• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.1
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• pp.16-23
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• 2001

Hydraulic transport of fines up to the surface of flotation cell was supposed to be a mechanism of fines fractionation through the froth-flotation. Efficient fractionation of fines means efficient skimming out of flotation rejects as much as possible with least long fiber loss. The selectivity of fines fractionation was found to be mainly affected by long fibers flocculation degree in this study. Lack of sufficient flocculation of long fibers could lead to extensive loss of long fibers. It was also found that higher flotation flux caused higher flotation reject as well as the increase of long fiber loss, but did not affect the fine content ratio in the flotation reject. We controlled the flotation flux and the stock consistency, and chose a cationic polymer to maximize the flocculation of long fibers and to increase the amount of flotation reject. The highest efficiency of fines fractionation was obtained at 1.3% of stock consistency and at 100L/min of flotation flux in our experimental set up. The cationaic polymer we chose was found to be very effective in fiber flocculation and flotation froth stabilization. New definitions of fractionation efficiency were introduced in this study to compare the results more clearly.

• Journal of Microbiology and Biotechnology
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• v.11 no.3
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• pp.458-462
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• 2001

The localization of paclitaxel was investigated in suspension culture cells of Taxus chinensis. Over 93% of the cell-associated paclitaxel were detected throughout the entire culture period. Intracellular localization of paclitaxel over the culture time was analyzed further by cell fractionation for days 21 and 42. Paclitaxel contents in intracellular organelles were decreased at day 42, while the content in the cell wall fraction was increased at day 42 compared to the value for day 21. The localization of paclitaxel in the cell wall was confirmed by using the immunocytochemical method with the aid of a confocal laser scanning microscope.

• Journal of Microbiology and Biotechnology
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• v.33 no.9
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• pp.1250-1256
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• 2023

Herein, different extracts of Scenedesmus deserticola JD052, a green microalga, were evaluated in vitro as a potential anti-aging bioagent. Although post-treatment of microalgal culture with either UV irradiation or high light illumination did not lead to a substantial difference in the effectiveness of microalgal extracts as a potential anti-UV agent, the results indicated the presence of a highly potent compound in ethyl acetate extract with more than 20% increase in the cellular viability of normal human dermal fibroblasts (nHDFs) compared with the negative control amended with DMSO. The subsequent fractionation of the ethyl acetate extract led to two bioactive fractions with high anti-UV property; one of the fractions was further separated down to a single compound. While electrospray ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) spectroscopy analysis identified this single compound as loliolide, its identification has been rarely reported in microalgae previously, prompting thorough systematic investigations into this novel compound for the nascent microalgal industry.

• Bulletin of the Korean Chemical Society
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• v.22 no.6
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• pp.616-622
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• 2001

Split-flow thin (SPLITT) cell Fractionation(SF) is a technique that allows separation of particulates and macromolecules into two fractions. A gravitational SF(GSF) system is constructed and tested for its applicability for separation of dust and ground water particulates. When tested with polystyrene latex particles, experimental data were in good agreements with theory. The 9.8 and 21.4㎛ polystyrene particles were successuflly separated in a continuous mode, where the mixture is continuously fed into the GSF channel allowing separation in a large sacle. The GSF system is successfully applied to continuous separation of dust and ground water particels based on the sedimentation coefficient, which is closely related to the particle size. The separations were confirmed by microscopy and energy-dispersive X-ray (EDX) analysos.

• Development and Reproduction
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• v.4 no.2
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• pp.237-242
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• 2000

Growth hormone releasing hormone (GHRH), the major hypothalamic stimulus of GH secretion from the anterior pituitary gland, has been found to be present in several extrahypothalamic sites including placenta testis, ovary and anterior pituitary gland. The present study was performed to elucidate the role of pituitary GHRH on proliferation of cells derived from rat anterior pituitary gland. The GHRH content of pituitary tissue, cultured pituitary cells, and the conditioned media was evaluated by radioimmunoassay (RIA). Primary cultures of pituitary cells derived from adult rats were prepared by enzymatic dispersion. Significant amounts of GHRH-like molecules were detected in both pituitary tissue and cell cultures by GHRH RIA. Competition curves with increasing amounts of tissue extracts and conditioned media were parallel with those of standard peptide, indicating that the pituitary GHRH-like material is similar to authentic GHRH. To analyze specific cell types responsible for producing GHRH in anteroior pituitary, cell fractionation technique combined with GHRH RIA was performed. In cell fractionation experiment, the highest level of GHRH content was found in gonadotrope enriched-fraction and followed by somatotrope-, lactotrope- and thyrotrope-fraction. Treatment of pituitary cells with GHRH resulted in a dose-dependent increase in [$^3$H] thymidine incorporation. The mitogenic effect of GHRH could be mediated by typical oncogenic activation since the GHRH induced transient increase in c-fos mRNA levels with peak response at 30 minutes. The present study demonstrated that i) the pituitary GHRH expressed in the rat anterior pituitary gland can be secreted, ii) among the various cell types, gonadotropes and somatotorpes are the major GHRH source, and iii) the GHRH treatment increased the [$^3$H] thymidine incorporation and c-fos transcriptional activity in the pituitary cell culture. These findings suggested that GHRH could participated in the paracrine and/or autocrine regulation of cell proliferation, as well as promoting growth hormone secretion.

