Induction of apoptosis by the tropical seaweed Pylaiella littoralis in HT-29 cells via the mitochondrial and MAPK pathways

We demonstrated that an extract from Pylaiella littoralis, collected from the Federate States of Micronesia (FSM), could inhibit the proliferation of tumor cells. P. littoralis extract (PLE) showed anti-proliferative activities in the tumorigenic cells tested, ranging from 20.2% to 67.9%. The highest inhibitory activity, in HT-29 cells, was selected for further experiments. PLE showed no cytotoxic effect in normal cells and inhibited the growth of HT-29 cells depending on concentration and incubation time. PLE-treated HT-29 cells showed the typical morphological characteristics of apoptosis, such as apoptotic body formation and DNA fragmentation. PLE also induced mitochondrial membrane potential depolarization and resulted in increased mitochondrial membrane permeability, compared with untreated cells. PLE decreased Bcl-2 protein and increased Bax protein expression, activating caspase-3 and poly (ADP-ribose) polymerase (PARP) expression via the caspase pathway. PLE also increased the phosphorylation of c-Jun N-terminal kinase (JNK), p38, and extracellular signal-regulated kinase (ERK), and it reduced cell viability in treatment cells with specific inhibitors such as PD98059 (a specific inhibitor of ERK), SP600125 (a specific inbibitor of JNK), and SB 203580 (a specific inbibitor of p38 MAPK). via the the mitogen-activated protein kinases (MAPKs) pathway. These results suggest that PLE inhibits the proliferation of HT-29 cells by affecting the caspase and MAPK pathways involved in the induction of apoptosis. Thus, we suggest that P. littoralis extract might be potential candidate agents for the treatment of human colorectal cancer.     

Estimation of asymptotic variances of quantiles for the generalized logistic distribution

In this study, the parameter estimations for the 3-parameter generalized logistic (GL) distribution are presented based on the methods of moments (MOM), maximum likelihood (ML), and probability weighted moments (PWM). The asymptotic variances of the MOM, ML, and PWM quantile estimators for the GL distribution are expressed as functions of the sample size, return period, and parameters. A Monte Carlo simulation was performed to verify the derived expressions for variances and covariances between parameters and to evaluate the applicability of the derived asymptotic variances of quantiles for the MOM, ML and PWM methods. The simulation results generally show good agreement with the analytical results estimated from the asymptotic variances of parameters and quantiles when the shape parameter (β) of the GL distribution is between −0.10 and 0.10 for the MOM method and between −0.25 and 0.45 for the ML and PWM methods, respectively. In addition, the actual sample variances and the root mean square error (RMSE) of asymptotic variances of quantiles for various sample sizes, return periods, and shape parameters were presented. In order to evaluate the applicability of the estimation methods to real data and to compare the values of estimated parameter, quantiles, and confidence intervals based on each parameter estimation method, the GL distribution was fitted to the 24-h annual maximum rainfall data at Pohang, Korea.     

Forest fire risk mapping of Kolli Hills, India, considering subjectivity and inconsistency issues

Forest fires have adverse ecological, economic, and social impacts. In this light, the present research aimed, first, to construct a fire risk model using a GIS-based multi-criteria analysis and second, to derive a forest fire risk modeling strategy that alleviates the problem of inconsistency in the assigning of scores and weights to forest fire categories and layers. Third, the local-orientation effects and causes, which are relevant to the subjectivity problem, were investigated by comparing the risk scoring and weighting outcomes from Indian and Korean expert groups (IEG and KEG). Fourth, forest fire factors that can be considered regional and global also were investigated. Kolli Hills, India, was selected as the study area in this research. In the interests of alleviating the inconsistency problem, a weighting and scoring scheme based on the analytic hierarchy process was applied. The experiences from the existence of prevailing westerly winds, the most common forest types (i.e., in Korea: pine trees), and the different anthropogenic pressures between Korea and India resulted in the different scoring and weighting decisions of the two expert groups. Among the five fire risk factors, slope, road, and settlement can be considered to be global factors. On the other hand, forest cover and aspect are regional factors that can be more influenced by local environmental conditions. When considering the producer’s accuracy, the approach of the IEG together with the natural breaks thresholding method provided the best fire risk mapping result. On the other hand, the model from the IEG with equal interval provided the best result from the viewpoint of user’s accuracy and overall accuracy. Overall, this paper proposes a forest fire risk mapping procedure as basis for developing a global forest fire risk modeling in the future, where a series of standardized modeling steps and variables should be defined.     

