• Composites Research
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• v.34 no.4
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• pp.241-248
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• 2021

As the electric vehicle market grows, there is an issue of light weight vehicles to increase battery efficiency. Therefore, it is going to replace the battery module cover that protects the battery module of electric vehicles with high strength/high heat-resistant polymer composite material which has lighter weight from existing aluminum materials. It also aims to respond to the early electric vehicle market where technology changes quickly by combining 3D printing technology that is advantageous for small production of multiple varieties without restrictions on complex shapes. Based on the composite material mechanics, the critical length of glass fibers in short glass fiber (GF)/polycarbonate (PC) composite materials manufactured through extruder was derived as 453.87 ㎛, and the side feeding method was adopted to improve the residual fiber length from 365.87 ㎛ and to increase a dispersibility. Thus, the optimal properties of tensile strength 135 MPa and Young's modulus 7.8 MPa were implemented as GF/PC composite materials containing 30 wt% of GF. In addition, the filament extrusion conditions (temperature, extrusion speed) were optimized to meet the commercial filament specification of 1.75 mm thickness and 0.05 mm standard deviation. Through manufactured filaments, 3D printing process conditions (temperature, printing speed) were optimized by multi-optimization that minimize porosity, maximize tensile strength, and printing speed to increase the productivity. Through this procedure, tensile strength and elastic modulus were improved 11%, 56% respectively. Also, by post-processing, tensile strength and Young's modulus were improved 5%, 18% respectively. Lastly, using the FEA (finite element analysis) technique, the structure of the battery module cover was optimized to meet the mechanical shock test criteria of the electric vehicle battery module cover (ISO-12405), and it is satisfied the battery cover mechanical shock test while achieving 37% lighter weight compared to aluminum battery module cover. Based on this research, it is expected that 3D printing technology of polymer composite materials can be used in various fields in the future.

• Tuberculosis and Respiratory Diseases
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• v.64 no.1
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• pp.8-14
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• 2008

Background: Acinetobacter infections are difficult to treat as they often exhibit multiple resistance to the antibiotics that are currently available for the treatment of pneumonia. Colistin is active against gram-negative bacteria, including the multiple drug resistant (MDR) Acinetobacter species. However, intravenous administration of colistin was abandoned because of its nephrotoxicity and neurotoxicity. The aims of this study were to examine the efficacy and safety of colistin administered by aerosol in the treatment of pneumonia caused by MDR Acinetobacter baumannii. Methods: We retrospectively reviewed the medical records of patients admitted to the intensive care unit (ICU) from Dec. 2006 to Aug. 2007 who had been diagnosed as suffering from pneumonia due to MDR Acinetobacter baumannii and had been treated with nebulized colistin. Results: 31 patients received aerosolized colistin. The average duration of the treatment was $14{\pm}7$ days and the daily dose of ranged from 225 mg to 300 mg. All patients received concomitant intravenous antimicrobial agents. The average length of the stay in the ICU was $34{\pm}21$ days and in the hospital $58{\pm}52$ days. The overall microbiological eradication was observed in 25 patients (80.6%). 14 of these (56%) were cured, and 11 (44%) were infected with other microorganisms. The overall crude mortality of the ICU was 48%. Nephrotoxicity and significant bronchial constriction did not occur in any patient during neublized colistin treatment. Conclusion: Nebulized colistin may be a safe and effective option in the treatment of pneumonia due to MDR Acinetobacter baumannii. Its role in therapy warrants further investigation in comparative studies.

