• Journal of Animal Science and Technology
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• v.44 no.2
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• pp.221-232
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• 2002

This study was conducted to investigate the effects of deficiency of essential amino acid in diet on feed intake and concentrations of free amino acid in plasma and brain(prepyriform cortex, PPC), and thereby to know the brain area engaged in the mechanism of feed intake regulation. In all trials, experimental diets were formulated with pure amino acid mixture to level of 15% nitrogen. Rats were trained to eat a single meal for 6 hours daily(meal feeding, 17:00-21:00). Feed intake and body weight were measured hourly on and after 7th day of feeding. In Exp. 1, feed intake and body weight were measured every hour, and the free amino acid concentrations of plasma and PPC were analysed at 0, 1, 2, 3 and 6 h on the 11th day of feeding. In Exp. 2, the complete diet was replaced with lysine devoid diet at the 11th day, and feed intake, body weight and free amino acid concentrations in plasma and PPC were samely measured on Exp. 1. In Exp. 1, feed intake on complete diet was self-sufficiented to daily feed intake level(15g/day) from the 7th day. Free amino acid concentrations of plasma and PPC at the 11th day were plateau at 1 hour after feeding. In Exp. 2, feed intake was quickly reduced by the diet replacement(P$<$0.05), and the free lysine concentration of plasma and PPC was also significantly decreased at 2 hour after feeding. However, cumulative feed intake was significantly decreased at 4 hour after feeding. These results may indicate that the concentrations of free lysine in plasma and PPC, under the condition of devoided lysine in diet, were more quickly droped than the reduction of feed intake rate. Hence, it is expected that PPC in brain might be a part of response area for limited amino acid.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.1
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• pp.69-77
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• 2010

Research on permeable pavement like asphalt and concrete pavement with porous structure has been increasing due to environmental and functional need such as reduction of run off and flood, and increase and purification of underwater resource. This study was performed to evaluate permeability, strengths and durability of permeable polymer concrete (PPC) using recycled aggregate that is obtained from waste concrete. Also, 6mm length of polypropylene fiber was used to increase toughness and interlocking between aggregate and aggregate surrounded by binder. In the test results, regardless of kinds of aggregates and fiber contents, the compressive strength and permeability coefficient of all types of PPC showed the higher than the criterion of porous concrete that is used in permeable pavement in Korea. Also, strengths of PPC with increase polypropylene fiber volume fraction showed slightly increased tendency due to increase binder with increase of fiber volume fraction. The weight reduction ratios for PPC after 300 cycles of freezing and thawing were in the range of 1.6~3.8 % and 2.2~5.6 %, respectively. The weight change ratio was very low regardless of the fiber volume fraction and aggregates. The weight reduction ratios of PPC with fiber and aggregate were in the range of 1.3~2.7 % and 2.2~3.2 % after 13 weeks and was very low regardless of the fiber volume fraction and aggregates.

• Korean Architects
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• s.551
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• pp.88-95
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• 2015

• Magazine of the Korea Concrete Institute
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• v.23 no.3
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• pp.53-55
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• 2011

• Journal of Korean Association for Spatial Structures
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• v.5 no.1 s.15
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• pp.35-43
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• 2005

• Journal of Microbiology and Biotechnology
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• v.18 no.3
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• pp.512-519
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• 2008

Three different polysaccharide-peptide complexes (PPC, named as Fr-I, Fr-II, and Fr-III) were produced by submerged mycelial culture of an entomopathogenic fungus Cordyceps sphecocephala, and their anticancer activities were investigated in human hepatocarcinoma (HepG2) and neuroblastoma (SK-N-SH) cells. The highest inhibitory effects of PPC on both HepG2 and SK-N-SH cells were achieved with Fr-I, whereas Fr-III with low molecular mass showed lower inhibition effects. Interestingly, the inhibitory effects of the three fractions were increased after protease digestion, suggesting that the inhibitory effects resulted mainly from the carbohydrate moiety, at least in the case of Fr-II and Fr-III, of PPC. The results of DNA fragmentation in PPC-induced apoptotic cells were confirmed by both DNA ladder assay and comet assay. Our investigation also showed that PPC-induced apoptosis of both cancer cells was associated with intracellular events including DNA fragmentation, activation of caspase-3, and modulation of Bcl-2 and Bax. We conclude that PPC has potential as a novel therapeutic agent for the treatment of both HepG2 and SK-N-SH cancer cells without any cytotoxicity against normal cells.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.6
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• pp.553-557
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• 1999

