Jung Hyun Cho

Seoul National University of Science and Technology, Sŏul, Seoul, South Korea

Are you Jung Hyun Cho?

Claim your profile

Publications (27)62.33 Total impact

  • Jung Hyun Cho · Jong Cheol Kim · Gil Won Yoon ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Arterial oxygen saturation (SpO2) monitoring for newborns requires special attention in neonatal intensive care units (NICUs). Newborns have very low photo-plethysmogram (PPG) amplitudes and their body movements are difficult to contain. Hardware design and its associated signal processing algorithms should be robust enough so that faulty measurements can be avoided. In this study, improved designs were implemented to deal with low perfusion, motion artifact, and the influence of ambient light. Dynamic range was increased by using different LED intensities and a feedback system. To minimize the effects of motion artifact and to discard other unqualified data, four additional algorithms were used, which were based on dual-trace detection, continuity of DC level, morphology of PPG, and simultaneity check of SpO2. Our SpO2 system was tested with newborns with normal respiration in the NICU. Our system provided fast, real-time responses and 100% artifact detection was accomplished under 84% of SpO2.
    Journal of Electrical Engineering and Technology 09/2014; 9(5):1780-1787. DOI:10.5370/JEET.2014.9.5.1780 · 0.53 Impact Factor
  • Source
    Jung Hyun Cho ·

