• Microbiology and Biotechnology Letters
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• v.38 no.4
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• pp.373-378
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• 2010

Studies on standardization and quality upgrade of nuruk which is a basic component in brewing are required to increase the quality level of Korean traditional rice wines and to develop the technology for practical use of it. It is important to isolate best strains, to improve the properties and effectively preserve them for brewing industry. In this study, 16 commercial nuruk samples were obtained from the commercial markets located in Chungcheong areas in Korea. 174 fungal strains were isolated from the samples on DG18 medium using a dilution plating method and then screened for enzyme activity and acid production. The active strains were identified based on the morphological characteristics and ITS sequence analysis. Out of 174 strains, 12 strains showed high amylase activity. Especially, Rhizopus sp. CN084, CN174, Aspergillus sp. CN161 and Mycocladus sp. CN042 showed high saccharogenic power and dextrinogenic enzyme activity on cooked wheat bran medium. On the other hand, Aspergillus sp. CN010, CN161, Rhizopus sp. CN105, CN168 and Rhizomucor sp. CN088 produced high acid production on the same medium. Our results showed that the active strains may be used as microbial sources for nuruk starter with good quality in brewing.

• Korean Journal of Optics and Photonics
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• v.12 no.5
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• pp.347-351
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• 2001

The neutral sodium atoms have been slowed down to the trap depth by using a Zeeman slower and trapped by the magneto-optical method. The density and the temperature of the trapped atoms are measured, and the frequency region where the trap is available is represented. We controlled the flux of slowed atoms by varying the slowing beam intensity, and we measured the increasing and decreasing rate of trapped atoms. We show that the difference between the increasing and decreasing rate of trapped atoms result from the loss proportional to $N_2$.

• Journal of Marine Bioscience and Biotechnology
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• v.13 no.1
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• pp.10-19
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• 2021

This study investigated how ozone treatment can successfully inactivate pathogenic bacteria in both artificial seawater and effluents discharged from the fishery quarantine station in Pyeongtaek Port, Korea. Vibrio sp. and Streptococcus sp. were initially inoculated into the artificial seawater. All microbes were almost completely inactivated within 10 min and 30 min by injecting 6.4 mg/min and 2.0 mg/min of ozone, respectively. It was discovered that the water storing Pleuronichthys, Pelteobagrus, and Cyprinus imported from China contained the indicator bacteria, Vibrio sp., Enterococcus sp., total coliforms, and heterotrophic microorganisms. Compared to the control, three indicator bacteria were detected at two to six times higher concentrations. The water samples displayed a diverse microbial community, comprising the following four phyla: Bacteroidetes, Proteobacteria, Firmicutes, and Actinobacteria. Almost all indicator bacteria were inactivated in 5 min at 2.0 mg/min of ozonation; comparatively, 92.9%-98.2% of the less heterotrophic microorganisms were deactivated within the same time period. By increasing the dosage to 6.4 mg/min, 100% deactivation was achieved after 10 min. Despite the almost complete inactivation of most indicator bacteria at high doses after 10 min, several bacterial strains belonging to the Proteobacteria have still been found to be resistant under the given operational conditions.

• Nuclear Engineering and Technology
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• v.53 no.12
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• pp.3861-3878
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• 2021

The steady-state simplified spherical harmonics equations (SP_N equations) are a higher order approximation to the neutron transport equations than the neutron diffusion equation that also have reasonable computational demands. This work extends these results for the analysis of transients by comparing of two formulations of time-dependent SP_N equations considering different treatments for the time derivatives of the field moments. The first is the full system of equations and the second is a diffusive approximation of these equations that neglects the time derivatives of the odd moments. The spatial discretization of these methodologies is made by using a high order finite element method. For the time discretization, a semi-implicit Euler method is used. Numerical results show that the diffusive formulation for the time-dependent simplified spherical harmonics equations does not present a relevant loss of accuracy while being more computationally efficient than the full system.

