• Geomechanics and Engineering
• /
• v.33 no.1
• /
• pp.29-40
• /
• 2023

Xanthan gum and starch compound biopolymer (XS), an environmentally friendly soil-binding material produced from natural resources, has been suggested as a slope protection material to enhance soil strength and erosion resistance. Insufficient wet strength and the consequent durability concerns remain, despite XS biopolymer-soil treatment showing high strength and erosion resistance in the dried state, even with a small dosage of soil mass. These concerns need to be solved to improve the field applicability and post-stability of this treatment. This study explored the utilization of an alkaline-based cation crosslinking method using calcium hydroxide and sodium hydroxide to induce non-thermal gelation, resulting in the enhancement of the wet strength and durability of biopolymer-treated soil. Laboratory experiments were conducted to assess the unconfined compressive strength and cyclic wetting-drying durability performance of the treated soil using a selected recipe based on a preliminary gel formation test. The results demonstrated that the uniformity of the gel structure and gelling time varied depending on the ratio of crosslinkers to biopolymer; consequently, the strength of the soil was affected. Subsequently, site soil treated with the recipe, which showed the best performance in indoor assessment, was implemented on the field slope at the bridge abutment via compaction and pressurized spraying methods to assess feasibility in field implementation. Moreover, the variation in surface soil hardness was monitored periodically for one year. Both slopes implemented by the two construction methods showed sufficient stability against detachment and scouring, with a higher soil hardness index than the natural slope for a year.

• Journal of Microbiology and Biotechnology
• /
• v.34 no.6
• /
• pp.1229-1238
• /
• 2024

This study aimed to develop and assess a chitosan biomedical antibacterial gel ZincOxide-GrapheneOxide/Chitosan/β-Glycerophosphate (ZnO-GO/CS/β-GP) loaded with nano-zinc oxide (ZnO) and graphene oxide (GO), known for its potent antibacterial properties, biocompatibility, and sustained drug release. ZnO nanoparticles (ZnO-NPs) were modified and integrated with GO sheets to create 1% and 3% ZnO-GO/CS/β-GP thermo-sensitive hydrogels based on ZnO-GO to Chitosan (CS) mass ratio. Gelation time, pH, structural changes, and microscopic morphology were evaluated. The hydrogel's antibacterial efficacy against Porphyromonas gingivalis, biofilm biomass, and metabolic activity was examined alongside its impact (MC3T3-e1). The findings of this study revealed that both hydrogel formulations exhibited temperature sensitivity, maintaining a neutral pH. The ZnO-GO/CS/β-GP formulation effectively inhibited P. gingivalis bacterial activity and biofilm formation, with a 3% ZnO-GO/CS/β-GP antibacterial rate approaching 100%. MC3T3-e1 cells displayed good biocompatibility when cultured in the hydrogel extract.The ZnO-GO/CS/β-GP thermo-sensitive hydrogel demonstrates favorable physical and chemical properties, effectively preventing P. gingivalis biofilm formation. It exhibits promising biocompatibility, suggesting its potential as an adjuvant therapy for managing and preventing peri-implantitis, subject to further clinical investigations.

• Journal of Sericultural and Entomological Science
• /
• v.30 no.1
• /
• pp.33-39
• /
• 1988

In the case of white cocoon, the fluorescence colors are classified as a yellowish fluorescence cocoon(Y.F.C.) and a violet fluorescence cocoon(V.F.C.) by exposing to ultra-violet ray. Accordingly, experiments were carried out to investigate the difference of sericin behaviors between Y.F.C. and V.F.C. by measuring the sericin solubility, surface tension and viscosity of the sericin solution. Also, the reelability of two different type of cocoons was investigated in the silk reeling process. The results were summarized as follows; 1. The sericin solubility of Y.F.C. shell is higher than that of V.F.C. shell with the dissolution temperature and time. It is shown that the sericin solubility curves of Y.F.c. and V.F.C. are similar in shape, but the difference of sericin solubility between Y.F.C. and V.F.C. is more significant at higher bath temperature. 2. The initial sericin dissolution curves of Y.F.C. and V.F.C. cocoon shell can be divided by four parts within the range of dissolving time from 5 minutes to 60 minutes. The initial dissolution velocity of Y.F.C. shell is faster than that of V.F.C. but the velocity difference is negligible after 30 minutes of dissolving time. 3. The gelation of V.F.C. sericin solution is faster than that of Y.F.C. at early stage(in the range of 15 minutes to 60 minutes). 4. In the silk reeling process, the reelability of Y.F.C. is better than that of V.F.C. with about 11%. This is mainly due to the higher sericin solubility in Y.F.C. followed by the fast dissolution velocity.

