• Journal of Environmental Science International
• /
• v.17 no.1
• /
• pp.7-17
• /
• 2008

Simultaneous removal of $NH_3,\;H_2S$ and toluene in a contaminated air stream was investigated over 185 days in a biofilter packed with Zeocarbon granule as microbial support. In this study, multi-microorganisms including Nitrosomonas and Nitrobacter for nitrogen removal, Thiobacillus thioparus (ATCC 23645) for $H_2S$ removal, and Pseudomonas aeruginosa (ATCC 15692), Pseudomonas putida (ATCC 17484) and Pseudomonas putida (ATCC 23973) for toluene removal were used simultaneously. The empty bed residence time (EBRT) was 40-120 seconds and the feed (inlet) concentrations of $NH_3,\;H_2S$ and toluene were 0.02-0.11, 0.05-0.23 and 0.15-0.21 ppmv, respectively. The observed removal efficiency was 85%-99% for $NH_3$, 100% for $H_2S$, and 20-90% for toluene, respectively. The maximum elimination capacities were 9.3, 20.6 and $17g/m^3/hr\;for\;NH_3,\;H_2S$ and toluene, respectively. The results of kinetic model analysis showed that there were no particular evidences of interactions or inhibitions among the microorganisms, and that the three bio degradation reactions took place independently within a finite area of biofilm developed on the surface of the Zeocarbon carrier.

• Journal of Biosystems Engineering
• /
• v.40 no.4
• /
• pp.373-393
• /
• 2015

Background: Cellulose is a ubiquitous, renewable and environmentally friendly biopolymer, which has high promise to fulfil the rising demand for sustainable and biocompatible materials. Particularly, the recent progress in the synthesis of highly crystalline cellulose-based nanoscale biomaterials, namely cellulose nanocrystals (CNCs), draws significant attention from many research communities, ranging from bioresource engineering, to materials science and engineering, to biological and biomedical engineering to bionanotechnology. The feasibility of harnessing CNCs' unique biophysicochemical properties has inspired their basic and applied research, offering much promise for new biomaterials with diverse advanced functionalities. Purpose: This review focuses on vital issues and topics on the recent advances in CNC-based biomaterials with potential, in particular, for bionanotechnology and biological and biomedical engineering. The challenges and limitations of CNC technology are discussed as well as potential strategies to overcome them, providing an essential source of information in the exploration of possible and futuristic applications of the CNC-based functional "green" nanomaterials. Conclusion: CNCs offer exciting possibilities for advanced "green" nanomaterials, driving innovative research and development in a wide range of fields, including biological and biomedical engineering.

• Journal of Microbiology and Biotechnology
• /
• v.20 no.2
• /
• pp.346-349
• /
• 2010

Coenzyme $Q_{10}$ ($CoQ_{10}$) production from Rhizobium radiobacter T6102 was monitored under various oxygen supply conditions by controlling the agitation speeds, aeration rates, and dissolved oxygen levels. As the results, the $CoQ_{10}$ production was enhanced by limited oxygen supply. To investigate whether the $CoQ_{10}$ production is associated with its physiological functions of electron carrier and antioxidant, the effects of sodium azide and hydrogen peroxide on the $CoQ_{10}$ production were studied, showing that the $CoQ_{10}$ contents were slightly enhanced with increasing sodium azide (up to 0.4 mM) and hydrogen peroxide (up to $10\;{\mu}M$) concentrations. These results suggest the plausible mechanism where the limited electron transfer stimulating the environments of limited oxygen supply and oxidative stress could accumulate the $CoQ_{10}$, providing the relationship between the $CoQ_{10}$ physiological functions and its regulation system.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.5
• /
• pp.1333-1338
• /
• 2013

Chitosan-based nanoparticles (CSNP) were prepared through ionic cross-linking and gelation of chitosan (CS) by tripolyphosphate (TPP). CS properties such as molecular weight, and preparation conditions were screened and the resulting nanoparticles were examined by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The obtained particles were consistently spherical with an overall diameter of approximately $107{\pm}20$ nm. They were successfully used as a carrier for Zidovudine, an anti-human immunodeficiency virus (HIV) which, to our knowledge, is novel. The encapsulation ability, loading capacity, and controlled release behavior for these CSNP was evaluated. Results indicated that their intrinsic properties were strongly affected by properties inherent to CS such as molecular weight, and by the preparation condition, such as cross-linking density, which depends on the concentration of the cross-linker. In vitro release tests for the entrapped zidovudine showed that the CNNP provided a continuous release that can last upwards 20 h.

