• Genomics & Informatics
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• v.21 no.2
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• pp.19.1-19.13
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• 2023

Liver cancer, particularly hepatocellular carcinoma (HCC), poses a significant global threat to human lives. To advance the development of innovative diagnostic and treatment approaches, it is essential to examine the hidden features of HCC, particularly its 3D genome architecture, which is not well understood. In this study, we investigated the 3D genome organization of four HCC cell lines-Hep3B, Huh1, Huh7, and SNU449-using in situ Hi-C and assay for transposase-accessible chromatin sequencing. Our findings revealed that HCC cell lines had more long-range interactions, both intra-and interchromosomal, compared to human mammary epithelial cells (HMECs). Unexpectedly, HCC cell lines displayed cell line-specific compartmental modifications at the megabase (Mb) scale, which could potentially be leveraged in determining HCC subtypes. At the sub-Mb scale, we observed decreases in intra-TAD (topologically associated domain) interactions and chromatin loops in HCC cell lines compared to HMECs. Lastly, we discovered a correlation between gene expression and the 3D chromatin architecture of SLC8A1, which encodes a sodium-calcium antiporter whose modulation is known to induce apoptosis by comparison between HCC cell lines and HMECs. Our findings suggest that HCC cell lines have a distinct 3D genome organization that is different from those of normal and other cancer cells based on the analysis of compartments, TADs, and chromatin loops. Overall, we take this as evidence that genome organization plays a crucial role in cancer phenotype determination. Further exploration of epigenetics in HCC will help us to better understand specific gene regulation mechanisms and uncover novel targets for cancer treatment.

• International Journal of Computer Science & Network Security
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• v.23 no.7
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• pp.1-8
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• 2023

An Orthogonal Frequency Division Multiplexing (OFDM) based wireless communication system has drawn wide attention for its high transmission rate and high spectrum efficiency in not only radio but also Underwater Acoustic (UWA) applications. Because of the narrow sub-carrier spacing of OFDM, orthogonality between sub-carriers is easily affected by Doppler effect caused by the movement of transmitter or receiver. Previously, Doppler compensation signal processing algorithm for Desired propagation path was proposed. However, other Doppler shifts caused by delayed Undesired signal arriving from different directions cannot be perfectly compensated. Then Receiver Bit Error Rate (BER) is degraded by Inter-Carrier-Interference (ICI) caused in the case of Multi-path Doppler channel. To mitigate the ICI effect, a modified Delay and Doppler Profiler (mDDP), which estimates not only attenuation, relative delay and Doppler shift but also sampling clock shift of each multi-path component, is proposed. Based on the outputs of mDDP, an ICI canceling multi-tap equalizer is also proposed. Computer simulated performances of one-tap equalizer with the conventional Time domain linear interpolated Channel Transfer Function (CTF) estimator, multi-tap equalizer based on mDDP are compared. According to the simulation results, BER improvement has been observed. Especially, in the condition of 16QAM modulation, transmitting vessel speed of 6m/s, two-path multipath channel with direct path and ocean surface reflection path; more than one order of magnitude BER reduction has been observed at CNR=30dB.

• IMMUNE NETWORK
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• v.16 no.2
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• pp.140-145
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• 2016

Ophiocordyceps sinensis is a natural fungus that has been valued as a health food and used in traditional Chinese medicine for centuries. The fungus is parasitic and colonizes insect larva. Naturally occurring O. sinensis thrives at high altitude in cold and grassy alpine meadows on the Himalayan mountain ranges. Wild Ophiocordyceps is becoming increasingly rare in its natural habitat, and its price limits its use in clinical practice. Therefore, the development of a standardized alternative is a great focus of research to allow the use of Ophiocordyceps as a medicine. To develop an alternative for wild Ophiocordyceps, a refined standardized extract, CBG-CS-2, was produced by artificial fermentation and extraction of the mycelial strain Paecilomyces hepiali CBG-CS-1, which originated from wild O. sinensis. In this study, we analyzed the in vitro immune-modulating effect of CBG-CS-2 on natural killer cells and B and T lymphocytes. CBG-CS-2 stimulated splenocyte proliferation and enhanced Th1-type cytokine expression in the mouse splenocytes. Importantly, in vitro CBG-CS-2 treatment enhanced the killing activity of the NK-92MI natural killer cell line. These results indicate that the mycelial culture extract prepared from Ophiocordyceps exhibits immune-modulating activity, as was observed in vivo and this suggests its possible use in the treatment of diseases caused by abnormal immune function.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1737-1743
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• 2006