• Elastomers and Composites
• /
• v.38 no.3
• /
• pp.213-226
• /
• 2003

The cure and rheological behavior of diglycidyl ether of bisphenol F/nadic methyl anhydride resin system with the kinds of imidazole were studied using a differential scanning calorimeter (DSC) and a rotational rheometer. The isothermal traces were employed to analyze cure reaction. The DGEBF/ anhydride conversion profiles showed autocatalyzed reaction characterized by maximum conversion rate at $20{\sim}40 %$ of the reaction. The rate constants ($k_1,\;k_2$) showed temperature dependance, but reaction order did not. The reaction order (m+n) was calculated to be close to 3. There are two reaction mechanisms with the kinds oi catalyst. The gel time was determined by using G'-G" crossover method, and the activation energy was obtained from this results. From measurement of rheological properties it was found that the logarithmic 1:elation time of fused silica filled DBEBF epoxy compounds linearly increased with the content of filler and decreased with temperature. The highly filled epoxy compounds showed typical pseudoplastic behavior, and the viscosity of those decreased with increasing maximum packing ratio.

• Journal of Conservation Science
• /
• v.21
• /
• pp.73-88
• /
• 2007

In this paper, the interaction between five biocides(commercial) and two ethylsilicate consolidants for stone monuments, reacted in different sequence, has been studied. Through the structures, weight and gelation time of mixture of biocides and consolidants have been evaluated the reactivity of biocide alone, the reactivity of consolidants and biocides, the reactivity of consolidants and dried biocide, and the reactivity of ethylsilicate gel and biocides. The tested biocides show quite different properties from those of consolidants; after evaporation, some biocides are remained white salt crystals, another need the long time for evaporation and one biocide shows pale brown color. The results have shown an interaction of the tested products each other in some application sequences of the products. When the application of liquid state biocides with consolidants, it was noted that some biocide seem to interfere with the formation of gel due to reaction of consolidants and water and salts in biocides. In the reaction of ethylsilicate with dried biocides have shown a heterogenous gel(transparent layer with ethylsilicate alone and white layer which is mixed biocide and ethylsilicate) and many cracks in product due to the different shrinkage, thus the products don't play a role as consolidants. There is no change in structures and color in reaction of the gas state biocide and ethylsilicate gel.

• Korean Journal of Food Science and Technology
• /
• v.31 no.5
• /
• pp.1262-1267
• /
• 1999

Optimum reaction conditions for gel formation of rapeseed, Brassica napus, protein catalyzed by microbial TGase(transglutaminase) were evaluated by measuring breaking strength and deformation of gel. The polymerization of the protein gel was ascertained by SDS-PAGE and content of GL crosslinking$[{\varepsilon}-({\gamma}-glutamyl)lysine]$. In the reaction between rapeseed protein and TGase at $45^{\circ}C$ for 60 min, the breaking strength and deformation of the gel was the maximum at the ratio of 1 : 40 of enzyme to substrate. 10%(w/v) of rapeseed protein concentrate was optimum for gel production. The maximum breaking strength and deformation was shown at $45^{\circ}C$ The breaking strength increased linearly up to 90 min of the reaction time and remained unchanged. The breaking strength and deformation by TGase treatment was pH dependent and pH 7 was optimum for 10% rapeseed protein solution. SDS-PAGE analysis indicated that new band of highmolecular polymers were formed by the enzyme reaction, with disappearing the original bands of rapeseed protein. According to HPLC analysis. the content of GL crosslinking was increased from 0 to $7.14\;{\mu}mol/g$ gel for 90 min of the reaction time.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.6
• /
• pp.1179-1185
• /
• 2008

The immune-stimulating activities of Bordetella bronchiseptica antigens containing dermonecrotoxin (BBD) loaded in chitosan microspheres (CMs) have already been reported in vitro and in vivo with a mouse alveolar macrophage cell line (RAW264.7) and mice. Therefore, this study attempted to demonstrate the successful induction of mucosal immune responses after the intranasal administration of BBD loaded in CMs (BBD-CMs) in colostrum-deprived pigs. The BBD was introduced to the CMs using an ionic gelation process involving tripolyphosphate (TPP). Colostrum-deprived pigs were then directly immunized through intranasal administration of the BBD-CMs. A challenge with a field isolate of B. bronchiseptica was performed ten days following the final immunization. The BBD-specific IgG and IgA titers, evident in the nasal wash and serum from the vaccinated pigs, increased with time (p<0.05). Following the challenge, the clinical signs of infection were about 6-fold lower in the vaccinated pigs compared with the nonvaccinated pigs. The grades for gross morphological changes in the turbinate bones from the vaccinated pigs were also significantly lower than the grades recorded for the nonvaccinated pigs (p<0.001). Therefore, the mucosal and systemic immune responses induced in the current study would seem to indicate that the intranasal administration of BBD-CMs may be an effective vaccine against atrophic rhinitis in pigs.

