• Korean Journal of Ecology and Environment
• /
• v.41 no.2
• /
• pp.117-127
• /
• 2008

Green algae are important primary producers in aquatic ecosystem, and they are sensitive test species in bioassay. Green algae are broadly used to assess the adverse effects of various chemicals by measuring the inhibition of metabolism, reproduction and survival. In this study, we extensively gathered domestic and foreign toxicity test methods conducted using green algae, which are distributed in Korean water environment. Selected eight domestic green algae were Chlamydomonas reinhardtii, Desmodesmus subspicatus (=Scenedesmus subspicatus), Scenedesmus abundans, Scenedesmus acutus, Scenedesmus quadricauda, Podohedriella falcata (=Ankistrodesmus falcatus), Pseudokirchneriella subcapitata (=Selenastrum capricornutum), and Chlorella vulgaris. Forty four test methods were collected from the standard test ones, government reports, SCI papers and Korean research papers. P. subcapitata and D. subspicatus are the most common test species recommended by the standard test methods. Initial cell density and dilution water were the main differences among the test methods we collected. We proposed the suitable ecotoxicity test methods based on domestic green algae in Korea. This study could be a fundamental basis to establish the ecotoxicity test methods by green algae distributed in Korea.

• Korean Journal of Environmental Biology
• /
• v.29 no.1
• /
• pp.17-22
• /
• 2011

The distributional pattern of benthic diatoms in tidal flats of Hampyeong Bay, Korea, was studied from January to October in 2009. As benthic diatoms of Hampyeong Bay tidal flats, 45 species were identified, and the most dominant species was Paralia sulcata. The most diverse flora was observed at Gaip and Songseok sites in April with 22 species, and the least at Hyeonhwa site in January. The ranges of chlorophyll-a concentration in tidal flats were 21.2~31.8 mg$m^{-2}$ at Hyeonhwa site, 23.6~35.4 mg $m^{-2}$ at Gaip site, and 24.2~34.3 mg $m^{-2}$ at Songseok site. The concentrations of pheopigment ranged between 25.3 and 45.2 mg$m^{-2}$. The standing crops of benthic diatoms showed highest density in April and lowest in January, February, and October. The cell volumes of benthic diatoms were highest in April. The taxa and biomass of benthic diatoms showed correlations with temperature. On temperature variables, the benthic diatoms showed optimal occurrences at the range of $14{\sim}17^{\circ}C$.

• Korean Journal of Environmental Biology
• /
• v.26 no.2
• /
• pp.76-86
• /
• 2008

The seasonal variations of primary production were investigated by phyto-PAM chlorophyll fluorometry as well as classical methods (standing crops of phytoplanktons and chlorophyll ${\alpha}$) in the Beopsu Marsh, Haman-gun, Gyeongsangnam-do. The amounts of turbidity, SS, T-N, T-P, BOD, COD, Ca$^{2+}$ and Cl$^-$ were the highest at the station 3, where located in flowout site of wastewater treated by the filtration plants. The water quality was the third level by the standard of BOD and COD. The amount of chlorophyll a (268.8 mg L$^{-1}$) was the highest at the station 2 in April because the cell density (2,677 cells mL$^{-1}$) of Micractinium pusillum increased suddenly from February (180 cells mL$^{-1}$). The patterns of primary production of phytoplankton by phyto-PAM chlorophyll fluorometry were fallen in with those of standing crops and chlorophyll a of phyto-planktons. The primary production was varied according to stations and seasons. The water environments of the Beopsu Marsh as a natural mounument should be under the control of a regular examination in order to preserve the ecosystem.

