• Journal of Nutrition and Health
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• v.27 no.10
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• pp.967-978
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• 1994

This study was done to investigate the effect of age and dietary linolenic acid content and the linolenic acid/linoleic acid(LNA/LA) ratio on the lipid metabolism and formation of PGI2 and TXA2. The male Sprague-Dawley rats were fed 6 different with 0.2, 0.4, 0.6 of LNA/LA ratio within either 8% LNA(high LNA) or 4% LNA(low LNA) of fatty acid content for different feeding period(1, 4, 12 month). The dietary fat used were sesame oil, perilla oil, soybean oil and beef tallow. The concentration of serum total lipid, total cholesterol and HDL-C were increased with aging. Triglyceride concentration was decreased in 0.2 ratio of LNA/LA. The lipid content of liver showed similar tendency to that of serum. The ratio of PGI2/TXA2 was increased in 1 month rats and antithrombotic effect was reduced significantly with increasing age. The PGI2/TXA2 ratio was tended to be higher in diet of 0.2 and 0.4 LNA/LA ratio at high LNA level and in diet of 0.6 LNA/LA ratio at low LNA level. Especially PGI2/TXA2 ratio was increased linearly with rising LNA/LA ratio at low LNA level. It seemed that the LNA content and LNA/LA ratio had interaction to increase the antithrombotic effect bychanging TXA2 synthesis. And the dietary fatty acid related effect lowering the serum and liver lipid content, excepting triglyceride, was increased when dietary n3/n6 ratio was high(0.6) at both high and low n3 level. Therefore, it could not be recommended to consume large amount of n3 fatty acid or high ratio of n3/n6 to prevent cardiovascular diseases. These results suggested that the dietary fatty acid ratio of n3/n6 could be determined based on the n-3 content of dietary fat to reduce the risk of cardiovascular disease.

• Journal of Microbiology and Biotechnology
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• v.13 no.2
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• pp.175-181
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• 2003

The production of a carotenoid astaxanthin, a growth-associated principal pigment, is limited in a batch cultivation, because a high glucose concentration severely inhibits the cell growth and also influences the carotenoid production. Therefore, a fermentation strategy including effective chemicals for the high-level production of cells and astaxanthin by a mutant strain Phaffia rhodozyma AJ-6-1 was developed in a fed-batch culture. First, a production medium for maximizing the cell and astaxanthin yields was formulated and optimized. Using this optimized medium, the highest cell and astaxanthin concentrations obtained were about 38.25 g/1 and 34.77 mg/1, respectively. In addition, an attempt was made to increase the amount of astaxanthin using effective chemicals such as ethanol and acetic acid, which are known at an inducer and/or precursor of carotenoid synthesis. When either 10g/1 ethanol or 5 g/1 acetic acid was added to investigate the resulting astaxanthin content, a relatively high astaxanthin concentration or 45.62 mg/l and 43.87 mg/1, respectively, was obtained, and the cell concentrations also increased slightly under these conditions. Therefore, these results imply that a fed-batch culture of the mutant strain P. rhodozyma AJ-6-1 could be effectively employed in the commercial production of astaxanthin, although the factors affecting the productivity remain to be elucidated.

• Proceedings of the Zoological Society Korea Conference
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• 1995.10b
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• pp.82-82
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• 1995

Regulation of enzyme synthesis by transcriptional and translational control systems provides rather stable adaptation to change of amino acid level in the growth medium, while manipulation of enzyme activity through endproduct feedback inhibition represents rather short-term and reversible ways of adjusting metabolic fluctuation of amino acid level. Various control mechanisms interplay to regulate genes encoding enzymes for amino acid biosynthesis in the yeast, Sacchromyces cerevisiae. When amino acids are in short supply, genes under a cross-pathway regulatory mechanism Or general amino acid control (general control) increase their action, in which Gcn4p is the major positive regulator of gene expression. When cells are cultured in minimal medium, basal level expression is also regulated by supplementary control elements, where inorganic phosphate level is additionally involved. Most of amino acid biosynthetic genes are also regulated by the level of endproduct of the pathway. This pathway-specific regulatory mechanism is called specific amino acid control (specific controD, under which gene expression is reduced when endproduct is present in the medium. Derepression of a gene through general control can be usually overridden by repression through specific control, where the endproduct level of that particular pathway is high and not limiting. In this presentation, regulatory factors for basal level expression and general control of yeast amino acid biosynthesis will be discussed, m addition to pathway-specific repression patterns and interaction between CrOSS- and specific-control mechanisms. Preliminary results are also presented from the investigation of the cloned genes in the threonine biosynthetic pathway of the yeast. yeast.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.3
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• pp.555-562
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• 2008

