Resumo Cryptosporidium é um parasita zoonótico que causa diarreia em uma ampla gama de animais, incluindo veados. Pouco se sabe sobre a prevalência e o genótipo de Cryptosporidium spp. no cervo de Père David. Neste estudo, 137 amostras fecais do cervo de Père David foram coletadas entre julho de 2017 e agosto de 2018, na Reserva Dafeng, e analisadas para Cryptosporidium spp. por nested-PCR baseado no gene do RNA ribossômico da subunidade pequena (SSU rRNA), seguido de análises de sequências para determinar as espécies. O gene da glicoproteína de 60 kDa (gp60) foi utilizado para caracterizar Cryptosporidium spp. Dentre as 137 amostras, 2 (1,46%) foram positivas para Cryptosporidium spp. de acordo com os resultados do sequenciamento gênico de SSU rRNA. Ambas as amostras pertenciam ao genótipo do cervo Cryptosporidium, com duas deleções nucleotídicas e uma substituição nucleotídica. Os dados de prevalência e a caracterização molecular deste estudo fornecem conhecimentos básicos para controlar e prevenir infecções por Cryptosporidium nos cervos de Père David nessa.

Abstract Cryptosporidium is a zoonotic parasite that causes diarrhea in a broad range of animals, including deer. Little is known about the prevalence and genotype of Cryptosporidium spp. in Père David’s deer. In this study, 137 fecal samples from Père David’s deer were collected between July 2017 and August 2018 in the Dafeng Reserve and analyzed for Cryptosporidium spp. by nested-PCR based on the small subunit ribosomal RNA (SSU rRNA) gene, followed by sequence analyses to determine the species. The 60 kDa glycoprotein (gp60) gene was used to characterize Cryptosporidium spp. Among 137 samples, 2 (1.46%) were positive for Cryptosporidium spp. according to SSU rRNA gene sequencing results. Both samples belonged to the Cryptosporidium deer genotype, with two nucleotide deletions and one nucleotide substitution. The prevalence data and molecular characterization of this study provide basic knowledge for controlling and preventing Cryptosporidium infections in Père David’s deer in this area.

Abstract Wax deposition behavior was investigated in a set of one-inch experiment flow loops, using a local crude oil with high wax content. The temperature of the oil phase is chosen as a variable parameter while the temperature of the coolant media is maintained constant. Detailed composition of the deposit is characterized using High Temperature Gas Chromatography. It was found that the magnitude of the diffusion of the heavier waxy components (C35-C50) decreases when the oil temperature decreases, but the magnitude of the diffusion of the lighter waxy components increases. This result means that the diffusion of wax molecules shifts towards lower carbon number, which further proves the concept of molecular diffusion. Meanwhile, a meaningful phenomenon is that the mass of the deposit increases with the oil temperature decrease, which definitely proves the influence of wax solubility on deposition, while the formation of an incipient gel layer reflects the fact that an increase in the mass of the deposit does not mean a larger wax percentage fraction at lower oil temperature.