• Toxicological Research
• /
• v.11 no.1
• /
• pp.31-36
• /
• 1995

Cyclophosphamide (CP) must be enzymatically activated by cytochrome P450(CYP)-linked mixed-function oxidation pathway to be either mutagenic or teratogenic. Influences of alterations in hepatic mixed-function oxidase acitivity and glutathione (GSH) content on the embryotoxicity of CP were studied in rat whole embryo culture system. The embryotoxicity of CP was compared using rat S-9 fraction (S-9) pretreated with chemicals inducing different CYP isozymes, acetone (ACE), Aroclor 1254 (ARO), $\beta$-naphthoflavone (NAF) and phenobarbital (PHE). When 10.5 day embryos were cultured in the immediately centrifuged rat serum for 48 hrs using general gas char{ging schedule, CP$(40{\mu}g/ml)$ with S-9 induced by either NAF or PHE increased the incidence of realformations and significantly decreased embryonic growth compared with the non-induced S-9 group. ACE or ARO induced S-9 group showed no significant difference in embryonic growth. These data suggest that PB and/or NAF inducible CYP isoenzymes are mainly involved in the activation of CP. To examine the effect of GSH on the embryotoxicity of CP, 10.5 day embryos were exposed to CP and S-9 after preincubation with 10 mM of GSH for 3 hrs. In the GSH pretreated group the growth of embryos increased significantly compared with that of the untreated group, suggesting that GSH may protect embryos in culture from some toxic effects of CP.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.690-693
• /
• 2005

In this paper, probabilistic distribution of fatigue life of chassis component is determined statistically by applying the design of experiments and the Pearson system. To construct $p-\varepsilon-N$ curve, the case that fatigue data are random variables is attempted. Probabilistic density function(p.d.f) for fatigue life is obtained by design of experiment and using this p.d.f fatigue reliability about any aimed fatigue life can be calculated. Lower control arm and rear torsion bar of chassis component are selected as examples for analysis. Component load histories, which are obtained by multi-body dynamic simulation for Belsian load history, are used. Finite element analysis are performed using commercial software MSC Nastran and fatigue analysis are performed using FE Fatigue. When strain-life curve itself is random variable, probability density function of fatigue life has very little difference from log-normal distribution. And the case of fatigue data are random variables, probability density functions are approximated to Beta distribution. Each p.d.f is verified by Monte-Carlo simulation.

• Journal of the Korean Magnetic Resonance Society
• /
• v.11 no.1
• /
• pp.10-23
• /
• 2007

A new disintegrin protein named saxatilin was purified from Korean snake venom (Gloydius saxatilis). Saxatilin is a 73 residue small ploypeptide, which has a primary recognition motif in extracellular matrix, Arg-Gly-Asp (RGD) sequence. Data from inhibition activity assay for the ${\alpha}_v{\beta}_3$ integrin showed that saxatilin showed about 5000-fold higher activity than those of RGD peptides, suggesting that RGD sequence may not be sufficient to induce full cellular function of this site. The solution structures calculated from NMR data were well converged for backbone atoms except RGD loop. The structure revealed that most of tight turns are stabilized by medium range NOE contacts and the RGD motif is located far from the rigid core of the C-terminal domain. The three-dimensional fold and biological function of saxatilin are discussed with those of salmosin, which is a disintegrin protein derived from Agkistrodon halys brevicaudus.

• BMB Reports
• /
• v.39 no.4
• /
• pp.355-360
• /
• 2006

To gain a better understanding on the function of the potato Solanum tuberosum Multiprotein Bridging Factor 1 protein (StMBF1) its interaction with the TATA box binding protein (TBP) was demonstrated. In addition we reported that StMBF1 rescues the yeast mbf1 mutant phenotype, indicating its role as a plant co-activator. These data reinforce the hypothesis that MBF1 function is also conserved among non closely related plant species. In addition, measurement of StMBF1 protein level by Western blot using anti-StMBF1 antibodies indicated that the protein level increased upon $H_2O_2$ and heat shock treatments. However, the potato $\beta$-1,3-glucanase protein level was not changed under the same experimental conditions. These data indicate that StMBF1 participates in the cell stress response against oxidative stress allowing us to suggest that MBF1 genes from different plant groups may share similar functions.

• Journal of Biosystems Engineering
• /
• v.11 no.1
• /
• pp.76-85
• /
• 1986

This study was intended to examine the failure characteristics and breakdowns of the head-fed type combines generally used on farms. The failure distribution was assumed to follow Weibull distribution function and the Weibull parameters of the major parts, units and combine as whole were estimated by using the data collected in a survey. A computer program for the estimation of the Weibull parameter was developed. Monte Carlo method was used in predicting the time between failures. The results of study may be summarized as follows: 1. The number of failures per combine was 4.83 times per year and 0.3 times per hectare of combines of different ages. 2. According to the Kolmogorov-Smirnov test method, it was proved that the Weibull distribution function is well fitted to the characteristics of the failure and breakdowns of combines. 3. Weibull parameters of failure distribution of the combine as a whole were estimated to give the shape parameter ${\beta}$=1.3089 and the scale parameter ${\alpha}$=105.2409. The combining area with 80% reliability was 1.1 ha, and the probability of operating the combine without any failure for a year, was $2.76{\times}10^{-4}$. 4. The mean time between failures (MTBF) of the combines was predicted to be 3.2 ha of operation, which corresponds to 32 hours of operation.

