• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.287-294
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• 2015

Relationship between growth rate and wood quality was investigated by mechanical properties with Alnus glutinosa L. (24 years old) from 4 different origins of seeds (Bulgary, Italy, United Kingdom and Yugoslavia). Compression strength was in the range of $231{\sim}326kgf/cm^2$, and there was some differences among different origins of seed. Wood cultivated from the seeds of Italy, United Kingdom, and Bulgary showed higher growth rate and had lower compression strength and compression young's modulus. Wood from Yugoslavia seed had the fastest growth rate with higher strength than other three origins of seed. Bending strength was in the range of $426{\sim}727kgf/cm^2$, and there was some differences among the origin of seed. Higher growth rate wood showed higher bending strength and young's modulus than other woods. Trees cultivated from Yugoslavia seed had two times in diameter than other different origins of seeds, also have compressive strength, bending strength than other origins, which can be recommended as best cultivar in Alnus glutinosa L.

• Journal of Korean Neurosurgical Society
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• v.51 no.5
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• pp.272-275
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• 2012

Objective : Choroid plexus papillomas (CPPs) are generally regarded as benign tumors with typical radiologic and pathologic findings. However, they sometimes have unusual findings. We have analyzed radiologic findings and pathologic growth patterns on CPPs. Methods : The study group included 5 male and 5 female patients (age range, 3 months to 58 years : median, 29 years). The study group included 3 pediatric and 7 adult patients. All patients underwent surgery; 9 patients had a gross total resection and 1 patient had a subtotal resection. We analyzed the radiologic findings (location, size, mottle-like appearance, enhancement, calcifications, and hydrocephalus) and pathologic growth patterns (typical papillary, papillary and solid, and papillary and tubular). Results : The median follow-up duration was 21.3 months (range, 4-47.8 months). There were no recurrences after initial treatment. All patients had benign CPPs. Pediatric CPPs were 3.2 cm masses (range, 2.7-4 cm) with homogeneous enhancement and a mottle-like appearance, which pathologically showed the papillary growth pattern. Hydrocephalus was present in all pediatric patients. Postoperatively, subdural hygroma had occurred in two patients. In adults, CPPs were located in the fourth ventricle in 6 patients and suprasellar area in 1 patient. The size varied from 0.5-4.2 cm. Hydrocephalus and calcifications occurred in 3 and 4 patients, respectively. Three patients showed the heterogeneous enhancement without a mottle-like appearance and pathologically showed combined papillary and solid growth in 2 patients and papillary and tubular growth in one. Postoperatively, two patients with large masses had injuries of the brainstem and underwent shunt procedures for aggravation of hydrocephalus. Conclusion : CPPs may show unusual radiologic findings, which preoperatively give the difficulty to be differentiated from other tumors. CPPs with unusual radiologic findings showed the combined pathologic growth patterns.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.8
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• pp.1198-1205
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• 2017

Objective: An experiment was conducted to isolate and identify new methanogens in Korea from an anaerobic digester that uses pig slurry. Methods: An anaerobic digestate sample was collected from an anaerobic digester using pig slurry. Pre-reduced media were used for the growth and isolation of methanogens. Growth temperature range, pH range, NaCl concentration range, substrate utilization, and antibiotic tolerance were investigated to determine the physiological characteristics of isolated methanogens. The isolates were also examined microscopically for their morphology and Gram-stained. Polymerase chain reaction of 16S rRNA and mcrA gene-based amplicons was used for identification purpose. Results: Four strains, designated KOR-3, -4, -5, and -6, were isolated and were non-motile, irregular coccoid, and 0.5 to $1.5{\mu}m$ in diameter. Moreover, the cell walls of isolated strains were Gram-negative. KOR-3 and KOR-4 strains used acetate for methane production but did not use $H_2+CO_2$, formate, or methanol as a growth substrate KOR-5 and KOR-6 strains utilized acetate, methanol, and trimethylamine for methanogenesis but did not use $H_2+CO_2$ or formate as a growth substrate. The optimum temperature and pH for growth of four strains were $39^{\circ}C$ and 6.8 to 7.2, respectively. The optimum concentration of NaCl for growth of KOR-3, KOR-5, and KOR-6 were 1.0% (w/v). The optimum NaCl concentration for KOR-4 was 0.5% (w/v). All of the strains tolerated ampicillin, penicillin G, kanamycin, streptomycin, and tetracycline; however, chloramphenicol inhibited cell growth. Phylogenetic analysis of 16S rRNA and mcrA genes demonstrated that strains KOR-3, -4, -5, and -6 are related to Methanosarcina mazei (M. mazei, 99% sequence similarity). Conclusion: On the basis of physiological and phylogenetic characteristics, strains KOR-3, -4, -5, and -6 are proposed to be new strains within the genus Methanosarcina, named M. mazei KOR-3, -4, -5, and -6.

