Effect of borates on the synthesis of nanoscale hexagonal boron nitride by a solid-state method.

This study delves deeply into the effect of different borates (lithium tetraborate, sodium tetraborate, calcium metaborate, ammonium pentaborate) on the production and fundamental characteristic features of nanoscale hexagonal boron nitride (hBN) structure with the assistant of standard characteristic measurement methods, namely, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM). The hBN samples are synthesized by reaction of powder urea, boron oxide, and different kinds of borates via the modified O'Connor method (performed at a relatively lower main heat treatment temperature of 1,100°C). All the results obtained show that the usage of borates affects positively the formation of nanoscale hBN structure. In more detail, the FTIR experiment results reveal that the presence of two strong c peaks appeared at ~1,380 and ~780 cm-1 in the spectra points out the conventional BN in-plane and out-of-plane vibrations, respectively. The XRD patterns also confirm the production of high-ordered hBN as the existence of the main peaks of the corresponding hexagonal system. As for the SEM examination, it is found that all the hBN materials exhibit totally different crystallinity quality and microstructural characteristics. The hBN compound prepared by the sodium tetraborate content shows the most uniform surface appearance with the smoothest/densest crystal structure, best grain orientations, and finest grain interactions. Hence, the material with strong stretching of interatomic bonds shows the highest material (fracture) strength. Moreover, the TEM images illustrate that all the products are composed of uniform multi-walled nanotubes and nanorods with an average length of ~250 nm.

Genetic variants in the microRNA machinery gene (Dicer) have a prognostic value in the management of endometrial cancer.

AIM: Although several associations were found between Dicer rs3742330 single nucleotide polymorphism (SNP) and development and prognosis of some epithelial cancers, relationship between the SNP rs3742330 and endometrial cancer (EC) has not yet been studied. We aimed to investigate the prognostic role of rs3742330 SNP of Dicer gene in EC patients. SUBJECTS AND METHODS: A total of 80 EC patients and 80 control subjects included in the study. Real-time polymerase chain reaction and the allele discrimination technique was used for genotyping of rs3742330 SNP. RESULTS: There was no significant difference between EC patients and control subjects with regard to the genotype and allele frequencies for Dicer rs3742330 SNP (P > 0.05). Despite Dicer rs3742330 SNP had no prognostic value in terms of stage, grade, lymphovascular invasion, myometrial invasion, tumor size, and histopathology; malignant peritoneal cytology has been detected higher in the patients bearing AA genotype compare with AG genotype (P = 0.023). Higher recurrence rate and shorter time to recurrence were found in patients bearing AG and GG genotype compare with AA genotype (P = 0.009). CONCLUSION: Dicer rs3742330 AG and GG genotypes may have the potential to be used as a predictor of poor prognosis in the management of EC case.

Seasonal variation, sources, and gas/particle concentrations of PCBs and OCPs at high altitude suburban site in Western Black Sea Region of Turkey.

Daily gas and particle phase samples were collected during winter and summer seasons in Bolu, which is located in the high altitude Western Black Sea Region of Turkey. Samples were analyzed to determine the concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). Concentrations of endosulfan sulfate and methoxychlor were found to be highest in the summer and winter periods, respectively. The measured average concentration of endrin was considerably higher (10-50 fold) than the values reported in the literature for similar sites. The agricultural areas located to the south, south-east and south-west of the sampling point were identified as source regions. PCBs were found predominantly in the gas phase in both seasons and 3-chlorinated biphenyls were found to be abundant in the winter period, due to pollutants transported from the city centre and a waste incineration plant by southerly and easterly winds. The concentrations of PCB-180 and PCB-194 were found to be higher than values reported in the literature. The correlation between atmospheric concentrations and temperature was obtained by using Clausius-Clapeyron (CC) plots. The CC plots for most of the OCPs showed shallow negative slopes with low r(2) values, which might be due to the presence of local sources, i.e., agricultural areas around the sampling site and the dominance of evaporation. The CC plots showed steep positive slopes for most of the PCB compounds. Most of the PCB compounds were carried from the ongoing local sources.