• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.122-130
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• 2013

This work proposes a 12b 100MS/s 45nm CMOS four-step pipeline ADC for high-speed digital communication systems requiring high resolution, low power, and small size. The input SHA employs a gate-bootstrapping circuit to sample wide-band input signals with an accuracy of 12 bits or more. The input SHA and MDACs adopt two-stage op-amps with a gain-boosting technique to achieve the required DC gain and high signal swing range. In addition, cascode and Miller frequency-compensation techniques are selectively used for wide bandwidth and stable signal settling. The cascode current mirror minimizes current mismatch by channel length modulation and supply variation. The finger width of current mirrors and amplifiers is laid out in the same size to reduce device mismatch. The proposed supply- and temperature-insensitive current and voltage references are implemented on chip with optional off-chip reference voltages for various system applications. The prototype ADC in a 45nm CMOS demonstrates the measured DNL and INL within 0.88LSB and 1.46LSB, respectively. The ADC shows a maximum SNDR of 61.0dB and a maximum SFDR of 74.9dB at 100MS/s, respectively. The ADC with an active die area of $0.43mm^2$ consumes 29.8mW at 100MS/s and a 1.1V supply.

• Journal of Life Science
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• v.30 no.12
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• pp.1078-1084
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• 2020

Protaetia brevitarsis seulensis is an insect belonging to the order Coleoptera. This insect is reported to contain large amounts of physiologically active substances useful for liver protective effect and improvements in blood circulation as well as a broad source of edible protein. Antimicrobial peptides (AMPs) are found in a variety of species, from microorganisms to mammals, and play an important role in the innate immune systems of living things. Microglia are the main source of proinflammatory cytokines and nitric oxide (NO) in the central nervous system. Activated microglia secrete large amounts of neuroinflammatory mediators (e.g., TNF-α, NO, and ROS), which are the main cause of neuronal cell death. In the present study, we investigated the inhibitory effect of Protaetiamycine 6 (PKARKLQKLSAYKTTLRN-NH2), an AMP derived from Protaetia brevitarsis seulensis, on LPS-induced neuroinflammation in BV-2 microglia. Protaetiamycine 6 significantly inhibited NO production without cytotoxicity and decreased the expression levels of inducible NO synthase and cyclooxygenase-2. In addition, Protaetiamycine 6 also reduced the production of neuroinflammatory cytokines on activated BV-2 microglia. These results suggest that Protaetiamycine 6 could be a good source of functional substance to prevent neuroinflammation and neurodegenerative diseases.

• Journal of Life Science
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• v.31 no.11
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• pp.987-994
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• 2021

Our previous studies have reported that antimicrobial peptides (AMPs) derived from the larvae of white-spotted flower chafer (Protaetia brevitarsis seulensis) exert anti-inflammatory and neuroprotective activities. This study explored the anti-inflammatory effects of protaetiamycine 9 (CVLKKAYFLTNLKLRG-NH₂), a novel AMP, derived from P. b. seulensis against lipopolysaccharide (LPS)-mediated inflammatory response in RAW264.7 macrophage cells. Protaetiamycine 9 (25, 50, 75, and 100 ㎍/ml) did not cause cytotoxic effects against RAW264.7 cells. The RAW264.7 cells were pre-treated with various concentrations of protaetiamycine 9 (25-100 ㎍/ml) for 1 hr and then exposed to LPS (100 ng/ml) for 24 hr. Protaetiamycine 9 treatments decreased the LPS-induced secretion of inflammatory mediators, such as nitric oxide (NO), in a dose-dependent manner. Protaetiamycine 9 (25-100 ㎍/ml) effectively downregulated the LPS-induced increase in mRNA and the protein expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2), which are involved in the production of inflammatory mediators. Protaetiamycine 9 also suppressed the production and gene expression of pro-inflammatory cytokines, including interleukin (IL)-6 and IL-1β, compared to the presence of LPS alone. Furthermore, protaetiamycine 9 inhibited the degradation of inhibitory kappa B alpha (IκB-α) and the phosphorylation of mitogen-activated protein kinases (MAPKs), such as extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38. In conclusion, these results suggest that protaetiamycine 9 exhibits LPS-mediated inflammatory responses by blocking IκB-α degradation and MAPK phosphorylation.