In this paper we proposed a practical low-power design technique using clock-gating in RTL. An efficient low-power methodology is that a high-level designer analyzes a generic system and designs a controller for clock-gating. Also the desirable flow is to derive clock-gating in normal synthesis process by synthesis tool than to insert directly gate to clock line. If low-power is considered in coding process, clock is gated in coding process. If not considered, after analyzing entire operation. clock is Bated in periods of holding data. After analyzing operation for clock-gating, a controller was designed for it, and then a low-power circuit was generated by synthesis tool. From result, we identified that the consumed power of register decreased from 922mW to 543mW, that is the decrease rate is 42%. In case of synthesizing the test circuit using synthesizer of Power Theater, it decreased from 322mW to 208mW (36.5% decrease).

• Journal of Ginseng Research
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• v.44 no.4
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• pp.627-636
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• 2020

Background: Cultivation of medicinal crops, which synthesize hundreds of substances for curative functions, was focused on the synthesis of secondary metabolites rather than biomass accumulation. Nutrition is an important restrict factor for plant growth and secondary metabolites, but little attention has been given to the plasticity of nutrient uptake and secondary metabolites synthesis response to soil nitrogen (N) change. Methods: Two year-field experiments of Sanqi (Panax notoginseng), which can synthesize a high level of saponin in cells, were conducted to study the effects of N application on the temporal dynamics of biomass, nutrient absorption, root architecture and the relationships between these parameters and saponin synthesis. Results: Increasing N fertilizer rates could improve the dry matter yields and nutrient absorption ability through increasing the maximum daily growth (or nutrient uptake) rate. Under suitable N level (225 kg/ha N), Sanqi restricted the root length and surface and enhanced the root diameter and N uptake rate per root length (NURI) to promote nutrient absorption, but the opposite status of Sanqi root architecture and NURI was found when soil N was deficient. Furthermore, increasing N rates could promote the accumulation of saponin in roots through improving the NURI, which showed a significant positive relationship with the content of saponin in the taproots. Conclusion: Appropriate N fertilizer rates could optimize both root architecture and nutrient uptake efficiency, then promote both the accumulation of dry matter and the synthesis of saponins.

• Journal of the Korean Ceramic Society
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• v.54 no.4
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• pp.272-277
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• 2017

Organic-inorganic hybrid thermoelectric materials have obtained increasing attention because it opens the possibility of enhancing thermoelectric performance by utilizing the low thermal conductivity of organic thermoelectric materials and the high Seebeck coefficient of inorganic thermoelectric materials. Moreover, the organic-inorganic hybrid thermoelectric materials possess numerous advantages, including functional aspects such as flexibility or transparency, low cost raw materials, and simplified fabrication processes, thus, allowing for a wide range of potential applications. In this study, the types and synthesis methods of organic-inorganic thermoelectric hybrid materials were discussed along with the methods used to enhance their thermoelectric properties. As a key factor to maximize the thermoelectric performances of hybrid thermoelectric materials, the nanoengineering to control the nanostructure of the inorganic materials as well as the modification of the organic material structure and doping level are considered, respectively. Meanwhile, the interface between the inorganic and organic phase is also important to develop the hybrid thermoelectric module with excellent reliability and high thermoelectric efficiency in addition to its performance in various electronic devices.

