• Journal of Microbiology and Biotechnology
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• v.30 no.2
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• pp.196-205
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• 2020

In this study, the acidic lipase from Aspergillus niger (ANL) was homologously expressed in A. niger. The expression of ANL was significantly improved by the expression of the native ANL with the introns, the addition of the Kozak sequence and the optimization of the signal sequences. When the cDNA sequence of ANL fused with the glaA signal was expressed under the gpdA promoter in A. niger, no lipase activity could be detected. We then tried to improve the expression by using the full-length ANL gene containing three introns, and the lipase activity in the supernatant reached 75.80 U/ml, probably as a result of a more stable mRNA structure. The expression was further improved to 100.60 U/ml by introducing a Kozak sequence around the start codon due to a higher translation efficiency. Finally, the effects of three signal sequences including the cbhI signal, the ANL signal and the glaA signal on the lipase expression were evaluated. The transformant with the cbhI signal showed the highest lipase activity (314.67 U/ml), which was 1.90-fold and 3.13-fold higher than those with the ANL signal and the glaA signal, respectively. The acidic lipase was characterized and its highest activity was detected at pH 3.0 and a temperature of 45℃. These results provided promising strategies for the production of the acidic lipase from A. niger.

• The Korean Journal of Food And Nutrition
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• v.29 no.5
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• pp.618-627
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• 2016

This study evaluated the hydration, gelatinization, and saccharification properties of rice processing for beverage development. The properties of rice were studied on 10 rice cultivars (Samkwang, Ilpum, Seolgaeng, Anda, Dasan-1, Goami-4, Danmi, American rice, Chinese rice, and Thai rice) and employing four kinds of pre-treatment methods (dry grain, wet grain, dry flour, and wet flour). The results showed that moisture content of rice was between 11.88~15.26%. Increase in soaking time along with highest water absorption was noted in American rice cultivar (46.81%). The water binding capacity of Thai rice was higher when compared to that of other rice flours. In addition, solubility and swelling power of rice were 4.52~26.65% and 0.19~2.05%, respectively. The amylose content of Goami-4 was higher in rice processing. Using a rapid visco analyzer (RVA), the initial pasting temperature of Danmi cultivar was found to be the highest; the peak viscosities of Anda cultivar and Dasan-1 cultivar, and Chinese rice were higher than of those of other rice flours. After saccharification, the pH, soluble solids content, and reducing sugar content of rice processed through different pre-treatment methods were in the range of 6.22~7.08, $4.67{\sim}16.07^{\circ}Brix$, and 0.35~11.67% (w/w), respectively. In terms of color values, the L-value of dry grain, a-value of wet (grain, flour), and b-value of dry sample (grain, flour) were found to be the highest. Assessment of various factors and cultivars characteristics of the raw grains are of importance in the development of rice beverage.

• Ultrasonography
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• v.32 no.1
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• pp.59-65
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• 2013

Purpose: The purpose of this study is to establish the methodology regarding synthesis of ultrasound contrast agent imaging, and to evaluate the characteristics of the synthesized ultrasound contrast agents, including size or degradation interval and image quality. Materials and Methods: The ultrasound contrast agent, composed of liposome and SF6, was synthesized from the mixture solution of $21{\mu}mol$ DPPC (1, 2-Dihexadecanoyl-sn-glycero-3-phosphocholine, $C_{40}H_{80}NO_8P$), $9{\mu}mol$ cholesterol, $1.9{\mu}mol$ of DCP (Dihexadecylphosphate, $[CH_3(CH_2)_{15}O]_2P(O)OH$), and chloroform. After evaporation in a warm water bath and drying during a period of 12-24 hours, the contrast agent was synthesized by the sonication process by addition of buffer and SF6 gas. The size of the contrast agent was controlled by use of either extruder or sonication methods. After synthesis of contrast agents, analysis of the size distribution of the bubbles was performed using dynamic light scattering measurement methods. The degradation curve was also evaluated by changes in the number of contrast agents via light microscopy immediate, 12 hours, 24 hours, 36 hours, 48 hours, 60 hours, 72 hours, and 84 hours after synthesis. For evaluation of the role as an US contrast agent, the echogenicity of the synthesized microbubble was compared with commercially available microbubbles (SonoVue, Bracco, Milan, Italy) using a clinical ultrasound machine and phantom. Results: The contrast agents were synthesized successfully using an evaporation-drying-sonication method. The majority of bubbles showed a mean size of 154.2 nanometers, and they showed marked degradation 24 hours after synthesis. ANOVA test revealed a significant difference among SonoVue, synthesized contrast agent, and saline (p < 0.001). Although no significant difference was observed between SonoVue and the synthesized contrast agent, difference in echogenicity was observed between synthesized contrast agent and saline (p < 0.01). Conclusion: We could synthesize ultrasound contrast agents using an evaporation-drying-sonication method. On the basis of these results, many prospective types of research, such as anticancer drug delivery, gene delivery, including siRNA or microRNA, targeted molecular imaging, and targeted therapy can be performed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1507-1510
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• 2005