OCR(On channel repeater) provides the high frequency reuse efficiency for allocating frequency bands to repeaters because the frequency of input and output signals of OCRs is the same. However the oscillation probability of OCRs is high due to the same input and output frequency. In order to prevent a repeater from oscillating, we must keep the antenna isolation higher than the gain of the repeater with a some margin. In this paper we simulated the effects of the amplitude, phase and time delay of feedback signals (m the characteristics of non-regeneration OCR. Simulation results show that the highest probability of oscillation is occurred when the gain of a repeater is the same value of the isolation. From the simulation results, we know that the phase of feedback signals can be adjusted to reduce the possibility of oscillation if a non-regeneration repeater has a narrow operation bandwidth or a signal bandwidth is narrow. As the time delay increases, the probability of oscillation and the fluctuation of gain over a certain frequency band increase also. The effects of the amplitude and phase of feedback signals on S/N of 8-VSB signal for generation and non-generation repeater were tested. The measured results show that the set-top can receive 8-VSB signal when the received signal power is $17{\sim}18dB$ higher than the noise power. When the isolation is almost same as the gain of the repeater, then the set-top can not receive 8-VSB signals due to the oscillation of the repeater. And the phase of feedback signals affects S/N at the output of the repeater when the isolation is $11.75{\sim}13.75dB$ larger than the gain of the repeater. In this case the set-top can not receive 8-VSB signal of at $48^{\circ}\;and\;347^{\circ}$ of the phase of feedback signals. However the phase of feedback signals can not affect the S/N of 8-VSB signals of the generation repeater because of the demodulation and modulation process of the generation repenter. The set-top can not receive 8-VSB signals when the amplitude of feedback signals is $12.6{\sim}13.6dB$ larger than the wanted signal power at the input port of the repeater. It's because that the amplitude of feedback signals saturates the front end of the repeater.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.248-256
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• 2007

In this paper, we propose a selective DFT spreading method to solve a high PAPR problem in uplink OFDMA system. A selective characteristic is added to the DFT spreading, so the DFT spreading method is mixed with SLM method. However, to minimize increment of computational complexity, differently with common SLM method, our proposed method uses only one DFT spreading block. After DFT, several copy branches are generated by multiplying with each different matrix. This matrix is obtained by linear transforming the each phase rotation in front of DFT block. And it has very lower computational complexity than one DFT process. For simulation, we suppose that the 512 point IFFT is used, the number of effective sub-carrier is 300, the number of allowed sub-carrier to each user's is 1/4 and 1/3 and QPSK modulation is used. From the simulation result, when the number of copy branch is 4, our proposed method has more than about 5.2 dB PAPR reduction effect. It is about 1.8 dB better than common DFT spreading method and 0.95 dB better than common SLM which uses 32 copy branches. And also, when the number of copy branch is 2, it is better than SLM using 32 copy branches. From the comparison, the proposed method has 91.79 % lower complexity than SLM using 32 copy branches in similar PAPR reduction performance. So, we can find a very good performance of our proposed method. Also, we can expect the similar performance when all number of sub-carrier is allocated to one user like the OFDM.

• Development and Reproduction
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• v.13 no.4
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• pp.207-215
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• 2009

Numerous factors can affect the activities of hypothalamus-pituitary-gonad (HPG) hormonal axis, resulting in alteration of reproductive capacity or status such as onset of puberty and menopause. Soon after the finding of leptin, a multifunctional hormone secreted from adipocytes, a close relationship between reproduction and body energy balance have been manifested. Ghrelin, another multifunctional hormone from gastrointestinal tract, is an endogenous ligand of growth hormone secretagogue receptor (GHSR), and is thought to be a counterpart of leptin in the regulation of energy homeostasis. As expected, ghrelin can also modulate the reproductive capacity through the modulation of activities of HPG axis. This paper summarizes the current knowledge on the discovery, gene structures, tissue distribution and roles of ghrelin and GHSRs in mammalian reproduction in particular modulation of reproductive hormone secretion in HPG axis. Like POMC gene expression in pituitary gland, preproghrelin gene can generate a complex repertoire of transcripts which further undergo alternative splicing and posttranslational modifications. Concerning the roles of preproghrelin gene products in the control of body physiology except energy homeostasis, limited knowledge is available so far. Several lines of evidence, however, show the interplay of ghrelin between metabolism and reproduction. In rat and human, the distribution of ghrelin receptor GHSRs (GHSR1a and GHSR1b) has been confirmed not only in the hypothalamus and pituitary which were originally postulated as target of ghrelin but also in the testis and ovary. Expression of the preproghrelin gene in the brain and gonads was also verified, suggesting the local role (s) of ghrelin in HPG axis. Ghrelin might play a negative modulator in the secretions of hypothalamic GnRH, pituitary gonadotropins and gonadal steroids though the action on pituitary is still questionable. Recent studies suggest the involvement of ghrelin in regulation of puberty onset and possibly of menopause entry. It is now evident that ghrelin is a crucial hormomal component in 'brain-gut' axis, and is a strong candidate links between metabolism and reproduction. Opposite to that for leptin, ghrelin signaling is likely representing the 'hunger' state of body energy balance and is necessary to avoid the energy investment into reproduction which has not a top priority in maintaining homeostasis. Further researches are needed to gain a deep insight into the more precise action mechanism and role of ghrelin in reproduction, and to guarantee the successful biomedical applications.

