• Journal of the Korea Furniture Society
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• v.12 no.2
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• pp.29-38
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• 2001

This study was carried out to develope a new process of flattening bamboo pieces(3 months old) by two steps of utilizing microwave oven and hot press. Internode bamboo pieces were impregnated with low molecular weight phenol formaldehyde resin (PF) under vacuum of 76 cmHg, heated in a household microwave oven in 1 minute, pressed on the temperature of $145^{\circ}C$ by the hot press for 10 minute, and then cooled by the cold press in their flattened form. The physical and mechanical . Properties of compressed flattened bamboo were as follows: 1) PF1(Mw:427) and PF2(Mw:246) sol. met the success of flattening of internode bamboo pieces in both of P. bambusoides and P. nigra var. PF2 showed the more plasticity to flatten the bamboo than PFI. The PF2 sol. with low molecular weight(Mw:246) gave the more weight gain than that of PF1 in the equal concentration. PF1 of 5% (NVC) and PF2 of 10% (NVC) sol. gave the best result for physical and mechanical properties and from a economical view point. 2) The PFI of 5% (NVC) sol. with low molecular weight decreased the water absorption of 62-63% and increased the bending strength (MaR) of 80-90%, compression strength of 43-54%. 3) The PF2 of 10% (NVC) sol. with low molecular weight decreased the water absorption of 56-57% and increased the bending strength (MaR) of 64-86%, compression strength of 39-63%.

• Journal of Nutrition and Health
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• v.30 no.7
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• pp.751-769
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• 1997

This study was performed to investigate the effect of chitosan and NOCC from different sources and of different molecular weights on cadmium toxicity. Sprague-Dawley rats were blocked into 26 groups according to body weight, and were raised for 4 weeks. Cadmium chloride was given at the level of 0 or 400 ppm in diet. Various forms of chitosan and NOCC were given at the level of 0 or 4%(w/w) of diet. Cd toxicity was alleviated by various chitosan and NOCC supplements. However, the alleviating effects were different with fiber source(crab and shrimp), type(chitosan and NOCC), and molecular weight (low, medium, and high). Molecular weight had no significant effect. Compared with shrimp-source-fiber-fed groups, crab-source-fiber-fed groups showed lower Cd concentrations in blood and kidney, lower kidney metallothionein concentration, and lower liver and kidney MT-Cd contents. Compared with NOCC -fed groups, chitosan-fed groups showed lower intestine and liver Cd concentrations, lower liver and kidney MT concentrations and MT-Cd content, and higher fecal Cd excretion. Among cadmium-exposed group, low molecular weight shrimp chitosan group showed low Cd concentrations of liver and kidney, high fecal Cd excretions, and the lowest intestine and liver MT concentrations and liver MT-Cd content. In summary, a crab source fiber was more effective than shrimp source fiber, chitosan was more effective than NOCC, and the most effective one in alleviating Cd toxicity was low molecular weight shrimp chitosan.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.4
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• pp.219-225
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• 2005

We studied the anticancer, antioxidative, ACE inhibitory, antithrombic, and cerebral ischemia inhibitory activities, of low molecular weight substances fractionated from the seasoned and smoked products of skipjack tuna (Euthynus pelamis). Low molecular weight substances fractionated from the liquid extract of seasoned and smoked skipjack tuna powder showed 7 peaks on gel permeation chromatography. Anticancer activity was the highest at Peak 3 $(54.23%)$ followed by Peak 4 $(41.58\%)$. The potency order of antioxidative activity was the highest at Peak 3 $(94.14\%)$ followed by Peak 2 $(82.07\%)$ and Peak 5 $(81.24\%)$. ACE inhibitory activity was the highest at Peak 3 $(67.27\%)$ followed by Peak 5 $(45.62\%)$. But there was weak anti thrombotic effect (PT and APTT) in the low molecular weight substances of the seasoned and smoked products of skipjack tuna. Cerebral ischemia inhibitory activity was the highest at Peak 3 $(80.0\%)$ followed by Peak 5 $(40.0\%)$.

• Food Science and Preservation
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• v.15 no.6
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• pp.903-908
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• 2008

This study investigated protein changes in soymilk and whole soymilk due to enzymatic hydrolysis. The total free amino acid contents of low molecular weight soymilk (LSM) and low molecular weight whole soymilk (LWSM) were higher than soymilk (SM) and whole soymilk (WSM). The essential amino acid content was similar in SM and LSM, but was higher in LWSM than WSM. In SDS-PAGE performed to tendency of becoming low molecules, the soy protein molecular weights were 3372 kDa for SM and WSM, but 17 kDa or less for LSM and LWSM. Also, high molecular weight protein spots were evident in 2-D electrophoresis of SM and LSM, but only low molecular weight protein spots of various sizes were evident in WSM and LWSM. This suggests that the high molecular weight protein in SM and WSM is changed to low molecular weight protein by enzymatic hydrolysis. Further investigations of the separation and qualities of these proteins are required.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.05a
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• pp.87-89
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• 1994

The effects of low molecular weight components of LDPE and sample molding condition were investigated to find the orgins for heterocharge in LDPE without any addtives. Low molecular weight chains of LDPE encourages the formation of heterocharge by being charged and migrating the counter electrode. The formation of heteroohage in LDPE was also effected by sample preparation process and the kind of a moling film. When PET film is used as a molding layer, the carbonyl, which may lead to increase the heterocharge, formed at surface of LDPE.

