Polyimides have attracted considerable attention owing to their excellent properties; however, their hydrophilicity makes them susceptible to hydrolytic degradation. In this study, polyaryletherketones (PAEKs) with different fluorine contents were coated onto the surface of the polyimide films to fabricate the hydrophobic surface. The wettability of the films changed, with a transition from hydrophilicity to hydrophobicity, upon coating with PAEKs. Thus, the coated films exhibited low moisture absorption. Due to the excellent thermal stability of fluorinated polyaryletherketones (F-PAEKs), the coated polyimide films retained their hydrophobicity even after extreme treatment. Furthermore, the dielectric properties of the coated polyimide film were superior to those of the unmodified film. The hydrophobic polyimide film can meet the requirements of extreme environments.

In this study, a polymer pH-indicator was synthesized by sulfonation of poly(styrene-co-acrylic acid) with concentrated sulfuric acid. The synthesized polymer pH-indicator exhibited pH-responsive color changes in aqueous solutions, being purple in alkaline medium (pH < 4), whereas yellow in acidic medium (pH > 9). The sulfonation process extent and polymer color were affected by time and temperature of the process, as well as acrylic acid (AA) content. The addition of acrylic acid was a crucial point for color change due to the facility of cyclic ketone structure to turn into phenol under acidic condition. Compared with low molecule pH-indicators, the sulfonated copolymer was prepared in form of films being repeatedly used as pH-indicator and easily removed from the acid-base medium.

Abstract The flow of proppant-laden fluid (PLF) in the fracture is a typical problem of solid-liquid two phase flow, and the transportation and deposition of proppants are essential to determine the flow conductivity of hydraulic fracturing. The self-suspending proppant with a water soluble surface coating is a newly presented supporting material and has great potential for hydraulic fracturing. The purpose of this paper is to understand the physical process, and investigate the effect of the self-suspending proppant on particle placement and transportation in the fracture. Two experiments of the PLF flow were conducted in a fracture, using the common ceramic proppant and self-suspending proppant, respectively. The fracture was formed by two parallel plexiglass planes, and was 4000 mm in length, 10 mm in width and 600 mm in height. It was found that four different zones developed when proppants were injected into the fracture continuously, which were the proppant bank zone, tumbling zone, suspending zone, and free zone. Compared with the common proppant, the self-suspending proppant changes the particle distribution in the fracture, and increases the thickness of proppant suspending and bank zone. The motion behavior of self-suspending proppants in the fracture is described. The conclusion is that appropriate reduction in the proppant concentration and density is beneficial to the good distribution and transportation of proppants in the fracture, and the self-suspending proppant favors the effective supporting of fracture.

ABSTRACT Objective Pendred syndrome (PS) is an autosomal recessive disorder characterised by sensorineural hearing loss and thyroid dyshormonogenesis. It is caused by biallelic mutations in the SLC26A4 gene encoding for pendrin. Hypothyroidism in PS can be present from birth and therefore diagnosed by neonatal screening. The aim of this study was to examine the SLC26A4 mutation spectrum and prevalence among congenital hypothyroidism (CH) patients in the Guangxi Zhuang Autonomous Region of China and to establish how frequently PS causes hearing impairment in our patients with CH. Subjects and methods Blood samples were collected from 192 CH patients in Guangxi Zhuang Autonomous Region, China, and genomic DNA was extracted from peripheral blood leukocytes. All exons of the SLC26A4 gene together with their exon-intron boundaries were screened by next-generation sequencing. Patients with SLC26A4 mutations underwent a complete audiological evaluation including otoscopic examination, audiometry and morphological evaluation of the inner ear. Results Next generation sequencing analysis of SLC26A4 in 192 CH patients revealed five different heterozygous variations in eight individuals (8/192, 4%). The prevalence of SLC26A4 mutations was 4% among studied Chinese CH. Three of the eight were diagnosed as enlargement of the vestibular aqueduct (EVA), no PS were found in our 192 CH patients. The mutations included one novel missense variant p.P469S, as well as four known missense variants, namely p.V233L, p.M147I, p.V609G and p.D661E. Of the eight patients identified with SLC26A4 variations in our study, seven patients showed normal size/location of thyroid gland, and one patients showed a decreased size one. Conclusions The prevalence of SLC26A4 pathogenic variants was 4% among studied Chinese patients with CH. Our study expanded the SLC26A4 mutation spectrum, provided the best estimation of SLC26A4 mutation rate for Chinese CH patients and indicated the rarity of PS as a cause of CH.

Objetivo O hipotireoidismo congênito disormonogenético (CH) foi relatado como associado a uma mutação no gene simportador sódio/iodeto (NIS). O presente estudo foi feito na região autônoma de Guangxi Zhuang na China para se determinar a natureza e a frequência das mutações no gene NIS entre pacientes com CH causado por disormonogênese. Sujeitos e métodos: Amostras de sangue foram coletadas de 105 pacientes com CH disormonogenéticos e o DNA genômico foi extraído de leucócitos do sangue periférico. Todos os éxons do gene NIS, junto com seus limites éxon-íntron, foram analisados por sequenciamento de nova geração. Resultados Foram encontradas duas variações silenciosas (T221T e T557T) e uma variação missense (M435L), assim como dois polimorfismos (rs200587561 e rs117626343). Conclusões Nossos resultados indicam que a taxa de mutação em NIS é muito baixa na região de Guangxi Zhuang. É necessário estudar mutações de outros genes que tenham efeitos maiores na disormonogênese da tiroide e que ainda não tenham sido estudados nesta população.

Objective Dyshormonogenetic congenital hypothyroidism (CH) was reported to be associated with a mutation in the sodium iodide symporter (NIS) gene. The present study was undertaken in the Guangxi Zhuang Autonomous Region of China, to determine the nature and frequency of NIS gene mutations among patients with CH due to dyshormonogenesis. Subjects and methods: Blood samples were collected from 105 dyshormonogenetic CH patients in Guangxi Zhuang Autonomous Region, China, and genomic DNA was extracted from peripheral blood leukocytes. All exons of the NIS gene together with their exon-intron boundaries were screened by next-generation sequencing. Results Two silent variations (T221T and T557T) and one missense variation (M435L), as well as two polymorphisms (rs200587561 and rs117626343) were found. Conclusions Our results indicate that the NIS mutation rate is very low in the Guangxi Zhuang Autonomous Region, China, and it is necessary to study mutations of other genes that have major effects on thyroid dyshormonogenesis and have not as yet been studied in this population.