• Restorative Dentistry and Endodontics
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• v.33 no.4
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• pp.341-351
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• 2008

This study investigated the effect of intermittent polymerization on the rate of polymerization shrinkage and cuspal deflection in composite resins. The linear polymerization shrinkage of each composite was measured using the custom-made linometer along with the light shutter specially devised to block the light at the previously determined interval. Samples were divided into 4 groups by light curing method; Group 1) continuous light (60s with light on); Group 2) intermittent light (cycles of 3s with 2s light on & 1s with light off for 90s): Group 3) intermittent light (cycles of 2s with 1s light on & 1s with light off for 120s); Group 4) intermittent light (cycles of 3s with 1s light on & 2s with light off for 180s). The amount of linear polymerization shrinkage was measured and its maximum rate (Rmax) and peak time (PT) in the first 15 seconds were calculated. For the measurement of cuspal deflection of teeth, MOD cavities were prepared in 10 extracted maxillary premolars. Reduction in the intercuspal distance was measured by the custom-made cuspal deflection measuring machine. ANOVA analysis was used for the comparison of the light curing groups and t-test was used to determine significant difference between the composite resins. Pyramid showed the greater amount of polymerization shrinkage than Heliomolar (p < 0.05). There was no significant difference in the linear polymerization shrinkage among the groups. The Rmax was group 4 < 3, 2 < 1 in Heliomolar and group 3 < 4 < 2, 1 in Pyramid (p < 0.05). Pyramid demonstrated greater cuspal deflection than Heliomolar. The cuspal deflection in Heliomolar was group 4 < 3 < 2, 1 and group 4, 3 < 2, 1 in Pyramid (p < 0.05). It was concluded that the reduced rate of polymerization shrinkage by intermittent polymerization can help to decrease the cuspal deflection.

• Journal of Korea Fair Competition Federation
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• no.150
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• pp.14-29
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• 2010

