• Mass Spectrometry Letters
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• v.5 no.2
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• pp.42-48
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• 2014

A specific and sensitive liquid chromatography-electrospray ionization tandem mass spectrometry method (LC-ESI-MS/MS) was developed and validated for the simultaneous quantification of porphyrins (coproporphyrin, pentacarboxylporphyrin, hexacarboxylporphyrin, heptacarboxylporphyrin, and uroporphyrin) in human plasma and urine. Acidified plasma samples and urine samples were prepared by using liquid-liquid extraction using ethyl acetate and protein precipitation with acetonitrile, respectively. The separation was achieved onto a Synergi Fusion RP column ($150mm{\times}2.0mm$, $4{\mu}m$) with a gradient elution of mobile phase A (0.1% formic acid in 2 mmol/L ammonium acetate, v/v) and mobile phase B (20% methanol in acetonitrile, v/v) at a flow rate of $450{\mu}L$/min. Porphyrins and the internal standard (IS), coproporphyrin I-$^{15}N_4$, were detected by a tandem mass spectrometer equipped with an electrospray ion source operating in positive ion mode. Multiple reaction monitoring (MRM) transitions of the protonated precursor ions and the related product ions were optimized to increase selectivity and sensitivity. The proposed method was validated by assessing selectivity, linearity, limit of quantification (LOQ), precision, accuracy, recovery, and stability. The calibration curves were obtained in the range of 0.1-100 nmol/L and the LOQs were estimated as 0.1 nmol/L for all porphyrins. Results obtained from the validation study of porphyrins showed good accuracy, precision, recovery, and stability. Finally, the proposed method was successfully applied to clinical studies on the autism spectrum disorder (ASD) diagnosis of 203 Korean children.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.753-766
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• 2013

Even though civilization is developing at a fast rate, human beings and their living environments do not look happy. Given that the civilization comes from the human mind, which is changing in interaction with human body, society, and nature, it is hard to think that the human mind is changing in the desirable direction. This paper described a whole changing paradigm of the human mind and its causes through the cognitive mechanism in the brain from which all the diverse minds are formed. According to the cognitive mechanism, the human mind can change from the first free and peaceful mind through the middle mind to the last obsessive and anguish mind in accordance with the change of one of the factors in the origin of the human mind. Today's unfavorable changes in human beings, society, and the natural environment including the excessive development of civilization are the results of the undesirable changes of the human mind. This paper specified the respective characteristics of the first, middle, and the last mind and discussed where individuals' minds are and where they are going. Lastly, this paper suggested the specific ways to return to the first original mind based on the cognitive mechanism.