7,417 research outputs found
Mass spectral analysis and quantification of Secondary Ion Mass Spectrometry data
This work highlights the possibility of improving the quantification aspect
of Cs-complex ions in SIMS (Secondary Ion Mass Spectrometry), by combining the
intensities of all possible Cs-complexes. Identification of all possible
Cs-complexes requires quantitative analysis of mass spectrum from the material
of interest. The important steps of this mass spectral analysis include
constructing fingerprint mass spectra of the constituent species from the table
of isotopic abundances of elements, constructing the system(s) of linear
equations to get the intensities of those species, solving them, evaluating the
solutions and employing a regularization process when required. These steps are
comprehensively described and the results of their application on a SIMS mass
spectrum obtained from D9 steel are presented. It is demonstrated that results
from the summation procedure, which covers entire range of sputtered clusters,
is superior to results from single Cs-complex per element. The result of
employing a regularization process in solving a mass spectrum from an SS316LN
steel specimen is provided to demonstrate the necessity of regularization.Comment: 10 pages, 3 figures; added reference for section "Theory", a few
sentences modified for clarit
Oxygen consumption changes with yoga practices: A systematic review
Oxygen consumption varies with physical and mental activity as well as pathological conditions. Although there is a strong relationship between yoga and metabolic parameters, the relationship between yoga and oxygen consumption has not yet been formally reviewed. This systematic review attempted to include all studies of yoga that also measured oxygen consumption or metabolic rate as an outcome. A total of 58 studies were located involving between 1 and 104 subjects (average 21). The studies were generally of poor methodological quality and demonstrated great heterogeneity with different experimental designs, yoga practices, time periods, and small sample sizes. Studies report yoga practices to have profound metabolic effects producing both increase and decrease in oxygen consumption, ranging from 383% increase with cobra pose to 40% decrease with meditation. Compared to nonpractitioners, basal oxygen consumption is reported to be up to 15% less in regular yoga practitioners, and regular yoga practice is reported to have a training effect with oxygen consumption during submaximal exercise decreasing by 36% after 3 months. Yoga breathing practices emphasize breathing patterns and retention ratios as well as unilateral nostril breathing, and these factors appear critical in influencing oxygen consumption. A number of studies report extraordinary volitional control over metabolism in advanced yoga practitioners who appear to be able to survive extended periods in airtight pits and to exceed the limits of normal human endurance. More rigorous research with standardized practices is required to determine the mechanisms of yoga's metabolic effects and the relevance of yoga practices in different clinical populations
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