• Environmental Engineering Research
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• v.15 no.2
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• pp.93-98
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• 2010

This study aims to determine the chemical composition and seasonal variation of atmospheric acid deposition in order to identify possible sources contributing to precipitation. Sampling and analysis of 132 wet deposition samples were carried out from January to December 2008 at Mae Hia Research Center, Chiang Mai University, Chiang Mai Province. Total precipitation was 1,286.7 mm. Mean electro-conductivity and pH values were 0.94 mS/m and 6.27, respectively. Major cations ($Na^+$, ${NH_4}^+$, $K^+$, $Ca^{2+}$, and $Mg^{2+}$) and major anions ($HCOO^-$, $CH_3COO^-$, $Cl^-$, ${NO_3}^-$, and ${SO_4}^{2-}$) were determined by Ion Chromatography. The relative volume weight mean concentrations of anions, in descending order, were ${SO_4}^{2-}$ > ${NO_3}^-$ > $Cl^-$ > $CH_3COO^-$ > $HCOO^-$ and those of cations were $NH_4^+$ > $Ca^{2+}$ > $Mg^{2+}$ > $K^{+}$ > $Na^+$. Results of a principle component analysis highlighted the influence of various possible sources of ions such as agricultural activity, fuel combustion, marine sources, soil resuspension, and biomass burning.

• Journal of Ocean Engineering and Technology
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• v.24 no.1
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• pp.99-105
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• 2010

The concentration and size analysis of in-situ suspended particulate material were measured using an optical instrument, LISST-100, in the bottom layer at the three inlets of the Seomjin River Estuary, mouth of Gwangyang bay, and Gwangyang bay-side of the Namhae Bridge. In the Seomjin river estuary and mouth of Gwangyang bay-side of the Namhae Bridge, the in-situ mean grain size of the suspended material changed from a uni-modal distribution with a dominant peak at a coarse fraction to a bi-modal distribution with a secondary peak at the finer particles. Seomjin River. The interactions between suspended particulate concentration and beam attenuation coefficient of suspended particulate matters depended on the supply of finer and coarser particles in the mouth of Gwangyang Bay and Seomjin River. So, interactions reflected difference of the concentration, mean size and sorting of suspended particulate matters. The difference of interaction showed dynamic behaviors to the resuspension and deflocculation processes increased river discharge. This showed that it may be possible to use the interactions between the suspended particle concentration and beam attenuation coefficient to monitor the temporal and spatial distributions of in-situ particles.

• Ocean and Polar Research
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• v.31 no.2
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• pp.219-229
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• 2009

In order to establish annual variations in the marine ecosystem of the East China Sea, suspended solids (SSs) and particulate organic carbon (POC) were extensively investigated in the northern part of the East China Sea from August 2003 to April 2008. Surface SS concentrations showed large spatial variations in spring and fall, but not in summer. Surface SS concentrations in spring were lower than those in summer and fall. In summer, SSs discharged from Changjiang were mostly deposited in the coastal areas and did not reach our study area which was located about 260 km from the river mouth. High SS concentrations were observed near the bottom, which resulted from resuspension of bottom sediments by the bottom currents. Surface POC concentrations did not exhibited large seasonal variations. Phytoplankton biomass was a main factor controlling surface POC concentrations. POC/chlorophyll ratios showed large seasonal variations, with maximum numbers in summer. POC/PON ratios were higher in summer than the Redefied ratio (6.6), while they were lower in spring and fall. In summer, higher POC/chlorophyll and POC/PON ratios were probably attributed to the high phytoplankton mortality caused by nutrient depletion in surface waters.

• Journal of Plant Biotechnology
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• v.30 no.3
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• pp.215-219
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• 2003

This study was conducted to find optimum bacterial density for improving the efficiency of transformation mediated by Agrobacterium tumefaciens in apples. Regeneration(15％) and transformation frequency(10％) were increased in resuspension-culture density $A_{600}$ 1.3 from preculture density $A_{600}$ 0.7 of Agrobacterium tumefaciens in ′Fuji′. In ′Gala′, 20% regeneration and 16% transformation frequency were observed at optimum bacterial density $A_{600}$ 0.7 form preculture density $A_{600}$ 1.3. ′Mclntosh as well as "Gala" were 25％regeneration and 10％ transformation frequency. Hence a frequency optimum condition of bacterial density for the efficient transformation of apple could be depend on apple genotypes.

• Journal of Microbiology and Biotechnology
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• v.11 no.5
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• pp.890-894
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• 2001

The isolation of genomic DNA from mammalian cells is usually performed by cell lysis followed by protein digestion, extraction, and finally, ethanol precipitation of the chromosomal DNA. However, in the case of large sample numbers or when only small amounts of starting materials are available, such conventional methods are not efficient and are cumbersome to be applied. Some alternative methods have been described as well as having commercial DNA isolation kits to be available, nevertheless, there is room left for much improvement. In the present study, a novel method is introduced, where it simplifies conventional protocols by omitting some time-consuming steps such as protease incubation or DNA precipitation and its resuspension. Using paramagnetic silica resins, the genomic DNA was purified over a magnetic field, and the bound DNA was eluted with a low-salt buffer. The fidelity and effectiveness of this novel method was determined by using normal and apoptotic cells as a starting material and then compared to other protocols. The high speed and convenience along with its high efficiency in detecting apoptotic chromosomal DNA will prove this method to be an improved alternative in the isolation of genomic DNA from mammalian cells.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.4
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• pp.574-579
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• 2005