비록 부정경쟁방지법의 제정 목적이 부정경쟁행위 등의 방지를 통하여 건전한 거래질서를 유지한다는 의미의 경쟁체제 확립에 있기는 하지만, 우리나라의 경우는 법 제정 당시와는 달리 사실상 산업스파이에 대한 영업비밀의 보호나 주지의 상표 영업표지의 보호와 같은 지적재산권의 보호 법률로서의 역할로 점차 변화하고 있고, 특히 부정경쟁방지법이 주지의 상표에 대한 출처의 혼동에 대한 규제뿐만이 아니라 별도로 저명상표의 희석화(稀釋化) 방지라는 법익, 이에 더 나아가 도메인 네임(Domain Name)의 선점과 원산지 및 품질의 오인(誤認) 야기행위, 주지 저명한 타인의 디자인(Design), 캐릭터(Character)와 같은 상품의 표지에 이르기까지 지적재산권과 관련된 보다 넓은 법익의 보호까지 수행하게 되면서 그 기능은 날로 강화되고 있는 상태이다. 이에 반하여 부정경쟁방지법상의 부정경쟁행위 자체에 대한 규제는 사실상 주지 저명한 타인의 상표나 상품표지의 식별력이나 출처표시기능 등의 보호라는 의미의 분쟁수준을 넘지 못하고 있어, '경쟁법'으로서의 역할은 상대적으로 미약해지고 있는 것 또한 현실이다. 또한, 공정거래법 제23조 제1항 제8호를 비롯하여 현행 공정거래법상의 불공정거래행위에 대한 규정체제를 살펴보면, 해석 여하에 따라서는 부정경쟁방지법상의 부정경쟁행위가 대부분 공정거래법상의 불공정거래행위의 범위 내로 포섭될 수도 있는 상황이기도 하다. 이에 양 법률의 성격과 역할, 앞으로 나아가야 할 방향을 고민하지 않을 수 없고, 이와 같은 논의는 발전적 입법론으로서의 가치를 갖는다. 물론 불공정거래행위(부정경쟁행위)에 대한 규제에 있어서 반드시 독일법체계에 따를 것인지 아니면 미국의 경우를 따를 것인지에 대한 선택 자체가 논리적으로 양립 불가능한 것은 아닐 것이지만 우리나라의 경우는 1980년 "독점규제 및 공정거래에 관한 법률"이 제정되는 과정에서 당시 부정경쟁방지법에 담겨 있던 기존의 부정경쟁행위에 대한 규정과 공정거래법상의 불공정거래행위와의 경합이나 중복문제는 마땅히 검토되었어야 했음에도 불구하고 공정 거래법의 제정과정에서 사실상 부정경쟁방지법의 존재 자체가 간과되어 오늘에 이르고 있다. 그동안 양 법률상의 규정 중복이나 충돌을 정식으로 문제 삼았던 바는 없었지만 '발전적 입법론' 이라는 차원에서 살펴 보면 부정경쟁방지법상의 부정경쟁행위에 대한 규제는 앞으로 공정거래법체계 내의 불공정거래행위로 포섭할 필요가 있고 이를 통하여 경쟁정책의 전문 전담기구로서 불공정거래행위에 대한 규제의 중심에 서 있는 공정거래위원회를 중심으로 효율적이고 통일적인 경쟁정책을 확립을 기대하여 볼 수 있을 것이다. 이 과정에서 공정거래법의 변화 또한 뒤따라야 하는데, 부정경쟁방지법상의 부정경쟁행위의 편입에 따라 불공정거래행위에 대한 규정 일부를 알맞게 다시 수정하는 것에 그치지 않고, 기존 부정경쟁방지법이 인정하고 있었던 사인간(私人間) 금지 또는 예방청구권 또한 공정거래법으로 그대로 편입되는 방향으로의 입법 개선이 이루어질 필요가 있으며, 그동안 '부정경쟁방지법의 공정거래법으로의 편입문제'와는 전혀 무관하게 공정거래법의 사적 구제 및 사소(私訴)의 활성화 차원의 논의로서 공정거래법상 사인간 금지청구권의 도입 여부가 검토되어 왔지만, 앞으로 이 문제는 부정경쟁방지법상 부정경쟁행위의 공정거래법체계 내로의 편입문제와 함께 이를 포함한 더욱 큰 논의로서 다시 적극적으로 검토될 필요가 있다고 본다. 이를 통하여 앞으로 부정경쟁방지법은 특허청을 중심으로 산업스파이에 대한 규제나 영업비밀의 보호와 기타 지적재산권의 보호에 온 힘을 다하고, 공정거래법은 공정거래위원회를 중심으로 불공정거래행위 (부정경쟁행위에 대한 보다 포괄적이고 통일적인 규제를 담당하여 '선택과 집중' 이라는 차원의 각 법률체계의 한 차원 높은 발전 또한 기대해 볼 수 있을 것으로 확신한다. 이러한 합의점을 시작으로 미시적인 다음 단계의 논의에 해당하는 사인간 금지청구권의 허용범위나 허용요건, 남용을 방지하기 위한 제도적 장치, 단체소송 등의 허용 여부 등의 논의도 함께 하여야 할 것이고, 이 과정에서 미국의 클레이튼법(Clayton Act)이나 가까운 일본의 입법례를 참고하여 우리의 실정에 맞는 규제의 틀을 마련함이 타당할 것이고, 이를 통하여 궁극적으로 그동안 공정거래법의 사적 집행의 활성화를 통한 경쟁질서의 확립의 강화라는 이상에 더욱 가까워질 수 있는 좋은 입법적 변화의 모습을 볼 수 있을 것이라 생각한다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.2
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• pp.6-14
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• 1980

One of the physiological disease, sudden wiliting of Yushin variety suggested that low sunlight, excessive nitrogen application, and highly reduced soil condions either singly or combined, might be possible causes of the disorder. Some visual symptom of sudden wilting are discoloration of leaves, development of nodal roots above the soil surface, total root rot, and lodging. Those observations led to the hypothesis that suffocation of root tissues was a direct cause of the wilting. The oxygen transport characteristics of Yushin, IR262 and Tongil were examined by two methods. First, Soil-cultured plants of the three varieties were subjected to paraffin treatment to decrease the oxygen supply from the air to root tissues through the soil-water system, liquid paraffin was applied to the water surface in the pots at panicle formation stage. In this experiment, sudden wilting was observed of Yushin and IR262 at about a week after the treatment, but Tongil remained green and healthy. Wilting-resistant variety Tongil had higher oxygen release, whereas the susceptible Yushin and IR262 had lower oxygen release. Second, the number and size of the air spaces in each internode were investigated in the 5th internode from the top, all three varieties have a similar number of air spaces, although the air spaces of Thongil were larger. In the 4th internode, Tongil had plenty air spaces, Yushin and one of the Yushin's parents IR262 had scanty or none. The observations indicated that the ability of Yushin and IR262 for oxygen transport is very limited compared with that of Tongil. The limited oxygen supply due to poor development of air space in internode of rice plants may cause suffocation of root tissues, weaken metabolic activity of the tissues, and induce root rot, subsequently inducing sudden wilting and lodging under unfavorable weather, soil and cultural conditions.