• Korean journal of applied entomology
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• v.34 no.1
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• pp.20-32
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• 1995

Adult diapause in insects is characterized by suppression of reproductive development. It is induced by environmental cues such as photoperiod, temperature, food availability, and other conditions Diapause-inducing environment is recognized and analyzed by the brain of the insects. The interpreted information is conveyed via endocrine system to target tissues such as ovaries, fat body, and other tissues. From this signal hierarchy of a brain-endocrine-target tissue axis, several factors are involved to express a diapause trait in a quantitative mode, even though the insects show a binomial phenotye between being in diapause or not. Recent works estimated that the number of the factors is relatively small by a series of crossing trials between high and low diapause lines. Heritability of the diapause is quite high (ca. 70%) in some species. Epistasis, sex-linkage, pleiotropism, and other nongenetic components also affect diapause inheritance. Most physiological studies have been focused on control mechanisms of the juvenile hormone (JH) synthesis in corpora allata (CA) because JH level in hemolymph of teneral adults is critical to decide a later developmental mode. Allatostatin, an antagonizer of JH synthesis, has been believed to be a potent brain message to CA for adult diapause induction.

• International Journal of Aeronautical and Space Sciences
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• v.11 no.1
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• pp.49-57
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• 2010

Several pyrotechnic devices are employed over the course of satellite's missions, generally for the separation of structural subsystems and deployment of appendages. Firing of pyrotechnic devices results in impulsive loads characterized by high peak acceleration and high frequency content which can cause failures of various flight hardware elements and small components. Thus, accurate prediction of acceleration level in various components of spacecraft due to pyrotechnic devices is important. In this paper, two methods for pyroshock prediction, an empirical model and statistical energy analysis in conjunction with virtual mode synthesis, are applied to predict shock response of a low altitude earth observation satellite during launch vehicle separation. The predicted results are then evaluated through comparison with the shock test results.

• Journal of Applied Biological Chemistry
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• v.62 no.1
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• pp.101-107
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• 2019

The objectives of this study were to evaluate the anti-aging effects and investigate the effect of simulated gastrointestinal (GI) digestion on the anti-aging properties and intestinal permeation of the potential fish collagen hydrolysates (FCH). Therefore, procollagen synthesis, matrix metalloproteinase-1 (MMP-1) production, and Caco-2 cell permeability were analyzed before and after in vitro digestion for FCHs, low-molecular weight fractions (<1 kDa), and high molecular weight fractions (>1 kDa). After being subjected to GI digestion, the level of MMP-1 inhibition was maintained, although the procollagen production was significantly (>20%) lower with all samples. Also, the digested FCHs and their <1 kDa fraction yielded 9.1 and 13.8% increased peptide transport, respectively, compared to undigested samples. Based on the effective intestinal permeation and high digestive enzyme stability, the <1 kDa fraction of FCHs is a potential bioactive material suitable for anti-aging applications in the food and cosmetics industries.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.198-198
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• 2011

Organocatalysis is a relatively new and popular area within the field of chiral molecule synthesis. It is one of the main branches of enantioselective synthesis with enzymatic and organometallic catalysis. In recent years, immense high quality studies on catalysis by chiral secondary amines were reported. These progresses instantly led to different organocatalytic activation concepts, so thousands of researchers from academia and the chemical industry are currently involved in this field and new ideas, new approaches, and creative thinking have been rapidly emerged. Organocatalysts, some of which are natural products, appear to solve the problems of metal catalysts. Compared to metal-based catalysis, they have many advantages including savings in cost, time, and energy, easier experimental procedure, and reduction of chemical waste. These benefits originate from the following factors. First, organocatalysts are generally stable in oxygen and water in the atmosphere, there is no need for special equipments or experimental techniques to operate under anhydrous or anaerobic conditions. Second, organic reagents are naturally available from biological materials as single enantiomers that they are easy and cheap to prepare which makes them suitable for small-scale to industrial-scale reactions. Third, in terms of safety related catalysis, small organic molecules are non-toxic and environmentally friendly. Therefore, the purpose of this research is to develop novel synthetic methods and design for various organocatalyst. Furthermore, it is expected that these organocatalysts can be applied to a variety of asymmetric reactions and study the transition state of these reactions using a metal sulface. Here, we report the synthesis of unprecedented organocatalysts, proline and pyrrolidine derivatives with quaternary carbon center.