The Pearson product-moment correlation coefficient is being used to evaluate the similarity of the high-performance liquid chromatographic fingerprints of traditional Chinese medicine (TCM) in China. It is confirmed that a large range of peak areas produced the wrong results. A new algorithm concerning weighted Pearson product-moment correlation coefficient is proposed in this article. The results for both real cases and simulated data sets show that the weighted Pearson product-moment correlation coefficients allow relatively larger differences for large values, smaller differences for small values, and more reliable results than the unweighted Pearson product-moment correlation coefficients. Weight selection depends on the specific scientific problem.
Mental fatigue is characterized by a reduced capacity for work and a loss of capacity to respond to stimulation and is usually accompanied by a feeling of tiredness and drowsiness. Mental fatigue at work is a serious problem and can raise safety concerns especially in the transportation system. It is believed that mental fatigue is a direct or contributing cause of road and air related accidents and incidents. Psychological studies indicate that fatigue results in reduced work efficiency, alertness, and impaired mental performance. However, its underlying biochemical mechanisms are poorly understood. We hypothesized that the human body is an integrated system, and mental fatigue results in changes not only in psychology but also in biochemistry of the human body. These biochemical changes are detectable in metabolites. We employed global metabolomic profiling methods to screen biochemical changes that occur with mental fatigue in air traffic controllers (ATCs) in civil aviation. A total of 45, all male, ATCs (two batches) were recruited as two mental fatigue groups and 23 executive staff acted as a control group for this study. The volunteers' urine samples were collected before and after their work. The samples were analyzed with liquid chromatography/mass spectrometry equipped with a polar, a weak polar, and a nonpolar column, respectively. Three candidate biomarkers were selected on the basis of statistical significance, coefficient of variance, and compared with data of the three groups. The results suggest that urine metabolites may provide a complete new clue from biochemistry to understand, monitor, and manage human mental fatigue.
Thiols can diffuse and form self-assembled monolayers (SAMs) on the gold surfaces covered with polydimethylsiloxane (PDMS) stamps. For the first time, with cells as the indicator of how far alkanethiols had diffused to form SAM, we studied the growth dynamics of SAMs of HS(CH 2 ) 11 (OCH 2 CH 2 ) 3 OH (EG 3 ) and HS(CH 2 ) 11 (OCH 2 CH 2 ) 6 OH (EG 6 ) on the gold surfaces covered with PDMS stamps. The growth of SAMs is well described by one-dimensional diffusion from a line source of concentration, with surface diffusion coefficient of 193.4 ± 19.2 lm 2 /min (EG 3 ) and 95.8 ± 18.9 lm 2 /min (EG 6 ).
The irregularity in herbal plant composition is influenced by multiple factors. As for quality control of traditional Chinese medicine, the most critical challenge is to ensure the dosage content uniformity. This content uniformity can be improved by blending different batches of the extracts of herbal plants. Nonlinear least-squares regression was used to calculate the blending coefficient, which means no great absolute differences allowed for all ingredients. For traditional Chinese medicines, even relatively smaller differences could present to be very important for all the ingredients. The auto-scaling pretreatment was used prior to the calculation of the blending coefficients. The pretreatment buffered the characteristics of individual data for the ingredients in different batches, so an improved auto-scaling pretreatment method was proposed. With the improved auto-scaling pretreatment, the relative. differences decreased after blending different batches of extracts of herbal plants according to the reference samples. And the content uniformity control of the specific ingredients could be achieved by the error control coefficient. In the studies for the extracts of fructus gardeniae, the relative differences of all the ingredients is less than 3% after blending different batches of the extracts. The results showed that nonlinear least-squares regression can be used to calculate the blending coefficient of the herbal plant extracts.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.