• Journal of the Korean Chemical Society
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• v.34 no.4
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• pp.360-369
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• 1990

Borosilicate, HZSM-5 zeolite and iron-substituted borosilicate and HZSM-5 zeolite were prepared and their catalytic properties in methanol conversion were studied. The effects of strength and amount of acid site determined from TPD spectra of ammonia on the product distribution was examined. Selectivity to propylene was high over borosilicate with small amount of strong acid site, but selectivity to aromatic compound was high over HZSM-5 zeolite with large amount of the strong acid site. The participation of weak acid site on the conversion did not confirmed, and the product distribution could be explained in terms of the amount of the strong acid site. Although the amount of the weak acid site was increased by substitution of iron, there was no meaningful change in the product distribution.

• Bulletin of the Korean Chemical Society
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• v.25 no.9
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• pp.1379-1384
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• 2004

Rearrangements of 1,3-oxathiolane sulfoxides 8 and 9 in the presence of base are described from a mechanistic viewpoint of sigmatropic and elimination reactions. In the presence of triethylamine the (Z)-sulfoxide 8 gave the corresponding thiolsulfinate 10 by way of dimerization of the sulfenic acid intermediate 2 at room temperature while the (E)-sulfoxide 9 was recovered even after refluxing in ethyl acetate by the reversal of the [2,3]-sigmatropic rearrangement of the sulfenic acid 4. Triethylamine promoted the developing charge separation in the transition state of the sigmatropic rearrangement of the (Z)-sulfoxide 8 to facilitate the ring opening to the sulfenic acid 2. The reason for more facile ring opening of the (Z)-sulfoxide 8 in comparison with the corresponding (E)-sulfoxide 9 is attributable to the differences in the reactivity of the hydrogen adjacent to the carbonyl group. Triethylamine was not strong base to deprotonate the carbonyl-activated methylene hydrogen of the (E)-sulfoxide 9 but enough to catalyze the sigmatropic process of the sulfoxides. The sulfenic acid 2 dimerized to the thiolsulfinate 10 while the sulfenic acid 4 proceeded the sigmatropic ring closure. In the presence of strong base such as potassium hydroxide, the elimination reaction was predominant over the sigmatropic rearrangement. In this reaction condition, both sulfoxides 8a and 9a gave a mixture of the disulfide 12, the isomeric disulfide 14, and the sulfinic acid 13. Under the strong alkaline condition an elimination of activated hydrogen from the carbon adjacent to the carbonyl group to furnish the sulfenic acid 2a and the isomeric sulfenic acid 18. The formation of the transient intermediate in the reaction was proven by isolation of the isomeric disulfide 14. The reactive entity was regarded as the sulfenic acid rather than sulfenate anion under these reaction conditions.

• Journal of Korean Society for Atmospheric Environment
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• v.8 no.1
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• pp.45-51
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• 1992

A study on acidity in fog, dew and frost was carried out. Samples were taken during May 1990-February 1991 at two sites in Chongwon, Choongbook. The acidity of dew and of fog collected from grass at site A was 4.89 and 5.46, respectively. Dew in summer showed very strong acidity. The volume of dew deposited on grass was much less than the volume of rain, but dew is effective to diffuse acid predursors and acid materials. Dew and fog can remove more effectively atmospheric acid materiasl deoposited on grass by diurnal turbulent motion rather than direct absorption of acid predursors and materials in the atmosphere. In a polluted area, acidic dew and fog can be occurred by the direct absorption and oxidation of acidic predursors in the atmosphere as well as the role of wet removal on grass surface. Acidity of frost collected on teflon surface showed little difference to acidity of dew and fog on teflon surface. This suggests a similar absorption mechanism of atmospheric precursors and materials into dew and frost in the atmosphere. Strong acidity in dew, fog and frost appeared to occur from local pollution sources of several ten kilometres. In particular, strong acidity in dew, fog, and frost together with acid rain can accelerate a damage in ecosystems. Discussion is made on scientific analyses and seasonal variations of acidity of fog, dew and frost. A mechanism on acidification of fog, dew and frost is also discussed.