• The Plant Pathology Journal
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• v.21 no.1
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• pp.7-12
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• 2005

Plant growth-promoting rhizobacteria (PGPR) are a wide range of root-colonizing bacteria with the capacity to enhance plant growth and control plant pathogens. Here we review recent progress that indicate some PGPR strains release a blend of volatile organic compounds (VOCs) that promote growth in Arabidopsis seedlings and induce resistance against Erwinia carotovora subsp. carotovora. In particular, the volatile components 2,3-butanediol and acetoin released exclusively from the PGPR strains triggered the greatest level of growth promotion and induced systemic resistance. Pharmacological applications of 2,3-butanediol promoted the plant growth and induced resistance, while bacterial mutants blocked in 2,3-butanediol and acetoin synthesis was devoid of growth-promotion and induced resistance capacities. The results suggested that the bacterial VOCs play a critical role in the plant growth promotion and induced resistance by PGPR. Using transgenic and mutant lines of Arabidopsis, we provide evidences that the signal pathway activated by volatiles from one PGPR strain is dependent on cyto-kinin activation for growth promotion and dependent on an ethylene-signaling pathway for induced pathogen resistance. This discovery provides new insight into the role of bacterial VOCs as initiators of both plant growth promotion and defense responses in plants.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.06a
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• pp.149-155
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• 1997

We have successfully grown colorless and transparent Rb-doped potassium niobate (KRN) single crystals using the top seeded solution growth(TSSG) technique. In our crystal growth experiments, the Rb doping concentrations within the melt range from 2-15 mol% relative to that of Nb$_2$O5. Atomic absorption measurements indicate that the Rb content in the KRN solid solution is rather low; the Rb segregation coefficient is found to be on the order of 0.05. It is believed that this is due to the relatively much larger Rb+ ionic radius compared to that of K+, rendering it more difficult for Rb to replace K in the KNbO$_3$(KN) host lattice. Preliminary single-pass second harmonic generation (SHG) experimental results indicate that there exists marginal improvement in the phase-matching temperature tolerance of KRN compared to that of pure Kn single crystals.

• Journal of Ginseng Research
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• v.14 no.2
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• pp.107-111
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• 1990

Ginseng root explants and calli were cultured on modified Murashine and Skoog's media supplemented with different concentrations of organic or inorganic compounds and plant growth requlators to clarify the effects of chemical compositon and plant growth regulators in the medium on the growth of ginseng calli and the production of ginseng saponin. For optimum growth of ginseng calli, the concentrations of 2, 4-D and sucrose were in the range of 1 to 5 mg/l and 1 to 3%, respectively. And it was clarified that sucrose, nitrogen, phosphate, calcium, magnesium, plant growth regulators and their concentrations influcenced the relative biosynthesis of saponin in tissue cultures of Panax ginseng.

• Journal of Welding and Joining
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• v.12 no.3
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• pp.82-89
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• 1994

In this paper the effect of stress ratio on the fatigue crack growth rate of aluminum alloy A5083-O was examined. The fatigue tests were carried out using CCT (center cracked tension) specimens and CT(compact tension) specimens which were subjected to 0.5 and -1.0 stress ratio respectively. The obtained results are as follows; 1) The $\DeltaK_{th}$ as the function of stress ratio R was introduced in evaluating the fatigue crack growth rate of A5083-O. 2) A new model evaluating the effect of stress ratio on the fatigue crack growth rate was developed over the region of low and high propagation rate.

• Journal of Veterinary Clinics
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• v.20 no.3
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• pp.403-405
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• 2003

A 11 month-old Shihtzu was referred to the Veterinary Medical Teaching Hospital, Seoul National University. Clinical signs of this patient were lameness, shortening limb, angular deformity, rotation of foot, subluxaion of elbow joint and restricted range of movement of left forelimb. For the evaluation of the abnormalities of left forelimb, radiographic examination was carried out. Radiographic findings were characteristics of premature closure of distal ulna such as closure of distal ulna growth plate and cranial bowing of radius. With radiographic signs and physical examination, it was diagnosed as premature closure of growth plate of the left forelimb. After osteotomy of the radius and ostectomy of the ulna, radiographic evaluation of limb about angulation of elbow joint was performed every 2-3 weeks for 3 months. In case of premature closure of distal growth plate of ulna, radiography was very useful for diagnositic method of premature closure of distal ulna and monitoring of healing process.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.365-372
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• 2001

This study is concerned with the application of an analytical model of cyclic crack growth that includes the effects of crack closure. The crack closure model is based on the Dugdale model and the strip model, considering the plasticity-induced closure which is caused by residual plastic deformation remaining in the wake of an advancing crack. This study is performed to get the relation between crack growth and crack opening stress with the constant stress ratio, and the relation between stress ratio and crack opening stress with the constant maximum stress under constant-amplitude loading. Under constant-amplitude loading, the crack opening stress is conversed the constant value as a crack grows and is proportion to both the stress ratio and the maximum stress. The crack closure effect, however, is decreased in the positive stress ratio and disappeared at about 0.7. The crack growth analysis using the crack closure model shows that the influence of stress ratio is minimized in the relation between crack growth ratio and effective stress intensity range specially at the negative stress ratio.

• Korean Journal of Microbiology
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• v.10 no.1
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• pp.1-8
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• 1972

This experiment was carried out to investigate the physiological characteristics of isolated bacteria, Ferrobacillus ferooxidans from copper mine water in Korea. The results obtained were as follows ; 1. The optimum pH range for the growth of these bacteria was 2.0-3.0 and optimum temperature was $20^{\circ}C$-$30^{\circ}C$. 2. The oxidation curves of ferrous iron to the ferric iron ran parallel with the growth curves. 3. The optimum nitrogen concentration was 400-800 ppm and the minimal flow rate of air for the maximal growth of the bactria was 70 ml air/min./200ml medium. 4. The growth of these bacteria was inhibited by the absence of ferrous iron and by the addition of sulfur. 5. Ferrous iron at a concentration of 9000 ppm, appeared to be optimum for the most rapid growth of Ferrobacillus ferrooxidans.