• International Journal of Contents
• /
• v.3 no.1
• /
• pp.1-8
• /
• 2007

The distributions of the minimum correlated F-variable arises in many applied statistical problems including simultaneous analysis of variance (SANOVA), equality of variance, selection and ranking populations, and reliability analysis. In this paper, negative binomial sampling technique is employed to derive the distributions of the minimum of chi-square variables and hence the distributions of the minimum correlated F-variables. The work presented in this paper is divided in two parts. The first part is devoted to develop some combinatorial identities arised from the negative binomial sampling. These identities are constructed and justified to serve important purpose, when we deal with these distributions or their characteristics. Other important results including cumulants and moments of these distributions are also given in somewhat simple forms. Second, the distributions of minimum, chisquare variable and hence the distribution of the minimum correlated F-variables are then derived within the negative binomial sampling framework. Although, multinomial theory applied to order statistics and standard transformation techniques can be used to derive these distributions, the negative binomial sampling approach provides more information regarding the nature of the relationship between the sampling vehicle and the probability distributions of these functions of chi-square variables. We also provide an algorithm to compute the percentage points of the distributions. The computation methods we adopted are exact and no interpolations are involved.

• BMB Reports
• /
• v.48 no.8
• /
• pp.473-478
• /
• 2015

The NEK6 (NIMA-related kinases 6) is reported to play po-tential roles in tumorigenesis. Although it is suggested to function in several cellular pathways, the underlying mechanism in tumorigenesis is still largely unknown. In the present study, we discovered interaction of NEK6 with Smad4, a key member of transforming growth factor beta (TGFβ) pathway. Over-expression of NEK6 in hepatocellular carcinoma (HCC) cell lines suppresses TGFβ-mediated transcription activity in a kinase activity-dependent manner. In addition, NEK6 suppresses the cell growth arrest induced by TGFβ. Mechanically, NEK6 blocks nuclear translocation of Smad4, which is essential for TGFβ function. Moreover, we identified that NEK6 could be regulated by TGFβ and hypoxia. Our study sheds new light on the roles of NEK6 in canonical TGFβ/Smad pathway and tum-origenesis. [BMB Reports 2015; 48(8): 473-478]

• Journal of the Korean Society for Precision Engineering
• /
• v.24 no.2 s.191
• /
• pp.110-117
• /
• 2007

In this paper, probabilistic distribution of chassis component fatigue life is determined statistically by applying the design of experiments and the Pearson system. To construct p - ${\varepsilon}$ - N curve, the case that fatigue data are random variables is attempted. Probabilistic density function (p.d.f) for fatigue life is obtained by the design of experiment and using this p.d.f fatigue reliability, any aimed fatigue life can be calculated. Lower control arm and rear torsion bar of chassis components are selected as examples for analysis. Component load histories which are obtained by multi-body dynamic simulation for Belsian load history are used. Finite element analysis is performed by using commercial software MSC Nastran and fatigue analysis is performed by using FE Fatigue. When strain-life curve itself is random variable, the probability density function of fatigue life has very little difference from log-normal distribution. And the cases of fatigue data are random variables, probability density functions are approximated to Beta distribution. Each p.d.f is verified by Monte-Carlo simulation.

• The Korean Journal of Applied Statistics
• /
• v.17 no.3
• /
• pp.489-498
• /
• 2004

In this paper, a new form of linear models referred to as generalized weighted linear models is proposed. The proposed models assume that the relationship between the response variable and explanatory variables can be modelled by a distribution function of the response mean and a weighted linear combination of distribution functions of covariates. This form addresses a structural problem of the link function in the generalized linear models in which the parameter space may not be consistent with the space derived from linear predictors. The maximum likelihood estimation with Lagrange's undetermined multipliers is used to estimate the parameters and resampling method is applied to compute confidence intervals and to test hypotheses.

• BMB Reports
• /
• v.44 no.3
• /
• pp.187-192
• /
• 2011

TGF-$\beta$ activated kinase-1 (TAK1) plays a pivotal role in developmental processes in many species. Previous research has mainly focused on the function of TAK1 in model organisms, and little is known about the function of TAK1 in hymenoptera insects. Here, we isolated and characterized the TAK1 gene from Apis cerana cerana. Promoter analysis of AccTAK1 revealed the presence of transcription factor binding sites related to early development. Real-time quantitative PCR and immunohistochemistry experiments revealed that AccTAK1 was expressed at high levels in fourth instar larvae, primarily in the abdomen, in the intestinal wall cells of the midgut and in the secretory cells of the salivary glands. In addition, AccTAK1 expression in fourth instar larvae could be dramatically induced by treatment with pesticides and organic solvents. These observations suggest that AccTAK1 may be involved in the regulation of early development in the larval salivary gland and midgut.