• Composites Research
• /
• v.20 no.2
• /
• pp.21-26
• /
• 2007

This paper summarizes the design procedure and constructibility of an ECC (Engineered Cementitious Composite), which is a synthetic fiber-reinforced composite produced with the Portland cement-based mortar matrix. This study employs a stepwise method to develop useful ECC in construction field, which possesses different fluid properties to facilitate diverse types of processing (i.e., self-consolidating or spray processing). To control the rheological properties of the composite, the aggregates and reinforcing fibers were initially selected based on micromechanical analysis and steady-state cracking theory. The stability and consequent viscosity of the suspensions were then mediated by optimizing the dosage of the chemical and mineral admixtures. The rheological properties altered through this approach were revealed to be effective in obtaining ECC-hardened properties, represented by pseudo strain-hardening behavior in uniaxial tension, allowing the readily achievement of the desired function of the fresh ECC.

• Restorative Dentistry and Endodontics
• /
• v.45 no.4
• /
• pp.50.1-50.11
• /
• 2020

Objectives: In this study, we investigated the potential of amoxicillin-loaded polymeric microspheres to be delivered to tooth root infection sites via a bioactive reparative cement. Materials and Methods: Amoxicillin-loaded microspheres were synthesized by a spray-dray method and incorporated at 2.5% and 5% into a mineral trioxide aggregate cement clinically used to induce a mineralized barrier at the root tip of young permanent teeth with incomplete root development and necrotic pulp. The formulations were modified in liquid:powder ratios and in composition by the microspheres. The optimized formulations were evaluated in vitro for physical and mechanical eligibility. The morphology of microspheres was observed under scanning electron microscopy. Results: The optimized cement formulation containing microspheres at 5% exhibited a delayed-release response and maintained its fundamental functional properties. When mixed with amoxicillin-loaded microspheres, the setting times of both test materials significantly increased. The diametral tensile strength of cement containing microspheres at 5% was similar to control. However, phytic acid had no effect on this outcome (p > 0.05). When mixed with modified liquid:powder ratio, the setting time was significantly longer than that original liquid:powder ratio (p < 0.05). Conclusions: Lack of optimal concentrations of antibiotics at anatomical sites of the dental tissues is a hallmark of recurrent endodontic infections. Therefore, targeting the controlled release of broad-spectrum antibiotics may improve the therapeutic outcomes of current treatments. Overall, these results indicate that the carry of amoxicillin by microspheres could provide an alternative strategy for the local delivery of antibiotics for the management of tooth infections.

• Asian-Australasian Journal of Animal Sciences
• /
• v.13 no.11
• /
• pp.1576-1583
• /
• 2000

Three experiments were conducted to determine the nutritional value of wheat gluten (WG) and spray-dried porcine plasma (SDPP) in diets for nursery pigs. In Exp. 1, 120 weanling pigs (5.7 kg avg initial BW) were used in a 35-d growth assay. Treatments for d 0 to 14 were: 1) dried skim milk (DSM)-dried whey-SBM based control; 2) WG to replace the protein from DSM; 3) SDPP; and 4) WG-SDPP (50:50 blend on a protein basis) to replace the protein from DSM. From d 14 to 35, all pigs were fed a common corn-SBM-whey-based diet. For d 0 to 14, there were no differences in ADG, ADFI, and gain/feed (p>0.11). However, for d 14 to 35, pigs fed diets with WG had greater gain/feed than those fed SDPP (p<0.05), and pigs fed diets with the WG-SDPP blend had greater ADG than pigs fed diets with WG or SDPP alone (p<0.07). In a second experiment, 60 weanling pigs (5.1 kg avg initial BW) were used in a 28-d growth assay. All pigs were fed the WG-SDPP diet fed in Exp. 1 for d 0 to 14, and changed to experimental diets for d 14 to 28. Treatments were: 1) the whey-SBM-based diet used for d 14 to 28 in Exp. 1; or 2) a whey-SBM based diet with 3% added SDPP. There were no differences in ADG, ADFI, gain/feed, or apparent digestibilities of DM and N among treatments for d 14 to 28 or overall (p>0.14). In a third experiment, 150 weanling pigs (5.6 kg avg initial BW) were used in a 32-d growth assay to determine the optimal blend of WG and SDPP for use after weaning. The SDPP was added as 8% of the control diet, and WG was substituted on a protein basis to yield the desired SDPP:WG blends. Treatments were (d 0 to 14): 1) SDPP; 2) 75% SDPP and 25% WG; 3) 50% SDPP and 50% WG; 4) 25% SDPP and 75% WG; and 5) WG. As in Exp. 1, all pigs were switched to a common corn-SBM-whey-based diet for d 14 to 32. For d 0 to 14, ADG and ADFI increased as replacement of the SDPP was increased up to 50% and decreased when more of the SDPP was removed from the diet (quadratic effects, p<0.004 and 0.02, respectively). Apparent digestibilities of DM and N (at d 13) were not affected by treatments (p>0.18). For d 14 to 32, treatments did not affect ADG (p>0.2), although there were quadratic responses in ADFI (p<0.04), with pigs fed the 50:50 blend suggested the greatest intake of feed. For the overall experimental period (d 0 to 32), ADG, ADFI, and gain/feed increased as WG was used to replace as much as 50% of the SDPP (quadratic effects p<0.04, 0.02, and 0.06, respectively). In conclusion, WG can successfully replace up to 50% of the SDPP in a complex nursery diet, when SDPP is included at the 8% level. There is no advantage to keeping SDPP in the diet after Phase I (d 0 to 14).