• The Plant Pathology Journal
• /
• v.23 no.1
• /
• pp.26-30
• /
• 2007

Phosphorous acid is known to effectively control various Oomycetes diseases. The phosphoric acid moves upward and downward through the xylem and phloem in plants. The sustainable forms of the slow releasing chemical in rhizosphere would be ideal to be up-taken by plants. Therefore, we developed a new system for phosphorous acid formulation using a carrier coated with polysaccharides. When the product was applied in rhizosphere, the adequate amount of phosphorous acid was consistently released up to 4 weeks in rhizosphere soils. While soil drenching with phosphorous acid at 1,000 ${\mu}g/ml$ and metalaxyl at 150 ${\mu}g/ml$ were not effective to control pepper Phytophthora blight for 4 weeks, direct application of our formulation product around basal stem of pepper plants resulted in excellent disease control effect against Phytophthora blight over 4 weeks. The application of 4 g of our product per plant was optimum to control the disease, and 8 g product/plant did not cause phytotoxicity. Based on the results, we conclude that the applications of the formulation product once or twice during cropping season can control Phytophthora diseases on various crops.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.122-122
• /
• 2010

ZnO is a widely investigated material for the blue and ultraviolet solid-state emitters and detectors. It has been promoted due to a wide-band gap semiconductor which has large exciton binding energy of 60 meV, chemical stability and low radiation damage. However, there are many problems to be solved for the growth of p-type ZnO for practical device applications. Many researchers have made an efforts to achieve p-type conductivity using group-V element of N, P, As, and Sb. In this letter, we have studied the optical characteristics of the antimony-doped ZnO (ZnO:Sb) thin films by means of photoluminescence (PL), PL excitation, temperature-dependent PL, and time-resolved PL techniques. We observed donor-to-acceptor-pair transition at about 3.24 eV with its phonon replicas with a periodic spacing of about 72 meV in the PL spectra of antimony-doped ZnO (ZnO:Sb) thin films at 12 K. We also investigate thermal activation energy and carrier recombination lifetime for the samples. Our result reflects that the antimony doping can generate shallow acceptor states, leading to a good p-type conductivity in ZnO.

• Food Science and Biotechnology
• /
• v.17 no.4
• /
• pp.829-832
• /
• 2008

A multiplex polymerase chain reaction (PCR) method was developed to simultaneously detect 4 varieties of genetically modified (GM) cotton. The event-specific primers were used to distinguish the 4 varieties of GM cotton (MON1445, MON15985, MON88913, and LLcotton25) using multiplex PCR. The acyl carrier protein 1 (Acp1) gene was used as an endogenous reference gene of cotton in the PCR detection. The primer pair Acp1-AF/AR containing a 99 bp amplicon was used to amplify the Acp1 gene and no amplified product was observed in any of the 13 different plants used as templates. This multiplex PCR method allowed for the detection of event-specific targets in a genomic DNA mixture of up to 1% GM cotton containing MON1445, MON15985, MON88913, and LLcotton25.

