Objective This study aims to investigate and compare the toxic effects of four types of metal oxide （ZnO, TiO2, SiO2, and Al2O3） nanoparticles with similar primary size （-20 nm） on human fetal lung fibroblasts （HFL1） in vitro.Methods The HFL1 cells were exposed to the nanoparticles, and toxic effects were analyzed by using MTT assay, cellular morphology observation and Hoechst 33 258 staining.Results The results show that the four types of metal oxide nanoparticles lead to cellular mitochondrial dysfunction, morphological modifications and apoptosis at the concentration range of 0.25-1.50 mg/mL and the toxic effects are obviously displayed in dose-dependent manner. ZnO is the most toxic nanomaterials followed by TiO2, SiO2, and Al2O3 nanoparticles in a descending order.Conclusion The results highlight the differential cytotoxicity associated with exposure to ZnO, TiO2, SiO2, and Al2O3 nanoparticles, and suggest an extreme attention to safety utilization of these nanomaterials.
Objective To perform the modulation of an assay system for the sensory integration of 2 sensory stimuli that inhibit each other.Methods The assay system for assessing the integrative response to 2 reciprocally-inhibitory sensory stimuli was modulated by changing the metal ion barrier.Moreover,the hen-1,ttx-3 and casy-1 mutants having known defects in integrative response were used to evaluate the modulated assay systems.Based on the examined assay systems,new genes possibly involved in the sensory integration control were identified.Results In the presence of different metal ion barriers and diacetyl,locomotion behaviors,basic movements,pan-neuronal,cholinergic and GABAergic neuronal GFP expressions,neuronal development,structures of sensory neurons and interneurons,and stress response of nematodes in different regions of examined assay systems were normal,and chemotaxis toward different concentrations of diacetyl and avoidance of different concentrations of metal ions were inhibited.In the first group,most of the nematodes moved to diacetyl by crossing the barrier of Fe2＋,Zn2＋,or Mn2＋.In the second group,almost half of the nematodes moved to diacetyl by crossing the barrier of Ag＋,Cu2＋,Cr2＋,or Cd2＋.In the third group,only a small number of nematodes moved to diacetyl by crossing the barrier of Pb2＋ or Hg2＋.Moreover,when nematodes encountered different metal ion barriers during migration toward diacetyl,the percentage of nematodes moving back and then turning and that of nematodes moving straight to diacetyl were very different.With the aid of examined assay systems,it was found that mutations of fsn-1 that encodes a F-box protein,and its target scd-2 that encodes a receptor tyrosine kinase,caused severe defects in integrative response,and the sensory integration defects of fsn-1 mutants were obviously inhibited by scd-2 mutation.Conclusion Based on the nematode behaviors in examined assay systems,3 groups of assay systems were obtained.The first group may be helpful in evaluating or identifying
This study aims to investigate the effects of a probe and a cup horn on the de-agglomeration efficiency in ultrasound vibration processes. TiO2 and Al2O3 nanoparticle dispersions were prepared in distilled water at a concentration of 50.0 mg/mL followed by treatment with a dispersion stabilizer （100% FBS） and ultrasound vibration at 20 kHz and 35% amplitude for 10 min by a probe and a cup horn, respectively. The average sizes of dispersed TiO2 and Al2O3 nanoparticles were measured by a dynamic light scattering device. Compared to dispersion with the probe sonicating, the average sizes of TiO2 and Al2O3 particles sonicated by the cup horn are markedly smaller at time points of 30, 60, 120, and 180 min. The TiOe and Al2O3 particle size distributions of cup horn-treated suspensions were narrower than those of probe-treated suspensions at time points of 120 and 180 min. It is suggested that the cup horn has a higher efficiency than the probe in dispersing nanoparticles, The cup horn is better than the probe for processing multiple small sample vessels simultaneously. Indirect cup horn sonication is ideal for processing pathogenic and sterile samples.
