Synthesis Optimization and Characterization of Nitrogen-Doped Bamboo-Shaped Carbon Nanotubes.

Nitrogen-doped bamboo-shaped carbon nanotubes (N-BCNT) were synthesized from butylamine using the catalytic chemical vapor deposition (CCVD) process. The carbon source was nitrogen content organic molecules, namely butylamine. Reaction conditions such as temperature, amount of carbon source and catalyst were optimized to produce high quality N-BCNT samples. The nitrogen content was measured by CHNS element analysis, while the butylamine conversion was calculated based on the weight of deposited carbon materials. The bamboo structure of the nanotubes was examined by high resolution transmission electron microscopy (HRTEM). Two different types of nitrogen incorporation forms, the pyridinic and the graphitic, were identified in the samples by X-ray photoelectron spectroscopy (XPS). The lattice defects were measured by Raman spectroscopy. The proportion of defect sites influenced by the nitrogen content which can be controlled by the synthesis temperature. The optimal conditions were identified for the economical synthesis of N-BCNTs with high nitrogen content for various applications.

Low-burden TP53 mutations represent frequent genetic events in CLL with an increased risk for treatment initiation.

TP53 aberrations predict chemoresistance and represent a contraindication for the use of standard chemoimmunotherapy in chronic lymphocytic leukaemia (CLL). Recent next-generation sequencing (NGS)-based studies have identified frequent low-burden TP53 mutations with variant allele frequencies below 10%, but the clinical impact of these low-burden TP53 mutations is still a matter of debate. In this study, we aimed to scrutinise the subclonal architecture and clinical impact of TP53 mutations using a sensitive, NGS-based mutation analysis in a 'real-world' cohort of 901 patients with CLL. In total, 225 TP53 mutations were identified in 17.5% (158/901) of the patients; 48% of these alterations represented high-burden mutations, while 52% were low-burden TP53 mutations. Low-burden mutations as sole alterations were identified in 39% (62/158) of all mutated cases with 82% (51/62) of these being represented by a single low-burden TP53 mutation. Patients harbouring low-burden TP53 mutations had significantly lower time to first treatment compared to patients with wild-type TP53. Our study has expanded the knowledge on the frequency, clonal architecture, and clinical impact of low-burden TP53 mutations. By demonstrating that patients with sole low-burden TP53 variants represent more than one-third of patients with TP53 mutations and have an increased risk for treatment initiation, our findings strengthen the need to redefine the threshold of TP53 variant reporting to below 10% in the routine diagnostic setting.