• Journal of Microbiology and Biotechnology
• /
• v.18 no.2
• /
• pp.234-241
• /
• 2008

Agrobacterum tumefaciens-mediated transformation (ATMT) is becoming an effective system as an insertional mutagenesis tool in filamentous fungi. We developed and optimized ATMT for two Colletotrichum species, C. falcatum and C. acutatum, which are the causal agents of sugarcane red rot and pepper anthracnose, respectively. A. tumefaciens strain SK1044, carrying a hygromycin phosphotransferase gene (hph) and a green fluorescent protein (GFP) gene, was used to transform the conidia of these two Colletotrichum species. Transformation efficiency was correlated with co-cultivation time and bacterial cell concentration and was higher in C. falcatum than in C. acutatum. Southern blot analysis indicated that about 65% of the transformants had a single copy of the T-DNA in both C. falcatum and C. acutatum and that T-DNA integrated randomly in both fungal genomes. T-DNA insertions were identified in transformants through thermal asymmetrical interlaced PCR (TAIL-PCR) followed by sequencing. Our results suggested that ATMT can be used as a molecular tool to identify and characterize pathogenicity-related genes in these two economically important Colletotrichum species.

• Clinical and Experimental Pediatrics
• /
• v.59 no.12
• /
• pp.471-476
• /
• 2016

Purpose: Chest radiography is often performed on patients hospitalized with typical clinical manifestations of bronchiolitis. We aimed to determine the proportion of subjects with pathologic chest radiographic findings and the clinical predictors associated with pathologic chest radiographic findings in young children admitted with the typical presentation of bronchiolitis. Methods: We obtained the following data at admission: sex, age, neonatal history, past history of hospitalization for respiratory illnesses, heart rate, respiratory rate, the presence of fever, total duration of fever, oxygen saturation, laboratory parameters (i.e., complete blood cell count, high-sensitivity C-reactive protein [hs-CRP], etc.), and chest radiography. Results: The study comprised 279 young children. Of these, 26 had a chest radiograph revealing opacity (n=24) or atelectasis (n=2). Multivariate logistic regression analysis showed that after adjustment for confounding factors, the clinical predictors associated with pathologic chest radiographic findings in young children admitted with bronchiolitis were elevated hs-CRP level (>0.3 mg/dL) and past history of hospitalization for respiratory illnesses (all P<0.05). Conclusion: The current study suggests that chest radiographs in young children with typical clinical manifestations of bronchiolitis have limited value. Nonetheless, young children with clinical factors such as high hs-CRP levels at admission or past history of hospitalization for respiratory illnesses may be more likely to have pathologic chest radiographic findings.

• Radiation Oncology Journal
• /
• v.37 no.2
• /
• pp.82-90
• /
• 2019

Purpose: To evaluate the results of hypofractionated radiotherapy (HFX) for early glottic cancer. Materials and Methods: Eighty-five patients with cT1-2N0M0 squamous cell carcinoma of the glottis who had undergone HFX, performed using intensity-modulated radiotherapy (IMRT, n = 66) and three-dimensional conformal radiotherapy (3D CRT, n = 19) were analyzed. For all patients, radiotherapy was administered at 60.75 Gy in 27 fractions. Forty-three patients received a simultaneous integrated boost (SIB) of 2.3-2.5 Gy per tumor fraction. Results: The median follow-up duration was 29.9 months (range, 5.5 to 76.5 months). All patients achieved complete remission at a median of 50 days after the end of radiotherapy (range, 14 to 206 days). The 5-year rates for locoregional recurrence-free survival was 88.1%, and the 5-year overall survival rate was 86.2%. T2 stage was a prognostic factor for locoregional recurrence-free survival after radiotherapy (p = 0.002). SIB for the tumor did not affect disease control and survival (p = 0.191 and p = 0.387, respectively). No patients experienced acute or chronic toxicities of ≥grade 3. IMRT significantly decreased the dose administered to the carotid artery as opposed to 3D CRT (V₃₅, p < 0.001; V₅₀, p < 0.001). Conclusions: Patients treated with HFX achieved acceptable locoregional disease control rates and overall survival rates compared with previous HFX studies. A fraction size of 2.25 Gy provided good disease control regardless of SIB administration.