• Journal of Korean Society for Atmospheric Environment
• /
• v.34 no.4
• /
• pp.554-566
• /
• 2018

The rice husk contains nutrients which can be easily utilized by microorganisms, and also has a water retaining ability, which played a crucial part in enabling it to become a biofilter media. In this study, we evaluated the applicability of rice husk pellet bio-scrubber as a microbiological carrier. The pelletization experiment of rice husk as a biological media was performed using PVA and EVA binder. Also, the feasibility tests of rice husk as a biological media for odor removal were carried out in order to know whether rice-husk contains useful components as a media for microbiological growth or not. Lastly, a combined test for odor gas absorption and biological oxidation was conducted using a lab scale bio-filter set-up packed with rice-husk pellets as wet-scrubber. The major components of the rice husk were carbon, hydrogen, nitrogen, and oxygen, while carbon acted as the main ingredient which comprised up to 23.00%. The C : N : P ratio was calculated as 45 : 1 : 2. Oxygen uptake rate, yield and decay rate of the rice husk eluent was calculated to be $0.0049mgO_2/L/sec$, 0.24 mgSS/mgCOD and 0.004 respectively. The most stable form of rice husk pellets was produced when the weight of the rice husk, EVAc, PVAc, and distilled water was 10 : 2 : 0.2 : 10. The prepared rice husk pellets had an apparent density of 368 g/L and a porosity of 59.00% upon filling. Dry rice husks showed high adsorption capacity for ammonia gas but low adsorption capacity for hydrogen sulfide. The bio-filter odor removal column filled with rice husk pellets showed more than 99.50% removal efficiency for NH3 and H2S gas. Through the analysis of circulation water, the prime removal mechanism is assumed to be the dissolution by water, microbial nitrification, and sulfation. Finally, it was confirmed that the microorganisms could survive well on the rice husk pellets, which provided them a stable supply of nutrients for their activity in this long-term experiment. This adequate supply of nutrients from the rice husk enabled high removal efficiency by the microorganisms.

• Journal of the Korean Chemical Society
• /
• v.54 no.6
• /
• pp.696-700
• /
• 2010

Yeast is immobilized upon $100{\mu}m$ CPG(controlled pore glass bead) to separate $Sb^{3+}$ and $Sb^{5+}$. Continuous hydride generation is performed after the bio-column. The optimum conditions are 0.8 M nitric acid as an eluent with the flow rate of 1.0 mL $min^{-1}$ and the optimum conditions for the generation of hydride are 2 M HCl, 3% (w/v) $NaBH_4$ with the flow rate of 0.83 mL $min^{-1}$, Ar carrier gas flow rate of 50 mL $min^{-1}$. Two species are separated at 112 and 354 seconds each. The sensitivity is enhanced by 10 times for $200{\mu}L$ of sample and the detection limits are 3.0 ppb and 7.0 ppb for $Sb^{3+}$ and $Sb^{5+}$, respectively. When compared with the standard samples, this method showed accurate results.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.33 no.5
• /
• pp.405-418
• /
• 2007

Mesenchymal stem cells(MSCs) have been though to be multipotent cells that can replicate that have the potential to differentiate into lineages of mesenchymal tissue including the bone, cartilage, fat, tendon, muscle, and marrow stroma. Especially, scaffolds to support cell-based tissue engineering are critical determinants of clinical efforts to regenerate and repair the body. Selection of a matrix carrier imvolves consideration of the matrix's role as a scaffold for physical support and host tissue integration as well as its ability to support of synergize the osteoinductive program of the implanted mesenchymal stem cell. The aim of this study is to evaluate the effect of autobone and Bio-$Oss^{(R)}$ to adherent mesenchymal stem cells as scaffolds on sinus augmentation with fibrin glue mixture in a rabbit model. 16 New Zealand White rabbits were divided randomly into 4 groups based on their time of sacrifice(1, 2, 4 and 8 weeks). First, mesenchymal stem cells were isolated from iliac crest marrow of rabbits and expanded in vitro. Cell culture was performed in accordance with the technique described by Tsutsumi et al. In the present study, the animals were sacrificed at 1, 2, 4 and 8 weeks after transplantation, and the bone formation ability of each sides was evaluated clinically, radiologically, histologically and histomorphologically. According to the histological observations, autobone scaffolds group showed integrated graft bone with host bone from sinus wall. At 2 and 4 weeks, it showed active newly formed bone and neovascularization. At 8 weeks, lamellae bone was observed in sinus graft material area. Radiologically, autobone with stem cell showed more radiopaque than Bio-$Oss^{(R)}$ scaffolds group. there were significant differences in bone volume between 4 and 8 weeks(p<0.05).