• Journal of Environmental Science International
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• v.4 no.1
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• pp.41-52
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• 1995

The effects of reaction temperature, SO2 and CO2 concentration in an air gas stream, particle sizes of limestone on the reactivity and capacity of SO2 removal have been determined in a thermogravimetric analyser(TGA). The apparent reaction order of sulfation reaction of pre-calcined lime(CaO) with respect to SO2 is found to be close to unity. The apparent activation energies are found to be 17,000 kcal/kmol for sulfation of pre-calcined lime and 19,500 kcal/kmol for direct sulfation of limestone(CaCO3). The initial sulfation reaction rate of pre-calcined lime increases with increasing temperature, whereas the sulfur capture capacity exhibits a maximum value at 90$0^{\circ}C$. In direct sulfation of limestone, sulfation reactivity and sulfur capature capacity of sorbent increase with increasing temperature and decreasing CO2 concentration in a gas bulk stream. The main pare of pre-calcined lime is shifted to the larger pore sizes and pore volume decreases with increasing sulfation time and temperature. The surface area of lime decreases with increasing calcination temperature under an air atmosphere, whereas is yearly constant under a CO2(5, 10%) atmosphere in a gas stream.

• The Plant Pathology Journal
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• v.32 no.3
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• pp.266-272
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• 2016

A bacterial tyrosine sulfotransferase, RaxST, is required for activation of rice XA21-mediated immunity, and it catalyzes sulfation of tyrosine residues of Omp1X and RaxX in Xanthomonas oryzae pv. oryzae, a causal agent of bacterial blight in rice. Although RaxST is biochemically well-characterized, biological functions of tyrosine sulfation have not been fully elucidated. We compared protein expression patterns between the wildtype and a raxST knockout mutant using shotgun proteomic analysis. Forty nine proteins displayed a more than 1.5-fold difference in their expression between the wildtype and the mutant strains. Clusters of orthologous groups analysis revealed that proteins involved in cell motility were most abundant, and phenotypic observation also showed that the twitching motility of the mutant was dramatically changed. These results indicate that tyrosine sulfation by RaxST is essential for Xoo movement, and they provide new insights into the biological roles of RaxST in cellular processes.

• Journal of environmental and Sanitary engineering
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• v.13 no.3
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• pp.19-29
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• 1998

The calcination reactivity of limestone and physical property changes of calcined lime were investigated with a temperature($720~1000^{\circ}C$ under atmospheric gas($N_2$, $CO_2$) conditions. The mechanisms of mass transport in a lime matrix were represented by the evaporation and condensation (${\gamma}=1.7$) at $1000^{\circ}C$ and the volume diffusion (${\gamma}=2.7$) at $800^{\circ}C$, which was obtained by the specific surface area of calcined lime with sintering conditions. Also, the effect of physical property on the reactivity of sulfation reaction was determined by the changes of pore size with $lime-SO_2$ reaction in this work. The initial sulfation rate of calcined lime increased with increasing temperature, whereas the capture capacity of $SO_2$ exhibited a maximum value at $900^{\circ}C$. The pore volume of sulfated lime was decreased with increasing sulfation time, but the major pores shifted to the distribution of larger size at a temperature of $850{\;}~{\;}1000^{\circ}C$. The mean pore size of sulfated lime based on pore volume decreased gradually at $1000^{\circ}C$; however, it increased with sulfation time up to 40 min and rapidly decreased thereafter.

• Korean Journal of Materials Research
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• v.32 no.3
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• pp.125-131
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• 2022

Effect of sulfation processes on the physicochemical properties of ZrO₂ and TiO₂ nanoparticles were thoroughly investigated. SO₄/ZrO₂ and SO₄/TiO₂ catalysts were synthesized to identify the acidity character of each. The wet impregnation method of ZrO₂ and TiO₂ nanoparticles was employed using H2SO₄ with various concentrations of 0.5, 0.75, and 1 M, followed by calcination at 400, 500, and 600 ℃ to obtain optimum conditions of the catalyst synthesis process. The highest total acidity was found when using 1 M SO₄/ZrO₂-500 and 1 M SO₄/TiO₂-500 catalysts, with total acidity values of 2.642 and 6.920 mmol/g, respectively. Sulfation increases titania particles via agglomeration. In contrast, sulfation did not practically change the size of zirconia particles. The sulfation process causes color of both catalyst particles to brighten due to the presence of sulfate. There was a decrease in surface area and pore volume of catalysts after sulfation; the materials' mesoporous structural properties were confirmed. The 1 M SO₄/ZrO₂ and 1 M SO₄/TiO₂ catalysts calcined at 500 ℃ are the best candidate heterogeneous acid catalysts synthesized in thus work.

• Journal of Energy Engineering
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• v.7 no.2
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• pp.216-222
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• 1998

Thermogravimetric analyses were conducted by isothermal technique in order to characterize the sulfation reaction of calcined sorbents such as Tanyang dolomite, Yongwol dolomite, Tanyang limestone, and Yongwol limestone. Sulfation reaction for 0.08 mm in particle diameter were carried out with respect to various factors.; isothermal reaction temperatures (650~85$0^{\circ}C$), SO$_2$ concentration (0.38~1%), and oxygen concentration (1.2~6.7%). Measured reaction orders of SO$_2$ concentration, oxygen concentration, and activation energy were 0.3~2.2, 0.22~0.51 and 23.6~36 kJ/mol, respectively. The kinetic equations of sulfation reaction of calcined dolomites were correlated with various factors.