• Composites Research
• /
• v.30 no.4
• /
• pp.247-253
• /
• 2017

In this study, the mechanical behavior and interface properties of boron nitride nanotube-poly(methyl methacrylate) nanocomposites are predicted using the molecular dynamics simulations and the double inclusion model. After modeling nanocomposite unit cell embedding single-walled nanotube and polymer, the stiffness matrix is determined from uniaxial tension and shear tests. Through the orientation average of the transversely isotropic stiffness matrix, the effective isotropic elastic constants of randomly dispersed microstructure of nanocomposites. Compared with the double inclusion model solution with a perfect interfacial condition, it is found that the interface between boron nitride nanotube and polymer matrix is weak in nature. To characterize the interphase surrounding the nanotube, the two step domain decomposition method incorporating a linear spring model at the interface is adopted. As a result, various combinations of the interfacial compliance and the interphase elastic constants are successfully determined from an inverse analysis.

• Korean Chemical Engineering Research
• /
• v.56 no.3
• /
• pp.376-380
• /
• 2018

The astaxanthin recovery efficiencies were compared in acetonitrile, acetone, methanol, dichloromethane : methanol (1:3, v/v) and ethylacetate : ethanol (1:1, v/v) as a extraction solvent after the grinding of the H. pluvialis cells. The astaxanthin extraction yield in acetone was 1.13~1.29 times higher than other extraction solvents. It was also found that 96.7% of astaxanthin accumulated in H. pluvialis could be recovered by a single extraction. Since astaxanthin exists mainly as astaxanthin esters in H. pluvialis, a gradient reversed-phase HPLC analysis was carried out for the separation of astaxanthin esters from the extracts of H. pluvialis. Among the astaxanthin inside the H. pluvialis cell, free astaxanthin was 45.9% and astaxanthin esters were the rest.

• Journal of the Korean Ceramic Society
• /
• v.44 no.12
• /
• pp.696-702
• /
• 2007

The family of (Sr,Mg)-doped $LaGaO_3$ compounds, which exhibit high ionic conductivity at $600-800^{\circ}C$ over a wide range of oxygen partial pressure, appears to be promising as the electrolyte for intermediate temperature solid oxide fuel cells. Conventional synthesis routes of (Sr,Mg)-doped $LaGaO_3$ compounds based on solid state reaction have some problems such as the formation of impurity phases, long sintering time and Ga loss during high temperature sintering. Phase stability problem especially, the formation of additional phases at the grain boundary is detrimental to the electrical properties of the electrolyte. From this point of view, we focused to synthesize single phase (Sr,Mg)-doped $LaGaO_3$ electrolyte at the stage of powder synthesis and to apply relatively low heat-treatment temperature using novel synthesis route based on combustion method. The synthesized powder and sintered bulk electrolytes were characterized by XRD, TG-DTA, FT-IR and SEM. AC impedance spectroscopy was used to characterize the electrical transport properties of the electrolyte with the consideration of the contribution of the bulk lattice and grain boundary to the total conductivity. Finally, relationship between synthesis condition and electrical properties of the (Sr, Mg)-doped $LaGaO_3$ electrolytes was discussed with the consideration of phase analysis results.

• KSBB Journal
• /
• v.31 no.4
• /
• pp.246-255
• /
• 2016

Co-production of 3-hydroxypropionic acid (3-HP) and 1,3-propanediol (1,3-PDO) was suggested as an innovative strategy to overcome several limitations occurring in the single production of 3-HP from glycerol. In this study, two new isolates of Klebsiella pneumoniae, which produce less lipopolysaccharide (LPS) thus considered less pathogenic than K. pneumoniae DSM 2026, were compared and evaluated for their potential for the co-production of 3-HP and 1,3-PDO. The newly isolated strains showed significantly faster sedimentation rate than DSM, which should be beneficial for downstream processing. Analysis of genome sequences of the isolates confirmed the presence of all genes necessary for glycerol assimilation, 1,3-PDO production and biosynthesis of coenzyme $B_{12}$. Co-production yield was highest under anaerobic condition while cell growth was highest under aerobic condition. Both strains showed similarly good performance for the co-production although J2B gave the slightly higher co-production yield of 0.80 mol/mol than GSC021 (0.75 mol/mol). The evaluation of the newly developed strains presented here should be useful in designing similar evaluation experiments for other microorganisms.

