Na(+) doping induced changes in the reduction and charge transport characteristics of Al2O3-stabilized, CuO-based materials for CO2 capture.

Chemical looping combustion (CLC) and chemical looping with oxygen uncoupling (CLOU) are emerging CO2 capture technologies that could reduce appreciably the costs associated with the capture of CO2. In CLC and CLOU, the oxygen required to combust a hydrocarbon is provided by a solid oxygen carrier. Among the transition metal oxides typically considered for CLC and CLOU, copper oxide (CuO) stands out owing to its high oxygen carrying capacity, exothermic reduction reactions and fast reduction kinetics. However, the low Tammann (sintering) temperature of CuO is a serious drawback. In this context, it has been proposed to support CuO on high Tammann temperature and low cost alumina (Al2O3), thus, reducing the morphological changes occurring over multiple CLC or CLOU redox cycles and stabilizing, in turn, the high activity of CuO. However, in CuO-Al2O3 systems, phase stabilization and avoiding the formation of the CuAl2O4 spinel is key to obtaining a material with a high redox stability and activity. Here, we report a Na(+) doping strategy to phase stabilize Al2O3-supported CuO, yielding in turn an inexpensive material with a high redox stability and CO2 capture efficiency. We also demonstrate that doping CuO-Al2O3 with Na(+) improves the oxygen uncoupling characteristics and coke resistance of the oxygen carriers. Utilizing in situ and ex situ X-ray absorption spectroscopy (XAS), the local structure of Cu and the reduction pathways of CuO were determined as a function of the Na(+) content and cycle number. Finally, using 4-point conductivity measurements, we confirm that doping of Al2O3-supported CuO with Na(+) lowers the activation energy for charge transport explaining conclusively the improved redox characteristics of the new oxygen carriers developed.

Optimization of circulating cell-free DNA recovery for KRAS mutation and HPV detection in plasma.

BACKGROUND: The precise analysis of tumour markers in blood such as circulating cell-free DNA (cfDNA) could have a significant impact in facilitating monitoring of patients after initial therapy. Although high levels of total cfDNA in plasma of cancer patients are consistently demonstrated, a low sensitivity of DNA alterations is reported. OBJECTIVE: The major question regards the recovery of tumour-specific cfDNA such as KRAS mutated DNA and cancer-associated type 16 of human papillomavirus (HPV16). METHODS: TaqMan technology was used for detection of KRAS mutation, HPV16 and to quantify cfDNA in blood plasma. RESULTS: Comparison of four different column-based commercial kits shows that the cfDNA purification carried out by the Genomic Mini AX Body Fluids kit and the QIAamp Circulating Nucleic Acid kit gave us the possibility to improve the sensitivity of detection of KRAS mutation and HPV16. The optimized method was used to follow the reduction in cancer-specific cfDNA after therapy. We found that large volume extractions with low volume of DNA eluate enabled trace amounts of tumour-specific cfDNA from cancer patients to be effectively identified. CONCLUSIONS: Data presented in this study facilitate detection of tumour-specific cfDNA and improve standards needed for the implementation of cfDNA technology into routine clinical practice.

Estimation of risk of inherited medullary thyroid carcinoma in apparent sporadic patients.

PURPOSE: The study was undertaken to evaluate the frequency of inherited medullary thyroid carcinoma (MTC) among patients with apparent sporadic disease. A stepwise algorithm was used depending on clinical indices and the age of patient at MTC diagnosis. PATIENTS AND METHODS: One hundred sixteen patients with MTC verified by postoperative pathologic examination were subjected to genetic analysis of RET exons 10, 11, 13, 14, and 16 by means of polymerase chain reaction, restriction endonuclease digestion, and DNA sequencing. RESULTS: Among 116 apparent sporadic MTC patients, we identified eleven (9.5%) RET germline mutation carriers. Seven of these (6.0%) were found by routine analysis (exons 10 and 11). The frequency of inherited disease among patients younger than 45 years at diagnosis was 10.2% by analysis of typical mutations in exons 10 and 11. Extended genetic analysis (sequencing of exons 11, 13, 14, and 16) yielded 6.1% additional diagnoses, giving a risk of 16.3% in this age group. One previously unreported mutation in exon 11 affected codon 649 (TCG>TTG, Ser>Leu). In the true sporadic MTC patients younger than 30 years at diagnosis, frequencies of 36% and 4.5% in polymorphic variants L769L and S836S, respectively, were observed. The frequency for L769L was higher than in older patients (P <.05). CONCLUSION: The frequency of inherited disease among apparent sporadic medullary thyroid carcinoma patients is close to 10% in the Polish population of MTC patients. The extended analysis of all known RET proto-oncogene mutation sites is obligatory in patients younger than 45 years at diagnosis, but we also see the need to analyze the impact of rarer mutations in older patients.

Identification of a microsatellite region composed of a long homopurine/homopyrimidine tract surrounded by AT-rich sequences upstream of the rat stress-inducible hsp 70.1 gene.

A DNA region containing several repetitive motifs has been detected about 1.9 kbp upstream of the transcription unit of the rat stress-inducible hsp 70.1 gene. The most interesting element of this area is a microsatellite sequence (GA)6CAG(TC)24 that consists of an inverted repeat partially overlapping with the long homopurine/homopyrimidine tract (Pu/Py). DNA molecule within the described sequence can theoretically adopt alternate, non-B structures (H-DNA or cruciform) containing single-stranded regions. This microsatellite region is flanked by AT-rich sequences containing several poly(A) tracts. The longest of them with a possible potential to destabilized a double-stranded DNA helix is localized around 160 bp downstream the (GA)6CAG(TC)24. The DNA fragment containing sequences described above was subcloned into the pUC19 vector and the resulting plasmid was subjected to the standard S1 susceptibility assay. Preliminary mapping of the S1 cleavage site indicates for the formation of the non-B-DNA structure within the Pu/Py tract. This is to our knowledge a first report on the existence of a complex microsatellite region on upstream the 5'-end of the hsp 70 gene in mammals.