• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.622-627
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• 2002

Diphtheria toxin repressor (DtxR) binds to approximately 30 to 35-bp regions containing an interrupted 9-bp inverted repeat within a 19-bp core sequence. The core sequence is fairly conserved and critical for DtxR binding. The flanking regions that are consisted of 5 to 8 more of nucleotides from the core are also required for DtxR binding. The nucleotides in both flanking regions are A-T rich. To examine whether the A-T nucleotides in both flanking regions from the core have significant roles for DtxR binding, a DNA fragment was constructed based on the diphtheria tox promoter/operator, and DNA fragments with substitution of A and T nucleotides In the flanking regions to G and C were also constructed. To assess the effect of these substitutions on binding of DtxR and repressibility by DtxR, $\beta$-galactosidase activity from lacZ fused to the region was assessed. Gel mobility shift of the region by purified DtxR was also examined. The DNA fragments containing the mutations in the flanking regions still exhibited repression and mobility shift with DtxR. The core segment with the mutation is still, therefore, recognized by DtxR. Nonetheless, the results from the assays indicated that the substitution significantly decreased repression of the operator by DtxR in vivo under high-iron condition and decreased binding of DtxR to the operator. These results suggest that A and T nucleotides fur both flanking regions are preferred for the binding of DtxR.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.1
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• pp.45-54
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• 2017

Our study aims to determine the metabolism and excretion of novel pulmonary-targeting docetaxel liposome (DTX-LP) using the in vitro and in vivo animal experimental models. The metabolism and excretion of DTX-LP and intravenous DTX (DTX-IN) in New Zealand rabbits were determined with ultra-performance liquid chromatography tandem mass spectrometry. We found DTX-LP and DTX-IN were similarly degraded in vitro by liver homogenates and microsomes, but not metabolized by lung homogenates. Ultra-performance liquid chromatography tandem mass spectrometry identified two shared DTX metabolites. The unconfirmed metabolite $M_{un}$ differed structurally from all DTX metabolites identified to date. DTX-LP likewise had a similar in vivo metabolism to DTX-IN. Conversely, DTX-LP showed significantly diminished excretion in rabbit feces or urine, approximately halving the cumulative excretion rates compared to DTX-IN. Liposomal delivery of DTX did not alter the in vitro or in vivo drug metabolism. Delayed excretion of pulmonary-targeting DTX-LP may greatly enhance the therapeutic efficacy and reduce the systemic toxicity in the chemotherapy of non-small cell lung cancer. The identification of $M_{un}$ may further suggest an alternative species-specific metabolic pathway.

• Journal of KIISE:Information Networking
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• v.37 no.3
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• pp.243-248
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• 2010

This thesis proposes a power saving MAC protocol for LTE base station which utilizes different graded DRX/DTX(Discontinuous. Reception/Transmission) that specified by 3GPP(Third Generation Partnership Project). Considering QoS in UE, proposed MAC protocol controls adaptive DRX/DTX cycle. When Packet delay of UE is less than normal time, LTE base station economize power by increasing DRX/DTX. When Packet delay of UE is more than normal time, delay of UE is decreased by guaranteed QoS. It depends on the traffic which is sent by UE. The proposed method is more improve power saving performance than another method which is unchanged DRX/DTX by conditions. Especially when set DRX/DTX up in conditions, it will meet the requirements of UE. In this thesis, I propose an power saving MAC protocol in an environment where LTE base station are communicated with UE and prove improvement in performance through simulations.

• The Korean Journal of Physiology and Pharmacology
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• v.25 no.5
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• pp.479-488
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• 2021

This study aimed to develop docetaxel (DTX) loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (DTX-NPs) and to evaluate the different pharmacological sensitivity of NPs to MCF-7 and MDA-MB-231 breast cancer cells. NPs containing DTX or coumarin-6 were prepared by the nanoprecipitation method using PLGA as a polymer and d-α-tocopherol polyethylene glycol 1000 succinate (TPGS) as a surfactant. The physicochemical properties of NPs were characterized. In vitro anticancer effect and cellular uptake were evaluated in breast cancer cells. The particle size and zeta potential of the DTX-NPs were 160.5 ± 3.0 nm and -26.7 ± 0.46 mV, respectively. The encapsulation efficiency and drug loading were 81.3 ± 1.85% and 10.6 ± 0.24%, respectively. The in vitro release of DTX from the DTX-NPs was sustained at pH 7.4 containing 0.5% Tween 80. The viability of MDA-MB-231 and MCF-7 cells with DTX-NPs was 37.5 ± 0.5% and 30.3 ± 1.13%, respectively. The IC₅₀ values of DTX-NPs were 3.92- and 6.75-fold lower than that of DTX for MDA-MB-231 cells and MCF-7 cells, respectively. The cellular uptake of coumarin-6-loaded PLGA-NPs in MCF-7 cells was significantly higher than that in MDA-MB-231 cells. The pharmacological sensitivity in breast cancer cells was higher on MCF-7 cells than on MDA-MB-231 cells. In conclusion, we successfully developed DTX-NPs that showed a great potential for the controlled release of DTX. DTX-NPs are an effective formulation for improving anticancer effect in breast cancer cells.