• Journal of the Korean Electrochemical Society
• /
• v.12 no.1
• /
• pp.34-39
• /
• 2009

In this study, a needle coke was oxidized in a mixture of dilute nitric acid and sodium chlorate ($NaClO_3$) solutions and followed by heat treatment. The samples were analyzed with using XRD, FESEM, elemental analyzer, BET, and Raman spectroscopy. Double layer capacitance was measured with the charge and discharge measurements. The consisting layers of the needle coke were expanded to single phase showing only (001) diffraction peak by the acid treatment for 24 hours. The oxidized coke returned to a graphite structure appearing (002) peak after heat treatment above $200^{\circ}C$. The structure returned could be more easily accessible to the ions by the first charge, and improve the double layer capacitance at the second charge. The two-electorde cell from acid treated coke and $300^{\circ}C$ heat treatment exhibited the maximum capacitances of 32.1 F/g and 29.5 F/ml at the potential of $0{\sim}2.5\;V$.

• Clinical and Experimental Pediatrics
• /
• v.59 no.6
• /
• pp.252-255
• /
• 2016

Purpose: Pneumocystis jirovecii pneumonia occurs in various immunocompromised patients. Despite the prophylaxis strategies in clinical practice, certain patients develop P. jirovecii pneumonia. This study was performed to investigate pediatric cases with P. jirovecii pneumonia in a single center. Methods: We identified pediatric patients younger than 19 years with microbiologically confirmed P. jirovecii pneumonia from January 2000 to February 2014. A retrospective chart review was performed. Results: Fifteen episodes of P. jirovecii pneumonia in 14 patients were identified with median age of 8.3 years (range, 0.4-18.6 years). Among these patients, 11 patients had hematology-oncology diseases, 2 had primary immunodeficiency disorders (one with severe combined immunodeficiency and the other with Wiskott Aldrich syndrome), 1 had systemic lupus erythematosus and 1 received kidney transplant. Four patients were transplant recipients; 1 allogeneic and 2 autologous hematopoietic cell transplant and 1 with kidney transplant. The median absolute lymphocyte count at the diagnosis of P. jirovecii pneumonia was $5,156cells/mm^3$ (range, $20-5,111cells/mm^3$). In 13 episodes (13 of 15, 86.7%), patients were not receiving prophylaxis at the onset of P. jirovecii pneumonia. For treatment, trimethoprim/sulfamethoxazole was given as a main therapeutic agent in all 15 episodes. Steroid was given in 9 episodes (60%). Median treatment duration was 15 days (range, 4-33 days). Overall mortality at 60 days was 35.7% (5 of 14). Conclusion: Majority of our patients developed P. jirovecii pneumonia while not on prophylaxis. Continuous efforts and more data are needed to identify high risk patients who may get benefit from P. jirovecii pneumonia prophylaxis.

• Biomedical Science Letters
• /
• v.16 no.4
• /
• pp.365-376
• /
• 2010

The purpose of this study was to clarify the effect of light emitting diode (LED) irradiation on healing of impaired wound and alteration of mast cells in experimental diabetic rats. Twenty-four male Sprague-Dawley rats were divided into four groups: excision (Ex), excision-LED irradiation (Ex-LED), diabetes + excision (DM) and diabetes + excision + LED irradiation (DM-LED). Diabetes was induced in rats by streptozotocin (STZ) injection (70 mg/kg, single dose) and 6 mm punch excision wounds were created on the back after shaving hair. The LED-irradiated rats were treated to a daily dose of $5\;J/cm^2$ LED (630 nm) light for 11 days after surgery, and were killed at day 1, 3, 7 and 11. The lesion and adjacent skin tissues were excised, fixed with 10% buffered formalin and embedded with paraffin. For evaluation of wound healing, hematoxylin-eosin (HE) and Masson trichrome staining were performed. Mast cells (MCs) were stained with toluidine blue (pH 0.5) and quantified using a computerized image analysis system. The proliferation activity of keratinocyte in skin tissues was analyzed on sections immunostained with proliferative cell nuclear antigen (PCNA). The results showed that wound healing rate, collagen density and neo-epidermis length, number of PCNA-positive cells, fibroblasts and mast cells were significantly higher in the LED-irradiated rats than in the DM and Ex rats throughout the periods of experiment. Exceptionally, the number of MCs was significantly lower at day 11 compared with day 7 after surgery in the all groups. These findings suggest that the LED irradiation may promote the tissue repair process by accelerating keratinocyte and fibroblast proliferation and collagen production in normal rats as well as in diabetic rats, and MCs may play an important role at an early stage of skin wound healing in normal and diabetic rats.