• Journal of Practical Agriculture & Fisheries Research
• /
• v.10 no.1
• /
• pp.43-58
• /
• 2008

This research was conducted to determine the alternative tool of chemical spray for rice cultivation using the unmanned helicopter(Yamaha, R-Max Type 2G-remote controlled system) at farmer's field in Korea. The unmanned helicopter tested was introduced form Japan. In Korea the application of chemicals by machine sprayer for pest management in rice cultivation has been ordinarily used at the farmer's level. However, it involved a relatively high cost and laborious for the small scale of cultivation per farm household. Farm population has been highly decreased to 7.5% in 2002 and the population is expected to rapidly reduce by 3.5% in 2012. In Japan, pest control depending on unmanned helicopter has been increased by leaps and bounds. This was due in part to the materialization of the low-cost production technology under agricultural policy and demand environmentally friendly farm products. The practicability of the unmanned helicopter in terms of super efficiency and effectiveness has been proven, and the farmers have understood that the unmanned helicopter is indispensable in the future farming system that they visualized. Also, the unmanned helicopter has been applied to rice, wheat, soybean, vegetables, fruit trees, pine trees for spraying chemicals and/or fertilizers in Japan Effect of disease control by unmanned helicopter was partially approved against rice blast and sheath blight. However, the result was not satisfactory due to the weather conditions and cultural practices. The spray density was also determined in this experiment at 0, 15, 30, and 60cm height from the paddy soil surface and there was 968 spots at 0cm, 1,560 spots at 15cm, 1,923 spots at 30cm, and 2,999 spots at 60cm height. However, no significant difference was found among the treatments. At the same time, there was no phytotoxicity observed under the chemical stray using this unmanned helicopter, nor the rice plant itself was damaged by the wind during the operation.