• Journal of Sensor Science and Technology
• /
• v.7 no.2
• /
• pp.131-139
• /
• 1998

$CdS_{0.67}Se_{0.33}$ single crystal was grown by vertical sublimation method of closed tube physical vapour deposition. The (0001) growth plane of oriented single crystals was confirmed from the back-ref1ection Laue patterns. From the Hall effects by van der Pauw method, the as-grown $CdS_{0.67}Se_{0.33}$ single crystals were found to be n-type semiconductors. The mobility appeared to be decreased by lattice scattering at temperature range from 150K to 293K and by impurity scattering at temperatures ranging from 30K to 150K In order to explore its applicability in photoconductive cells, we measured the ratio of photo-current to dark-current (pc/dc), maximum allowable power dissipation (MAPD), spectral response and response time respectively. The results indicated that for the samples annealed in Cu vapour the photoconductive characteristics are best. We obtained sensitivity of 0.99, the value of pc/de of $1.84{\times}10^{7}$, the MAPD of 323mW and the rise and decay time of 9.3 ms and 9.7 ms, respectively.

• Applied Microscopy
• /
• v.40 no.2
• /
• pp.101-108
• /
• 2010

Vitex negundo is an aromatic plant which releases a unique scent due to the presence of essential oil stored presumably within glandular trichomes. The focus of this research was to study developmental patterns of glandular trichomes in Vitex negundo leaves using electron microscopy. There are two types of glandular trichomes which develop on the leaf epidermis of Vitex negundo, peltate glandular type (PT) and capitate glandular type (CT). Structural features differ significantly depending on size and density, formation of secretory cavity, plastid, etc during developmental stages. In young leaves, undifferentiated PTs are densely distributed in the upper epidermis, but are not externally exposed in the lower epidermis because they are covered by non-glandular simple trichomes. Upon leaf development, PTs and CTs show clear structural differentiation in the upper and lower epidermis. PTs are composed of up to eight head cells (ca. 35~40 ${\mu}m$) and one stalk cell (ca. 5 ${\mu}m$), while CTs are composed of four head cells (ca. 10~15 ${\mu}m$) and 1~2 stalk cells (ca. 10 ${\mu}m$). Although secretory cavities develop on the secretory head cells, their size, structure, and formation proceed very differently depending on trichome type. In early development of PT, a large cavity with numerous secretory vesicles form rapidly from the head cells. In CT, however, only a small secretory cavity is formed, slowly relative to PT, without secretory vesicles. The PTs are considered to play an important role in releasing the aromatic components of Vitex negundo.

• Journal of Pharmacopuncture
• /
• v.20 no.1
• /
• pp.52-56
• /
• 2017

Objectives: Neutrophils represent the front line of human defense against infections. Immediately after stimulation, neutrophilic enzymes are activated and produce toxic mediators such as pro-inflammatory cytokines, nitric oxide (NO) and myeloperoxidase (MPO). These mediators can be toxic not only to infectious agents but also to host tissues. Because flavonoids exhibit antioxidant and anti-inflammatory effects, they are subjects of interest for pharmacological modulation of inflammation. In the present study, the effects of rutin on stimulus-induced NO and tumor necrosis factor $(TNF)-{\alpha}$ productions and MPO activity in human neutrophils were investigated. Methods: Human peripheral blood neutrophils were isolated using Ficoll-Hypaque density gradient centrifugation coupled with dextran T500 sedimentation. The cell preparations containing > 98% granulocytes were determined by morphological examination through Giemsa staining. Neutrophils were cultured in complete Roswell Park Memorial Institute (RPMI) medium, pre-incubated with or without rutin ($25{\mu}M$) for 45 minutes, and stimulated with phorbol 12-myristate 13-acetate (PMA). Then, the $TNF-{\alpha}$, NO and MPO productions were analyzed using enzyme-linked immunosorbent assay (ELISA), Griess Reagent, and MPO assay kits, respectively. Also, the viability of human neutrophils was assessed using tetrazolium salt 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), and neutrophils were treated with various concentrations of rutin ($1-100{\mu}M$), after which MTT was appended and incubated at $37^{\circ}C$ for 4 hour. Results: Rutin at concentrations up to $100{\mu}M$ did not affect neutrophil viability during the 4-hour incubation period. Rutin significantly decreased the NO and $TNF-{\alpha}$ productions in human peripheral blood neutrophils compared to PMA-control cells (P < 0.001). Also, MPO activity was significantly reduced by rutin (P < 0.001). Conclusion: In this in vitro study, rutin had an anti-inflammatory effect due to its inhibiting NO and $TNF-{\alpha}$ productions, as well as MPO activity, in activated human neutrophils. Treatment with rutin may be considered as a therapeutic strategy for neutrophil-mediated inflammatory/autoimmune diseases.

