Because of their global distribution, persistence, and tendency to bioaccumulate, concerns about perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are growing. We determined the toxicity of PFOS and PFOA in several freshwater organisms, including two cladocerans, Daphnia magna and Moina macrocopa, and the teleost Oryzias latipes. In general, PFOS is approximately 10 times more toxic than PFOA in these organisms. In M. macrocopa, the median lethal concentration (LC50) was 17.95 mg/L for PFOS and 199.51 mg/L for PFOA. Moina macrocopa exhibited greater sensitivity than D. magna to both perfluorinated compounds in both acute and chronic exposures. In the 48-h acute toxicity test, M. macrocopa was approximately two times more sensitive than D. magna. In the 7-d chronic toxicity test, M. macrocopa showed significant reproductive changes at 0.31 mg/L for PFOS, which was approximately seven times lower than the effect concentrations observed over the 21-d exposure in D. magna. Two-generation fish toxicity tests showed that parental exposure to both compounds affected the performance of offspring. Unexposed progeny-generation (F1) fish exhibited elevated mortality and histopathological changes that were correlated with exposure in the parental generation (F0). Continuous exposure from F0 through F1 generations increased the extent of adverse effects. Considering the persistent nature of PFOS and PFOA, more research is required to determine potential consequences of long-term exposure to these compounds in aquatic ecosystems.

Aggressive surgical resection in selected patients with brain metastases from colorectal cancer may prolong survival, even in the presence of extracranial metastatic lesions.

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Micro-computed tomography with novel software provided valuable anatomical information for optimizing instrumentation and minimizing mishaps in nonsurgical root canal treatment.

The purpose of this study was to assess the influence of the types and thicknesses of glass ceramic plates on light transmittance and compare the degrees of conversion (DC) of resin cement under the ceramic materials. Three ceramic plates with thicknesses of 0.5, 1.0, 2.0, and 4.0 mm were fabricated from each of five commercial ceramic blocks in shade A2: high-translucency and low-translucency IPS Empress CAD (Emp_HT and Emp_LT); high-translucency and low-translucency IPS e.max CAD (Emx_HT and Emx_LT); and Vita Mark II (Vita). The translucency parameter was obtained using a colorimeter. The light transmittance rate was measured using a photodetector attached to an optical power meter. The DC of a resin cement (Variolink N) underneath the ceramic plates was examined by Fourier transform infrared spectroscopy. The translucency parameter, light transmittance rate, and DC showed significant differences by ceramic type and thickness (P < 0.05). The Emp_HT specimens showed the highest light transmission and DCs, and the Emx_LT showed the least light transmission and the lowest DCs. The high-translucency Empress showed significantly higher DCs than the low-translucency types (P < 0.05), but there was no significant difference in e.max (P > 0.05). Both type and thickness of the glass ceramics significantly influenced the light transmittance and DC of the light-cured resin cement beneath the ceramic of the same shade.