Contact angle hysteresis in the clay-water-air system of soils

The purpose of this research is to study the change in wettability of clays due to the influence of mesophilic soil microorganisms' activity when adding model contaminants: water-in-oil emulsion, glycerol and oleic acid. During the experiments, the objectives of this study were to specify peculiarities of wetting contact angle hysteresis of clays with substrates of different mineral composition and microbial activity. Hydrophilicity/hydrophobicity of the stimulator for microbial activity does not have a clear effect on clay properties. The surface heterogeneity mostly increases with time, perhaps, due to biofilm exudates whatever was a type of microbial stimulator. Chemical and geometric heterogeneities played comparable roles in the surface hydrophilic-hydrophobic balance. Results obtained prove that microbial communities and/or the Fe chemical state alteration (pyrite, hematite or goethite) were responsible for both hydrophilization and hydrophobization of the surface. The equation for the drop spreading rate was presented and verified by well comparison of experimental results with simulations.179-19

Dioxin-induced changes in epididymal sperm count and spermatogenesis Mudanças induzidas por dioxina na contagem epididimal de esperma e espermatogênese

A single in utero exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on gestation day 15 decreased epididymal sperm count in adult rats and thus was used to establish a tolerable daily intake for TCDD. However, several laboratories have been unable to replicate these findings. Moreover, conflicting reports of TCDD effects on daily sperm production suggest that spermatogenesis may not be as sensitive to the adverse effects of TCDD as previously thought. We performed a PubMed search using relevant search terms linking dioxin exposure with adverse effects on reproduction and spermatogenesis. Developmental exposure to TCDD is consistently linked with decreased cauda epididymal sperm counts in animal studies, although at higher dose levels than those used in some earlier studies. However, the evidence linking in utero TCDD exposure and spermatogenesis is not convincing. Animal studies provide clear evidence of an adverse effect of in utero TCDD exposure on epididymal sperm count but do not support the conclusion that spermatogenesis is adversely affected. The mechanisms underlying decreased epididymal sperm count are unknown; however, we postulate that epididymal function is the key target for the adverse effects of TCDD.<br>Uma única exposição in utero a 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) no 15º dia de gestação diminuiu a contagem de esperma epididimal em ratos adultos e por isso foi utilizada para estabelecer uma dosagem diária tolerável para TCDD. No entanto, diversos laboratórios não conseguiram reproduzir esses resultados. Além disso, relatórios conflitantes dos efeitos de TCDD na produção diária de esperma sugere que espermatogênese pode não ser tão sensível aos efeitos adversos do TCDD como antes se pensava. Foi feita uma pesquisa no PubMed usando termos de pesquisa relevantes, relacionados à exposição à dioxina com efeitos adversos na reprodução e na espermatogênese. Exposição em desenvolvimento ao TCDD é consistentemente relacionada à diminuição da contagem da cauda epididimal de esperma, mas não apoia a conclusão de que a espermatogênese é afetada. Os mecanismos por trás da diminuição da contagem de esperma epididimal são desconhecidos; no entanto, contestamos que a função epididimal é a chave para efeitos adversos do TCDD

Asynchronous Circuit Synthesis by Direct Mapping: Interfacing to Environment

info:eu-repo/semantics/publishe