• Journal of Soil and Groundwater Environment
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• v.19 no.6
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• pp.6-12
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• 2014

We reviewed literature focusing on the amounts of domestic production, distribution, and consumption of strong acids and their spill cases. In particular, we investigated the chemistry and toxicity of four strong acids classified as "accident preparedness substances," including hydrochloric, nitric, sulfuric, and hydrofluoric acid. We recommend sulfuric and hydrofluoric acid as the chemicals of priority control based on the amounts used and toxicity. An advanced prevention/response system needs to be established along with an improved human and social infrastructure to prevent and efficiently respond to chemical accidents. Understanding the behavior and transport of spilled strong acids in the soil and groundwater environments requires a multi-disciplinary approach since they go through a variety of chemical and biogeochemical reactions with complex geomedia. However, no such research has been done in this area in Korea to the best of our knowledge. We expect the results of this study to contribute as basic data to future research.

• Bulletin of the Korean Chemical Society
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• v.32 no.10
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• pp.3687-3691
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• 2011

Ion exchange experiments of molybdenum(VI) from strong HCl and $H_2SO_4$ solution have been done to investigate the existence of anionic complexes. The concentration of HCl and $H_2SO_4$was changed from 1 to 9 M. From the data on the complex formation of molybdenum in aqueous solution, a new distribution diagram of Mo(VI) was constructed in the pH range from zero to 10. AG 1 X-8, an anion exchange resin, and Diphonix, a cation exchange resin were used in the loading experiments. Ion exchange results indicate that anionic complexes of Mo(VI) begins to form from 3 M HCl and 1 M $H_2SO_4$ solution and the tendency to form anionic complexes is stronger in HCl than in $H_2SO_4$ solution. Our results can be utilized in the analysis of Mo(VI) in strong acid solution and in the design of a process to separate Mo(VI).

• Journal of Biomedical Engineering Research
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• v.14 no.4
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• pp.349-354
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• 1993

To investigate the relations between the physical constitutions, the acid-base balance, and the autonomic nervous function, the blood gas, the heart rate and the concentrations of Na, K of serum were measured pre-and poststimulation. As the result, it is shown that in the normal condition the macro-negative(strong liver- weak lung type) is the metabolic alkalosis, the macro-positive (strong lung-weak liver type) is the metabolic acidosis, the micro-negative(strong kidney-weak spleen type) is the alkalosis and the micro-positive (strong spleen-weak kidney type) is the acidosis. And the ntacro-positive and micro-positive are the sympathetic lead, the macro-negative and micro-negative are the parasympathetic lead. In the macro-positive and micro-positive subjects, the concentration of K in serum is relatively high. This si coincided with the acidosis. But in the macro-negative and micro-negative subjects, the concentration of K in serum is relatively low. This is coincided with the alkalosis.

• The Korean Journal of Food And Nutrition
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• v.6 no.1
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• pp.1-7
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• 1993

19 Samples of koji-starters using in brewing were collected from Korea and Japan, and then 31 strains of koji-molds were isolated from them. After Identification of the Isolate, rice koji was made with each strains, and its saccharogenic activity, dextrogenic activity, proteolytic activity, acid Producing ability, browning reaction and flavor were tested. Among 31 strains of isolates, 10 strains were Identified as Asp nwamori var. kawachii, 18 strains as Asp. oryzae, 3 strains as Asp. usamii mkt. shirousamii. The koji-starters made in Korea were composed of single species of koji-mold with same strain, but those made in Japan were composed of the mixture of different two species or the mixture of different 2 ∼4 strains in same species. Judging from amylolytic and proteolytic ability by species, Asp. awamori var. kawachii H1, I1 and 11, Asp. owsae J2, L2, M2, P3 and P4, and Asp. usamii writ. shirousamii S1 were better than the others. Mold strains isolated from Korean koji-starters were much lower in amylolytic or proteolytic activity than those from Japanese koji-starters. The typical characteristics for the 3 species of koji-molds were that Asp. awamori var. kawachii was strong in acid producing ability, but week in amylolytic and proteolytic ability, that Asp. owzae had strong amylolytic activity and good aroma, but produced little amount of acid, and that Asp. usamii mut. shirousamii had strong Proteolytic activity but some off-flavor.