• Korean Journal of Food Science and Technology
• /
• v.49 no.1
• /
• pp.110-116
• /
• 2017

${\gamma}-Oryzanol-loaded$ calcium-pectin micro- and nanocapsules were prepared by ionic gelation to improve oxidation stability and the effect of particle size on capsule properties was investigated. The physical properties were influenced by preparation conditions such as concentrations of pectin, $CaCl_2$, ${\gamma}-oryzanol$, and hardening time. Particle sizes of micro- and nanocapsules that showed the maximum encapsulation efficiency and sustained release were $2.27{\pm}0.02mm$ and $347.7{\pm}58.1nm$, respectively. Microcapsules showed higher encapsulation efficiency ($50.73{\pm}1.98%$) than nanocapsules ($17.70{\pm}2.04%$), while nanocapsules showed more sustained release and higher stability than microcapsules. Release of ${\gamma}-oryzanol$ from both microand nanocapsules, which was low in gastric environments and promoted in intestinal environments, showed suitable characteristics for oral administration. Furthermore, antioxidant activity of ${\gamma}-oryzanol$ against autoxidation of linoleic acid was prolonged by both micro- and nanoencapsulation in a ferric thiocyanate test. Therefore, micro- and nanoencapsulation using pectin can be effective for improving biodelivery, stability, and antioxidant activity of ${\gamma}-oryzanol$.

• Journal of the Korean Ceramic Society
• /
• v.42 no.3 s.274
• /
• pp.165-170
• /
• 2005

Sol-gel methods offer many advantages over conventional slip-casting, including the ability to produce ceramic membranes. They are purer, more homogeneous, more reactive and contain a wider variety of compositions. We produced ormosil sol using sol-gel process under various molecular weight of polymer species[polyethylene glycol(PEG)] in total system [Tetraethyl ortho silicate(TEOS)-polyethylene glycol(PEG)]. The properties of as-prepared ormosil sol such as viscosity and gelation time are characterized. Also, the ceramic membrane was prepared by dip-coating with synthetic sol and its microstructure was observed by scanning electron microscopy. The permeability and rejection efficiency of membrane for oil/water emulsion were evaluated as cross­flow apparatus. The ormosil sol coated membrane was easily formed by steric effect of polymer and it improved flux efficiency because infiltration into porous support decreased. Its flux efficiency was elevated about $200\;l/m^2h$ compared with colloidal sol coated membrane at point of five minutes from starting test.

• Advances in concrete construction
• /
• v.10 no.5
• /
• pp.403-416
• /
• 2020

This study investigated the effect of alkaline activators - NaOH_aq (NH) (NH: 0-16 M) and Na₂SiO_3aq (NS) (NS/NH: 0-3.5) in the synthesis of silico-manganese fume (SMF) and ground blast furnace slag (BFS) blended alkali-activated mortar (AASB). The use of individual activator was ineffective in producing AASB of sufficient fresh and hardened properties, compared to the synergy of both activators. This may be attributed to incomplete dissolution and condensation of oligomers required for gelation of the binder. An inverse relationship was noted among the fresh properties and the NH concentration or NS/NH ratio. This was influenced by the dissolution and condensation of silicate monomers under polymerization process. The maximum 28-day strength of ~45 MPa, setting time of 60 min and flow of 182 mm was obtained with the use of combined activators (10M-NH and NS/NH=2.5). The combined activators at NS/10M-NH=2.5 constituted SiO₂/Na₂O, H₂O/Na₂O and H₂O/SiO₂ molar ratio of 1.61, 17.33 and 10.77, respectively. This facilitated the formation of C-S-H, C/K-A-S-H and C-Mn-S-H in the framework together with an increase in the crystallinity due to more silicate re-organization within the aluminosilicate chain. On comparison of the high concentrated with mild alkali synthesized product, it revealed that the concentration of OH^- and Si monomers together with alkali metals influenced the dissolution of precursors and embedment of the constituent elements in the polymeric matrix. These factors eventually contributed to the microstructural densification of the mortar prepared with NS/10M-NH=2.5 thereby enhancing the compressive strength.