• Plant Biotechnology Reports
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• v.4 no.3
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• pp.193-199
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• 2010

An olive-green mutant was generated in Synechocystis sp. strain PCC 6803 by inactivation of the sll0396 gene. Whole-cell absorption spectra of the mutant revealed the missing of phycocyanin peak. An investigation of the low-temperature fluorescence emission spectra revealed that the $sll0396{\Omega}$ mutant has a reduced amount of phycocyanin. Western blot analysis showed that the mutant contained less phycocyanin ${\beta}$- and ${\alpha}$-subunits and lacked the 30- and 32-kDa linker polypeptides, and northern blot analysis revealed that the transcription of the 1.4-kb cpcBA gene encoding the phycocyanin ${\beta}$- and ${\alpha}$-subunits was lower in the mutant. The Sll0396 protein has a DNA-binding motif and shares homology with known response regulators. Our results indicate that Sll0396 plays a regulatory role in the transcription of the phycocyanin genes during phycobilisome synthesis.

• Korean Journal of Optics and Photonics
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• v.12 no.6
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• pp.446-451
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• 2001

We made a laser induced grating spectrometer(LIGS) and measured the thermal grating signal generated in a $C_3$ $H_{8}$ flame. The thermal grating was formed in the C7Ha flame with two second-harmonic Nd:YAG pulse laser beams, and an LIGS signal was generated by Bragg scattering of a probe laser beam A $r^+.laser(488 nm). We found the modulation period of the signal depends linearly on the spacing of the grating set in the flame. We determined flame temperature by fitting the modulated signal and soot concentration with signal strength. Using this technique, we also obtained temperature profile and soot-particle distribution in a $C_3$ $H_{8}$ flame .e .

• Parasites, Hosts and Diseases
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• v.45 no.2 s.142
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• pp.115-120
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• 2007

Parvatrema chaii n. sp. (Digenea: Gymnophallidae) is described using the worms recovered from experimentally infected mice in Korea. The metacercariae were collected from surf-clams, Mactra veneriformis, from a tidal flat in Sochon-gun, Chungchongnam-do. The metacercariae were elliptical ($0.262{\times}0.132 mm$), and the genital pore had an anterior arch of 16-17 sensory papillae in scanning electron microscopic view, Adult worms were ovoid to foliate (0.275-0.303 by 0.140-0.150 mm), and their characteristic features included the presence of lateral lips, short esophagus, genital pore located some distance anterior to the ventral sucker, club-shaped seminal vesicle, a compact to slightly lobed vitellarium, elliptical eggs (0.018-0.020 by 0.010-0.013 mm), and absence of the ventral pit. This gymnophallid is classified as a member of the genus Parvatrema because of the location of the wide genital pore some distance from the ventral sucker, and the absence of the ventral pit. It differs from previously reported Parvatrema species, including the type species, P. borinquenae. In particular, the morphologies of the vitellarium and the genital pore with an anterior arch of 16-17 sensory papillae are unique features. Therefore, we propose it as a new species, Parvatrema chaii n. sp. (Digenea: Gymnophallidae).

• Clinical Endoscopy
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• v.57 no.2
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• pp.196-202
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• 2024

Background/Aims: Hypoxemia is a common side effect of propofol sedation during endoscopy. Applying mild positive airway pressure (PAP) using a nasal mask may offer a simple way to reduce such events and optimize the conditions for diagnostic and therapeutic upper gastrointestinal endoscopies. Methods: We compared overweight patients (body mass index >25 kg/m²) with a nasal PAP mask or standard nasal cannula undergoing upper gastrointestinal endoscopies by non-anesthesiologists who provided propofol sedation. Outcome parameters included the frequency and severity of hypoxemic episodes. Results: We analyzed 102 procedures in 51 patients with nasal PAP masks and 51 controls. Episodes of hypoxemia (oxygen saturation [SpO₂] <90% at any time during sedation) occurred in 25 (49.0%) controls compared to 8 (15.7%) patients with nasal PAP masks (p<0.001). Severe hypoxemia (SpO₂ <80%) occurred in three individuals (5.9%) in both groups. The mean delta between baseline SpO₂ and the lowest SpO₂ recorded was significantly decreased among patients with nasal PAP mask compared to controls (3.7 and 8.2 percentage points difference, respectively). There were significantly fewer airway interventions performed in the nasal PAP mask group (15.7% vs. 41.2%, p=0.008). Conclusions: Using a nasal PAP mask may be a simple means of increasing patient safety and ease of examination.

