• Fisheries and Aquatic Sciences
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• v.5 no.2
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• pp.114-121
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• 2002

A correction index of catchability (CIC) was derived using a 6 year research data set to examine the seasonal variation in catchability for the night time prawn fishery in Albatross Bay. CIC reflects the composite effect of the monthly variation in size selectivity, emergence­burying behaviour and population density variation of prawn populations. The values of CIC for four dominant species, Metapenaeus endeavouri, M. ensis, Penaeus semisulcatus and P. esculentus, were examined. The value of CIC for M. endeavouri varied substantially and was the highest in August. The values of CIC for M. ensis were high during November to March and the seasonality was weaker than that for M. endeavouri. The monthly variation in CIC for P. semisulcatus reflected the seasonal variation in population density, being high during November to February. These results suggest that the catch ability of P. esculentus is steady throughout the year but it varies greatly on a seasonal basis for M. endeavouri.

• Biotechnology and Bioprocess Engineering:BBE
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• v.4 no.1
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• pp.1-11
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• 1999

Considerations of partition coefficients, selectivity, biocompatibility, and waste generation are important in selection of appropriate solvents to be used for extractive recovery of products from fermentation broths. Several selection criteria can be used based upon the nature of different species present in the broth. These criteria, along with examples of specific case studies, were presented. These serve not only in screening of useful solvents, but also in pointing to the specific modes of operation of recovery-coupled bioprocesses.

• Journal of Environmental Science International
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• v.9 no.4
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• pp.319-323
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• 2000

Nitrate-selective ion exchange resin which have bulky tertiary amine as functional group have been synthesized by the reaction of chloromethylated polystyrene-divinylbenzene copolymer and the corresponding tertiary amine [$NR_3=NE_{t3} 1, N{(C_2 H_4 H_3)}_32]$in ethanol, while commercial resin has $NMe_3$ as functional group. The fundamental properties such as bulk density, water content, appearance index, exchange capacity, effective size, uniformity coefficient of synthesized anion exchange resin (1) have been measured. The ion exchange resin (1) and (2) exhibited the better selectivity for nitrate than sulfate in both batch and continuous column experiments.

• Bulletin of the Korean Chemical Society
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• v.22 no.4
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• pp.405-408
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• 2001

New lipophilic triesters of calix[4]arene and calix[4]quinone are investigated as sodium ion-selective ionophores in poly(vinyl chloride) membrane electrodes. For an ion selective electrode based on calix[4]arene triester I, the linear response is 1 ${\times}$10-3.5 to 1 ${\times}$ 10-1 M of Na+ concentrations. The selectivity coefficients for sodium ion over alkali metal and ammonium ions are determined. The detection limit (logaNa+ = -4.50) and the selectivity coefficient (logKNa+,K+pot = -1.86) are obtained for polymeric membrane electrode containing calix[4]arene triester I.

• Bulletin of the Korean Chemical Society
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• v.12 no.4
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• pp.406-410
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• 1991

Second order rate constants have been measured spectrophotometrically for reactions of 4-nitrophenyl substituted benzoates with various aryloxides and aryl benzoates with p-chlorophenoxide. The reactivity has exhibited significant dependences on the electronic nature of the substituent in the acyl moiety of the substrate and in the nucleophilic phenoxide, while the substituent in the leaving phenoxide has little influenced the reactivity. The Bronsted coefficient $\beta$ values so obtiained support that the present acyl transfer reaction proceeds via a stepwise mechanism in which the nucleophilic attack would be the rate-determining step. Interestingly, the magnitude of the $\betaacyl$ and $\beta$ nuc increases with increasing reactivity, implying that the reactivity selectivity principle is not operative in the present system. The failure of the reactivity selectivity principle is attributed to a change in transition state structure upon the substituent variation in the present acyl transfer reaction.

• Bulletin of the Korean Chemical Society
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• v.22 no.12
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• pp.1345-1349
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• 2001

New quadruply-bridged calix[6]arenes (I-V) have been studied as cesium selective ionophores in poly(vinyl chloride) (PVC) membrane electrodes. PVC membranes were prepared with dioctyl sebacate (DOS) or 2-nitrophenyl octyl ether (o-NPOE) as the sol vent mediator and potassium tetrakis(p-chlorophenyl)borate as the lipophilic salt additive. These ionophores produced electrodes with near-Nernstian slope. The selectivity coefficients for cesium ion with respect to alkali, alkaline earth and ammonium ions have been determined. The lowest detection limit (logaCs+ = -6.3) and the higher selectivity coefficient (logkpotCs+,Rb+ = -2.1 by SSM, -2.3 by FIM for calix[6]arene I) for Cs+ have been obtained for membranes containing quadruply-bridged calix[6]arenes (I, Ⅱ, Ⅲ), which have no para t-butyl substituents on the bridging benzene ring.