In order to investigate the optical properties of the $Al_XGa_{1-X}N/GaN$ thin film grown by metalorganic chemical vapor deposition (MOCVD) method, the photoluminescene (PL), photocurrent (PC) and persistent photoconductivity (PPC) measurements were carried out at room temperature. The band gap of the $A1_x$$Ga_{1-x}$N/GaN was determined to 3.70 eV by the PL and PC measurements. The PC measurement on the light illumination from the top of the $A1_x$$Ga_{1-x}$N/GaN thin film provides peaks at 3.70, 3.43, and around 2.2 eV. The PC spectrum by the illumination passing through from the substrate of the sample can be shown at 3.43 eV together with a broad tail band from the GaN band edge to around 2.23 eV. The photocurrent quenching and anomalous PPC decay observed in PPC measurements indicate that metastable electron states are fomed in the band gap of GaN layer to trap electrons which can be tunneled the potential barrier for long recovery time.

• Microbiology and Biotechnology Letters
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• v.34 no.1
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• pp.35-39
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• 2006

One of the fermentative metabolism of enteric Escherichia coli was imitated after rumen bacteria, which have high C4 metabolism. E. coli expresses phosphenolpyruvate carboxylase (PPC) for the pathway between phosphoenolpyruvate (PEP) and oxaloacetate (OAA) during glycolytic condition while expresses phosphoenolpyruvate carboxykinase (PCK) during gluconeogenic condition. In contrast to enteric E. coli, rumen bacteria express the PEP-OAA pathway only by PCK. To verify the effect of the regulation imitation on the C4 metabolism of E. coli, PPC-deficient E. coli strain with PCK expression in glycolytic condition was constructed. The PEP-OAA regulation modified E. coli strain increased 2.5-folds higher C4 metabolite than the wild type strain. The potential use of C4 metabolism by regulation control is discussed.

• Clean Technology
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• v.17 no.3
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• pp.244-249
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• 2011

We synthesized low molecular-weight polymers bearing hydrophobic and hydrophilic parts in a chain through $CO_2$/propylene oxide copolymerization. When hydrophilic poly (ethylene glycol) bearing -OH group (s) at the end group (s) was added as a chain transfer agent in the $CO_2$/propylene oxide copolymerization catalyzed by a highly active catalyst, block polymers were formed. If poly (ethylene glycol) (PEG) bearing -OH group only at an end was fed, PEG-block-PPC diblock copolymer was obtained. When PEG bearing -OH group at both ends was fed, PPC-block-PEG-block-PPC triblock copolymer was obtained. We confirmed formation of block copolymers by $^1H$-NMR spectroscopy and GPC studies.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.45.1-45.1
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• 2021

The polarization degree as a function of phase angle (the Sun-target-observer's angle), so-called the polarimetric phase curves (PPC), have provided priceless information on asteroids' albedos since B. Lyot (1929). Succeeding experimental works in 1970s have confirmed the Umow law: There is a universal and strong correlation between the albedo and the PPC slope (slope of the tangential line at the zero of the PPC at phase angle ~ 20 degrees). Experiments in 1990s (ref [1]), on the other hand, have demonstrated that the negative branch of PPC is dependent on the size parameter (X ~ π * particle-size / wavelength), especially when X <~5. The change in particle size changed the minimum polarization degree, location of the minimum, and the width of the negative branch (called the inversion angle). From polarimetry[2] and spectroscopy[3], large asteroids are expected to be covered with fine (<~ 10 ㎛ size) particles due to the gravity. The size parameters are X ~ 30 at the optical wavelength (λ ~ 0.5 ㎛) and X ~ 10 in near-infrared (J, H, Ks bands; λ ~ 1.2-2.2 ㎛), if the representative particle size of 5 ㎛ is considered. Accordingly, the near-infrared polarimetry has a great potential to validate the idea in ref[1]. We conducted near-infrared photopolarimetry of the large asteroid (4) Vesta using the Nishiharima Infrared Camera (NIC) at Nishi-Harima Astronomical Observatory (NHAO). NIC allows simultaneous polarimetric measurements in J, H, and Ks bands, and thus the change of PPC is obtained for three different size parameters. As a result, we found a signature of the change in the negative branch in the PPC of asteroid (4) Vesta. We will introduce our observation and the results and give an interpretation of the regolith on Vesta.