Jun Ho Cho - Academia.edu (original) (raw)

Papers by Jun Ho Cho

Parasitology Research, 2000

The Plasmodium vivax merozoite surface protein 1 (Pvmsp-1) locus codes for a major asexual blood-... more The Plasmodium vivax merozoite surface protein 1 (Pvmsp-1) locus codes for a major asexual blood-stage antigen currently proposed as a malaria vaccine candidate antigen. However, extensive polymorphism of this protein has been observed in isolates from different geographical areas. Here, we investigate the extent and the frequency of allelic diversity at the Pvmsp-1 locus in field isolates collected in the Republic of Korea during the past decade. Among the 45 Korean isolates, six Pvmsp-1 gene types (SKOR-I to SKOR-VI) were identified as unique combinations of type sequences in each variable block. Of these six different Pvmsp-1 gene types, two major Pvmsp-1 allelic types were found in 72% (SKOR-I) and 28% (SKOR-II) of field isolates collected in 1996 to 2000, and four different allelic types (SKOR-III to SKOR-VI) emerged in 70% (10–25%) of isolates collected in 2007 to 2009. These results suggest that allelic diversity of Pvmsp-1 increased in several variable regions, including the N- and C-terminals, after reemergence of P. vivax parasites in the Republic of Korea.

2012 Picture Coding Symposium, 2012

This paper proposes a new frame rate up-conversion (FRUC) method. In the paper, we propose an ove... more This paper proposes a new frame rate up-conversion (FRUC) method. In the paper, we propose an overlap ratio between motion vectors, with which we determine adaptive block size for the motion estimation. In addition, the proposed method estimates the region of repeated patterns and treats them in a special manner. Conventional motion estimation methods usually produce wrong motion vectors for

IEEE Transactions on Speech and Audio Processing, 2000

A doubletalk detector (DTD) is used with an echo canceler to sense when far-end speech is corrupt... more A doubletalk detector (DTD) is used with an echo canceler to sense when far-end speech is corrupted by near-end speech. Its role is to freeze the adaptation of the model filter when near-end speech is present in order to avoid divergence of the adaptive algorithm. Several authors have proposed to use the cross-correlation coefficient vector between the input signal vector x and the scalar output for a DTD. We show in this paper that this measure is not appropriate and propose a modified form that meets, in an optimal way, the needs for an efficient DTD. By extension, we also propose a definition of the normalized cross-correlation matrix between two vectors and show a link with the coherence function.

Journal of Telemedicine and Telecare - J TELEMED TELECARE, 2007

ABSTRACT

Neuroscience Letters - NEUROSCI LETT, 2004

We examined ischemia-related changes of calbindin D-28k (CB) immunoreactivity in L 7 of the spina... more We examined ischemia-related changes of calbindin D-28k (CB) immunoreactivity in L 7 of the spinal ventral horn after transient spinal cord ischemia in rabbits. In the sham-operated group, CB immunoreactivity was not present in the spinal ventral horn, but CB immunoreactivity was detectable in the dorsal horn. CB immunoreactivity was detectable in the ventral horn at 30 min after ischemia: the CB immunoreactivity was found in glial cells identified as astrocytes. At 1 h after ischemia, CB immunoreactivity was highest and present at a few somata located in the lamina VII as well as many glial cells. CB immunoreactivity was lower in the lamina VII at 3 h after ischemia compared to 1 h post-ischemic group. By 2 days after ischemia, CB immunoreactivity was decreased in this region. In addition, the result of Western blot result showed the pattern of CB expression similar to that of immunohistochemistry. In conclusion, the ischemia-related changes of CB immunoreactivity in neurons and glial cells in the ischemic spinal ventral horn in rabbits may be related to modulation of intracellular calcium following transient ischemia.

Critical Care Medicine - CRIT CARE MED, 2010

The current standard of manual chest compression during cardiopulmonary resuscitation requires pa... more The current standard of manual chest compression during cardiopulmonary resuscitation requires pauses for rhythm analysis and shock delivery. However, interruptions of chest compression greatly decrease the likelihood of successful defibrillations, and significantly better outcomes are reported if this interruption is avoided. We therefore undertook a prospective randomized controlled animal study in an electrically induced ventricular fibrillation pig model to assess the effects of timing of defibrillation on the manual chest compression cycle on the defibrillation threshold. Prospective, randomized, controlled animal study. University-affiliated research laboratory. Yorkshire-X domestic pigs (Sus scrofa). In eight domestic male pigs weighing between 24 and 31 kg, ventricular fibrillation was electrically induced and untreated for 10 secs. Manual chest compression was then performed and continued for 25 secs with the protection of an isolation blanket. The depth and frequency of chest compressions were guided by a cardiopulmonary resuscitation prompter. Animals were randomized to receive a biphasic electrical shock in five different compression phases with a predetermined energy setting. A control phase was chosen at a constant 2 secs after discontinued chest compression. A grouped up-down defibrillation threshold testing protocol was used to compare the success rate at different coupling phases. After a recovery interval of 4 mins, the sequence was repeated for a total of 60 test shocks for each animal. No difference in coronary perfusion pressure before delivering of the shock was observed among the six study phases. The defibrillation success rate, however, was significantly higher when shocks were delivered in the upstroke phase of manual chest compression. Defibrillation efficacy is maximal when electrical shock is delivered during the upstroke phase of manual chest compression.