• The Korean Journal of Pesticide Science
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• v.10 no.4
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• pp.313-319
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• 2006

Two hundred bacterial strains were isolated from the soil around healthy tomato plants in a polyvinyl house, where most of the other plants showed bacterial wilt symptoms. The strains were screened in vitro for their antibacterial activity. Among them, a strain, KPB3 showed strong bactericidal activity against bacterial wilt pathogen, Ralstonia solanacearum. The strain KPB3 was identified using physiological and biochemical tests, and 16S rRNA analyses. Based on these tests, the strain was found to be closer to genus Paenibacillus. To control the bacterial wilt caused by R. solanacearum, greenhouse experiments were conducted to determine the effectiveness of the Paenibacillus strain KPB3. Drench application of this strain ($4{\times}10^8$ CFU $mL^{-1}$) into the pots containing tomato plants, post-inoculated with the pathogen, R. solanacearum could drastically reduce the disease severity, compared to the non-treated plants. To evaluate effectiveness of this strain under field conditions, experiments were carried out in polyvinyl houses infested with R. solanacearum, during spring and autumn of the year 2006. It was observed that, during spring, bacterial wilt was more prevalent compared to the autumn. During spring, 50.9% disease incidences occurred in non-treated controls, while, Paenibacillus strain KPB3 treated plants showed 24.6% disease incidences. Similarly, during autumn, around 17.2% plants were infected with bacterial wilt in non- treated polyvinyl houses, compared to the Paenibacillus strain KPB3 treated plants, which showed 7.0% disease incidences. These results demonstrated that, Paenibacillus strain KPB3 is a potential biological control agent against bacterial wilt caused by R. solanacearum, effective under greenhouse as well as field conditions. This is the first report showing biocontrol of R. solanacearum using a Paenibacillus spp. under field conditions.

• The Korean Journal of Pesticide Science
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• v.5 no.2
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• pp.45-50
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• 2001

In recent, non virus-induced mosaic symptoms(NVMS) on potato leaves were observed in the seed potato fields, and its incidence rate was $5{\sim}20%$ nationwide. It made difficult to rogue out virus-infected plants, and caused much arguments between seed potato production farmers and seed potato inspectors. The objectives of these experiments were to find out the causes of NVMS, and also to induce mosaic symptom(phytotoxicity) on potato plants by treatment of several herbicides. No significant correlations were found between incidence rates of NVMS and values from soil analyses; soil pH, soil EC, organic matter content, and contents of inorganic constituents($P_2O_5,\;NO_3$, Ca, Mg, K) in the soil around the potato planted. The examinations by ELISA, virus indicator plants, and TEM showed that NVMS on potato leaves was not caused by the viruses infection. But, the use of herbicides could induced the NVMS on potato leaves. The incidence rates of potato treated with pendimethalin linuron of 400 mL/10 a, pendimethalin of 200 mL/10 a, pendimethalin.oxadiazon of 300 mL/10 a, and control were 61.1%, 47.2%, 19.4%, and 1.4%, respectively. Based on these results, we confirmed that the treatment of pendimethalin alone and in mixture with other herbicides were the reason of NVMS on potato leaves. The yields among test plots were similar except dicamba treated plot, which decreased by about 23% compared to control plot. When their progenies harvested in 1999 were planted in the following season, no symptoms of mosaic were observed.

• Restorative Dentistry and Endodontics
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• v.32 no.4
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• pp.343-355
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• 2007