• Tuberculosis and Respiratory Diseases
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• v.64 no.2
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• pp.102-108
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• 2008

Background: Recently, multidrug-resistant (MDR) A. baumannii has been implicated for a significant proportion of nosocominal pneumonia in many intensive care units (ICUs), and its acquisition may increase mortality and the length of stay in the ICU. Aerosolized colistin has been successfully used in patients with cystic fibrosis, but there is a lack of data regarding the use of aerosolized colistin in patients with nosocomial pneumonia. Methods: We conducted the present study to assess the effectiveness of aerosolized colistin for the treatment of MDR A. baumannii nosocomial pneumonia. We retrospectively reviewed the medical records of 10 patients who had been hospitalized in the medical ICU and had received aerosolized colistin as a therapy for MDR A. baumannii pneumonia. Results: The mean duration of aerosolized colistin therapy was $12.7{\pm}2.4$ days. Nine (90%) of 10 patients showed a favorable response to the therapy. Follow-up cultures were available for all patients, and the responsible pathogen was completely eradicated. One patient suffered from bronchospasm, which resolved after treatment with nebulized salbutamol. Conclusion: Our results corroborate previous reports that aerosolized colistin may be an effective and safe choice for the treatment of nosocomial pneumonia caused by MDR A. baumannii. Larger prospective controlled clinical studies are warranted to validate further the effectiveness and safety of aerosolized colistin therapy.

• Horticultural Science & Technology
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• v.29 no.5
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• pp.474-481
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• 2011

Potato late blight caused by the fungus Phytophthora infestans is one of the most vital diseases damaging the potato plant. It is for this reason that breeding potato cultivars resistant to late blight is now becoming a major concern around the world. The B3C1 clones has been introduced by the Highland Agriculture Research Center, RDA. The clones which came from International Potato Center in 2005 have a durable resistance to late blight. The clones were bred under a short-day condition in Peru. However, there was still no report on the adaptability of these clones to the long-day condition in Korea. Therefore, this study was conducted to evaluate the late blight resistance and major agronomic characteristics of B3C1 clones under Korea's long-day condition. This study was also done to generate genetic resources for developing new varieties resistant to late blight. In this study it was found out that in naturally infested field with P. infestans, AUDPC (area under disease progress curve) values of all B3C1 clones were significantly lower than those of the control varieties, 'Superior', 'Atlantic', and 'Haryeong'. It was found out that B3C1 clones had a high level of resistance to late blight and that they could be used as genetic resources to breed potato varieties with late blight resistance. However, several undesirable characteristics such as extremely late maturity, excessive growth of stems and stolons, and production of tubers that cannot easily be removed from the stolons were also observed. Among the twenty B3C1 clones, two clones, LB-8 (CIP393077.159) and LB-11 (CIP393371.159), were selected for cultivating at the highland area of Korea. Two B3C1 clones were crossed with Korean breeding lines and clonal selection for the progenies is still in progress.

• Journal of Chest Surgery
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• v.31 no.11
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• pp.1063-1069
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• 1998

Background: Multi-loculated empyema makes treatment difficult, and more so when thoracentesis or chest tube drainage fails. Materials and methods: From December 1991 to December 1997, we performed closed rib resectional drainage for 18 cases of loculated empyema on the fibrinopurulent or early chronic phase. Results: Surgery was performed on patients with loculated empyema complaining of persistent symptoms due to failure of treatment by thoracentesis(8 cases) or chest tube drainage(10 cases). Predisposing factors of empyema were pneumonia in 13 cases, clotted hemothorax in 3 cases, cholecystectomy, and tuberculous pleurisy in 1 case. Causal organisms were cultured in 8 cases(42.1%), and methicillin-resistant staphylococcus aureus was found in 3 cases, pseudomonas aeruginosa in 2 cases, and enterococcus aerogens, α-hemolytic streptococcus, and acinetobacter baumannii were found in 1 case. Size of loculations was various, and computed chest tomogram showed multiple loculations of empyema numbering 1∼4(mean 1.78±1.00). Operating time was relatively short, about 55∼140 mins(mean 102.8±30.8). All toxic symptoms including fever disappeared postopratively and general conditions improved very quickly in all patients. Length of chest tube indwelling time and hospital stay after surgery were 3∼42 days(mean 11.4±11.5) and 6∼36 days(mean 12.9±8.1), respectively. Complications of prolonged drainage occurred in 2 cases and no death occurred. There were no recurrences and chest x-rays taken 3∼6 months after surgery showed normal findings in 14 cases and slight pleural thickening in 4 cases. Conclusions: Closed rib resectional drainage requires very simple techniques and has excellent outcomes and little complications, therefore, we think that it is the choice of operation for patients with loculated empyema on the fibrinopurulent or early chronic phase.