• Journal of Broadcast Engineering
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• v.15 no.1
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• pp.29-39
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• 2010

This paper presents and analyzes laboratory test results of distributed translator (DTxR) for distributed frequency network (DFN) in the ATSC (Advanced Television Systems Committee) terrestrial digital TV broadcasting system. The DTxR laboratory test is classified to receiving part test and transmitting part test. The receiving part test includes dynamic range, random noise, single echo, and adjacent channel interference. The transmitting part test includes quality of output signal (out-of channel emission, quality of transmitting signal, and phase noise), frequency synchronization among output signals, and TxID (Transmitter Identification) signal's affect to the legacy receiver. By the laboratory test results, the receiving part of DTxR eliminates average -2.5 dB of single echo and has average 17.5 dB at TOV (Threshold of Visibility) under random noise environment. In addition, the transmitting part of DTxR satisfies the specification of US FCC (Federal Communications Commission), and frequency difference among DTxR output signals is less than 0.001 Hz.

• Journal of Internet Computing and Services
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• v.24 no.4
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• pp.15-24
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• 2023

Digital therapeutics (DTx) are utilized to replace or supplement drug therapy to treat patients. DTx are developed as a mobile application for portability and convenience. The government requires security verification to be performed on digital medical devices that manage sensitive information during the transmission and storage of patient data. Although safety verification is included in the approval process for DTx, the cybersecurity checklist used as a reference does not reflect the characteristics of mobile applications. This poses the risk of potentially overlooking vulnerabilities during security verification. This study aims to address this issue by comparing and analyzing existing items based on the mobile tactics, techniques, and procedures of MITRE ATT&CK, which manages globally known and occurring vulnerabilities through regular updates. We identify 16 items that require improvement and expand the checklist to 29 items to propose improvement measures. The findings of this study may contribute to the safe development and advancement of DTx for managing sensitive patient information.

• Journal of Broadcast Engineering
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• v.15 no.1
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• pp.40-51
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• 2010

This paper presents and analyzes field test results of distributed translator (DTxR) for distributed frequency network (DFN) in the ATSC (Advanced Television Systems Committee) terrestrial digital TV broadcasting system. In the field test, according to types of antennas and receivers in areas where are overlapped by two DTxRs' coverage, we measured reception power, noise margin reception possibility, and ease of reception at each test point. By the field test results, when two DTxRs are on, reception power and noise margin are increased than when one DTxR is on. However, reception rate and ease of reception are similar or increased according to types of receivers.

• Korean Journal of Food Science and Technology
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• v.41 no.4
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• pp.458-463
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• 2009

To establish and validate a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the rapid and accurate quantitation of diarrhetic shellfish poisoning (DSP) toxins, we compared the results from different mobile phases and columns used for their analysis and collision energies for MS/MS experiments. Clear peaks of okadaic acid (OA) and dinophysistoxin-1 (DTX1) were obtained by using a mobile phase comprising aqueous acetonitrile containing 2 mM ammonium formate and 50 mM formic acid. The collision energies were optimized to facilitate the most sensitive detection for each toxin, namely, OA, DTX1, pectenotoxin-2 (PTX2), or yessotoxin (YTX). Further, the maximum ion response was obtained at a collision energy of 48 V for OA and DTX1. We compared the analytical performance of $C_8$ and $C_{18}$ columns. A wide range of toxins namely, OA, DTX1, PTX2, and YTX, except DTX3, were detected by both the columns. Although DTX3 was only detected by the $C_8$ column, we found that the $C_{18}$ column was also suitable for the quantitation of OA and DTX1 the toxins responsible for inducing diarrhea. The limit of detection of OA and DTX1 by the established LC-MS/MS conditions was 1 ng/g, and the limit of quantitation of the toxins under the same conditions was 3 ng/g. The process efficiencies were 91-118% for oysters (Crassostrea gigas) and 96-117% for mussels (Mytilus galloprovincialis) further, we observed no significant effect of matrix during the ionization process in LC-MS/MS. The comparison between mouse bioassay (MBA) and LC-MS/MS yielded varying results because low concentrations of OA and DTX1 were detected by LC-MS/MS in some shellfish samples, which provided positive results on MBA for DSP. The analysis time required by MBA for DSP analysis can be reduced by LC-MS/MS.

• Journal of Broadcast Engineering
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• v.15 no.1
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• pp.14-28
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• 2010

This paper considers technological requirements to broadcast digital television signals using distributed frequency network (DFN) in the advanced television systems committee (ATSC) transmission system and proposes distributed translator (DTxR) to meet such requirements. In the DFN, DTxR uses different frequency from main transmitter, but same among DTxRs. In addition, this paper introduces digital signal processing (DSP) techniques, which consist of demodulation, equalization, transmitter identification (TxID) generation and insertion, and modulation, to implement DTxR.

• Archives of Obesity and Metabolism
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• v.1 no.2
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• pp.47-52
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• 2022

Digital therapeutics (DTx) are emerging as a novel solution to improve lifestyle and prevent non-communicable diseases. Obesity is a complex, multi-factorial, chronic condition that requires patient-centered lifestyle modification. DTx, such as mobile applications and wearables, may offer easily accessible, efficient, and personalized care in the field of obesity and metabolic diseases. Yet, there is controversy over its clinical usefulness. This review will provide a comprehensive overview of DTx, including its potential role and current limitation in obesity care, based on recent literature.