Publications by authors named "Janghwan Jekal"

6 Publications

  • Page 1 of 1

Instant, multiscale dry transfer printing by atomic diffusion control at heterogeneous interfaces.

Sci Adv 2021 Jul 9;7(28). Epub 2021 Jul 9.

Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, South Korea.

Transfer printing is a technique that integrates heterogeneous materials by readily retrieving functional elements from a grown substrate and subsequently printing them onto a specific target site. These strategies are broadly exploited to construct heterogeneously integrated electronic devices. A typical wet transfer printing method exhibits limitations related to unwanted displacement and shape distortion of the device due to uncontrollable fluid movement and slow chemical diffusion. In this study, a dry transfer printing technique that allows reliable and instant release of devices by exploiting the thermal expansion mismatch between adjacent materials is demonstrated, and computational studies are conducted to investigate the fundamental mechanisms of the dry transfer printing process. Extensive exemplary demonstrations of multiscale, sequential wet-dry, circuit-level, and biological topography-based transfer printing demonstrate the potential of this technique for many other emerging applications in modern electronics that have not been achieved through conventional wet transfer printing over the past few decades.
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http://dx.doi.org/10.1126/sciadv.abh0040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8270493PMC
July 2021

Publisher Correction: MAOA variants differ in oscillatory EEG & ECG activities in response to aggression-inducing stimuli.

Sci Rep 2019 Jun 26;9(1):9505. Epub 2019 Jun 26.

School of Undergraduate Studies, DGIST, Daegu, Korea.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.
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http://dx.doi.org/10.1038/s41598-019-45227-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6592876PMC
June 2019

MAOA variants differ in oscillatory EEG & ECG activities in response to aggression-inducing stimuli.

Sci Rep 2019 02 25;9(1):2680. Epub 2019 Feb 25.

School of Undergraduate Studies, DGIST, Daegu, Korea.

Among the genetic variations in the monoamine oxidase A (MAOA) gene, upstream variable number tandem repeats (uVNTRs) of the promoter have been associated with individual differences in human physiology and aggressive behaviour. However, the evidence for a molecular or neural link between MAOA uVNTRs and aggression remains ambiguous. Additionally, the use of inconsistent promoter constructs in previous studies has added to the confusion. Therefore, it is necessary to demonstrate the genetic function of MAOA uVNTR and its effects on multiple aspects of aggression. Here, we identified three MAOA alleles in Koreans: the predominant 3.5R and 4.5R alleles, as well as the rare 2.5R allele. There was a minor difference in transcriptional efficiency between the 3.5R and 4.5R alleles, with the greatest value for the 2.5R allele, in contrast to existing research. Psychological indices of aggression did not differ among MAOA genotypes. However, our electroencephalogram and electrocardiogram results obtained under aggression-related stimulation revealed oscillatory changes as novel phenotypes that vary with the MAOA genotype. In particular, we observed prominent changes in frontal γ power and heart rate in 4.5R carriers of men. Our findings provide genetic insights into MAOA function and offer a neurobiological basis for various socio-emotional mechanisms in healthy individuals.
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http://dx.doi.org/10.1038/s41598-019-39103-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6390082PMC
February 2019

Gender Differences in Aggression-related Responses on EEG and ECG.

Exp Neurobiol 2018 Dec 28;27(6):526-538. Epub 2018 Dec 28.

School of Undergraduate Studies, DGIST, Daegu 42988, Korea.

Gender differences in aggression viewed from an evolutionary and sociocultural perspective have traditionally explained why men engage in more direct and physical aggression, and women engage in more indirect and relational aggression. However, psychological and behavioral studies offer inconsistent support for this theory due to personal or social factors, and little is known about the gender-based neurobiological mechanisms of aggression. This study investigates gender differences in aggression through an analysis of electroencephalography (EEG) and electrocardiography (ECG) based neurobiological responses to commonly encountered stimuli, as well as psychological approaches in healthy Korean youth. Our results from self-reports indicate that overall aggression indices, including physical and reactive/overt aggression, were stronger in men. This agrees with the results of previous studies. Furthermore, our study reveals prominent gender-related patterns in γ signals from the right ventrolateral frontal cortex and changes in heart rate through stimulation by aggressive videos. In particular, gender differences in EEG and ECG responses were observed in response to different scenes, as simple aversion and situation-dependent aggression, respectively. In addition, we discovered decisive gender-distinct EEG signals during stimulation of the situation-dependent aggression regions within the right ventromedial prefrontal and ventrolateral frontal regions. Our findings provide evidence of a psychological propensity for aggression and neurobiological mechanisms of oscillation underlying gender differences in aggression. Further studies of oscillatory responses to aggression and provocation will expand the objective understanding of the different emotional worlds between men and women.
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http://dx.doi.org/10.5607/en.2018.27.6.526DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6318556PMC
December 2018

A novel supportive assessment for comprehensive aggression using EEG and ECG.

Neurosci Lett 2019 02 4;694:136-142. Epub 2018 Dec 4.

School of Undergraduate Studies, DGIST, Daegu, Republic of Korea. Electronic address:

Aggression is a complex, ubiquitous phenomenon that impacts behavioral traits and psychological health. Assessing aggression is challenging because aggression constitutes multiple subtraits, such as anger, reactive aggression, and overt aggression. Conventional methods of assessing aggression are susceptible to bias because they mainly rely upon self-reports. Thus, more objective methods that provide a multifaceted understanding of aggression in individuals are required. Here, we propose a supportive method of assessing specific aggression subtraits in Koreans using electroencephalography (EEG) and electrocardiography (ECG). Our evaluations and statistical analyses revealed that EEG and ECG signals in subjects responding to video cues that induced aggression are associated with aggression subtraits. In particular, we identified spectral differences in EEG signals in response to stimuli with situation-dependent aggression. The α and β signals of the Fp2 site (the right ventromedial prefrontal region) are highly associated with anger, reactive aggression, and overt aggression. Moreover, ECG signals are associated with anger and overt aggression. These results link neurobiological findings to psychological explanations of aggression and multiple aspects of human behavior. Our findings can potentially be applied to supportive assessment methods for psychological counseling or psychiatric diagnoses.
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http://dx.doi.org/10.1016/j.neulet.2018.12.005DOI Listing
February 2019
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