• Research in Plant Disease
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• v.16 no.1
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• pp.21-26
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• 2010

Viral diseases, especially Barley yellow mosaic virus (BaYMV) and Barley mild mosaic virus (BaMMV) have been most serious in barley fields. In this study, we investigated the effect of different level of resistance to viral diseases on the plant growth and yield in malting barley. In diagnosis of virus infection, BaYMV and BaMMV were detected in 'Doosan 29' (susceptible), however, 'Jinyangbori' (moderate susceptible) and 'Hopumbori' (moderate) was infected by only BaYMV. Plant height was restrained about 8~29% in overwintered plant regeneration stage depending on the resistant of each cultivar. The culm length damaged also to 9~12% by BaYMV infection. The tiller numbers reduced to 10~14% in overwintering season, however, the head numbers in harvest season more decreased to 26~33%. Heading date was delayed to 3~3 days by the infection. In examination of yield components, 1,000 kernel weight and $\ell$ weight reduced according to culrivar's resistant degrees to 4.0~6.4% and 1.0~4.2%, respectively. The yield of abortive grain was doubled in BaYMV infection comparing to non-infested field. Three varieties tested in the non-infected field over two years were not significantly different for yield potential with ranges of 509kg~632kg/10a. However, significant yield reduction was observed in 'Saessalbori' and 'Baegdong' with ranges of 77~177kg/10a as compared to 'Hopumbori' (467 kg/10a) when tested in the virus-infected field. Yield potentials of these cultivars reduced by 26~43%, respectively, in the virus-infected field as compared to those in the non-infected field.

• Journal of Korean Society of Forest Science
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• v.65 no.1
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• pp.1-11
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• 1984

Susceptible trees of Pinus densiflora and resistant trees of Pinus rigida following pine gall midge (Tnecodiplosis japonensis Uchida et Inouye) attack were seasonally compared to examine the variation in needle growth and photosynthetic ability, respiration rate, chlorophyll contents, carotenoid and anthocyanin contents. Also, carotenoid and anthocyanin contents of larvae both from soil and from galled tissue were compared during March and September, respectively. The plantation damaged severely by this insect consisted mostly of 10-to 15-year old P. rigida and P. densiflora. The results obtained in this study were as follows: 1) The length of the infested needles of P. densiflora decreased by 48.1 percent compared with the normal needles, while that of P. rigida did 37.4 percent. 2) All of P. densiflora and P. rigida showed higher photosynthetic ability in normal needles than in infested needles. The maximum photosynthetic ability of P. densiflora was shown in mid-August, while that of P. rigida in mid-October. In contrast to that, respiration rate of infested needles was higher than that of normal needles in both species. The respiration rate of P. rigida was higher than that of P. densiflora. 3) P. rigida had higher total chlorophyll contents than P. densiflora. The total carotenoid contents tents in infested needles were higher than those in normal needles of both species. 4) Total carotenoid contents were generally higher in P. rigida than in P. densiflora during the growing season. The total carotenoid content (0.094mg/g) in larvae from soil was similar to that (0.092mg/g) in larvae from galled tissues. 5) Infested needles of both species showed higher anthocyanin contents than normal needles. Higher anthocyanin contents in galled needles were due primarily to its active formation stimulated by larval attack. Thus, reddish-brown coloration occurred only in galled needles of P. densiflora.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.3
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• pp.249-255
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• 1987

