• Biomolecules & Therapeutics
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• 제26권6호
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• pp.546-552
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• 2018

A comprehensive collection of proteins senses local changes in intracellular $Ca^{2+}$ concentrations ($[Ca^{2+}]_i$) and transduces these signals into responses to agonists. In the present study, we examined the effect of sphingosine-1-phosphate (S1P) on modulation of intracellular $Ca^{2+}$ concentrations in cat esophageal smooth muscle cells. To measure $[Ca^{2+}]_i$ levels in cat esophageal smooth muscle cells, we used a fluorescence microscopy with the Fura-2 loading method. S1P produced a concentration-dependent increase in $[Ca^{2+}]_i$ in the cells. Pretreatment with EGTA, an extracellular $Ca^{2+}$ chelator, decreased the S1P-induced increase in $[Ca^{2+}]_i$, and an L-type $Ca^{2+}$-channel blocker, nimodipine, decreased the effect of S1P. This indicates that $Ca^{2+}$ influx may be required for muscle contraction by S1P. When stimulated with thapsigargin, an intracellular calcium chelator, or 2-Aminoethoxydiphenyl borate (2-APB), an $InsP_3$ receptor blocker, the S1P-evoked increase in $[Ca^{2+}]_i$ was significantly decreased. Treatment with pertussis toxin (PTX), an inhibitor of $G_i$-protein, suppressed the increase in $[Ca^{2+}]_i$ evoked by S1P. These results suggest that the S1P-induced increase in $[Ca^{2+}]_i$ in cat esophageal smooth muscle cells occurs upon the activation of phospholipase C and subsequent release of $Ca^{2+}$ from the $InsP_3$-sensitive $Ca^{2+}$ pool in the sarcoplasmic reticulum. These results suggest that S1P utilized extracellular $Ca^{2+}$ via the L type $Ca^{2+}$ channel, which was dependent on activation of the $S1P_4$ receptor coupled to PTX-sensitive $G_i$ protein, via phospholipase C-mediated $Ca^{2+}$ release from the $InsP_3$-sensitive $Ca^{2+}$ pool in cat esophageal smooth muscle cells.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제39A권12호
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• pp.746-755
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• 2014

Compressive sensing (CS) has drawn much interest as a new sampling technique that enables signals to be sampled at a much lower than the Nyquist rate. By noting that the block-based compressive sensing can still keep spatial correlation in measurement domain, in this paper, we propose a novel encoding technique for measurement data obtained in the block-based CS of natural image. We apply discrete wavelet transform (DWT) to decorrelate CS measurements and then assign a proper quantization scheme to those DWT coefficients. Thus, redundancy of CS measurements and bitrate of system are reduced remarkably. Experimental results show improvements in rate-distortion performance by the proposed method against two existing methods of scalar quantization (SQ) and differential pulse-code modulation (DPCM). In the best case, the proposed method gains up to 4 dB, 0.9 dB, and 2.5 dB compared with the Block-based CS-Smoothed Projected Landweber plus SQ, Block-based CS-Smoothed Projected Landweber plus DPCM, and Multihypothesis Block-based CS-Smoothed Projected Landweber plus DPCM, respectively.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권1호
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• pp.126-142
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• 2016

This paper presents a wide-frequency-range, low-power transceiver with an automatic impedance-matching calibration for TV-white-space (TVWS) application. The wide-range automatic impedance matching calibration (AIMC) is proposed for the Drive Amplifier (DA) and LNA. The optimal $S_{22}$ and $S_{11}$ matching capacitances are selected in the DA and LNA, respectively. Also, the Single Pole Double Throw (SPDT) switch is integrated to share the antenna and matching network between the transmitter and receiver, thereby minimizing the systemic cost. An N-path filter is proposed to reject the large interferers in the TVWS frequency band. The current-driven mixer with a 25% duty LO generator is designed to achieve the high-gain and low-noise figures; also, the frequency synthesizer is designed to generate the wide-range LO signals, and it is used to implement the FSK modulation with a programmable loop bandwidth for multi-rate communication. The TVWS transceiver is implemented in $0.13{\mu}m$, 1-poly, 6-metal CMOS technology. The die area of the transceiver is $4mm{\times}3mm$. The power consumption levels of the transmitter and receiver are 64.35 mW and 39.8 mW, respectively, when the output-power level of the transmitter is +10 dBm at a supply voltage of 3.3 V. The phase noise of the PLL output at Band 2 is -128.3 dBc/Hz with a 1 MHz offset.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제10권3호
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• pp.511-516
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• 2006