• Applied Chemistry for Engineering
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• v.26 no.2
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• pp.234-238
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• 2015

The separation of nitrogen heterocyclic compound (NHC) contained in a model coal tar fraction was compared by the methanol and formamide extraction. The model coal tar fraction comprising four kinds of NHC (NHCs : quinoline, iso-quinoline, indole, quinaldine) and three kinds of bicyclic aromatic compound (BACs : 1-methylnaphthalene, 2-methylnaphthalene, dimethylnaphthalene), biphenyl and phenyl ether was used as a raw material. The aqueous solution of methanol and formamide were used as solvents. A batch-stirred tank was used as the raw material - a solvent contact unit of this work. Independent of the solvent used, the distribution coefficient of NHCs sharply increased by decreasing the initial volume ratio of water to the solvent and increasing the equilibrium operation temperature, whereas, the selectivity of NHCs in reference to BACs decreased. Decreasing the initial volume ratio of solvent to feed resulted in deteriorating distribution coefficients, but the selectivity of NHCs in reference to BAC was almost the constant. The distribution coefficient of NHCs by the methanol extraction was 3~5 times higher than that of NHCs by the formamide extraction, inversely, the selectivity of NHCs based on BACs by the formamide extraction was 3~7 times higher than that of NHCs by the methanol extraction. Furthermore, two different solvent extraction methods by adding the extraction processing speed to the balance between solvency and selectivity of NHCs were compared.

• Applied Chemistry for Engineering
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• v.33 no.4
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• pp.431-435
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• 2022

The reduction of nitrogen-containing compounds (NC) containing the model crude methylnaphthalene oil (CMNO) of 5 compounds system was experimentally studied by solvent extraction. The model CMNO consisting of 3 kinds of NC including quinolone (QU), iso-quinoline (IQU), indole(IN) and 2 kinds of bicyclic aromatic compounds such as 1-methylnaphthalene (1MNA), 2-methylnaphthalene (2MNA) as raw materials, as well as the aqueous solution of formamide as a solvent, were used. The increase in the volume fraction of water to the solvent at the initial state (y_w,0) sharply decreased, but the distribution coefficient and the yield of NC conversely increased the selectivity of NC based on 2MNA, and an increase in the volume fraction of solvent to feed (S/F) simultaneously increased the distribution coefficient, yield and selectivity of NC. The yields of QU, IQU and IN under constant conditions (y_w,0 = 0.1, S/F = 1, equilibrium temperature 303 K) were 30%, 31% and 10%, respectively, and selectivity was 15, 15 and 20, respectively. From the excellent yield and selectivity of NC, the formamide extraction method of this study was expected as a method for reducing the NC contained in the model CMNO.

• Archives of Pharmacal Research
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• v.17 no.6
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• pp.443-451
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• 1994

The binding characteristics of pirenzepine and oxomemazine to muscarinic receptor were studied to evaluate the selectivity of oxomemazine for the muscarinic receptor subtypes in rat cerebral microsomes. Equililbrium dissociation constant $(K_D){\;}of{\;}(-)[^3H]$quinuclidinyl benzilate$([^3H)QNB)$ determined from saturation isotherms was 64-pM. Analysis of the pirenzepine inghibition curve of [$^3H$]QNB binding to cerebral microsome indicatd the presence of two receptor subtypes with high $(K_1 = 16 nM, M_1 receptor)$two receptor subypes with about 20-fold difference in the affinity for high $(k_1 = 84nM, {\;} O_H receptor){\;} and {\;}low{\;} (K_1{\;} ={\;} 1.65\muM, {\;} O_L receptor$) affinity sites. The percentage populations of $M_1{\;} and M_3$, /TEX> receptors to the total receptors were 61 : 39, and those of $O_H{\;} and{\;} O_L$ receptors 39 : 61, resepectively. Both pirenzepine and oxomemazine increaed the $K_D$ value for $[^3H]QNB$ without affecting the binding site concentrations and Hii coefficient for the $[^3H]QNB$ without affecting the binding site concentractions and Hill coefficient for the [$^{3}$H]QNB binding. Oxomemazine had a 10-fold higher affinity at $M_1$ receptors than at $M_3$ receptors, and pirenzepine a 8-fold higher affinity at $O_H$ receptors were of $O_H$ receptors and 71% of $M_3$ receptors. However, $M_3$for oxomemazine and $O_H$for pirenzepine were composed of a uniform population. These results suggest that oxomemazine could be classified as a selective drug for $M_1$ receptors and also demonstrate that rat cerebral microsomes contain three different subtypes of $M_1{\;} M_3$ and the other site which is different from $M_1, {\;} M_2$, /TEX> receptors.

• Journal of the Korean Chemical Society
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• v.28 no.2
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• pp.86-94
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• 1984

The single crystal ion-selective electrode,$ {\beta}-Ag_3SI/PVC-THF $membrane electrode has showed a linear potential response to the activities of iodide ion (10-1${\sim}$10-7M). The $ {\beta}-Ag_3SI$ membrane electrode was compared with AgI/PVC-THF membrane and copper metal plate membrane electrodes. In order to measure the selectivity coefficient of the electrodes toward $Cl^-$ and $Br^-$, the separation and mixed solution method were employed. The potential-time curve was obtained by the usual immersion technique and pH effect was also examined. The orders of selectivity for $Br^-$, $Cl^-$ and stability of response time are ${\beta}-Ag_3SI/PVC-THF $membrane > AgI/PVC-THF membrane > copper metal plate membrane. These electrodes could be used as indicating electrodes in the potentiometric titration of a single halide and mixed halides with the standard solution of silver nitrate.