Paraffin wax deposition has long been a vexing problem in industry. Especially, in offshore oil production, paraffin wax deposits and clogs pipes and containers because of low temperature, causing severe economic loss. It has been known that the crystallization of n-alkanes mainly causes the deposition of paraffin wax, which is necessary to understand the mechanism of the crystallization behavior of paraffin wax. We solve the challenge of describing the crystallization behavior of the alkane mixture system and evaluate the contributions of every carbon atom to crystallization based on the occupied volume, structure entropy, and order parameter. These results demonstrate that the middle atoms are the main contributor to crystallization, and the end atoms of n-alkanes are unfavorable for the crystallization of nalkanes, showing that increasing the number of end atoms, for example, adding branched alkanes, will hinder the crystallization of paraffin wax. Furthermore, perhydrosqualene is chosen to study the inhibition of crystallization by adding branched alkanes. As there are different properties between the end and the middle atoms, based on the principle of dissolution with similar properties, a small number of branched alkanes will promote crystallization. Also, an inhibitory effect of the end atoms is observed when the proportion of branched alkanes increases to a certain percentage. Our simulation work describes the crystallization behavior of paraffin wax in detail, providing theoretical assistance for preventing and controlling paraffin deposition.

ObjectiveTo explore the prognostic significance of nicotinamide adenine dinucleotide (NAD)-dependent protein deacetylase sirtuin-6 (SIRT6), encoded by the sirtuin 6 (SIRT6) gene, in a population of Chinese Han patients with non-small cell lung cancer (NSCLC).MethodsCancer tissues and normal lung tissues (>5 cm adjacent to cancer tissue) were collected from Chinese Han patients with NSCLC. Expression levels of SIRT6 and histone H3-acetyl K56 (H3K56), in cancer and normal lung tissues from patients with NSCLC, were detected by reverse-transcription polymerase chain reaction, Western blot and immunohistochemistry. Correlations between SIRT6 expression and various clinicopathologic features were investigated.ResultsOut of 86 patients included in the study, mRNA and protein SIRT6 levels were down-regulated in NSCLC tissue versus normal lung tissue, and SIRT6 levels were inversely correlated with H3K56 levels. Positive rates of SIRT6 were significantly correlated with degree of cell differentiation, TNM stage, lymph node metastasis, overall survival and metastasis-free survival.ConclusionDownregulation of SIRT6 expression may promote NSCLC malignancy in the Chinese Han population. SIRT6 may be a potential therapeutic target in Chinese Han patients with NSCLC.

We designed a template-free strategy to induce inorganic nanoparticles to self-assemble into different patterns by the surface patterning of copolymers.

No abstract

No abstract