• Journal of Bio-Environment Control
• /
• v.23 no.4
• /
• pp.329-336
• /
• 2014

As an abiotic stress, chilling stress is one of the major factors limiting plant growth and increasing susceptibility to pathogens. Therefore, enhancing stress tolerance in plants is an important strategy for their survival under unfavorable environmental conditions. The objective of this study was to determine the effects of the exogenous application of salicylic acid (SA) or nitric oxide (NO) on chilling tolerance in pepper seedlings. Pepper (Capsicum annuum L. 'kidaemanbal') seedlings were grown under normal growing conditions ($20/25^{\circ}C$, 15 hours photoperiod, $145{\pm}5{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, fluorescence lamps) for 23 days after transplanting. The solution (3 mL) of 1 mM SA and 0.3 mM NO with surfactant triton 0.1% were sprayed two times a week, respectively. Right after the completion of chemical application, seedlings were subjected to chilling condition at $4^{\circ}C$ for 6 hours under dark condition and then the seedlings were recovered at the normal growing conditions for 2 days. In order to assess plant tolerance against chilling stress, growth characteristics, chlorophyll fluorescence (Fv/Fm), and membrane permeability were determined after chilling stress imposition. Total phenolic concentration and antioxidant capacity were measured during the whole experimental period. Disease incidence for pepper bacterial spot and wilt was also analyzed. Pepper seedlings treated with SA or NO were maintained similar dry mass ratio, while the value in control increased caused by chilling stress suggesting relatively more water loss in control plants. Electrolyte leakage of pepper seedlings treated with SA or NO was lower than that of control 2 days after chilling treatment. Fv/Fm rapidly decreased after chilling stress in control while the value of SA or NO was maintained about 0.8. SA increased higher total phenolic concentration and antioxidant capacity than NO and control during chemical treatment. In addition, increase in total phenolic concentration was observed after chilling stress in control and NO treatment. SA had an effect on the reduction of bacterial wilt in pepper seedlings. The results from this study revealed that pre-treatment with SA or NO using foliar spray was effective in chilling tolerance and the reduction of disease incidence in pepper seedlings.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.3 no.2
• /
• pp.24-34
• /
• 2000

The project for rehabilitation and revegetation of the abandoned coal-mine lands is a very important national environmental restoration project in the view point of rehabilitation and revegetation of denuded forest-lands caused by coal mining as well as restoration of disturbed natural environment and control of the variable pollutions. In Korea, because a large number of coal mines had been developed in order to fill up abundantly consumption of coal as a major energy source in the developing period, a lot of denuded forest-lands caused by coal mining had distributed in the whole country. And, due to the absence of effective rehabilitation and revegetation works on the denuded forestlands caused by coal-mining, most of them had been remained with being damaged. In 1990, area of the abandoned coal-mine lands, requiring the rehabilitation and revegetation works, was about 1,437.1 ha. For the past ten years ('90~'99), about 1,081.8 ha out of them had been rehabilitated and revegetated, and the rehabilitation planning area was about 33.0 ha in 2000. So, remaining area out of abandoned coal-mine lands will be about 322.3 ha after 2000. In principle, after abandoning coal-mine, mine owners must carry out the rehabilitation and revegetation works on the abandoned mine lands by themselves. But, most of mine owners were in financial difficulty after abandoning coal-mine, so that principle couldn't have obtained the desired effects. To solve this problem, from 1995, Coal Industry Promotion Board (CIPB) have carried out the rehabilitation and revegetation works on the abandoned coal-mine lands at government budgets, and they have obtained good results in the construction area. However, due to application of the "conventional erosion control measures and techniques" to the rehabilitation and revegetation measures on the abandoned coal-mine lands, the results and effects of the works excuted have not been successful. Therefore, unique measures and techniques for rehabilitation and revegetation of the abandoned coal-mine lands will have to be developed, especially including development of new techniques on the soil-dressing and soil-covering, seed spray and hydro-seeding measures with seed-fertilizer-soil materials as the mechanized measures, and using of new materials for the tree planting and seedling measures.

• The Korean Journal of Pesticide Science
• /
• v.17 no.3
• /
• pp.213-219
• /
• 2013

This study focused on the promotion of the insecticidal activity of eco-friendly insecticidal materials against four major insect pest in the organic Chinese cabbage cultivation area. Among insecticidal materials mixture, BT+Matrine+Neem against leaf beetle larva, Phaedon brassicae, showed the highest 94.1% at 0.05% which is the lowest concentration of three treated concentrations. The insecticidal activity of Matrine, Neem, and BT alone (0.1%, w/v) or the mixtures (0.05%, w/v) against Cabbage worm larva, Artogeria rapae, was investigated by leaf disc spray method. The insecticidal efficacy of the mixtures of two or three eco-friendly materials was higher than the single treatment of each material with 94.3%, 100% and 100%. Control efficacy of 0.3% COY+0.05% (95.3%) against the green peach aphid, Myzus persicae was higher than that of 0.3% COY+0.05% Neem (90.2%) and lasted for more than 21 days after one time treatment. At 35 days after treatment, the effect of 0.05% BT+0.05% Matrine and 0.05% BT+0.05% Matrine+0.05% Neem treatments against diamondback moth showed very high insecticidal activity with more than 90% of control value. Therefore, BT, Neem, and Matrine where are properly treated could be effective eco-friendly materials for controlling major insect pests in an organic Chinese cabbage field.