    Clinical and Experimental Reproductive Medicine 03/2014; 41(1):39. DOI:10.5653/cerm.2014.41.1.39
  • [Show abstract] [Hide abstract]
    ABSTRACT: The goal of this research was to develop a novel prolonged release tablet bioequivalent to the commercial sustained release capsule. A number of tacrolimus-loaded fast-dissolving solid dispersions containing various amounts of DOSS were prepared using the spray drying technique. Their solubility, dissolution and pharmacokinetics in rats were studied. DOSS increased drug solubility and dissolution in the solid dispersions. Compared with the drug powder, the solubility, dissolution and bioavailability of tacrolimus with the fast-dissolving solid dispersion containing tacrolimus/HP-β-CD/DOSS in the weight ratio of 5:40:4 were boosted by approximately 700-, 30- and 2-fold, respectively. Several tablet formulations were accomplished with this solid dispersion in combination with various ratios of HPMC/ethylcellulose. The release behaviour and pharmacokinetic studies in beagle dogs were assessed compared with the commercial prolonged release capsule. A decrease in HPMC/ethylcellulose ratios reduced the dissolution of tacrolimus from the tablets. Particularly, the tacrolimus-loaded prolonged release tablet consisting of fast-dissolving tacrolimus solid dispersion, HPMC, ethylcellulose and talc at the weight ratio of 20:66:112:2 exhibited a dissolution profile similar to that produced by the commercial prolonged release capsule. Furthermore, there were no significant differences in the AUC, Cmax, Tmax and MRT values between them in beagle dogs. Consequently, this tacrolimus-loaded prolonged release tablet might be bioequivalent to the tacrolimus-loaded commercial capsule.
    European journal of pharmaceutical sciences: official journal of the European Federation for Pharmaceutical Sciences 12/2013; 54(1). DOI:10.1016/j.ejps.2013.12.016 · 3.35 Impact Factor
  • Source
    Jung Hyun Cho · Moon Kyu Lee · Seon-Mi Park · Seokmoo Hong · Naksoo Kim ·
    [Show abstract] [Hide abstract]
    ABSTRACT: The use of polymethylmethacrylate (PMMA) plates is limited by some of their typical features, particularly the tendency to be deformed when conjugated with other materials, while remaining stable if it becomes homogeneous. This paper describes PMMA deformation caused by injection molding at high temperature. The relocation of the injection gate in order to minimize the deformation is also studied. Results rule out residual stresses as the main cause of the deformation, which are predicted by inverse engineering as described in the paper. Further study of residual stresses among different injection gates is made, and deformations of the PMMA-touch screen panel (TSP) laminated plate based on the locations of the injection gates are measured. In conclusion, one of the ways by which to reduce deformation at high temperature is to locate the injection gate at a symmetrical position of the plate.
    Journal of Mechanical Science and Technology 12/2012; 25(12). DOI:10.1007/s12206-011-0819-8 · 0.84 Impact Factor
  • Source
    Eun Duc Na · Dong Hyun Cha · Jung Hyun Cho · Mi Kyoung Kim ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Many studies have demonstrated that hydrosalpinx has a detrimental effect on the outcome of IVF. Treating hydrosalpinges prior to the IVF procedure in women with hydrosalpinges is thought to improve the likelihood of successful IVF outcome. Vaginal ultrasound-guided aspiration of hydrosalpinx fluid (HSF) with injection of the sclerosing agent in situ might be simpler than invasive procedures like salpingectomy. Therefore, we carried out a retrospective study on the effects of ultrasound-guided HSF aspiration and injection of the sclerosing agent of ultrasonically diagnosed hydrosalpinx on IVF outcome. In our retrospective study, 97 tubal factor infertile female patients that underwent IVF treatment between January 2005 and December 2012 at the Reproductive Medicine Center of CHA Hospital were divided into two study groups. Fifty-six patients underwent interventional ultrasound sclerotherapy (group 1), and the remaining 41 patients received laparoscopic salpingectomy (group 2) before IVF. We compared the IVF outcomes of the two groups. The results showed that ultrasound-guided HSF aspiration and sclerotherapy have IVF outcomes comparable to laparoscopic salpingectomy. Interventional ultrasound guided sclerotherapy before IVF is an effective and less invasive prophylactic intervention alternative to salpingectomy with hydrosalpinx.
    Clinical and Experimental Reproductive Medicine 12/2012; 39(4):182-6. DOI:10.5653/cerm.2012.39.4.182
  • [Show abstract] [Hide abstract]
    ABSTRACT: Human pre-ovulatory follicular fluid (FF) contains a higher concentration of melatonin than serum. The aim of this study was to evaluate the effect of melatonin supplementation of culture medium on the clinical outcomes of an in-vitro maturation (IVM) IVF-embryo transfer programme for patients with polycystic ovarian syndrome (PCOS). Melatonin concentrations in the culture media of granulosa cells (GC) or cumulus-oocyte-complexes (COC) were measured and the clinical outcomes after using IVM media with or without melatonin were analysed. In the culture media of GC or COC, melatonin concentrations gradually increased. When human chorionic gonadotrophin priming protocols were used, implantation rates in the melatonin-supplemented group were higher than those of the non-supplemented control group (P < 0.05). Pregnancy rates were also higher, although not significantly. The findings suggest that the addition of melatonin to IVM media may improve the cytoplasmic maturation of human immature oocytes and subsequent clinical outcomes. It is speculated that follicular melatonin may be released from luteinizing GC during late folliculo-genesis and that melatonin supplementation may be used to improve the clinical outcomes of IVM IVF-embryo transfer. RBMOnline
    Reproductive biomedicine online 10/2012; 26(1). DOI:10.1016/j.rbmo.2012.10.007 · 3.02 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Quercetin-3-O-β-D-glucuronopyranoside (QGC) is a flavonoid glucoside extracted from Rumex Aquaticus Herba. We aimed to explore its protective effect against ethanol-induced cell damage and the mechanism involved in the effect in feline esophageal epithelial cells (EEC). Cell viability was tested and 2',7'-dichlorofluorescin diacetate assay was used to detect intracellular H(2)O(2) production. Western blotting analysis was performed to investigate MAPK activation and interleukin 6 (IL-6) expression. Exposure of cells to 10% ethanol time-dependently decreased cell viability. Notably, exposure to ethanol for 30 min decreased cell viability to 43.4%. When cells were incubated with 50 µM QGC for 12 h prior to and during ethanol treatment, cell viability was increased to 65%. QGC also inhibited the H(2)O(2) production and activation of ERK 1/2 induced by ethanol. Pretreatment of cells with the NADPH oxidase inhibitor, diphenylene iodonium, also inhibited the ethanol-induced ERK 1/2 activation. Treatment of cells with ethanol for 30 or 60 min in the absence or presence of QGC exhibited no changes in the IL-6 expression or release compared to control. Taken together, the data indicate that the cytoprotective effect of QGC against ethanol-induced cell damage may involve inhibition of ROS generation and downstream activation of the ERK 1/2 in feline EEC.
    Korean Journal of Physiology and Pharmacology 12/2011; 15(6):319-26. DOI:10.4196/kjpp.2011.15.6.319 · 1.38 Impact Factor