Optimal management of indoor air quality in a confined pig house, especially in winter, is indispensable for preventing infectious respiratory disease to workers and animals. This study was performed to elucidate the correlation of aerial contaminants and climate factors in a confinement. It was observed that indoor air contaminants ion in the confinement was the highest at 2:00-5:00 pm in a day, followed by 8:00-11:00 pm and 8:00-11:00 am. This was attributed to the increase of pig activities in the afternoon. The concentration of total dust and total airborne bacteria was found to have a significant correlation with temperature and relative humidity (p<0.05). Correlation of total dust and total airborne bacteria, total dust and ammonia, and total dust and odor were shown statistically significant at 95% confidence level. In conclusion, temperature and total dust concentration correlated significantly with all the parameters except for hydrogen sulfide ($H_2S$). This could be explained by the fact the dryness of pig feces by increase of interior temperature and resuspension of feed deposited on the floor by the pig activity, resulted in high generation of dust which adsorbed and carried the airborne bacteria and odor compounds in a confined pig house. It was proved that the adsorptive capacity of dust with ammonia ($NH_3$) was higher than that with hydrogen sulfide ($H_2S$).

• Journal of Korean Society on Water Environment
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• v.25 no.6
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• pp.935-942
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• 2009

During period of the rainy season of spring tide Aug. 2005, the suspended sediment transport rate from Seomjin River increased ten times as high as neap tide of low river discharge. During ebb tide of high terrestrial input, the grain size of suspended particles of both surface and bottom layer of the water column, showed a uni-modal distribution with a dominant peak at coarse fraction, which suggests a characteristic development of floc-sized particles of low mean effective density. On the contrary, the particles supplied toward upstream of Seomjin river from Gwangyang Bay during flood tide showed a bi-modal distribution with a secondary peak at finer fraction, possibly due to the resuspension and the deflocculation associated with the increased shear velocity at near bottom. Break-up of large flocs is also suggested by the increased mean effective density. However, settling velocity was lower during flood tide because of smaller grain size. Thus, net deposition of suspended sediment is expected at within Gwangyang Bay instead of upstream of Seomjin River, even though suspended sediment transport rate at near bottom water was three times higher than that at surface water during flood tide.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.2 no.3
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• pp.1-9
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• 1999

This paper described the results of the characteristics of the near-bottom flow and field analysis of the tidal flats sediment. It was the aim of this paper to grasp current flow of tidal flat's environment and influence factor for environmental change forecast of tidal flats. Field measurement of water velocity, water elevation, bed materials test, and temperature distribution of tidal flat were conducted. Thereafter, current flow, turbidity and temperature distribution of tidal flat sediment have been discussed. The field research results showed that the fluctuating velocity near the seabed before and after its appearance at low tide was strongly affected by the wind wave. The resuspension of the sea-bottom sediment took place with great intensity before and after the appearance of the seabed at low tide. Both the sea water level and the weather condition were a significant influential factors. Such as, temperature and turbidity just on the surface and the shallow layer of seabed sediments were varied largely with time and weather conditions, but that its deeper layers was almost constant. Temperature on the seabed sediments was strongly influenced by irradiance and water depth. The temperature variation of the tidal flat and the variation characteristics of the current flow and turbidity depend greatly on the inhabiting environment of the tidal flat benthic organism.

• Food Science and Biotechnology
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• v.18 no.5
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• pp.1150-1154
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• 2009

Low levels of virus contamination and naturally occurring reverse transcription-polymerase chain reaction (RT-PCR) inhibitors restrain virus detection in oysters. A rapid and efficient oyster-processing procedure that can be used for sensitive virus detection in oysters was developed. Poliovirus type 1 Sabin strain was used to evaluate the efficacy of virus recovery. The procedure included (a) acid-adsorption and elution with buffers (0.25M glycine-0.14 M NaCl, pH 7.5; 0.25M threonine-0.14M NaCl, pH 7.5); (b) polyethylene glycol (PEG) precipitation; (c) resuspension in Tween 80/Tris solution and chloroform extraction; (d) the second PEG precipitation; (e) viral RNA extraction with TRIzol and isopropanol precipitation; and (f) RT-PCR combined with semi-nested PCR. The overall recovery of elution/concentration was 19.5% with poliovirus. The whole procedure usually takes 19 hr. The overall detection sensitivity was 4 RT-PCR units of genogroup I norovirus (NoV) and 6.4 RT-PCR units of genogroup II Nov/25 g of oysters initially seeded. The virus-detecting method developed in this study should facilitate the detection of low levels of NoV in oysters.

• KSBB Journal
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• v.5 no.2
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• pp.183-189
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• 1990

An efficient method has been developed for the purification of urokinase from 1, 000 liter batches of human urine. The procedure involved precipitation of urokinase with 2mM zinc chloride, resuspension of the precipitate with 0.1M EDTA/0.5M Glycine solution, and CM-Toyopearl and benzamidine-Sepharose column chromatography. The purified urokinase was fully active and possessed a specific activity of 1.07$\times$105IU/mg. The recoveries ranged from 42 to 65% in several preparations(mean value was 51%). And the urokinase purified by this process consisted of about 13% of single chain urokinase (pro-urokinase) as evaluated by SDS-polyacrylamide gel electrophoresis in reducing condition and by S-2444 amldolytic activity under plasmin treatment.