• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.379-387
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• 2007

This research was conducted to evaluate the influence of pre-planting fertilizer levels (PFL) and initiation time of fertigation (ITF) on growth and nutrient contents of tomato plug seedlings. The pre-planting fertilizer levels in a coir+peatmoss+perlite (4:4:2, v/v/v) substrate were adjusted to 0.5X, 1.0X and 1.0X, and initiation time of fertigation was set to 7, 14,21 and 28 days after sowing. Elevated PFL in same ITF increased plant growth such as fresh and dry weights at 35 and 70 days after sowing. Plugs with early feeding among treatments of equal amount of PFL also showed better growth as compared to those of later feeding. In each ITF, 0.5X treatment had the higher tissue $P_2O_5$ contents than 1.0X and 1.5X treatments. Elevated PFL resulted in the decrease of tissue K, Mg and Fe contents and increase of tissue Ca contents. The pH in soil solution of all root substrates except 0.5X treatment at 35 and 70 days after sowing were greater than 7.0, which is too high. This suggests that the amounts and kinds of Ca containing fertilizers should be altered to decrease the pH. The results of this research indicated that fertilizer levels should be increased to 1.5X except Ca fertilizer, and fertigation immediately after moving plug trays from germination room to greenhouse is required to increase crop growth and decrease cropping time.

• The Korean Journal of Pain
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• v.25 no.4
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• pp.213-220
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• 2012

Background: It has been demonstrated that the expression of tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) and apoptotic cell death in the dorsal root ganglion (DRG) following spinal nerve constriction injury play a role in the initiation and continuation of hyperalgesia and allodynia. The present study was designed to investigate the effects of ethyl pyruvate (EP) on mechanical and cold allodynia, TNF-${\alpha}$ expression, and apoptosis in DRG after spinal nerve ligation injury. Methods: Rats were divided into 3 groups: control, pre-EP, and post-EP. EP (50 mg/kg) was intraperitoneally injected 30 minutes before (pre-EP) or after (post-EP) surgery. Behavioral tests to determine mechanical and cold allodynia were conducted before surgery and 4 and 7 days after surgery. Seven days after surgery, TNF-${\alpha}$ protein levels in DRG were evaluated by enzyme-linked immunosorbent assay, and DRG apoptosis was determined by immunohistochemical detection of activated caspase-3. Results: Treatment with EP significantly reduced mechanical and cold allodynia following spinal nerve ligation injury. TNF-${\alpha}$ protein levels in the pre-EP ($4.7{\pm}1.2$ pg/200 ${\mu}g$; P < 0.001) and post-EP ($6.4{\pm}1.8$ pg/200 ${\mu}g$; P < 0.001) groups were 2-3 times lower than the control group ($14.4{\pm}1.2$ pg/200 ${\mu}g$). The percentages of neurons and satellite cells that co-localized with caspase-3 were also significantly lower in the pre-EP and post-EP groups than the control group. Conclusions: These results demonstrate that EP has a strong anti-allodynic effect that acts through the inhibition of TNF-${\alpha}$ expression and apoptosis in DRG after spinal nerve ligation injury.

• Korean Journal of Agricultural Science
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• v.42 no.4
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• pp.423-429
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• 2015

This study was conducted to evaluate the effects of reduced nitrogen (N) and potassium (K) fertigation as additional fertilizer on tomato yield and nutrient contents in excessively nutrients-accumulated soil. Shoot and root dry weights (DW), dry matter rate for shoot, root and fruit and number of fruit in both AF50 and AF100 (50 and 100% levels of additional fertilizer) treatments were increased in comparison with those in AF0 (0% level of additional fertilizer) treatment. In case of nutrient uptake by tomato, nitrogen, phosphorous (P) and potassium contents in all tomato parts (leaf, stem, root and fruit) in AF50 and AF100 treatment were lower than those in AF0 treatment. On the contrary, soluble sugar and starch contents in all tomato parts in AF50 and AF100 were higher than those in AF0 treatment. There were differences between AF0 and AF50 or AF100 in tomato growth, yield, nutrient level and contents of soluble sugar and starch. In contrast, the level and initiation point of fertigation did not significantly affect the parameters. Based on our results, the application of properly reduced level of additional fertilizer is possible to maintain the productivity of tomato and alleviate the nutrient accumulation in plastic film house soils.

• The Plant Pathology Journal
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• v.20 no.2
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• pp.81-84
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• 2004

Branched broomrape (Orobanche ramosa) is a holo-parasitic flowering plant that attaches to the root of its host, green plant, by means of a specialized structure known as haustorium. Following successful contact and penetration on susceptible plant root, complex tissue of Orobanche cells is formed which is known as the tubercle. Newly formed tubercles contain high activity ofindole-3-acetic acid (IAA). Triiodobenzoic acid (TIBA), as an inhibitor of IAA polar transport, was utilized to investigate the supply and requirement of auxin to the developing O. ramosa on tomato plant. There was no significant reduction in the incidence of O. ramosa per pot of different TIBA treatments. However, infection severity in terms of the number of O. ramosa shoots that emerged per plant and number of attachments per plant root system were significantly reduced by 60 % and 45 % on TIBA treated plants, respectively. Histo-logical studies revealed conspicuous delay in the initiation of xylem vessel differentiation inside tubercles of the TIBA treated tomato plants. Also, differentiated vessels showed thinner secondary wall deposition, and improper alignment within bundles inside those tubercles. They were wider and shorter in diameter in comparison to those of untreated plants. These findings were attri-buted to the short supply of IAA required for normal development, and to the xylem vessel differentiation of O. ramosa tubercles on infected tomato. Hence, this parasitic flowering plant seems to depend upon its host in its requirements for IAA, in a source to sink relation-ship.