The objectives of this study was to evaluate the durability of 4 resin cements by means of microtensile bond strength test combined with thermocycling method and fractographic FE-SEM analysis. Experimental groups were prepared according to thermocycling (0, 1,000, 5,000) and the kind of resin cements, those were Variolink II, Multilink, Panavia F 2.0, Rely X Unicem. Flat dentin surfaces were created on mid-coronal dentin of extracted third molars. Then fresh dentin surface was grounded with 320-grit silicon carbide abrasive papers to create uniform smear layers. Indirect composite block (Tescera, Bisco Inc., Schaumburg, IL, USA) was fabricated ($12\;{\times}\;12\;{\times}\;6\;mm^3$). It's surface for bonding to tooth was grounded with silicon carbide abrasive papers from 180- to 600-grit serially, then sandblasted witk $20\;-\;50\;{\mu}m$ alumina oxide. According to each manufacturer's instruction, dentin surface was treated and indirect composite block was luted on it using each resin cement. For Rely X Unicem, dentin surface was not treated. The bonded tooth-resin block were stored in distilled water at $37^{\circ}C$ for 24 hours. After thermocycling, the bonded tooth-resin block was sectioned occluso-gingivally to 1.0 mm thick serial slabs using all Isomet slow-speed saw (Isomet, Buehler Ltd, Lake Bluff, IL, USA). These sectioned slabs were further sectioned to $1.0\;{\times}\;1.0\;mm^2$ composite-dentin beams. The specimens were tested with universal testing machine (EZ-Test, Shimadzu, Japan) at a crosshead speed of 1.0 mm/min with maximum load of 500 N. The data was analyzed using one-way ANOVA and Duncan's multiple comparison test at $p\;{\leq}\;0.05$ level. Within the limited results, we conclude as follows; 1. The bond strength of Variolink II was evaluated the highest among experimental groups and was significantly decreased after 1,000 thermocycling (p < 0.05). 2. The bond strength of Multilink was more affected by thermocycling than the other experimental groups and significantly decreased after 1,000 thermocycling (p < 0.05). 3. Panavia F 2.0 and Rely X Unicem showed the gradually decreased tendency of microtensile bond strength according to thermocycling but there was no significant difference (p > 0.05). 4. Adhesive based-resin cements showed lower bond strength with or without thermocycling than composite based-resin cements. 5. Variolink II & Multilink showed high bond strength and mixed failure, which was occurred with a thin layer of luting resin cement before thermocycling and gradually increased adhesive failure along the dentin surface after thermocycling. The bonding performance of resin cement can be affected by application procedure and chemical composition. Composite based-resin cement showed higher bond strength and durability than adhesive based-resin cement.

• Restorative Dentistry and Endodontics
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• v.32 no.4
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• pp.377-384
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• 2007

Present tooth bonding system can be categorized into total etching bonding system (TE) and self-etching boding system (SE) based on their way of smear layer treatment. The purposes of this study were to compare the effectiveness between these two systems and to evaluate the effect of number of themocycling on microleakage of class V composite resin restorations. Total forty class V cavities were prepared on the single-rooted bovine teeth and were randomly divided into four experimental groups: two kinds of bonding system and another two kinds of thermocycling groups. Half of the cavities were filed with Z250 following the use of TE system, Single Bond and another twenty cavities were filled with Metafil and AQ Bond, SE system. All composite restoratives were cured using light curing unit (XL2500, 3M ESPE, St. Paul, MN, USA) for 40 seconds with a light intensity of $600mW/cm^2$. Teeth were stored in distilled water for one day at room temperature and were finished and polished with Sof-Lex system. Half of teeth were thermocycled 500 times and the other half were thermocycled 5,000 times between $5^{\circ}C$ and $55^{\circ}C$ for 30 second at each temperature. Teeth were isolated with two layers of nail varnish except the restoration surface and 1 mm surrounding margins. Electrical conductivity (${\mu}A$) was recorded in distilled water by electrochemical method. Microleakage scores were compared and analyzed using two-way ANOVA at 95% level. From this study, following results were obtained: There was no interaction between variables of bonding system and number of thermocycling (p = 0.485). Microleakage was not affected by the number of thermocycling either (p = 0.814). However, Composite restoration of Metafil and AQ Bond, SE bond system showed less microleakage than composite restoration of Z250 and Single Bond, TE bond system (p = 0.005).

