observed in 15% of spermatozoa and 50% of spermatozoa were estimated as morphologically normal. The blood testosterone concentration amounted to <0,2 ng/ml. In conclusion, electroejaculation could be an effective method of semen collection in cheetah.
The aim of this study was to compare the efficiency of in vitro maturation in relationship to pathomorphology of uterus and oocytes quality. Morphological evaluation of the uterus helped to classify the queens into one of three groups: those with normal uteri, those with transformed uteri and pregnant queens. Cumulus-oocyte complexes were separated at recovery into three types according to pigmetation, uniformity and smoothness of ooplasm, compactness and number of layers of cumulus cells, as well as integrity of zona pellucida. Oocytes were maturated for 36 hours at 38°C in M199 medium containing cysteine and 17b oestradiol. After IVM, the meiotic status of oocytes was determined and the percentage of matured oocytes was calculated in relationship to COCs quality and uterus condition. In the group with normal uterus, oocytes of class A maturated (63.93%) better than oocytes class B and C, although the differences in maturation of oocytes class A and B were not statistically significant. The worst results of IVM were for oocytes class C. In the group of transformed uterus, 55.17% of oocytes class A maturated, while in only 7.84% of oocytes class C metaphase II had been observed. Significant differences were established in availability to IVM between oocytes class A and C as well as class B and C. In the group with pregnant uteri, the highest percentage of matured oocytes was in class A (46.27%), though there are no statistically significant differences in IVM between oocytes class A and B (28.8%), and the oocytes class C maturated in only 1.82%. Only oocytes of class A and B should be qualified for IVM procedure. Pregnant queens as well as queens with transformed uteri can also serve as oocyte donors for in vitro maturation.
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