  • Journal of vascular and interventional radiology: JVIR 10/2011; 22(10):1489-91. DOI:10.1016/j.jvir.2011.06.018 · 2.41 Impact Factor
  • Jung Hyun Cho · Seung Jae Yang · Kunsil Lee · Chong Rae Park ·
    [Show abstract] [Hide abstract]
    ABSTRACT: We identified several parameters that correlate with the hydrogen physisorption energy and physicochemical properties of heteronuclear bonding in single-walled carbon nanotubes (SWCNT) and graphene. These parameters were used to find the most promising heteronuclear doping agents for SWCNTs and graphene for enhanced hydrogen storage capacity. Si-doping was showed to increase the amount of physisorbed hydrogen on such surfaces. Grand Canonical Ensemble Monte Carlo (GCMC) simulations showed that the hydrogen storage capacity of 10 at% Si-doped SWCNT (Si-CNT10) could reach a maximum of 2.5 wt%, almost twice the storage capacity of undoped SWCNTs, which were showed to reach a maximum capacity of 1.4 wt% at room temperature. To achieve this capacity, debundling effects of the uneven surfaces of Si-doped SWCNTs were found to be necessary. Similarly, 10 at% Si-doping on graphene (Si-GR10) was showed to increase the hydrogen storage capacity from 0.8 to 2.4 wt%.
    International Journal of Hydrogen Energy 09/2011; 36(19):12286-12295. DOI:10.1016/j.ijhydene.2011.06.110 · 3.31 Impact Factor
  • Kunsil Lee · Hyeongjun Lim · Jung Hyun Cho · Sang Won Kim · Chong Rae Park ·

    Spring Meeting of Korean Carbon Society, Seoul, Korea; 05/2011
  • Kunsil Lee · Jung Hyun Cho · Sang Won Kim · Chong Rae Park ·