In this raper, we propose the Sequentiel Couleur Avec Memoire or Sequential Color with Memory (SECAM) video encoder system using modified anti-cloche filters and the SECAM video decoder system using a band pass filter (BPF) and an error-free square root. The SECAM encoder requires an anti-cloche filter recommended by International Telecommunication Union-Recommendation (ITU-R) Broadcasting service Television (BT) 470. However, the design of the anti-cloche filter is difficult because the frequency response of the anti-cloche filter is very sharp around rejection-frequency area. So, we convert the filter into a hish pass filter (HPF) by shifting the rejection frequency of 4.286MHz to 0Hz frequency. The design of HPF becomes very easy, compared to that of the anti-cloche filter. The proposed decoder also uses an error-free square root, two differentiators and trigonometric functions to extract color-component information of Db and Dr accurately from frequency modulation (FM) signals in SECAM systems. Also, the BPF in decoder it used for removing color noise in chrominance and dividing CVBS into chrominance and luminance. The proposed systems are experimentally demonstrated with Altera FPGA APEX20KE EP20K1000EBC652-3 device and TV sets.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제40권8호
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• pp.1507-1514
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• 2015

Non-orthogonal multiple access (NOMA) is a promising candidate for 5G networks. NOMA achieves superior spectral efficiency than conventional orthogonal multiple access (OMA), as in NOMA multiple users uses the same time and frequency resources. Multiple-input-multiple-output (MIMO) is one another promising technique that can enhance system performance. In this paper we present a spectral and energy efficient multiple antenna based NOMA scheme, known as spatially modulated NOMA. In the proposed scheme the cell edge users are multiplexed in spatial domain, which means the information to cell edge users is conveyed using the transmit antenna indices. In NOMA the performance of cell edge users are deeply effected as it treats signals of others as noise. The proposed scheme achieves superior spectral efficiency than the conventional NOMA. The number of decoding steps involved in decoding NOMA signal reduces by one as cell edge user is multiplexed in spatial domain. The proposed scheme is more energy efficient as compare to conventional NOMA. All of the three gains high spectral, energy efficiency and one step reduction in decoding comes at cost of multiple transmit antennas at base station.

• Development and Reproduction
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• 제13권4호
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• pp.297-303
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• 2009

Implantation of blastocyst into the uterine endometrium is established by the existence of histologically and functionally prepared uterine endometrium. Doc-1, an oral cancer suppressor gene, is expressed under the control of steroid hormones and has been suggested as a proliferation regulator of endometrial cells. However, the role is not much clear and in this study we examined the expression modulation of Doc-1 in decidualizing cells in vitro. In vitro decidualization was performed in endometrial stroma cells using progesterone and estrogen. Until 24 hr after decidual induction the proliferation of stroma cell was significantly increased but decreased after then. On the other hand, most of the cells differentiated into decidual cell after 48 hr of induction. The Doc-1 protein was co-localized in a specific deciudal cells and colocalization rate was increased in a parallel manner with the induction time. Based on these results, it is suggested that Doc-1 expression is under the control of both steroid hormones and decidual signals, and Doc-1 protein is involved in suppression of the proliferation of decidualizing cells.

• Journal of Life Science
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• 제23권8호
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• pp.1064-1072
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• 2013

Circadian rhythm is controlled by hormonal oscillations governing the physiology of all living organisms. In mammals, the main function of the pineal gland is to transform the circadian rhythm generated in the hypothalamic suprachiasmatic nucleus into rhythmic signals of circulating melatonin characterized by a largely nocturnal increase that closely reflects the duration of night time. The pineal gland has lost direct photosensitivity, but responds to light via multi-synaptic pathways that include a subset of retinal ganglion cells. Rhythmic control is achieved through a tight coupling between environmental lighting and arylalkylamine-N-acetyltransferase (AANAT) expression, which is the rhythm-controlling enzyme in melatonin synthesis. Previous studies on the nocturnal expression of AANAT protein have described transcriptional, post-transcriptional, and post-translational regulatory mechanisms. Molecular mechanisms for dependent AANAT expression provide novel aspects for melatonin's circadian rhythmicity. Extensive animal research has linked pineal melatonin for the expression of seasonal rhythmicity in many mammalian species to the modulation of circadian rhythms and to sleep regulation. It has value in treating various circadian rhythm disorders, such as jet lag or shift-work sleep disorders. Melatonin, also, in a broad range of effects with a significant regulation influences many of the body's physiological functions. In addition, this hormone is known to influence reproductive, cardiovascular, and immunological regulation as well as psychiatric disorders.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.146-147
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• 2011