To find out the optimum planting date of silage corn in the rice black-streaked dwarf virus (RBSDV) pre-valent area, a resistant hybrid of Jinjuok and a susceptible hybrid of Suweon 19 were planted at the 8 planting dates from April 1 to June 10 at the la-day intervals. Considering escape of RBSDV and silage yield, the optimum planting date seems to be during the April in both hybrids. At the April plantings silage yield of two hybrids ranged from 17 to 23 tons/ha on the dry matter base due to a lower infection rate and higher tolerance to RBSDV and there was no difference in silage yield between two hybrids. At the May plantings yield of ear, stover, and silage, culm length, and digestible dry matter decreased significantly as planting date delayed due to an increase in RBSDV infection rate in both hybrids although performance of a resistant hybrid of Jinjuok was better than a susceptible hybrid of Suweon 19. At the June 10 planting RBSDV infection rate was low and performance of corn was better than that at the May plantings but poorer than that at the April plantings. The peak of small brown planthopper population occurred in late March or early April, middle June, middle July, and early September although it fluctuated a little yearly. Very low small brown planthopper population during the May may attribute to a lower RBSDV infection and high silage yields at the April plantings because the plants grow enough to be tolerant when infected by RBSDV in middle June. However, at the May plantings plants are too young to be tolerant when infected by RBSDV in middle June.

• Tuberculosis and Respiratory Diseases
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• v.50 no.4
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• pp.473-483
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• 2001

Background : There are only a few studies regarding the causes of treatment failure for tuberculosis. Therefore, this study aimed to determine the causes of intractable tuberculosis. Methods : M. tuberculosis, differentiated MOTT (Mycobacterium Other Than Tuberculosis) were isolated, and the RFLP (Restriction fragments length polymorphisms) pattern was analyzed from 204 patients with pulmonary tuberculosis and 53 suffering from neck tuberculosis. The IL-$1{\beta}$, IL-12, $^*1\;IFN{\gamma}$ and $^*2\;TNF{\alpha}$ blood levels were measured. All patients were regularly followed for 18 months after treatment. Results : There was no correlation between the RFLP patterns of M. tuberculosis treatment failure. From the 204 cases, 31.9% were intractable. The characteristics of patients with intractable tuberculosis were old age, being male and recurrent cases. The causes of treatment failure were identified as follows ; a decrease in the IL-12(59.4%) concentration, drug resistant strain(54.7%), irregular medication(15.4%), MOTT(6.2%) and a heavy infection(4.6%). The causes of all cases of intractable tuberculosis could be investigated. The IL-12 concentration in the blood was significantly lower in the intractable cases, where it disclosed a maximum sensitivity(64.7%) and specificity(75.4%) at 165.0 pg/mL. Most of the 53 cases of neck node tuberculosis were treated successfully. Therefore, we were unable to analyze the cause of treatment failure. Conclusion : A decrease in the blood IL-12 concentration and drug resistant strains were identified as the most significant causes of treatment failure for tuberculosis. In Korea, infection by clusters were prevalent, but no difference in the clinical course between clusters and non-clusters could be found.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.547-551
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• 2009

A new commercial rice variety "Chilbo" is a japonica rice (Oryza sativa L.) with resistance to rice stripe virus and high grain quality. It was developed by the rice breeding team of Yeongdeog Substation, NICS, RDA in 2007. This variety was derived from a cross between "Yeongdeog 26" with wind tolerance and lodging resistance and "Koshihikari" with good grain quality. A promising line, YR21324-119-3-2 was selected by a pedigree breeding method and designated as "Yeongdeog 44" in 2004. Regional adaptation yield trials were carried out at eleven locations from 2005 to 2007. As a result, "Yeongdeog 44" was released as a high yielding rice variety with high grain qualilty and virus resistance with the name of "Chilbo". It is short 76cm in culm length and has medium-late growth duration. This variety is resistant to stripe virus and middle resistant to leaf blast disease. It is also tolerant to cold, dried wind. Milled rice kernel of "Chilbo" is translucent, clear in chalkiness. Panel test proved that and it has good eating quality. Head rice ratio of Chilbo is high compared to the check variety, Hwaseongbyeo. Yield potential of "Chilbo" in milled rice is about 5.57MT/ha at ordinary fertilizer level of local adaptability test. This variety would be adaptable to Yeongnam plain, south & east-south coastal, south mid-mountainous, middle plain area of Korean peninsula.