    The Annual World Conference on Carbon (Carbon 2011), Shanghai, China; 05/2011
  • [Show abstract] [Hide abstract]
    ABSTRACT: A series of structurally isomeric water-soluble azo naphthalene dyes were synthesized, and their thermal properties were examined by thermogravimetric analysis and differential scanning calorimetry. Dye-based color filters were also fabricated using the synthesized dyes. Transmittance (98.9%) at 650 nm and a wide color gamut (62.8%) were achieved using one of the color filters. All the prepared dyes had a degradation temperature above 280 °C, which varied with the dye structure. The degradation temperatures of the dyes were presumed to be related to the intra- and inter-molecular interactions of the structural isomers. From quantum mechanics calculations, their intra-molecular interactions were similar. However, the degradation temperatures generally increased in proportion to their density. According to the molecular mechanics calculations, the different structures induced changes in electrostatic attraction, steric hindrance and linearity of the dyes, which in turn caused changes in their molecular packing geometry, density and degradation temperature.
    Dyes and Pigments 04/2011; 89(1):1-8. DOI:10.1016/j.dyepig.2010.07.008 · 3.97 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate the safety and effectiveness of a new embolization technique named the 1-2-3 protocol to achieve complete necrosis of adenomyosis after uterine artery embolization (UAE) and to determine predictive factors on magnetic resonance (MR) imaging. A total of 40 patients with adenomyosis without leiomyomas diagnosed on MR imaging were prospectively enrolled. They were subdivided into three categories based on MR signal intensity (SI) of the adenomyosis on T2-weighted imaging: dark, low, and heterogeneous SI or SI equal to that of the myometrium. Nonspherical polyvinyl alcohol particles were used in all cases, beginning with 150-250-μm particles and progressively increasing to 250-355-μm and then 355-500-μm particles to the endpoint. Patients were assessed for extent of devascularization on MR imaging and for durability of symptom control. Of the 40 patients who underwent UAE for adenomyosis with the 1-2-3 protocol, 33 (82.5%) exhibited complete necrosis of adenomyosis. All six patients with dark SI of adenomyosis exhibited complete necrosis (100%). Of the 28 patients with low SI of adenomyosis, 25 (89.3%) showed complete necrosis. Among the six patients with heterogenous SI or SI equal to that of myometrium, only two (33.3%) showed complete necrosis (P < .01). Of 16 patients with complete necrosis followed up to 18 months, none reported recurrent menorrhagia. Of the five patients without necrosis, only one had no symptoms at 18 months. UAE with the 1-2-3 protocol is safe and highly effective to achieve complete necrosis of adenomyosis. Dark SI of adenomyosis is the most favorable predictive factor for UAE on MR imaging, followed by low SI. Heterogenous SI or SI equal to that of the myometrium is an unfavorable predictive factor.
    Journal of vascular and interventional radiology: JVIR 03/2011; 22(4):497-502. DOI:10.1016/j.jvir.2011.01.426 · 2.41 Impact Factor
  • Seung Jae Yang · Jung Hyun Cho · Kee Suk Nahm · Chong Rae Park ·
    [Show abstract] [Hide abstract]
    ABSTRACT: We report on an easy synthesis method for the preparation of a hybrid composite of Pt-loaded MWCNTs@MOF-5 [Zn4O(benzene-1,4-dicarboxylate)3] that greatly enhanced hydrogen storage capacity at room temperature. To prepare the composite, we first prepared Pt-loaded MWCNTs, which were then incorporated in-situ into the MOF-5 crystals. The obtained composite was characterized by various techniques such as powder X-ray diffractometry, optical microscopy, porosimetry by nitrogen adsorption, and hydrogen adsorption. The analyses confirmed that the product has a highly crystalline structure with a Langmuir specific surface area of over 2000 m2/g. The hybrid composite was shown to have a hydrogen storage capacity of 1.25 wt% at room temperature and 100 bar, and 1.89 wt% at cryogenic temperature and 1 bar. These H2 storage capacities represent significant increases over those of virgin MOF-5s and Pt-loaded MWCNTs.
    International Journal of Hydrogen Energy 12/2010; 35(23):13062-13067. DOI:10.1016/j.ijhydene.2010.04.066 · 3.31 Impact Factor
  • Kunsil Lee · Jung Hyun Cho · Sang Won Kim · Chong Rae Park ·

