Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:6.2.1.1 (ACS)
 78,556 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Clays, hydrous aluminous phyllosilicates, have a significant impact on the interpretation of physical measurements and properties of porous media. In particular, the presence of paramagnetic and/or ferromagnetic ions like iron, nickel, and magnesium in clays can complicate the analysis of nuclear magnetic resonance (NMR) data for porous media characterization. This is due to the internal magnetic field gradient induced by the clay minerals. In this study, we aim to investigate the impact of clay content on spin-spin relaxation time (T 2), which is strongly influenced by the pore surface chemistry. Seven rock core plugs, characterized with variable clay content, were used for this purpose. The clay mineralogy and volume were determined by means of quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN). The T 2 relaxation time was measured using a Carr-Purcell-Meiboom-Gill (CPMG) sequence with variable echo spacing (T E). The maximum percentage difference in dominant T 2 values (MRDT 2) between shortest and longest echo spacing was subsequently correlated with clay content obtained from QEMSCAN. Our results show that the reduction in T 2 distribution with increasing echo time T E is more significant in samples characterized by higher clay contents. The MRDT 2 was found to be strongly correlated with clay content. An analytical equation is presented expressing MRDT 2 as a function of clay content providing a quick and non-destructive approach for clay content estimation. Moreover, the MRDT 2-clay content relationship showed a nonlinear behavior: MRDT 2 increases drastically as the clay content increases up to 15%, beyond which the rate of MRDT 2 change with clay content diminishes. This behavior could be attributed to the clay distribution. At higher clay contents (above 15%), it is more likely for clay to form clusters (structural clays), which will not significantly increase the clay surface in contact with the pore fluid. Further, experimental data suggests that ignoring the impact of clay on internal magnetic gradients and T 2 signal may result in considerable underestimation of the actual pore size distribution.
ACS Omega 2020 Mar 31
PMID:The Effect of Clay Content on the Spin-Spin NMR Relaxation Time Measured in Porous Media. 3225 90

The detection of single-nucleotide variants (SNVs) in circulating tumor DNA (ctDNA) in liquid biopsies has increasingly been shown to exhibit unique benefits for early detection or minimal residual disease monitoring in cancer. Yet, current clinically validated assays for ctDNA SNV detection are challenged by (i) time-consuming and laborious spin column-based ctDNA purification protocols, (ii) limited detection specificity to discriminate between mutated SNVs from large excess of closely similar wild-type sequences, and (iii) insufficient detection sensitivity required for trace ctDNA target analysis in blood. Herein, a ctDNA assay is demonstrated to tackle these triple key issues by fusing magnetics for quick ctDNA enrichment directly from unprocessed blood, selected bioenzyme activities for rapid discrimination, and molecular amplification of target SNVs, and designed magnetic-assisted bioelectrocatalytic cycling of DNA-intercalating and freely diffusing redox probes for electrochemical signal intensification. The described ctDNA SNV assay enables the detection of clinically relevant ctDNA SNVs in melanoma (BRAFV600E, KITL576P, and NRASQ61K) from unprocessed plasma samples with unprecedented 0.005% detection sensitivity, ultrabroad dynamic range over four orders of magnitude, and excellent single-base specificity.
ACS Sens 2020 10 23
PMID:Direct Enhanced Detection of Multiple Circulating Tumor DNA Variants in Unprocessed Plasma by Magnetic-Assisted Bioelectrocatalytic Cycling. 3289 19