• Journal of the Korean Vacuum Society
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• v.21 no.6
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• pp.342-347
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• 2012

The optical properties of InAs quantum dots (QDs) grown on a GaAs substrates by migration enhanced molecular beam epitaxy method have been investigated by using photoluminescence (PL) and time-resolved PL measurements. The luminescence properties of InAs/GaAs QDs have been studied as functions of temperature, excitation laser power, and emission wavelength. The PL peak of InAs QDs capped with $In_{0.15}Ga_{0.85}As$ layer (QD2) measured at 10 K is redshifted about 80 nm compared with that of InAs QDs with no InGaAs layer (QD1). This redshift of QD2 is attributed to the increase in dot size due to the diffusion of In from the InGaAs capping layer. The PL decay times of QD1 and QD2 at 10 K are 1.12 and 1.00 ns taken at the PL peak of 1,117 and 1,197 nm, respectively. The reduced decay time of QD2 can be explained by the improved carrier confinement and enhanced wave function overlap due to increased QD size. The PL decay times for both QD1 and QD2 are independent on the emission wavelength, indicating the uniformity of dot size.

• IMMUNE NETWORK
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• v.24 no.2
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• pp.17.1-17.16
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• 2024

We have reported that anterior cruciate ligament (ACL) injury leads to the differential dysregulation of the complement system in the synovium as compared to meniscus tear (MT) and proposed this as a mechanism for a greater post-injury prevalence of post traumatic osteoarthritis (PTOA). To explore additional roles of complement proteins and regulators, we determined the presence of decay-accelerating factor (DAF), C5b, and membrane attack complexes (MACs, C5b-9) in discarded surgical synovial tissue (DSST) collected during arthroscopic ACL reconstructive surgery, MT-related meniscectomy, osteoarthritis (OA)-related knee replacement surgery and normal controls. Multiplexed immunohistochemistry was used to detect and quantify complement proteins. To explore the involvement of body mass index (BMI), after these 2 injuries, we examined correlations among DAF, C5b, MAC and BMI. Using these approaches, we found that synovial cells after ACL injury expressed a significantly lower level of DAF as compared to MT (p<0.049). In contrast, C5b staining synovial cells were significantly higher after ACL injury (p<0.0009) and in OA DSST (p<0.039) compared to MT. Interestingly, there were significantly positive correlations between DAF & C5b (r=0.75, p<0.018) and DAF & C5b (r=0.64 p<0.022) after ACL injury and MT, respectively. The data support that DAF, which should normally dampen C5b deposition due to its regulatory activities on C3/C5 convertases, does not appear to exhibit that function in inflamed synovia following either ACL injury or MT. Ineffective DAF regulation may be an additional mechanism by which relatively uncontrolled complement activation damages tissue in these injury states.

• Food Science and Preservation
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• v.11 no.3
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• pp.411-416
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• 2004

Botanical antimicrobial agent-grapefruit seed extract mixture(BAAG), which could be applied to the preparation of antimicrobial packaging paper, was investigated in order to prove the preservative function of fruits and vegetables. HAAG showed remarkable antimicrobial effects against Fusarium solani Botrytis cinerea, Pencillium crustosum, Erwinia carotovora, Phoma destructiva and Alternaria radicina causing the postharvest decay of fruits and vegetables. We have examined that HAAG could inhibit the growth of microorganims when treated with more than 500 $\mu$g/mL concentration. The activities of HAAG were stable in the wide spectrum of pH and temperature. Direct visualization of microbial cells by using scanning electron microscope showed the loss of microbial cell membrane function, which was destroyed by treating with the dilute solutions of HAAG. We could confirm that HAAG be an antimicrobial agent for the preparation of antimicrobial packaging paper.