• Journal of Nutrition and Health
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• v.50 no.3
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• pp.225-235
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• 2017

Purpose: This study aimed to investigate the potential of freeze-dried persimmon powder (Diospyros kaki Thumb.) to protect against dyslipidemia induced by a high-fat/cholesterol diet (HFD) in a rat model. Methods: Fifty Wistar rats were randomly divided into five groups: normal control (NC), high-fat/cholesterol control (HC), tannin in HFD (HT, 1% of diet), immature persimmon in HFD (HI, 7% of diet), and mature persimmon in HFD (HM, 7% of diet). Tannin was used as a positive control. Biochemical, molecular, and histopathological changes were observed in the blood and liver. Results: We confirmed that a high fat/cholesterol diet successfully induced dyslipidemia, which was characterized by significantly altered lipid profiles in the plasma and liver. However, oxidized low-density lipoprotein levels, histopathological damage in the liver, and hepatic triglyceride levels were significantly reduced in all HT, HI, and HM groups compared to those in the HF group. In contrast, plasma apolipoprotein B level was significantly reduced only in the HT and HM groups, whereas reduction of the LDL-C level was detected only in the HI group. Although HF-induced sterol regulatory element-binding protein (SREBP) gene expression was significantly reduced in all treated groups, downstream gene expression levels varied among the different groups; significant reduction of fatty acid synthase (FAS) and 3-hydroxy-3-methylglutaryl-CoA (HMGCR) gene expression was detected only in the HI group, whereas cholesterol $7{\alpha}$-hydroxylase (CYP7A1) gene expression was significantly elevated only in the HM group. Conclusion: Taken together, the data suggest that protection of LDL oxidation and hepatic lipogenesis might be, at least partly, attributed to tannin in persimmons. However, the identified mechanisms varied up to the maturation stage of persimmon. In the case of immature persimmon, modulation of FAS and HMGCR gene expression was prominent, whereas in the case of mature persimmon, modulation of CYP7A1 gene expression was prominent.

• Journal of IKEEE
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• v.12 no.3
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• pp.176-183
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• 2008

The high efficiency power management IC(PMIC) with DTMOS(Dynamic Threshold voltage MOSFET) switching device is proposed in this paper. PMIC is controlled with PWM control method in order to have high power efficiency at high current level. DTMOS with low on-resistance is designed to decrease conduction loss. The control parts in Buck converter, that is, PWM control circuits consist of a saw-tooth generator, a band-gap reference circuit, an error amplifier and a comparator circuit as a block. The Saw-tooth generator is made to have 1.2 MHz oscillation frequency and full range of output swing from ground to supply voltage(VDD:3.3V). The comparator is designed with two stage OP amplifier. And the error amplifier has 70dB DC gain and $64^{\circ}$ phase margin. DC-DC converter, based on Voltage-mode PWM control circuits and low on-resistance switching device, achieved the high efficiency near 95% at 100mA output current. And DC-DC converter is designed with LDO in stand-by mode which fewer than 1mA for high efficiency.

• Korean Journal of Food Science and Technology
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• v.52 no.5
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• pp.538-545
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• 2020

Kimchi is a widely consumed traditional Korean food, and its probiotic properties have received great attention. In this study, changes in the quality characteristics of fermentation broths obtained from two types of Chinese cabbage kimchi (red with red pepper and white without red pepper) were assessed after the administration of blue light emitting diode (BLED) irradiation at 4℃; characteristics assessed included acidity, chromaticity, antioxidant activity, and growth modulation of isolated microorganisms. The pH of the white kimchi (WK) broth decreased with time; the decrease was delayed significantly under BLED irradiation (p<0.05). BLED irradiation decreased the L (lightness) and b (yellowness) values and increased a (redness) in WK, whereas the a and b values of the red kimchi (RK) broth increased with BLED irradiation. Growth stimulation of lactic acid bacteria by BLED irradiation was observed in both WK and RK. The numbers of yeast and mold were also increased in RK (p<0.05), but not in WK. There was no change observed in the scavenging activities against ABTS (2,2'-azido-bis(3-ethylbenzthiazoline-6-sulfonic acid) radicals in both kimchi broths after BLED treatment. The results of this study indicated that BLED irradiation could modulate the fermentation process and the quality characteristics of kimchi during storage.

• Korean Journal of Food Science and Technology
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• v.39 no.2
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• pp.175-180
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• 2007

Toll-like receptors induce innate immune responses recognizing conserved microbial structural molecules that are known as pathogen-associated molecular patterns (PAMPs). Ligand-induced homotypic oligomerization was found to proceed in LPS-induced activation of TLR4 signaling pathways. TLR2 is known to heterodimerize with TLR1 or TLR6 and recognize diacyl- or triacyl-lipopeptide, respectively. These results suggest that ligand-induced receptor dimerization of TLR4 and TLR2 is required for the activation of downstream signaling pathways. Therefore, receptor dimerization may be one of the first lines of regulation in the activation of TLR-mediated signaling pathways and induction of subsequent innate and adaptive immune responses. Here, we report biochemical evidence that curcumin from the plant Curcuma longa inhibits activation of $NF-{\kappa}B$, expression of COX-2, and dimerization of TLRs induced by TLR2, TLR3 and TLR4 agonists. These results imply that curcumin can modulate the activation of TLRs and subsequent immune/inflammatory responses induced by microbial pathogens.