This study was carried out as a part of the research on the development of a maskless and electroless process for fabricating metal micro/nanostructures by using a nanoindenter and an electroless deposition technique. $2-\mu{m}-deep$ indentation tests on Ni and Cu samples were performed. The elastic recovery of the Ni and Cu was 9.30% and 9.53% of the maximum penetration depth, respectively. The hardness and the elastic modulus were 1.56 GPa and 120 GPa for Ni and 1.49 GPa and 100 GPa for Cu. The effect of single-point diamond machining conditions such as the Berkovich tip orientation (0, 45, and $90^{\circ}$) and the normal load (0.1, 0.3, 0.5, 1, 3, and 5 mN), on both the deformation behavior and the morphology of cutting traces (such as width and depth) was investigated by constant-load scratch tests. The tip orientation had a significant influence on the coefficient of friction, which varied from 0.52-0.66 for Ni and from 0.46-0.61 for Cu. The crisscross-pattern sample showed that the tip orientation strongly affects the surface quality of the machined area during scratching. A selective deposition of Cu at the pit-like defect on a p-type Si(111) surface was also investigated. Preferential deposition of the Cu occurred at the surface defect sites of silicon wafers, indicating that those defect sites act as active sites for the deposition reaction. The shape of the Cu-deposited area was almost the same as that of the residual stress field.

• Journal of Powder Materials
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• v.16 no.5
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• pp.326-335
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• 2009

Fe based (Fe$_{68.2}$C$_{5.9}$Si$_{3.5}$B$_{6.7}$P$_{9.6}$Cr$_{2.1}$Mo$_{2.0}$Al$_{2.0}$) amorphous powder, which is a composition of iron blast cast slag, were produced by a gas atomization process, and sequently mixed with ductile Cu powder by a mechanical ball milling process. The Fe-based amorphous powders and the Fe-Cu composite powders were compacted by a spark plasma sintering (SPS) process. Densification of the Fe amorphous-Cu composited powders by spark plasma sintering of was occurred through a plastic deformation of the each amorphous powder and Cu phase. The SPS samples milled by AGO-2 under 500 rpm had the best homogeneity of Cu phase and showed the smallest Cu pool size. Micro-Vickers hardness of the as-SPSed specimens was changed with the milling processes.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.61-66
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• 2006

Over the past 20 years there has been a revolution involving the use of nano or macro size particles as drainage and retention systems during the manufacture of paper. More recently a group of patented technologies called Synthetic Mineral Microparticles (SMM) has been invented and developed. This system has potential to further promote the drainage of water and retention of fine particles during papermaking. Prior research, as well as our on preliminary research showed that the SMM system has advantages in both of drainage and retention compared with montmorillonite (bentonite), which one of the most popular materials presently used in this kind of application. In spite of the demonstrated advantages of this SMM system, the properties and activity of SMM particles in the aqueous state have not been elucidated yet. Streaming current titrations with highly charged polyelectrolytes were used to measure the charge properties of SMM and to understand the interactions among SMM particles, fibers, fiber fines, and cationic polyacrylamide (cPAM) as a retention aid. It was found that pH profoundly affects the charge properties of SMM, due to the influence of Al-ions and the Si-containing particle surface. SEM pictures, characterizing the morphology, geometry and size distribution of SMM, showed an broad distribution of primary particle size. Dilution of SMM mixturee appeared to wash out particles smaller than 100 nm from the surface of larger particles, which themselves appeared to be composed of fused primary particles. DSC thermoporometry was used to measure the size distribution of nanopores within SMM particles.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.6
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• pp.849-856
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• 2015

This study was performed to obtain basic data regarding the development of fish steak products using olive flounder and pork leg. Olive flounder and pork leg were ground separately in a chopper. The methods used for processing were as follows. Chopped olive flounder (100 g) and other ingredients (bread crumbs, 13 g; onion, 12 g; garlic, 4 g; egg wash, 18 g; salt, 0.05 g; pepper, 0.05 g) were mixed in a chopper. The mixture was molded into a steak shape ($12{\times}7cm$) and roasted in an oven at $180^{\circ}C$ for 12 min (OF). FP consisting of a mixture of olive flounder (70 g) and pork leg meat (30 g) and OP consisting of pork leg meat alone (100 g) were processed according to the same procedure as described for OF. Various factors (viable bacterial count, chemical composition, pH, salinity, hardness value, color value, total amino acid content, free amino acid content, fatty acid composition, mineral content) were measured, and sensory evaluation was conducted. Based on the results of the sensory evaluation and hardness value, OP was deemed to be the most desirable, followed in order by FP and OF. There was a slight but significant difference between OP and FP.