• Geomechanics and Engineering
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• v.3 no.1
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• pp.61-81
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• 2011

In this paper, a complement to the Hoek-Brown criterion is proposed in order to derive the strength of anisotropic rock from strength of the corresponding truly intact rock. The complement is a decay function, which unlike other modifications or suggestions made in the past, is multiplied to the function of the original Hoek-Brown failure criterion for intact rock. This results in a combined and extended form of the criterion which describes the strength of anisotropic rock as a varying fraction of the corresponding truly intact rock strength. Statistical procedures and in particular regression analyses were conducted into data obtained in experiments conducted in the current research program and those collected from the literature in order to define the Hoek-Brown's criterion complement. The complement function was best described by a simple polynomial including only three constants to be empirically evaluated. Further investigations also showed that these constants can be related to the other readily available parameters of rock material which further facilitate determining the constants. A great and prime advantage of the proposed complement is that it is mathematically simple including the least possible number of empirical constants which are easily estimated with minimum experimental effort. Moreover, proposed concept does not suggests any change to the original Hoek-Brown criterion itself or its constants and serves whenever anisotropy does exist in the rock. This further implies on the possibility of using any other failure criterion for intact rock in conjunction with the compliment to reach the strength of anisotropic rock.

• Journal of Korean Neurosurgical Society
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• v.66 no.4
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• pp.382-392
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• 2023

Objective : The use of indocyanine green videoangiography (ICG-VA) to assess blood flow in the brain during cerebrovascular surgery has been increasing. Clinical studies on ICG-VA have predominantly focused on qualitative analysis. However, quantitative analysis numerical modelling for time profiling enables a more accurate evaluation of blood flow kinetics. In this study, we established a multiple exponential modified Gaussian (multi-EMG) model for quantitative ICG-VA to understand accurately the status of cerebral hemodynamics. Methods : We obtained clinical data of cerebral blood flow acquired the quantitative analysis ICG-VA during cerebrovascular surgery. Varied asymmetric peak functions were compared to find the most matching function form with clinical data by using a nonlinear regression algorithm. To verify the result of the nonlinear regression, the mode function was applied to various types of data. Results : The proposed multi-EMG model is well fitted to the clinical data. Because the primary parameters-growth and decay rates, and peak center and heights-of the model are characteristics of model function, they provide accurate reference values for assessing cerebral hemodynamics in various conditions. In addition, the primary parameters can be estimated on the curves with partially missed data. The accuracy of the model estimation was verified by a repeated curve fitting method using manipulation of missing data. Conclusion : The multi-EMG model can possibly serve as a universal model for cerebral hemodynamics in a comparison with other asymmetric peak functions. According to the results, the model can be helpful for clinical research assessment of cerebrovascular hemodynamics in a clinical setting.

• Korean Journal of Environmental Biology
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• v.39 no.3
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• pp.374-382
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• 2021

In the present study, we analyzed the decay rate and nutrient dynamics during leaf litter decomposition of Pinus densiflora and Pinus thunbergii in Gongju for 60 months, from 2014 to 2019. P. thunbergii leaf litter decomposed faster than that of P. densiflora. The decay constant of P. densiflora and P. thunbergii leaf litter after 60 months was 3.02 and 3.59, respectively. The initial C/N ratio of P. densiflora and P. thunbergii leaf litter were 14.4 and 14.5, respectively. After 60 months, C/N ratio of decomposing P. densiflora and P. thunbergii leaf litter decreased to 2.26 and 3.0, respectively. The initial C/P ratio of P. densiflora and P. thunbergii leaf litter were 144.1 and 111.3. After 60 months elapsed, the C/P ratio of decomposing P. densiflora and P. thunbergii leaf litter decreased to 40.1 and 45.8, respectively. After 60 months, the percentage of the remaining N, P, K, Ca, and Mg in decomposing P. densiflora leaf litter was 231.08, 130.13, 35.68, 48.58, and 36.03%, respectively. After 60 months, the percentage of the remaining N, P, K, Ca, and Mg in decomposing P. thunbergii leaf litter was 143.91, 74.02, 28.59, 45.08, and 44.99%, respectively. The findings of the present study provide an insight into the forest ecosystem function of coniferous forests through the analysis of the amount of nutrient transfer into the soil through a long-term decomposition process; this information is intended to be used as basic data for preparing counter measures for future climate and ecosystem changes.