    Fall Meeting of Korean Carbon Society, Pohang, Korea; 11/2010
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We evaluated cytogenetic results occurring with first trimester pregnancy loss, and assessed the type and frequency of chromosomal abnormalities after assisted reproductive treatment (ART) and compared them with a control group. We also compared the rate of chromosomal abnormalities according to infertility causes in ICSI group. A retrospective cohort analysis was made of all patients who were referred to the Genetics Laboratory of Fertility Center of CHA Gangnam Medical Center from 2005 to 2009 because of clinical abortion with a subsequent dilation and evacuation (D&E) performed, and patients were grouped by type of conception as follows: conventional IVF (in vitro fertilization) (n = 114), ICSI (intracytoplasmic sperm injection) (n = 140), and control (natural conception or intrauterine insemination [IUI]) (n = 128). Statistical analysis was performed using SPSS software. A total 406 specimens were referred to laboratory, ten abortuses were excluded, and in 14 cases, we did not get any spontaneous metaphase, chromosomal constitutions of 382 specimens were successfully obtained with conventional cytogenetic methods. Overall, 52.62% of the miscarriages were found to be cytogenetically abnormal among all patients, the frequency was 48.4% in the control group, 54.3% of miscarriages after ICSI and 55.3% after conventional IVF (p = 0.503). The most prevalent abnormalities were autosomal trisomy, however, nine (11.69%) sex chromosome aneuploidy were noted in the ICSI group vs. four (6.45%) and two (3.23%) cases in the conventional IVF group and control group. We compared chromosomal abnormalities of miscarriages after ICSI according to infertility factor. 55.71% underwent ICSI due to male factors, 44.29% due to non-male factors. ICSI group having male factors showed significantly higher risk of chromosomal abnormalities than ICSI group having non-male factors (65.8% vs. 34.2%, p = 0.009, odds ratio = 1.529, 95% CI = 1.092-2.141). There is no increased risk of chromosomal abnormalities due to ART was found with the exception of a greater number of sex chromosomal abnormalities in the ICSI group with male factor infertility. Therefore, these alterations could be correlated with the underlying parental risk of abnormalities and not with the ICSI procedure itself.
    BMC Medical Genetics 11/2010; 11(1):153. DOI:10.1186/1471-2350-11-153 · 2.08 Impact Factor
  • Seung Jae Yang · Jung Hyun Cho · Kunsil Lee · Taehoon Kim · Chong Rae Park ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Despite that metal organic frameworks (MOFs) have been considered as an effective hydrogen adsorbent, there has been little systematic information available on the effect of synthetic parameters on the evolution of structural features such as crystal structure and pore characteristics and further on hydrogen storage capacity of MOFs. We, therefore, carried out a systematic study to find the effects of the synthetic conditions on the evolution of crystal structure, pore characteristics, and hydrogen storage capacities of MOF-5s through both experimental and computational studies. We found that the precursor concentration had a noticeable influence on the degree of interweaving in the MOF-5s: high concentrations favored interwoven crystal forms, whereas low concentrations favored noninterwoven crystal forms. This variation has led to a substantial difference in the pore characteristics. Since the interweaving reduced pore volume and constricted pore dimensions, the Langmuir specific surface areas of the MOF-5s decreased from 2696 to 1006 m2/g, with concurrent evolution of ultramicroporosity. Moreover, the changes in the pore characteristics have significantly affected the hydrogen storage capacities of the product. Cryogenic hydrogen storage capacity at 1 bar of the interwoven MOF-5s was enhanced from 1.03 wt % (noninterwoven MOF-5) to 1.76 wt % due to highly developed ultramicroporosity. Our results indicate that this simple but efficient concentration controlled synthesis method not only provides highly interwoven and/or noninterwoven MOF-5s but also allows a control of the pore characteristics and H2 storage capacity of MOF-type materials. The understanding of this correlation is particularly useful to establish favorable synthetic criteria for the preparation of MOF-type materials with rational designs.