• Restorative Dentistry and Endodontics
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• v.33 no.5
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• pp.463-471
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• 2008

This study investigated the clinical effectiveness and safety of sealed bleaching compared to conventional in-office bleaching using a randomized clinical trial of split arch design. Ten participants received a chairside bleaching treatment on the upper anterior teeth, and each side was randomly designated as sealed or control side. A mixture of Brite powder (PacDent, Walnut, USA), 3% hydrogen peroxide and carbamide peroxide (KoolWhite, PacDent, Walnut, USA) were used as bleaching agent. The control side was unwrapped and the experimental side was covered with a linear low density polyethylene (LLDPE) wrap for sealed bleaching. The bleaching gel was light activated for 1 hour. The tooth shades were evaluated before treatment, after treatment, and at one week check up by means of a visual shade (VS) assessment using a value oriented shade guide and a computer assisted shade assessment using a spectrophotometer (SP). The data were analyzed by paired t-test. In the control and sealed groups, the visual shade scores after bleaching treatment and at check up showed statistically significant difference from the preoperative shade scores (p<.05). The shade scores of the sealed group were significantly lighter than the control immediately after bleaching and at the check-up appointment (p<0.05). Compared to prebleaching status, the ${\Delta}E$ values at post bleaching condition were $4.35{\pm}1.38\;and\;5.08{\pm}1.34$ for the control and sealed groups, respectively. The ${\Delta}E$ values at check up were $3.73{\pm}1.95\;and\;4.38{\pm}2.08$ for the control and sealed groups. ${\Delta}E$ values were greater for the sealed group both after bleaching (p<.05) and at check up (p<.05). In conclusion, both ${\Delta}E$ and shade score changes were greater for the sealed bleaching group than the conventional bleaching group, effectively demonstrating the improvement of effectiveness through sealing.

• Restorative Dentistry and Endodontics
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• v.33 no.5
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• pp.472-480
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• 2008

This study was conducted to evaluate the influence of the C-factor on the bond strength of a 6th generation self-etching system by measuring the microtensile bond strength of four types of restorations classified by different C-factors with an identical depth of dentin. Eighty human molars were divided into four experimental groups, each of which had a C-factor of 0.25, 2, 3 or 4. Each group was then further divided into four subgroups based on the adhesive and composite resin used. The adhesives used for this study were AQ Bond Plus (Sun Medical, Japan) and XenoIII (DENTSPLY, Germany). And composite resins used were fantasists (Sun Medical, Japan) and Ceram-X mono (DENTSPLY, Germany). The results were then analyzed using one-way ANOVA, a Tukey's test, and a Pearson's correlation test and were as follows. 1. There was no significant difference among C-factor groups with the exception of groups of Xeno III and Ceram-X mono (p<0.05). 2. There was no significant difference between any of the adhesives and composite resins in groups with C-factor 0.25, 2 and 4. 3. There was no correlation between the change in C-factor and microtensile bond strength in the Fantasista groups. It was concluded that the C-factor of cavities does not have a significant effect on the microtensile bond strength of the restorations when cavities of the same depth of dentin are restored using composite resin in conjunction with the 6th generation self-etching system.

• Korean Journal of Soil Science and Fertilizer
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• v.6 no.2
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• pp.115-127
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• 1973

Leaf discoloration of IR667 lines (tropical) and leading locals (temperate) in fields was classified according to the probable causes and nutritional disorder due to soil reduction in 1972 was investigated. 1. The causes of leaf discoloration in IR667 were low air temperature, soil reduction, seed born, insect bite, nitrogen depression, overdose pesticide, strong wind, early senescence and unknown one. 2. Leaf discoloration due to soil reduction which has been called Sageumbyeong by famers, was caused by the heavy application of $Ca(OH)_2$, compost and poor drainage followed by Zn and K deficiency and Fe toxicity. 3. About 30 days after transplanting deficiency concentration of K and Zn in leaf blade appears to be less than 2.0% and 20ppm respectively, and greater than 200ppm, 500ppm, and 1.0% respectively for toxicity or excess of Fe, Mn and Ca. and in the shoot 2.4% for K, 30ppm for Zn and 800ppm for Fe. The value of K/Ca should be greaterthan 2.0 for health. 4. When plants were damaged by soil reduction the contents of N, P, Ca, Mg, Fe, Mn, Na in shoot were increased and those of K, Zn, Si were decreased. 5. IR667 lines show in shoot higher content of N, P, Ca, Mg, Si, Na, and lower content K, Zn, Fe, Mn and lower root activity than local leading varietles in either healthy or disieased case, indicating IR667 lines are likely more suseptible to soil reduction damage. 6. Normal soil was less than 6.5 of pH and greater than -50 mv of Eh, but pH of problem soil was ranged from 6.7 to 7.4 and Eh from -100 to -190. 7. The root activity (${\alpha}$-naphthylamine oxidation) decreased at early stage of soil redudtion damage, then increased with severity and at the end it decreased again, but IR667 lines showed always lower root activity than local ones.