A study on measurement and analysis of radon-222 (uranium series) emitted to the atmosphere from construction materials (cement block, kaolin brick, and gypsum board) in living environment

The purpose of this study was to measure, compare, and analyze the air concentration of radon that was emitted to the atmosphere from construction materials such as cement brick, tile, red clay tile, and gypsum tile. The study method was to use continuous radon monitoring equipment (RTM 1688-2) to measure concentrations of radon and thoron contained in brick, tile, red clay tile, and gypsum tile. According to the measurement results, the cement brick among the four samples showed the highest measurement value for radon, while the red clay tile showed the highest measurement value for thoron. When the radon emission concentration was estimated based on materials required for construction per unit area (3.3 m²) in an actual construction, the cement brick had the highest measurement values for radon and thoron. This study confirmed the degree of radon emission from construction materials. The purpose of this study was also to suggest a method to examine the effects of radon and reduce the dose of personal radiation exposure. It is believed that the government should be active in publicizing and managing use of construction materials that have lower levels of radon emission.     

A comparative study of the adaptive choice of thresholds in extreme hydrologic events

In the hydrologic analysis of extreme events such as precipitation or floods, the data can generally be divided into two types: partial duration series and annual maximum series. Partial duration series analysis is a robust method to analyze hydrologic extremes, but the adaptive choice of an optimal threshold is challenging. The main goal of this paper was to determine the best method for choosing optimal thresholds. Ten semi-parametric tail index estimators were applied to find the optimal threshold of a 24-h duration precipitation period using data from the Korean Meteorological Administration. The mean square errors of the 10 estimators were calculated to determine the optimal threshold using a semi-parametric bootstrap method. A modified generalized Jackknife estimator determined the best performance in this study among the 10 estimators evaluated with regard to estimating the mean square error of the shape estimator for the generalized Pareto distribution.     

Meta-heuristic maximum likelihood parameter estimation of the mixture normal distribution for hydro-meteorological variables

In the water resources field, there are emerging problems such as temporal changes of data and new additions of water sources. Non-mixture models are not efficient in analyzing these data because these models are developed under the assumption that data do not change and come from one source. Mixture models could successfully analyze these data because mixture models contain more than one modal. The expectation maximization (EM) algorithm has been widely used to estimate parameters of the mixture normal distribution for describing the statistical characteristics of hydro meteorological data. Unfortunately, the EM algorithm has some disadvantages, such as divergence, derivation of information matrices, local maximization, and poor accuracy. To overcome these disadvantages, this study proposes a new parameter estimation approach for the mixture normal distribution. The developed model estimates parameters of the mixture normal distribution by maximizing the log likelihood function using a meta-heuristic algorithm—genetic algorithm (GA). To verify the performance of the developed model, simulation experiments and practical applications are implemented. From the results of experiments and practical applications, the developed model presents some advantages, such as (1) the proposed model more accurately estimates the parameters even with small sample sizes compared to the EM algorithm; (2) not diverging in all application; and (3) showing smaller root mean squared error and larger log likelihood than those of the EM algorithm. We conclude that the proposed model is a good alternative in estimating the parameters of the mixture normal distribution for kutotic and bimodal hydrometeorological data.     