• Journal of Microbiology and Biotechnology
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• v.18 no.3
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• pp.427-433
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• 2008

The cephabacins produced by Lysobacter lactamgenus are ${\beta}$-lactam antibiotics composed of a cephem nucleus, an acetate residue, and an oligopeptide side chain. In order to understand the precise implication of the polyketide synthase (PKS) module in the biosynthesis of cephabacin, the genes for its core domains, ${\beta}$-ketoacyl synthase (KS), acyltransferase (AT), and acyl carrier protein (ACP), were amplified and cloned into the pET-32b(+) expression vector. The sfp gene encoding a protein that can modify apo-ACP to its active holo-form was also amplified. The recombinant KS, AT, apo-ACP, and Sfp overproduced in the form of $His_6$-tagged fusion proteins in E. coli BL21(DE3) were purified by nickel-affinity chromatography. Formation of stable peptidyl-S-KS was observed by in vitro acylation of the KS domain with the substrate [L-Ala-L-Ala-L-Ala-L-$^3H$-Arg] tetrapeptide-S-N-acetylcysteamine, which is the evidence for the selective recognition of tetrapeptide produced by nonribosomal peptide synthetase (NRPS) in the NRPS/PKS hybrid. In order to confirm whether malonyl CoA is the extender unit for acetylation of the peptidyl moiety, the AT domain, ACP domain, and Sfp protein were treated with $^{14}C$-malonyl-CoA. The results clearly show that the AT domain is able to recognize the extender unit and decarboxylatively acetylated for the elongation of the tetrapeptide. However, the transfer of the activated acetyl group to the ACP domain was not observed, probably attributed to the improper capability of Sfp to activate apo-ACP to the holo-ACP form.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.115-120
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• 2015

$K_2CO_3$-based dry regenerable sorbents were prepared by spray-drying techniques to improve mass produced $K_2CO_3-Al_2O_3$ sorbents (KEP-CO2P, hereafter), and then tested for their $CO_2$ sorption capacity by a $2,000Nm^3/h$ (0.5 MWe) $CO_2$ capture pilot plant built for Unit 3 of the Hadong thermal power station in 2010. Each of the sample sorbents contained 35 wt.% $K_2CO_3$ as the active materials with various support materials such as $TiO_2$, MgO, Zeolite 13X, $Al_2O_3$, $SiO_2$ and hydrotalcite (HTC). Their physical properties and reactivity were tested to evaluate their applicability to a fluidized-bed or fast transport-bed $CO_2$ capture process. The $CO_2$ sorption capacity and percentage utilization of $K_2CO_3$-MgO based sorbent, Sorb-KM2, was $8.6g-CO_2/100g$-sorbents and 90%, respectively, along with good mechanical strength for fluidized-bed application. Sorbs-KM2 and KT were almost completely regenerated at $140^{\circ}C$. No degradation of Sorb-KM by $SO_2$ added as a pollutant in flue gas was observed during a cycle test.

• The Journal of Korean Academy of Sensory Integration
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• v.6 no.1
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• pp.35-46
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• 2008

Objective : This study verifies the effects of sensory integrative (SI) therapy on vestibular- and proprioceptive sensory (BPS) processing ability of a child with Asperger Syndrome (AS). Method : A boy who is 11 years and 2 months old took the Functional Independence Measure for Children (Wee-FIM), Canadian Occupational Performance Measure (COPM), Short Sensory Profile, Bruininks-Oserestky Test of Motor Proficiency-2 (BOT-2), and Test of Playfulness (ToP) for the baseline. The child participated in 3 evaluation sessions and 8 therapy sessions based on the AB research design. Duration of each session is 50 min and the therapy session is divided into 40 minutes for treatment and 10 minutes for evaluation. Since the vestibular sense and proprioception build up one's ability of postural control, several tests were employed to evaluate the child' postural control as outcome measure; distance from front leg of chair to heel of the child with sitting (C-H distance), angle between trunk and thigh (hip joint angle) with sitting, and the 'prone-extension posture' which is a subtest of Clinical Observation of Motor and Postural Skill (COMPS) to examine postural control embodied with integration of reflex and BPS processing. Result : During the therapy, average data of the C-H distance is decreased from 27.33cm to 11.69cm, average data of the hip joint angle is also decreased from $43.3^{\circ}$ to $20^{\circ}$, and average time for the prone-extension posture is increased from 13.15seconds to 24.84seconds. Conclusion : This result indicates that the ability to postural control in sitting and to maintain the prone-extension posture can be improved by sensory integrative therapy, with enhanced BPS processing.