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Nowadays, with the applications of titanium dioxide nanoparticles (TiO₂-NPs) in pharmacy, food industry, cosmetics, toothpaste and sunscreens, pregnant women are exposed to nanoparticles. Since tooth development is vuln-erable to environmental impacts and mandibular first molar bud develops before maxillary first molar bud, in this ex-perimental study the effects of TiO₂-NPs on the development of first mandibular molar bud in NMRI mouse was inve-stigated. Twenty five female NMRI mice were randomly divided into five groups (N=5); Control group (pregnant mice without any treatment), sham group (treated with distilled water), experimental groups 1, 2 and 3 (treated with 50, 150 and 500 mg/kg BW TiO₂-NPs, respectively, via gavage from embryonic days 10.5-14.5). On E14.5, embryos heads were prepared for histological examination and dental tissues were evaluated. Data were analyzed by ANOVA and post hoc test (Tukey). Microscopic observation showed tissue disorganization in experimental groups. Findings showed that in experimental groups 1 and 2, the diameter of bud and dental papilla and the length of dental bud decreased sign-ificantly. In experimental group 2, decrease in the diameter of dental follicle, dental bud and dental papilla and the le-ngth of dental bud was significant. On the other hand, in experimental group 3, only the decrease in the length of dental bud was significant. These findings showed that nano titanium dioxide can reduce the size of dental buds and is capable of preventing tooth development.

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In this study, the morphology and organization of the retina of Caspian kutum and fish response to ambient light as retinomotor reaction was investigated. The Rutilus frisii subsp. kutum is an anadromous fish and important native fish specimen of Caspian Sea. The specimens were obtained from Shahid Ansari Teleost Reproduction and Culture center (Guilan province, Iran). For light and dark adaptation fish were left in dark and light at least 30 minute prior to death. The eye retina were dissected out and processed for histological and SEM studies. The eye retina of Caspian kutum like most vertebrates, was composed of ten layers. Two types of photoreceptor cells including rod and short single cone were identified. Sagittal and transverse retinal sections did not show any particular patterns of cone arrangement. The retinomotor response observed in adapted retina to light and dark conditions revealed that Caspian kutum strongly reacts to changing light conditions. A remarkable pigment index indicated kutum relied mostly on rod rather than cone vision. The movement of pigment granules and slight change of cone myoid showed that the fish could recognize colors.

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Background: Nowadays, due to the increasing growth of production and consumption of nanoparticles, problems such as their entry into fersh waters and aquatic poisoning have arisen. Iron oxide nanoparticles are among the most widely used in this field. Alfalfa (Medicago sativa), a flowering plant belonging to the legume family, contains high amounts of protein, calcium, various vitamins and antioxidant effects. The aim of this research was to investigate the combined effect of iron oxide nanoparticles (Fe2O3)and alfalfa plant on growth parameters and pathology of digestive tract, liver and kidney of koi fish (an example of carp fish with a variety of colors and eye-catching effect).
Materials and Methods: In this experimental research, the number of 60 koi fish larvae were randomly divided into 6 groups including the control group and 5 experimental groups. The effect of feeding koi fish larvae with biomar combined with 10% and 20% alfalfa and being exposed to iron oxide nanoparticles with a concentration of 100 mg/l for 14 days in 5 treatment groups was investigated in comparison with the control group. The collected data were analyzed by Excel and SPSS 20 statistical software.