• Journal of Mycology and Infection
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• v.23 no.4
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• pp.105-110
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• 2018

Background: Otomycosis is a fungal infection that comprises 7~10% of outer ear infections. Although the occurrence is higher in humid climates, relatively few studies have investigated otomycosis occurrences in humid environments. While recurrent chronic otitis media discharge in the ear creates a milieu in which otomycosis is likely to occur, investigations of otomycosis co-occurring with chronic otitis media have been rare. Objective: To examine the characteristics of patients with otomycosis co-occurring with chronic otitis media and identify causative fungi. Methods: The study included 60 patients with chronic otitis media who presented typical otomycosis findings in the outer ear canal and the presence of fungi. Patients were treated in the department of otolaryngology, Daegu Catholic University Medical Center, between July 2011 and June 2018. Results: The mean patient age was 57.77 years, and our study included 20 men and 40 women (p=0.010). The lesion was on the right in 39 patients and on the left in 21 (p=0.020). Ear discharge was the most common chief complaint at diagnosis. Of the 54 patients over age 19, 10 had diabetes (18.5%). Aspergillus was causative in 29 patients and Candida in 31. Aspergillus niger was identified in 15 patients, Aspergillus sp. in 14, Candida parapsilosis in 12, Candida sp. in six, and Candida albicans in five. Conclusion: Otomycosis and chronic otitis media co-occurrences increase with age. The Aspergillus and Candida genera were similar in proportion. A. niger was the most common Aspergillus species, while C. parapsilosis was the most common Candida.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.34 no.1
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• pp.57-66
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• 2024

Objective: Chronic obstructive pulmonary disease (COPD) is characterized by progressive airflow obstruction that is only partly reversible, inflammation in the airways, and systemic effects. This study aimed to investigate the association between low peripheral oxygen saturation levels (SpO₂), and composite indices predicting death in male patients with (COPD). Method: A total of 140 participants with post-bronchodilator FEV₁/FVC ratio less than 0.7 were included. Three composite indices (ADO, DOSE, BODEx) were calculated using six variables such as age (A), airflow obstruction (O), body mass index (B), dyspnea (D), exacerbation history (E or Ex), and smoking status (S). Severity of airflow limitation was classified according to Global Initiative for Obstructive Lung Disease (GOLD) guidelines. SpO₂ was measured by pulse oximetry, and anemia and iron deficiency were assessed based on blood hemoglobin levels and serum markers such as ferritin, transferrin saturation, or soluble transferrin receptor. Results: Participants with low SpO₂ (<95%) showed significantly lower levels of %FEV₁ predicted (p=0.020) and %FEV₁/FVC ratio (p=0.002) compared to those with normal SpO₂ levels. The mMRC dyspnea scale (p<0.001) and GOLD grade (p=0.002) showed a significant increase in the low SpO₂ group. Receiver Operating Characteristic analysis revealed higher area under the curve for %FEV₁ (p=0.020), %FEV₁/FVC(p=0.002), mMRC dyspnea scale (p=0.001), GOLD grade (p=0.010), ADO (p=0.004), DOSE (p=0.002), and BODEx (p=0.011) in the low SpO₂ group. Conclusion: These results suggest that low SpO₂ levels are related to increased airflow limitation and the composite indices of COPD.