On drag coefficient parameterization with post processed direct fluxes measurements over the ocean

This study presents an evaluation of the atmospheric factors influencing the post-processing for fast-response data of horizontal momentum, vertical wind component, temperature, and water vapor to measure turbulent fluxes. They are observed at the Ieodo ocean research station over the Yellow Sea during the period of October 2004 to February 2008. The post process methods employed here are composed of quality control and tilt correction for turbulent flux measurement. The present result of quality control on the fast-response data shows that total removal ratio of the data generally depends on the factors such as a wind speed, relative humidity, significant wave height, visibility, and stability parameter (z/L). Especially, the removal ratio of water vapor data is significantly increased on light wind and strong stability conditions. The results show that the total removal ratio of water vapor data increases when wind speed is less than 3 m s^?1 and wave height is less than 1 m. The total removal ratio of water vapor data also increases with the value of the stability parameter. Three different algorithms of tilt correction methods (double rotation, triple rotation, and planar fit) are applied to correct the tilt of the sonic anemometer used in the observation. Friction velocities in near neutral state are greater than friction velocity in other states. Drag coefficients are categorized in terms of stabilities and seasons.     

Evaluation of the Effect of Penetration Ratios on Composite Grounds Improved with Sand Compaction Piles

In this paper, centrifuge model tests were conducted in order to understand the deformation characteristics and behavior of sand compaction piles (SCPs) reinforced grounds in relation to area replacement ratios and penetration ratios. To simulate ground stress conditions, preliminary compaction was conducted to form grounds that maintained a certain level of strength. SCPs were installed in the grounds using compaction methods, and the relationship between loads and settlement as well as stress under rigid loading conditions were compared and analyzed. In addition, finite element analyses were conducted in order to verify the results of the centrifuge model tests and assess the effects of penetration ratios and depths on variations in stress. According to the results of the analyses, stress concentration ratios gradually decreased as depths increased, and the decreasing rate increased as penetration ratios decreased. However, in regions close to the surface layer in depth in which SCPs were installed, stress concentration ratios showed almost the same range regardless of penetration ratios. Stress concentration ratios showed proportional relations with penetration ratios. However, they showed similar values in regions close in depth to the surface of the ground. In particular, they showed very close ranges at penetration ratios of 100% and 80%.     

Mesothermal Gold Vein Mineralization of the Seolhwa Mine,Asan Mining District,Korea

Gold mineralization of the Seolhwa mine occurs in a single stage of massive quartz veins which filled the north‐east‐trending fault shear zones in the Jurassic granitoid of 161 Ma within the Gyeonggi Massif. The vein quartz contains three main types of fluid inclusions at 25°C: (i) aqueous type I inclusions (0–15 wt.% NaCl) containing small amounts of CO₂; (ii) gas‐rich (more than 70 vol. %), vapor‐homogenizing, aqueous type II inclusions; and (iii) low‐salinity (less than 5 wt.% NaCl), liquid CO₂‐bearing, type III inclusions. The H₂O‐CO₂‐CH₄‐N₂‐NaCl inclusions represent immiscible fluids trapped earlier along the solvus curve in the temperature range 250–430°C at pressures of ～1 kb. Detailed fluid inclusion chronologies suggest a progressive decrease in pressure during the mineralization. Aqueous inclusion fluids represent either later fluids evolved through extensive fluid unmixing from a homogeneous H₂O‐CO₂‐CH₄‐N₂‐NaCl fluid due to decreases in temperature and pressure, or the influence of deep circulated meteoric waters. Initial fluids were homogeneous H₂O‐CO₂‐CH₄‐N₂‐NaCl fluids as follows: 250° to 430°C, 16–62 mol% CO₂, 5–14 mol% CH₄, 0.06–0.31 mol% N₂ and salinities of 0.4–4.9 wt.% NaCl. The T‐X data for the Seolhwa mine suggest that the hydrothermal system has been probably located nearer to the granitic melt, which facilitated the CH₄ formation and resulted in a reduced fluid state indicated by the predominance of pyrrhotite. Measured and calculated isotopic compositions of the hydrothermal fluids [δ¹⁸O = 5.3–6.5‰; δD =?69 to ?84‰] provide evidence of the CH₄‐H₂O equilibria and further indicate that the auriferous fluids were magmatically derived. Both the dominance of δ³⁴S values of sulfides close to the meteoric reference (?0.6–1.4‰; δ³⁴S_ΣS values of 0.3–1.1‰) and the available δ¹³C data (?4‰) are consistent with their deep igneous source. The Seolhwa mine was probably formed by extensive fracturing and veining due to the thermal expansion of water derived from the Jurassic granitoid melt.