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Cancer Biomarkers
Published in Trevor F. Cox, Medical Statistics for Cancer Studies, 2022
The R function concordance() will calculate Harrell's c. For the ESPAC4 multivariate predictor (see Section 5.2), with . The values of c must lie between 0 and 1, but values much less than 0.5 should not happen since indicates no predictive value. It is hard to give a guide to the interpretation of the c value, some say implies a good model and a very good model.
A Critical Review of Some Terminologies used for Additional DNA in Plant Chromosomes
Published in S. K. Dutta, DNA Systematics, 2019
The repeated sequences have given rise to a paradoxical situation with regard to the genomic content of different species. In most eukaryotic systems, the amount of DNA in the genome, otherwise known as C-value, is much in excess of the total number of structural genes as already mentioned in the case of human cells. This has led to the situation termed as C-value paradox. It is indeed very difficult to correlate the degree of differentiation with the amount of DNA in an organism. The best examples are the lilies and amphibians where the range in amount of DNA is 20 to 100 pg, as compared to 2 to 3 pg in mammals and 7 pg in the human system.13 Evidently, the repeated sequences are involved with genes which do not code for structural proteins but which lead to variability of DNA values in a different hierarchy of organization. The redundancy is suggested in view of the absence of information content. The C-value paradox may not hold to the same extent for all members of a species. The extent of variability in C-values at the intraspecific level, so far noted in certain organisms, is not fully known.14–16 Even in the human system, quantitative variations of the genome have been recorded.17,18 A correct interpretation of the significance of C-value will have to await an analysis of its variability in natural populations at the intraspecific level.
Nested Statistical Designs
Published in Daryl S. Paulson, Applied Statistical Designs for the Researcher, 2003
Example Cont. Recall that factor A is fixed and factor B(A) is random in our example. Also, one would not perform comparisons if the FC value was not significant. In this example, it is not significant, so the computation is for demonstration purposes only.
Evidence of variable human Fcγ receptor-Fc affinities across differentially-complexed IgG
Published in mAbs, 2023
Andrew R. Crowley, Matthew R. Mehlenbacher, Mohammad M. Sajadi, Anthony L. DeVico, George K. Lewis, Margaret E. Ackerman
Complexes were formed from equal volumes of 20 µM solutions containing VRC01 in an IgG1 heavy chain and either antigen or anti-human CH1 capture reagent. For the free IgG condition, VRC01 was instead diluted 1:2 in 1× PBS. FcγRIIIa-V158 at 100 μM was injected using 6 μL per injection and injections spaced 90 s apart. These concentrations of macromolecules and FcγR were chosen based on the theoretically complete formation of 10 µM complex following the mixture of 20 µM reagents. This would yield an ITC c value of 10 or greater when calculated as c = n * Ka * [macromolecule], where n is the stoichiometry of the ligand for the macromolecule and Ka is the association constant of the ligand. Temperature was maintained at 25°C and the sample cell mixed at 750 rpm. Measurements were made with a reference power of 6.0 using a MicroCal PEAQ-ITC (Malvern Panalytical).
Cs-131 as an experimental tool for the investigation and quantification of the radiotoxicity of intracellular Auger decays in vitro
Published in International Journal of Radiation Biology, 2023
Pil M. Fredericia, Mattia Siragusa, Ulli Köster, Gregory Severin, Torsten Groesser, Mikael Jensen
The height of the CMs and the sizes of the nuclei were determined by confocal microscopy. A cross section of the 100% confluent CM can be seen in Figure 5. As is evident from the illustration, neighboring cells are so close to each other that their plasma membranes (green) are touching, leaving no space between them. A high cell density is central for the geometry assumed in the SC-value calculations and its verification is important for correct absorbed dose calculations. The average heights of the confluent cell layers were determined to be 10 μm for the HeLa cell culture and 7.5 μm for the V79 cell culture, with an estimated uncertainty of ± 1–2 μm due the variations in cellular height (as evident from Figure 5) and to limitations of the confocal microscopy technique. The cell cultures used for the clonogenic assay had this level, 100%, of confluence, while the cell cultures used for the γH2AX assay were 80% confluent.
Prognosis of severe drug-induced acute interstitial nephritis requiring renal replacement therapy
Published in Renal Failure, 2021
Li Huang, Shaoshan Liang, Jianhua Dong, Wenjing Fan, Caihong Zeng, Ti Zhang, Shuiqin Cheng, Yongchun Ge
It has been attempted to find reliable serum biomarkers that predict renal recovery in AKI. Serum cystatin C concentration has long been known as a reliable biomarker for predicting AKI because it rises earlier, and less dependent on age, sex, race, diet, and muscle mass compared to serum creatinine. However, whether it is associated with renal function recovery had not been well established in previous studies. Zhang et al. [10] had reported that lower cystatin C concentration was an independent predictor of renal recovery in intensive care unit (ICU) patients with AKI of all-cause requiring continuous renal replacement therapy (CRRT), although the follow-up period was only 30 days. At the cutoff value of 3.13 mg/L, the sensitivity and specificity were 57.69% and 86.79%, respectively, indicating that patients with cystatin C value > 3.13 mg/L may have a poor renal outcome. Hu et al. [11] also reported cystatin C value independently predicted the risk of 2-year mortality and rehospitalization, as well as renal recovery failure in coronary care unit (CCU) patients with AKI. Our study provided more evidence to support the predictive performance of serum cystatin C concentration in identifying DAIN patients who are at risk for poor renal outcome with a cutoff value of 4.34 mg/L.