• Analytical Science and Technology
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• v.28 no.6
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• pp.453-459
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• 2015

Split-flow thin cell fractionation (SPLITT fractionation, SF) is a particle separation technique that allows continuous (and thus a preparative scale) separation into two subpopulations based on the particle size or the density. In SF, there are two basic performance parameters. One is the throughput (TP), which was defined as the amount of sample that can be processed in a unit time period. Another is the fractionation efficiency (FE), which was defined as the number % of particles that have the size predicted by theory. Full-feed depletion mode (FFD-SF) have only one inlet for the sample feed, and the channel is equipped with a flow stream splitter only at the outlet in SF mode. In conventional FFD-mode, it was difficult to extend channel due to splitter in channel. So, we use large scale splitter-less FFD-SF to increase TP from increase channel scale. In this study, a FFD-SF channel was developed for a large-scale fractionation, which has no flow stream splitters (‘splitter less’), and then was tested for optimum TP and FE by varying the sample concentration and the flow rates at the inlet and outlet of the channel. Polyurethane (PU) latex beads having two different size distribution (about 3~7 µm, and about 2~30 µm) were used for the test. The sample concentration was varied from 0.2 to 0.8% (wt/vol). The channel flow rate was varied from 70, 100, 120 and 160 mL/min. The fractionated particles were monitored by optical microscopy (OM). The sample recovery was determined by collecting the particles on a 0.1 µm membrane filter. Accumulation of relatively large micron sized particles in channel could be prevented by feeding carrier liquid. It was found that, in order to achieve effective TP, the concentration of sample should be at higher than 0.4%.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2015.10a
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• pp.171-172
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• 2015

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.373.2-373.2
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• 2002

In search for plant-derived cytotoxic compounds, it was found that the MeOH extracts obtained from Amanita pantherina(DC. ex Fr.) Krombh exhibited significant cytotoxic activity against human tumor cell line. The classical fractionation on the basis of the inhibitory activity upon the growth human tumor cell line. in vitro, and repeated column chromatography afforded several cytotoxic compounds from Amanita pantherina (DC, ex Fr.) Krombh. (omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.210.2-210.2
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• 2003

Cornis fructus were extracted by successive extractions and then fractionated with chloroform extract to get active fractions. This study was performed to determine the cytotoxic effect of chloroform extract from Cornis fructus on NIH 3T3 fibroblasts and cancer cell lines using MTT assay. All extracts did not exhibit cytotoxicity in HIH 3T3 fibroblasts. Chloroform extract exhibited antitumor activity in A549, MDA-MB-123, B16 melanoma and SNU-C4 cells. Futher fractionation with chloroform extract was performed to obtain effective fractions. (omitted)

• Korean Journal of Medicinal Crop Science
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• v.10 no.4
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• pp.269-272
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• 2002

Ethanol and butanol fractionation of E. senticosus showed strong anti-oxidant activity, and methanol and water extracts also had high anti-oxidant activity. The anti-oxidant activities in ethanol and butanol fractionation were higher than or similar to those of ${\alpha}-tocopherol$. The cytotoxic effect of root extract of E. senticosus was evaluated on seven different human cancer cell lines, The extracts of leaf and stem of E. senticosus also had strong antioxidant activity, but the antioxidant activity in root extract was higher than those in leaf and stem extracts. Methanol, hexane, and aqueous fraction layer had much higher inhibitory activities on lipid peroxidation in rat liver microsomes compared with ${\alpha}-tocopherol$. The effect of root extract of E. senticosus was evaluated on six human cancer cell lines. The values of 50% growth inhibition $(GI_{50})$ for the extracts were mostly below $30{\mu}g/ml$, and the extracts are considered as active inhibitory compounds on cancer cells.