• Journal of Periodontal and Implant Science
• /
• v.24 no.1
• /
• pp.144-154
• /
• 1994

Final goal of periodontal treatment is to reconstruct the destructed periodontal tissue as well as to remove the necrotic pathologic elements. The purpose of this study is to investigate on the effect of Zizyphi extract to the inhibitory ability on collagenolytic activity of P gingivalis, biologic activity of gingival fibroblasts, and on the collagen and protein synthesis of gingival fibroblasts. Gingival fibroblast from giniva of first bicuspids from patient for orthodontic treatment were used and cultured. For the measurement of inhibitory ability of collagenolytic activity, crude enzyme was extracted and used on the basis of modified Ono's method. On the inhibition of collagenolytic enzyme from herbal extracts, collagenokit CLN-100 were used. The cellular activity of gingival fibroblast, were studied using MTT solution and measured optical density on 570mm by ELISA reader. To measure the effects on the ability of whole protein and collagen synthesis, cell membrane was destructed with ultrasonic grinder after culturing, centrifuged and counted by liquid scintilation counter. The inhibitory effects on producing of $IL-l{\beta}$ by monocyte, after promotion of producing $IL-l{\beta}$ by LPS, were compared with the mixture of herbal extracts and other drugs using thymocyte stimulation assay. About inhibitory effects of $PGF_2$. by gingival fibroblasts, herbal extract was compared with the addition of the other control groups using enzyme imunoassay. On the inhibition of collagenolytic activity by P. gingivalis, benzene extracts showed the most efficient inhibitory effects among the $19{\mu}g/ml$ of the compared extracts and 40.5% by Tetracycline. On the cellular activity promoting effects, compared extracts showed a bit of more effects than PDGF of $100{\mu}g/ml$ concentration and IGF of $20{\mu}g/ml$ concentration. All of the PDGF, IGF, Zizyphi Fructus extract should increase in collagen synthesis, but especially 70% ethylalcohol extracts of Zizyphi Fructus showed comparably high effects among the compared extracts. Effects on whole protein synthesis were slightly increased on every extract but especially 70% ethylalcohol extract showed significantly effective than any other estract. On the inhibitory effects of Zizyphi Fructus $IL-l{\beta}$ production by monocyte, compared extracts showed 70% of highly inhibitory effect than that of 60% inhibition effects on controlled group and each extracts showed no significant difference. In $PGF_2$ production inhibitroy effect of Zizyphi Fructus gingival fibroblasts, Herbal extracts showed 70% of inhibition comparing with tat of 90.2% of controlled group, but each extracts showed similar effects excluding the $H_2O$ extracts. These results suggested that Zizyphi Fructus might be useful medicine for inhibition of inflammatory mediator including $IL-l{\beta}$ and $PGF_2$.