• Korean Journal of Veterinary Research
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• v.43 no.4
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• pp.703-708
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• 2003

This study was carried out to compare the efficacy of carboxymethyl chitosan fabric (CMCF) with that of the combination of low molecular weight heparin (LMWH) and CMCF for the prevention of postoperative adhesions in the rat. Adhesions were induced by suturing both the ileal serosa and peritoneum scraped until petechial bleeding occurred. CMCF were sutured between two surfaces, and LMWH were instilled intraperitoneally immediately before closure of the peritoneomuscular layer. The adhesions were blindly assessed 2 weeks later by using a tensiometer. The mean tensile strength(Newton) of formed adhesions was $2.59{\pm}0.85$ in control group, $2.10{\pm}0.75$ in the CMCF group and $1.53{\pm}0.44$ in the CMCF+LMWH group. The most favorable prevention against adhesion was achieved in the CMCF+LMWH group. Therefore, we could conclude that CMCF+LMWH were effective in prevention against postoperative adhesion in the rat.

• The Microorganisms and Industry
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• v.20 no.3
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• pp.14-21
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• 1994

Low molecular weight molecules and high molecular weight substances were found to have anti-tumor and immuno-modulating activity. Previously polysaccharides have been received much attention because of adhesives, food additives or animal foods (Whistler et al., 1976). In effort of developing new anti-tumor substances with low toxicity, numerous polysaccharides from yeast, algae, bacteria, higher plants and especially fungi have been investigated for anti-tumor and immuno-modulating activities. Thus the high molecular weight molecule was reported to have anti-tumor activity through host mediated immunity. In this brief article, attention will be paid to polysaccharides which is especially fungal origin.

• Journal of the Korean Graphic Arts Communication Society
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• v.12 no.1
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• pp.145-157
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• 1994

Litho printing ink vehicles based on rosin modified phenolic are faster drying, have better durability, are harder and glosser and have greater resistance to water than ones based on ester gums. Ink-Water balance and rheological properties are important in litho printing process. These physical properties is concerned with molecular weight of Resin to use vehicle. So this paper was studied about the effects of changing molecular weight of Rosin modified phenolic on surface tension, viscosity, pseudoplasticity and printability of Litho Inks. The results were as follows. 1) The surface tension of model inks depended on the molecular \veight of the resin : Dispersion componnent of ink increase but non dispersion component decrease as molecular weight of Resin increase. 2) Water pick-up of litho ink is more fast balance, using low molecular weight of Resin. 3) Viscosity, Yield value and Newtonian value of model inks increase as molecular weight of Resin increase. 4) The litho ink prepared with the modified phenolic of which molecular weight is about 20000 showed the highest printing density and gloss.

• Textile Coloration and Finishing
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• v.30 no.2
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• pp.130-140
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• 2018

In the bio-synthesis of poly(3-hydroxybutyrate)(PHB), which is a kind of poly(3-hydroxyalkanoate)(PHA), aimed to control the low molecular weight of PHB and obtain a telechelic PHB. As a result of incubation of R. eutropha at $30^{\circ}C$ with ethylene glycol added as a chain transfer agent, PHB content on the dry cell weight increased up to 24h, however, it decreased after that, and the molecular weight of PHB increased from 9h to 12h, and then, decreased up to 72h. The decrease of the content and the molecular weight of PHB indicates that PHB was decomposed as an energy source in bacterial cells and was incorporated into metabolic pathways. $^1H-NMR$ of the obtained PHB after incubation for 72h was measured to determine the terminal groups of the PHB during incubation. As the results of $^1H-NMR$ measurement, the peaks derived from ethylene glycol in both terminals of PHB were observed. Which indicate that the terminal reaction was caused by the addition of ethylene glycol, and that telechelic PHB having hydroxyl group at the both terminals where molecular weight was controlled was successfully synthesized.

• Bulletin of the Korean Chemical Society
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• v.33 no.8
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• pp.2731-2736
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• 2012

The use of pyrimethamine as antibacterial drug is limited by the poor solubility. To enhance its solubility, we prepared complexes of pyrimethamine with low-molecular-weight succinoglycan isolated from Sinorhizobium meliloti. Low-molecular-weight succinoglycans are monomers, dimers, and trimers of the succinoglycan repeating unit. The monomers and dimers were separated into their three species (M1, M2, and M3) and four fractions (D1 to D4) using chromatographic techniques, which were shown to be nontoxic. The solubility of pyrimethamine was markedly increased up to 42 fold by succinoglycan D3, where the level of its solubility enhancement was even 8-20 fold higher comparing with cyclodextrin or its derivatives. The complex formation of succinoglycan D3 with pyrimethamine was confirmed by $^1H$ nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy, and molecular modeling studies. Herein, we suggest that the low-molecular-weight succinoglycans may be utilized as highly effective solubilizers of pyrimethamine for pharmaceutical purposes.