• Journal of the Korean Electrochemical Society
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• v.15 no.3
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• pp.160-164
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• 2012

The lead-acid batteries are the most often used in human life, because of their low cost, good reversibility and high potential but they have limit cycle ability with low capacitance. The main causes of this problem are forming recrystallization of $PbSO_4$ on electrodes surface during cycles which the recrystallization of $PbSO_4$ is known as sulfation. In this study, formation process of sulfation was investigated depending on charge and discharge cycle numbers. And we decomposed sulfation to renew cycle ability of lead-acid batteries. The renewed lead-acid batteries recovered to 84% compared to first capacity after 600 cycles.

• Biomolecules & Therapeutics
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• v.3 no.1
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• pp.85-90
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• 1995

Phenol, acetaminophen (AA) and salicylamide are all known to be sulfated in rats and mice. We have previously demonstrated that capacity-limited sulfation of xenobiotics in rats is due to the reduced availability of hepatic 3'-phosphoadenosine 5'-phosphosulfate (PAPS), the cosubstrate for sulfation, which in turn is limited by the availability of its precursor, inorganic sulfate. Because species differences have been reported in the extent of sulfation, this study was conducted to determine whether these xenobiotics lower hepatic PAPS and sulfate in ICR mice. All three substrates decreased serum sulfate concentrations in a dose- and time-dependent manner. However, contrary to the observations in rats, phenol markedly increased hepatic PAPS concentrations in a dose-dependent manner, 1 hr after ip injection of 0∼4 mmol/kg. Following ip injection of 4 mmol/kg phenol, hepatic PAPS concentraions were enhanced 2∼3 fold, 0.5-2 hr after dosing and returned to control values 3 hr after dosing, whereas AA and salicylamide had little effect on hepatic PAPS concentraions. In summary, these studies demonstrate that phenol markedly enhances hepatic PAPS concentrations in mice, whereas hepatic PAPS levels are not affected by AA and salicylamide. Our data suggest that 1) hepatic sulfation for high dosages of xenobiotics in ICR mice is not limited by the availability of cosubstrate and 2) there are significant species differences in the regulation of PAPS between rats and mice.

• Resources Recycling
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• v.25 no.5
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• pp.57-63
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• 2016

This study were carried out sulfation roasting and selective leaching test for the effective recovery of copper component in concentrate obtained by froth floatation of Autrallian low grade copper ore. The optimum conditions of sulfation roasting were temp. $450^{\circ}C$, $Na_2SO_4$ 2 mole ratio and time 1.5 h, and then selective leaching were room temperature and $H_2O$ or 1M $H_2SO_4$ solutions. Leaching efficiency of optimum sulfation product were 90 wt.% of copper, 20 wt.% of iron and 15wt.% of nickel elements. In this results, it was possible to selective decomposition leaching of the copper component under optimum conditions in this research.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.76-76
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• 1993

헤파린은 혈액응고계에서 antithrombin III 존재하에서 thrombin과 factor Xa의 작용을 억제함으로써 항응고제로서 작용을 한다. 심정맥혈전증 등 임상에 응용성이 높지만 장기적 사용시 혈소판 감소효과, 출혈, 골다공증 등의 부작용이 나타나고 있다. 본연구는 식물성 생약으로부터 당을 분리 정제하여 화학적으로 sulfation시켜 in vitro와 ex vivo에서 항응고활성을 비교하였다. 우선적으로 aPTT를 측정하여 응고시간의 연장을 시키는 다섯종류의 식물생약을 선택하였고 이 중에서 청호(Artemisiae apiaceae)로부터 산성당을 분리하여 pyridine과 chlorosulfonic산으로 sulfation 시켰율 때 in vitro상에서 항응고활성은 sulfation전에 비해 두드러지게 증가하였다. 농도를 달리 하여 실험동물에 투여시 응고시간의 연장 역시 비슷한 양상을 보여주었다. Thrombin 억제는 발견되지 않았지만 sulfate기와 항응고 활성과는 관계가 있는 것처럼 보였다.

• Food Science and Biotechnology
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• v.17 no.4
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• pp.870-872
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• 2008

Barley $\beta$-glucan was subjected to chemical modification and the anticoagulant activity of the derivative was investigated. The barley $\beta$-glucan was successfully sulfated, showing the degree of substitution calculated by elemental analysis of 0.40. In addition, the Fourier transform infrared (FT-IR) spectra of the derivative confirmed the sulfation, which generated two new absorption bands at 1,250/cm (S=O) and 810/cm (C-O-S) compared to the native. Specially, the anticoagulant activity of barley $\beta$-glucan was created by sulfation, which increased in a concentration-dependent manner. This result demonstrated that the incorporation of sulfate groups into the $\beta$-glucan structure added a blood clotting prevention effect.