• Textile Coloration and Finishing
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• v.27 no.2
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• pp.105-112
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• 2015

In order to detect gas phase strong acid on fabrics, a hexyl-substituted monoazo yellow dye, which was the modified form of a conventional pH-indicating dye, Methyl Yellow, was studied in view of acid-gas sensing properties and its fastness. The dye was printed on polypropylene non-wovens for protective coveralls and examined under various conditions of strong acid such as hydrochloric acid. The dye showed color change from yellow to red on exposure to gas phase hydrochloric acid as low concentration as 1~3 ppm very instantly. Considering reuse of the dye-printed non-wovens, the repeatability of color change was tested on the same sample for 50 repeats and 100 days. The acid-gas sensing function was maintained almost the same level of initial performance. The color fastness of the dye on polypropylene non-wovens was very good showing higher than ratings 4 except for 3~4 to rubbing under wet condition.

• Journal of Life Science
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• v.25 no.5
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• pp.577-584
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• 2015

Orostachys malacophyllus grow on the old roofing tile or on the rock of mountain and is belong to Crassulaceae family. After air drying for Orostachys malacophyllus (OM), using the mixture of lactic acid bacteria (Lactobacillus bulgaricus, Streptococcus thermophilus, Lactobacillus acidophilus) was fermented (FOM). OM and FOM extracted using water (W), ethanol (E) and methanol (M) and were measured extracts yield, pH and Brix. Extracted OM and FOM were tested by in vitro experimental models of α,α´-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging activity, Fe/Cu reducing power, linoleic acid peroxidation using ferric thiocyanate and thiobarbituric acid (TBA) methods and peroxidation of rat liver homogenate. In addition, the bioactive materials (phenolic compounds, flavonoids and minerals) were measured. The highest phenolic compounds and flavonoids were OME 122.2 mg/100 g and OME 84.0 mg/100 g. OM and FOM′s major minerals were K, Ca and Mg. The highest free radical scavenging activity showed in FOMM (93.9%), OMM (93.4%), FOME (92.1%) and OME (91.9%) at 0.5% additional level. Fe reducing powers were strong in FOME and FOMM and Cu reducing powers were strong in OME and FOMM. Antioxidant activities on lipid peroxidation using rat homogenate as measured by TBARS method showed strong in FOME and on lipid peroxidation of linoleic acid as measured by ferric TBA method showed strong in OME and FOME and measured by ferric thiocyanate showed strong in FOME and FOMM.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.3
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• pp.279-286
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• 2016

Caffeic acid phenethyl ester (CAPE), derived from honeybee hives, is a bioactive compound with strong antioxidant activity. This study was designed to test the neuroprotective effect of CAPE in 3-nitropropionic acid (3NP)-induced striatal neurotoxicity, a chemical model of Huntington's disease (HD). Initially, to test CAPE's antioxidant activity, a 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid (ABTS) antioxidant assay was employed, and CAPE showed a strong direct radical-scavenging effect. In addition, CAPE provided protection from 3NP-induced neuronal cell death in cultured striatal neurons. Based on these observations, the in vivo therapeutic potential of CAPE in 3NP-induced HD was tested. For this purpose, male C57BL/6 mice were repeatedly given 3NP to induce HD-like pathogenesis, and 30 mg/kg of CAPE or vehicle (5% dimethyl sulfoxide and 95% peanut oil) was administered daily. CAPE did not cause changes in body weight, but it reduced mortality by 29%. In addition, compared to the vehicle-treated group, robustly reduced striatal damage was observed in the CAPE-treated animals, and the 3NP-induced behavioral deficits on the rotarod test were significantly rescued after the CAPE treatment. Furthermore, immunohistochemical data showed that immunoreactivity to glial fibrillary acidic protein (GFAP) and CD45, markers for astrocyte and microglia activation, respectively, were strikingly reduced. Combined, these data unequivocally indicate that CAPE has a strong antioxidant effect and can be used as a potential therapeutic agent against HD.