• Journal of Photoscience
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• v.9 no.2
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• pp.55-58
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• 2002

The reaction center Dl protein of photosystem II is the target of photodamage by excess illumination. The Dl protein is damaged by reactive oxygen species generated by photochemical reactions and then degraded by specific proteolytic enzymes. We found that the Dl protein also cross-links with the surrounding polypeptides, such as D2 and CP43 in isolated thylakoids or photosystem II-enriched membranes from spinach under the illumination with strong visible light. The cross-linking was observed in spinach leaf discs as well when they were illuminated at higher temperature (40°C). It was also shown that the cross-linked products are digested efficiently by a protease(s) in the stroma. Thus the cross-linking/digestion processes of the Dl protein seem to comprise a new pathway in the turnover of the photodamaged Dl protein. It should be noted, however, that the cross-linked products of the Dl protein and CP43 induced by endogenous cationic radicals in the donor-side photoinhibition are resistant to proteolytic digestion. Accumulation of these cross-linked products in the thylakoids may lead to the decay of the function of chloroplasts and finally to the death of plant cells. Thus, we suggest that the quality control of photosystem II, especially removal of the cross-linked products of the Dl protein, is crucial for the survival of chloroplasts under the light stress.

• Animal cells and systems
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• v.7 no.4
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• pp.289-294
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• 2003

To quantify nutrient loading from emergent macrophytes through leaching in the littoral zones of Paldang Reservoir, we conducted incubation experiments using leaf litter of the emergent macrophyte, Zizaniz latifolia. To separate the leaching process from microbial decay, we used $HgCl_2$ to suppress microbial activity during the experiment. We measured electric conductivity, absorbance at 280nm, total nitrogen and dissolved inorganic nitrogen, total phosphorus and soluble reactive phosphorus, Na, K, Mg and Ca amounts in leaf litter and in water. In addition, we examined the effects of water temperature and ion concentrations of ambient water on the leaching process. A total of 6% of the initial ash-free dry mass of leaf litter was lost due to leaching during incubation (four days). Electric conductivity and A280 continued to increase and saturate during the incubation. To compare reaching rates of different nutrients, we fitted leaching dynamics with a hyperbolic saturation function [Y=AㆍX/(B+X)]. From these fittings, we found that ratios of leaching amounts to nutrient concentration in the litter were in the order of K > Na > Mg > P > Ca > N. Leaching from leaf litter of Z. latifolia was dependent on water temperature while it was not related with ion concentrations in the ambient water. Our results suggest that the leaching process of nutrients, especially phosphorus, from aquatic macrophytes provides considerable contribution to the eutrophication of the Paldang Reservoir ecosystem.

• Journal of Ocean Engineering and Technology
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• v.30 no.2
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• pp.75-83
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• 2016

An experimental study on a subsea installation using an offshore crane was conducted. Concrete blocks, suction piles, and manifolds were considered in this study. Free decay tests were conducted to investigate the fluid characteristics of the subsea structures. The added masses of the structures were estimated. The motion response amplitudes of the subsea structures were compared for different structures and water depths. In addition, the dynamic tension transfer function of the crane wire was investigated. The root mean square values of the heave motion and the dynamic amplification factor of the wire tension were investigated in irregular waves.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.489-491
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• 2012

An $^{125}I$-labeled resveratrol derivative 1 was synthesized. It was purified by reverse phase HPLC. Radiochemical purity of the product was more than 98%, and the yield was 35% (decay-corrected). Its biodistribution in tumorbearing mice was studied. The results showed that the highest radioactivity was located in intestine and stomach. The biodistribution profile suggests that compound 1 can be effectively used as a promising imaging probe for intestine and stomach.