• The Korean Journal of Pesticide Science
• /
• v.17 no.4
• /
• pp.411-418
• /
• 2013

The black pine bast scale, Matsucoccus thunbergianae is one of the most serious insect pest in Japanese black pine, Pinus thunbergii forest in Korea. Insecticidal activity of 10 folds hot water extracts from 7 herbal plants (Atractylodes lancea, Eugenia caryophyllata, Lonicera japonica, Melia azedarach, Quisqualis indica, Sophora flavescens and Taraxacum mongolicum) were tested against different stage of M. thunbergianae using spray method both in laboratory and field. Efficacies of herbal extracts were different depending on stage of M. thunbergianae. Q. indica sprayed with hand sprayer produced the highest corrected mortality of 95.7% on intermidiated nymph stage, however, A. lancea produced the highest corrected mortality (51.3%) on pupae of M. thunbergianae in laboratory. Q. indica and A. lancea were highly effective against female M. thunbergianae in laboratory, however, corrected mortality was lower than other stage (40.0%). Efficacy of Q. indica was similar to effective insecticide, fenitrothion 50% EC against M. thunbergianae in field trials. These results indicated that Q. indica could be an environmental friendly control agent of M. thunbergianae.

• Korean journal of applied entomology
• /
• v.18 no.2 s.39
• /
• pp.111-116
• /
• 1979

The experiments were carried out to evaluate the effectiveness of some insecticides in the control of the pine gall midges (Thecodiplosis japonensis Uchida et Inouye) when the low-volume of the insecticides were applied by the mist foliar sprayer. The insecticides, Salithion $(24\%\;Ec)$, Omethoate $(Folimat^{(R)}\;50\%\;Ec)$, Monocrotopos $(Azodrin^{(R)}24\%\;Ec)$, Acephate $(Ortran^{(R)}\;50\%\;Wp)$, Metalkamate $(Bux^{(R)}24\%\;Ec)$. BPMC $(Bassae^{(R)}50\%\;Ec)$ and MIPC $(Mipcin\;50\%\;Wp)$ were tested with 100, 200 and 400 times of water solution on the basis of single application at the six different intervals. Salithion was the most effective for the pressure of the gall formation by the pine gall midges and Omethoate, Monocrotophos and Metalkamate were relativey effective and others no effective. The most reliable concentration of the insecticides was 100 times of water solution, and the feasible timing of insecticide application on the basis of single application would be from May 9 to July 1 with Salithion, June 6 with Metalkamate and June 20 with Omethoate and Monocrotophos. The number of pine needles with the larval injured signs (no larvae in the needles) excluded the gall-formed needles were relatively higher in the treatments of Omethoate, Salithion and Monocrotophos than other insecticides. The treatments of Omethoate, Salithion and Monocrotophos caused the lower larval population in the gall than other insecticides.

• The Korean Journal of Pesticide Science
• /
• v.8 no.1
• /
• pp.71-78
• /
• 2004

A promising hyperparasite, Ampelomyces quisqualis 94013(AQ94013) was selected as a biological control agent to cucumber powdery mildew caused by Sphaerotheca fusca. Effect of agrochemicals on mycelium growth and spore germination of AQ94013 and effect of spread stickers on hyperparasitical activity of AQ94013 to powdery mildew pathogen were evaluated. Finally it was confirmed that mycelial growth and spore germination of AQ94013 on potato dextrose agar amended with two fungicides for controlling powdery mildew, triadimefon and pyrazophos; five fungicides for controlling downy mildew, dimethomorph, kasugamycin+copper oxychloride, dichlofluanid+copper oxychloride and tribasic copper sulfate; three fungicides for controlling gray mold, iprodione, vinclozolin and procymidone; and six insecticides immidacloprid, teflubenzuron, bifenthrin, ethofenprox, deltamethrin and phenthoate were slightly reduced. Addition of mineral oil in the spore suspension of AQ94013 enhanced 7.9% control value to cucumber powdery mildew.