Processing a large area substrate for liquid crystal display (LCD) or solar panel applications in a capacitively coupled plasma (CCP) reactor is becoming increasingly challenging because of the size of the substrate size is no longer negligible compared to the wavelength of the applied radio frequency (RF) power. The situation is even worse when the driving frequency is increased to the Very High Frequency (VHF) range. When the substrate size is still smaller than 1/8 of the wavelength, one can obtain reasonably uniform process results by utilizing with methods such as tailoring the precursor gas distribution by adjustingthrough shower head hole distribution or hole size modification, locally adjusting the distance between the substrate and the electrode, and shaping shower head holes to modulate the hollow cathode effect modifying theand plasma density distribution by shaping shower head holes to adjust the follow cathode effect. At higher frequencies, such as 40 MHz for Gen 8.5 (2.2 m${\times}$2.6 m substrate), these methods are not effective, because the substrate is large enough that first node of the standing wave appears within the substrate. In such a case, the plasma discharge cannot be sustained at the node and results in an extremely non-uniform process. At Applied Materials, we have studied several methods of modifying the standing wave pattern to adjusting improve process non-uniformity for a Gen 8.5 size CCP reactor operating in the VHF range. First, we used magnetic materials (ferrite) to modify wave propagation. We placed ferrite blocks along two opposing edges of the powered electrode. This changes the boundary condition for electro-magnetic waves, and as a result, the standing wave pattern is significantly stretched towards the ferrite lined edges. In conjunction with a phase modulation technique, we have seen improvement in process uniformity. Another method involves feeding 40 MHz from four feed points near the four corners of the electrode. The phase between each feed points are dynamically adjusted to modify the resulting interference pattern, which in turn modulate the plasma distribution in time and affect the process uniformity. We achieved process uniformity of <20% with this method. A third method involves using two frequencies. In this case 40 MHz is used in a supplementary manner to improve the performance of 13 MHz process. Even at 13 MHz, the RF electric field falls off around the corners and edges on a Gen 8.5 substrate. Although, the conventional methods mentioned above improve the uniformity, they have limitations, and they cannot compensate especially as the applied power is increased, which causes the wavelength becomes shorter. 40 MHz is used to overcome such limitations. 13 MHz is applied at the center, and 40 MHz at the four corners. By modulating the interference between the signals from the four feed points, we found that 40 MHz power is preferentially channeled towards the edges and corners. We will discuss an innovative method of controlling 40 MHz to achieve this effect.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제33권6C호
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• pp.505-511
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• 2008

The global navigation satellite system (GNSS) is using a direct sequence/spread spectrum (DS/SS) modulation. In order to recover the information data, the DS/SS system first performs a two-step synchronization process: acquisition and tracking. The acquisition process adjusts the phase difference between the received and locally generated acquisition sequences within ${\pm}T_c/2$ or less, where $T_c$ is the chip period. The tracking process performs fine synchronization. In this paper, we focus on the tracking issue. The single delta delay locked loop($\Delta$-DLL) is the optimal tracking scheme for a GNSS in the absence of multipath signals, where $\Delta$ means the spacing between the early and late correlation time offset. In the multipath environments, however, the $\Delta$-DLL suffers from huge estimation bias(denoted by $\beta$) caused by distorted correlation values. Although some modified schemes such as a $\Delta$-DLL with a narrow $\Delta$ and a double delta DLL (${\Delta}^{(2)}$-DLL) were proposed to reduce the estimation bias, they cannot remove the estimation bias completely and need more accurate acquisition process. This paper proposes a novel tracking scheme that can dramatically reduce the estimation bias, using the maximum slope change among the correlation outputs.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제18권7호
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• pp.1557-1564
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• 2014

In this paper, we propose a signal detection technique based on the parallel orthogonal matching pursuit (POMP) is proposed for generalized shift space keying (GSSK) systems, which is a modified version of the orthogonal matching pursuit (OMP) that is widely used as a greedy algorithm for sparse signal recovery. The signal recovery problem in the GSSK systems is similar to that in the compressed sensing (CS). In the proposed POMP technique, multiple indexes which have the maximum correlation between the received signal and the channel matrix are selected at the first iteration, while a single index is selected in the OMP algorithm. Finally, the index yielding the minimum residual between the received signal and the M recovered signals is selected as an estimate of the original transmitted signal. POMP with Quantization (POMP-Q) is also proposed, which combines the POMP technique with the signal quantization at each iteration. The proposed POMP technique induces the computational complexity M times, compared with the OMP, but the performance of the signal recovery significantly outperform the conventional OMP algorithm.