Free Radical Biology and Medicine - FREE RADICAL BIOL MED, 2005

In the present study, we investigated the chronological alterations in SOD1 and its copper chaper... more In the present study, we investigated the chronological alterations in SOD1 and its copper chaperone (chaperone for superoxide dismutase, CCS) immunoreactivities and their neuroprotective effects against neuronal damage in the gerbil hippocampus after 5 min of transient forebrain ischemia. SOD1 and CCS immunoreactivities were significantly increased in the stratum pyramidale of the CA1 region at 24 and 12 h after ischemic insult, respectively. At 24 h after ischemic insult, the SOD1 and CCS immunoreactivities were colocalized in the CA1 pyramidal cells of the stratum pyramidale. Thereafter, their immunoreactivities were significantly decreased in the CA1 region. To elucidate the effects of CCS or CCS/SOD1, we constructed the expression vectors PEP-1-SOD and PEP-1-CCS. In the CCS-treated group and the CCS/SOD1-treated group, 43.9 and 78.9% pyramidal cells, respectively, compared to the sham-operated group, were stained with cresyl violet 5 or 7 days after ischemic insult. The distribution pattern of active astrocytes and microglia in the PEP-CCS/SOD1-treated group 5 days after ischemic insult was similar to that of the sham-operated group. In addition, the SOD activity in the PEP-CCS- or PEP-CCS/SOD1-treated group was maintained by 10 days after ischemic insult. The SOD activity was higher in the PEP-CCS/SOD1-treated group vs the CCS-treated group. These results suggest that the enhanced expression of SOD1 and CCS may be related to compensatory mechanisms against ischemic damage and that cotreatment with CCS and SOD1 has a greater neuroprotective effect than treatment with CCS or SOD1 in isolation.

IEEE Transactions on Audio, Speech, and Language Processing, 1999

Page 1. 718 IEEE TRANSACTIONS ON SPEECH AND AUDIO PROCESSING, VOL. 7, NO. 6, NOVEMBER 1999 An Obj... more Page 1. 718 IEEE TRANSACTIONS ON SPEECH AND AUDIO PROCESSING, VOL. 7, NO. 6, NOVEMBER 1999 An Objective Technique for Evaluating Doubletalk Detectors in Acoustic Echo Cancelers Jun H. Cho, Member, IEEE ...

IEEE Transactions on Consumer Electronics, 2006

Journal of The American Academy of Dermatology, 2011

To investigate the level of awareness and contact routes to electronic cigarette (e-cigarette), a... more To investigate the level of awareness and contact routes to electronic cigarette (e-cigarette), and to identify significant factors that may affect adolescent use of e-cigarettes; this study explores the experience of e-cigarettes among adolescents.Using the data from the 2008 Health Promotion Fund Project in Korea, we used a hierarchical logistic regression analysis to evaluate gender, level of school, family smoking, perception of peer influence, satisfaction in school life, and cigarette smoking experience as predictors of trying e-cigarettes among adolescents in five schools in Korea.Overall, 444 (10.2%) students responded as having seen or heard of e-cigarettes. Twenty-two (.5%) students reported as having used an e-cigarette. The contact routes of information on e-cigarettes were the Internet (249, 46.4%), friends (150, 27.9%), television (59, 11.0%), books (50, 9.3%), and others (29, 5.4%). The following factors were determined to be statistically significant predictors of e-cigarette experience: male gender, perception of peer influence, satisfaction in school life, and cigarette smoking experience.In light of this fact, continuous attention needs to be paid on the marketing of e-cigarettes on Internet sites to prevent adolescents from being exposed to unsupported claims about e-cigarettes and to provide appropriate information on health effects.

Neuroscience Letters, 2004

Olfactory dysfunction could happen following various insults such as ischemic-hypoxic state. Neur... more Olfactory dysfunction could happen following various insults such as ischemic-hypoxic state. Neurons of the main olfactory bulb (MOB) are resistant to ischemic damage. In the present study, we investigated the ischemia-related changes of neurons and glial cells in the glomerular layer (GL) of the gerbil MOB after transient ischemia. The number of NeuN-immunoreactive neurons became to decrease from 10 days after ischemic insult. Fifteen days after ischemic insult, astrocytes and microglia were increased in number. By 60 days after ischemia, NeuN-immunoreactive neurons were significantly decreased by 42% per glomerulus. At this time period, astrocytes and microglia were pronouncedly increased. This result indicates that neuronal loss must be much delayed in the GL following transient ischemia.

Atmospheric Environment, 2010

This study assessed bacterial concentrations in indoor air at 25 underground railway stations in ... more This study assessed bacterial concentrations in indoor air at 25 underground railway stations in Seoul, Korea, and investigated various related factors including the presence of platform screen doors (PSD), depth of the station, year of construction, temperature, relative humidity, and number of passengers. A total of 72 aerosol samples were collected from all the stations. Concentrations of total airborne bacteria (TAB) ranged from not detected (ND) to 4997 CFU m À3 , with an overall geometric mean (GM) of 191 CFU m À3 . Airborne bacteria were detected at 23 stations (92%) and Gram-negative bacteria (GNB) were detected at two stations (8%). TAB concentrations of four stations (16%) exceeded 800 CFU m À3 , the Korea indoor bio-aerosol guideline. The results of the study showed that TAB concentrations at the stations without PSD showed higher TAB concentrations than those with PSD, though not at statistically significant levels. TAB concentrations of deeper stations revealed significantly higher levels than those of shallower stations. Based on this study, it is recommended that mitigation measures be applied to improve the indoor air quality (IAQ) of underground railway stations in Seoul, with focused attention on deeper stations.