• Journal of Periodontal and Implant Science
• /
• v.43 no.2
• /
• pp.72-78
• /
• 2013

Purpose: The purpose of this study was to compare the phototoxic effects of blue light exposure on periodontal pathogens in both planktonic and biofilm cultures. Methods: Strains of Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, and Porphyromonas gingivalis, in planktonic or biofilm states, were exposed to visible light at wavelengths of 400.520 nm. A quartz-tungsten-halogen lamp at a power density of $500mW/cm^2$ was used for the light source. Each sample was exposed to 15, 30, 60, 90, or 120 seconds of each bacterial strain in the planktonic or biofilm state. Confocal scanning laser microscopy (CSLM) was used to observe the distribution of live/dead bacterial cells in biofilms. After light exposure, the bacterial killing rates were calculated from colony forming unit (CFU) counts. Results: CLSM images that were obtained from biofilms showed a mixture of dead and live bacterial cells extending to a depth of $30-45{\mu}m$. Obvious differences in the live-to-dead bacterial cell ratio were found in P. gingivalis biofilm according to light exposure time. In the planktonic state, almost all bacteria were killed with 60 seconds of light exposure to F. nucleatum (99.1%) and with 15 seconds to P. gingivalis (100%). In the biofilm state, however, only the CFU of P. gingivalis demonstrated a decreasing tendency with increasing light exposure time, and there was a lower efficacy of phototoxicity to P. gingivalis as biofilm than in the planktonic state. Conclusions: Blue light exposure using a dental halogen curing unit is effective in reducing periodontal pathogens in the planktonic state. It is recommended that an adjunctive exogenous photosensitizer be used and that pathogens be exposed to visible light for clinical antimicrobial periodontal therapy.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.6C
• /
• pp.429-437
• /
• 2008

Multiple-input multiple-output (MIMO) techniques can be used for the spectral efficiency enhancement of the cellular systems, which can be categorized into spatial multiplexing (SM) and spatial diversity schemes. MIMO systems suffer a severe performance degradation due to the intercell interference from the adjacent cells as the mobile terminal moves toward the cell boundary. Therefore for the spectral efficiency enhancement, an appropriate transmission scheme for the given channel environment and reception scheme which can mitigate the intercell interference are required. In this paper, we propose an adaptive signal transmission/reception scheme for the spectral efficiency improvement of $M_R{\times}M_T$ MIMO systems, present the decision criteria for the adaptive operation of the proposed scheme, and demonstrate the performance gain. The proposed scheme performs adaptive transmission using spatial multiplexing and spatial diversity, and adaptive reception using maximal ratio combining (MRC) and intercell spatial demultiplexing (ISD) when the spatial diversity transmission is used at the transmitter. Spatial multiplexing/demultiplexing is performed at the high signal-to-interference ratio (SIR) range, and the transmit diversity in conjunction with the adaptive reception uses either conventional MRC or ISD which can mitigate the $M_R-1$ interference signals, based on the mobile location. For the performance evaluation of the proposed adaptive scheme, the probability density function (pdf) of the effective SIR for the transmission/reception methods in consideration are derived for $M_R{\times}M_T$ MIMO systems. Using the results, the average effective SIR and spectral efficiency are presented and compared with simulation results.

• Korean Journal of Poultry Science
• /
• v.39 no.3
• /
• pp.215-222
• /
• 2012

This study was conducted to investigate the effects of supplementation diets of powdered mulberry leaves on egg production, egg quality and blood characteristics in laying hens. Laying hens were fed diets for 30 days containing 0% powdered mulberry leaves (Control), 1% powdered mulberry leaves (T1), 2% powdered mulberry leaves (T2), and 5% powdered mulberry leaves (T3). The egg production, yolk weight and albumen weight were no significant difference among treatment groups. The albumen weight was significantly decreased by the supplementation of powdered mulberry leaves in all treatment groups (P<0.05). The albumen high, yolk color score, egg sell thickness and egg shell breaking strength were no significant difference. The total cholesterol and triglyceride concentration of control was higher than T3, and the high density lipoprotein (HDL)-cholesterol concentration and glucose of control were lower than treatment groups (P<0.05). The white blood cell (WBC) was significantly increased by the supplementation of powdered mulberry leaves compared to the control (P<0.05). In conclusion, these data indicate that 5% powdered mulberry leaves supplementation was most effective in decreasing total cholesterol and triglyceride and increasing HDL-cholesterol, glucose and WBC.