• Proceedings of the Ginseng society Conference
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• 1978.09a
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• pp.43-49
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• 1978

This study was devised to observe the cytotoxic activity of extracts of Panax ginseng root against some cancer cells and to purify the crude extract. Three kinds of cancer cells(leukemic cells L5178Y, HeLa cells and Sarcoma 180 cells) and mouse embryo cells (as normal cells) were used for this study. The ginseng roots were extracted with petroleum ether in soxhlet apparatus, and the crude extracts were purified by the silicic acid column chromatography and thin-layer chromatography methods. The results obtained are summarized as follows; 1. Eight to ten mg of the petroleum ether extract (crude extract) were obtained from 1 g of Panax ginseng root, and its activities per mg were about 1,000 units. 2. Doubling time of the L5178Y cells was increased to two fold by 24 hours incubation in culture medium containing about one ${\mu}g$ of extract per ml, and eight and ten folds higher concentration of ginseng extract were required for the Sarcoma 180 cells and HeLa cells, respectively, than for the leukemic cells(L5178Y) to inhibit the cellular growth to the same degree. 3. When the L5178Y cells were exposed to medium containing various concentration of the extract for 24 hours before initiation of the soft agar cloning procedure, about $99\%$ of the L5178Y cells were killed at concentration of 8 units per ml. 4. The growth rate of mouse embryo cell (as normal cell) was not affected by the culture with media containing various amounts (1.45 to 30.0 ${\mu}g/ml$) of the extract. 5. The crude extract could be purified about four times by silicic acid column chromatography using several solvent systems, and one spot of active compound could be obtained on the thin-layer chromatogram. 6. In the Swiss mice inoculated with Sarcoma 180 cells, a survival time of the experimental group (injection group of active compound) was extended more. 1.5 to 2.0 times than the control group's(no injection group).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.487-490
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• 2004

In this paper, we investigated the characteristics of initiation and propagation behavior for fatigue crack observed by changing various shapes of initial crack and magnitudes of loading in modified compact tension shear(CTS) specimen subjected to shear loading. In the low-loading condition, the secondary fatigue crack was created in the notch root due to friction on the pre-crack face grew to a main crack. In the high-loading condition, fatigue crack under shear loading propagated branching from the pre-crack tip. Influenced by the shear loading condition, fatigue crack propagation retardation appeared in the initial propagation region due to the reduction of crack driving force and friction on crack face. In both cases, however, fatigue cracks grew in tensile mode type. The propagation path of fatigue crack under the Mode II loading was 70 degree angle from the initial crack regardless of its shape and load magnitude.

• Journal of Ocean Engineering and Technology
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• v.6 no.2
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• pp.71-75
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• 1992

기구나 구조물의 피로수명은 노치에서의 피로균열 방생수명에 의하여 지배되기때문에 노치로 인한 피로강도감소계수 $K_f$는 피로설계상 대단히 중요한 인자이다. 노치 선단(Notch root)에서의 피로균열발생명수 N$_c$를 기준으로하면 탄성응력집중계수 $K_t$가 10 정도까지 $K_f$와 $K_t$간에는 거의 직선적인 관계가 있음이 이다- 고에 의하여 명석해졌으나 이는 인장,압축의 축력이 작용하였을 때이며 따라서 기구나 구조부재는 축력외에도 굽힘 피로 하중이 작용하였을때도 많으므로 본 연구에서는 굽힘 피로 하중을 받았을때도 있다. -고의 결론이 적용되는지는 검시코져 본 연구를 실시하였다.

• Current Research on Agriculture and Life Sciences
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• v.27
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• pp.43-52
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• 2009

Most soybean sprouts grown in factories are sold on the market. When the soybean sprouts grow up to lateral root initiation, the rate and absolute amount of asparagine in the roots of all sprouts are comparatively low. To extract the greatest amount of asparagine from soy-sprouts, it is advantageous to grow sprouts more than 16 days. When sprouts were grown with ozonic water, it was possible to grow sprouts more than 16 days without any rotting problems. The content of asparagine in the sprouts were proportionally increased up to 16 days. When sprouts were grown in 0.2% of urea, the content of asparagine in sprouts were significantly increased. Soybean sprouts grown at $20^{\circ}C$ room temperature showed the highest yield rate and asparagine content, at the same time.

• Journal of Korean Society of Steel Construction
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• v.8 no.3 s.28
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• pp.13-20
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• 1996

With the adoption of welded joints rather than bolted joints, we investigate the fatigue strength and the fatigue crack initiation of U-type trough rib and welded specimen with misalignment in a steel deck plate. The stress concentration factor of welded specimens with a misalignment is also verified by a finite element method. The main conclusions obtained from this study are as follows Experimental results of full-scaled U-type trough rib models have indicated that fatigue life depends on misalignments of welded joints in steel deck plate ; The more misalignments are, the less the fatigue life is. It has also shown that fatigue crack propagates from the welded root to the bead surface. We have also obtained the same results from both the fatigue test of welded specimens with a misalignment and the stress analysis of a finite element method.

• Transactions of the Korean Society of Mechanical Engineers
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• v.2 no.1
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• pp.10-18
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• 1978

Kikukawa's compliance method using the conventional crack mouth clip-on gauge was proposed as a desired measurement technique to monitor the notched specimen fatigue behavior. The measurement technique makes it possible to continuously monitor the initiation and growth of incipient small part-through crack originated at the notch root and the phenomenon of crack closure. The variarion of natural flaw geometry with fatigue cycling was investigated. The test results on 7075-T6 aluminium alloy suggest the dependence of effective stress intensity factor range ratio .upsilon. on the maximum stress intensity factor .KAPPA.max.