    Chemistry of Materials 10/2010; 22:6138. DOI:10.1021/cm101943e · 8.35 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The root of Bupleurum falcatum L. (Apiaceae) has long been one of the most important traditional herbal medicines in Asian countries. A group of triterpene saponins (saikosaponins) are the major constituents of this plant. Squalene synthase (SS) may play a regulatory role in directing triterpene intermediates and sterol pathways. Here, we investigated the regulatory role of the squalene synthase (BfSS1) gene in the biosynthesis of phytosterol and triterpene in B. falcatum. BfSS1 mRNA accumulated ubiquitously in plant organs and markedly increased in roots after treatment with methyl jasmonate (MeJA), ABA and ethephon. Transgenic B. falcatum constructs overexpressing BfSS1 in the sense and antisense orientations were assembled using the Agrobacterium-mediated method. Transgenic roots overexpressing BfSS1 in the sense orientation resulted in enhanced production of both phytosterol and saikosaponins. Overexpression of the BfSS1 gene in the sense orientation increased the mRNA accumulation of downstream genes such as squalene epoxidase and cycloartenol synthase but unexpectedly decreased the mRNA levels of β-amyrin synthase (β-AS), a triterpene synthase mRNA. MeJA treatment of wild-type roots strongly stimulated β-AS mRNA accumulation and saikosaponin production but suppressed phytosterol production. MeJA treatment of transgenic roots overexpressing BfSS1 in the sense orientation failed to stimulate β-AS mRNA accumulation but still enhanced saikosaponin and phytosterol production. These results indicate that overexpression of BfSS1 in B. falcatum regulates more powerfully the downstream genes than elicitor (MeJA) treatment in triterpene and phytosterol biosynthesis.
    Planta 10/2010; 233(2):343-55. DOI:10.1007/s00425-010-1292-9 · 3.26 Impact Factor
  • Source
    Miok Kim · Sue Kim · S.-B. Chang · J.-S. Yoo · Hee Kyung Kim · Jung Hyun Cho ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Purpose The study aimed to develop a mind-body therapeutic program and evaluate its effects on mitigating uncertainty, anxiety, and implantation rate of second-trial in vitro fertilization (IVF) women. Methods This study employed a nonequivalent control group nonsynchronized design. The conceptual framework and program content were developed from a preliminary survey of eight infertile women and the extensive review of the literature. Program focuses on three uncertainty-induced anxieties in infertile women: cognitive, emotional, and biological responses. To evaluate the effect of the intervention, the infertile women with unknown cause preparing for a second IVF treatment were sampled at convenience (26 experimental and 24 control). Results The experimental group in the study showed greater decrease in uncertainty and anxiety in premeasurements and postmeasurements than the control group did. However, no statistically significant differences in the implantation rate between groups were observed. Conclusion This study is meaningful as the first intervention program for alleviating uncertainty and anxiety provided during the IVF treatment process. The positive effects of the mind-body therapeutic program in alleviating both uncertainty and anxiety have direct meaning for clinical applications.
    Asian Nursing Research 09/2009; 92(3). DOI:10.1016/j.fertnstert.2009.07.1190 · 1.00 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Metal−organic frameworks (MOFs) are a rapidly growing class of microporous materials. Various MOFs with tailored nanoporosities have recently been developed as potential storage media for natural gases and hydrogen. However, wider applications have been limited because even atmospheric moisture levels cause MOF instability, and unexpectedly low H2 storage capacity, at 298 K. To overcome these problems, we synthesized a hybrid composite of acid-treated multiwalled carbon nanotubes (MWCNTs) and MOF-5 [Zn4O(bdc)3; bdc = 1,4-benzenedicarbocylate] (denoted MOFMC). In a successful synthesis, well-dispersed MWCNTs in dimethylformamide (DMF) were mixed with a DMF solution of zinc nitrate tetrahydrate and terephthalic acid. The MOFMCs obtained had the same crystal structure and morphology as those of virgin MOF-5, but exhibited a much greater Langmuir specific surface area (increased from 2160 to 3550 m2/g), about a 50% increase in hydrogen storage capacity (from 1.2 to 1.52 wt % at 77 K and 1 bar and from 0.3 to 0.61 wt % at 298 K and 95 bar), and much improved stability in the presence of ambient moisture.
    Chemistry of Materials 05/2009; 21:1893. DOI:10.1021/cm803502y · 8.35 Impact Factor

Publication Stats

423 Citations
62.33 Total Impact Points


  • 2014
    • Seoul National University of Science and Technology
      Sŏul, Seoul, South Korea
  • 2006-2014
    • CHA University
      • • College of Medicine
      • • Department of Obstetrics and Gynecology
      Sŏul, Seoul, South Korea
  • 2013
    • Yeungnam University
      • College of Pharmacy
      Onyang, South Chungcheong, South Korea
  • 2012
    • Sogang University
      • Department of Mechanical Engineering
      Sŏul, Seoul, South Korea
  • 2011
    • Chung-Ang University
      • College of Pharmacy
      Seoul, Seoul, South Korea
  • 2009-2011
    • Seoul National University
      • Department of Materials Science and Engineering
      Sŏul, Seoul, South Korea
    • Gyeongsang National University
      • Department of Internal Medicine
      Chinju, South Gyeongsang, South Korea
  • 2010
    • Chonnam National University
      Gwangju, Gwangju, South Korea