• Journal of Aquaculture
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• v.15 no.4
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• pp.253-260
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• 2002

To find the optimal rearing conditions for Saxidomus purpuratus juvenile, filtering activity was estimated as functions of algal concentration and temperature by measuring the rates of clearance (CR) and ingestion (IR), when S. purpuratus was feeding. The clams were fed on unialgal diet of Isochrysis galbana at 6 algal concentrations (4.6$\times$$10^4$~2.6$\times$$10^6$ cells/ml) and at 6 temperatures (5, 10, 15, 20, 25, and 30^{\circ}C ). Algal concentration significantly affected the CR and the IR at all temperatures. At lower algal concentrations, CR increased, but decreased beyond a particular concentration. The maximum CR ($CR_{max}$) at 5, 10, 15, 20, 25, and 30^{\circ}C were 0.30, 1.73, 5.95, 15.17, 21.12, and 0.33 $l/g/h$, respectively. Below the level of 5.6$\times$10$^{5}$ cells/ml, IR increased as algal concentration increased, but was saturated at higher concentrations. To maintain high growth rate of S. purpuratus, I. galbana should be supplied with more than 5.6$\times$10$^{5}$ cells/ml. The maximum IR ($IR_{max}$) at 5, 10, 15, 20, 25 and30^{\circ}C were $2.2$\times$10^8, $1.5\times$10^9, 3.4$\times$10^9, 4.9$\times$10^9, 5.3$\times$10^9, and 1.0$\times$10^8$ cells/g/h, respectively. As for temperature, both $CR_max$ and $IR_max$ increased remarkably with raising temperature from 5 to 25^{\circ}C, but rapidly decreased at 30^{\circ}C. Between 15 and 25^{\circ}C $CR_{max} and IR_{max}$ were higher and most stable, At this temperature range, the $Q_{10}/s for CR_{max} and IR_{max}$ were 3.5 and 1.6, respectively. Therefore the optimal thermal range for the juvenile is 15~$25^{\circ}C$. The annual variation in IR$_{max}$ predicted by natural seawater temperature shows that inactive period (with lower $IR_max$) lasts for 5 months (from December to April). To ensure higher growth of juvenile during this inactive period at hatcheries, rearing temperature should be elevated to $15^{\circ}C$.>.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.8
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• pp.1089-1095
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• 2012

Neonatal Fc receptor (FcRn) gene encodes a receptor that binds the Fc region of monomeric immunoglobulin G (IgG) and is responsible for IgG transport and stabilization. In this report, the 8,900 bp porcine FcRn genomic DNA structure was identified and putative FcRn protein included 356 amino acids. Alignment and phylogenetic analysis of the porcine FcRn amino acid sequences with their homologies of other species showed high identity. Tissues expression of FcRn mRNA was detected by real time quantitative polymerase chain reaction (Q-PCR), the results revealed FcRn expressed widely in ten analyzed tissues. One single nucleotide polymorphism (SNP) (HQ026019:g.8526 C>T) in exon6 region of porcine FcRn gene was demonstrated by DNA sequencing analysis. A further analysis of SNP genotypes associated with serum Classical Swine Fever Virus antibody (anti-CSFV) concentration was performed in three pig populations including Large White, Landrace and Songliao Black pig (a Chinese indigenous breed). Our results of statistical analysis showed that the SNP had a highly significant association with the level of anti-CSFV antibody (At d 20; At d 35) in serum (p = 0.008; p = 0.0001). Investigation of expression and polymorphisms of the porcine FcRn gene will help us in further understanding the molecular basis of the antibody regulation pathway in the porcine immune response. All these results indicate that FcRn gene might be regarded as a molecular marker for genetic selection of anti-CSFV antibody level in pig disease resistance breeding programmes.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.15
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• pp.6397-6403
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• 2014

Background: Aberrant promoter hypermethylation has been recognized in human breast carcinogenesis as a frequent molecular alteration associated with the loss of expression of a number of key regulatory genes and may serve as a biomarker. The E-cadherin gene (CDH1), mapping at chromosome 16q22, is an intercellular adhesion molecule in epithelial cells, which plays an important role in establishing and maintaining intercellular connections. The aim of our study was to assess the methylation pattern of CDH1 and to correlate it with the expression of E-cadherin, clinicopathological parameters and hormone receptor status in breast cancer patients of Kashmir. Materials and Methods: Methylation specific PCR (MSP) was used to determine the methylation status of CDH1 in 128 invasive ductal carcinomas (IDCs) paired with the corresponding normal tissue samples. Immunohistochemistry was used to study the expression of E-cadherin, ER and PR. Results: CDH1 hypermethylation was detected in 57.8% of cases and 14.8% of normal adjacent controls. Reduced levels of E-cadherin protein were observed in 71.9% of our samples. Loss of E-cadherin expression was significantly associated with the CDH1 promoter region methylation (p<0.05, OR=3.48, CI: 1.55-7.79). Hypermethylation of CDH1 was significantly associated with age at diagnosis (p=0.030), tumor size (p=0.008), tumor grade (p=0.024) and rate of node positivity or metastasis (p=0.043). Conclusions: Our preliminary findings suggest that abnormal CDH1 methylation occurs in high frequencies in infiltrating breast cancers associated with a decrease in E-cadherin expression. We found significant differences in tumor-related CDH1 gene methylation patterns relevant to tumor grade, tumor size, nodal involvement and age at diagnosis of breast tumors, which could be extended in future to provide diagnostic and prognostic information.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.1901-1906
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• 2012

Background: The discovery that microRNA (miRNA) regulates metastasis provide a principal molecular basis for tumor heterogeneity. A characteristic of solid tumors is their heterogenous distribution of blood vessels, with significant hypoxia occurring in regions (centers of tumor) of low blood flow. It is necessary to discover the mechanism of breast cancer metastasis in relation to the fact that there is a differential distribution of crucial microRNA in tumors from centers to edges. Methods: Breast tissues from 48 patients (32 patients with breast cancer) were classified into the high invasive and metastatic group (HIMG), low invasive and metastatic group (LIMG), and normal group. Samples were collected from both the centers and edges of all tumors. The first six specimens were detected by microRNA array, and the second ten specimens were detected by real-time qRT-PCR and Western blot analyses. Correlation analysis was performed between the miRNAs and target proteins. Results: The relative content of miR-20a and miR-20b was lower in the center of the tumor than at the edge in the LIMG, lower at the edge of the tumor than in the center in the HIMG, and lower in breast cancer tissues than in normal tissues. VEGF-A and HIF-1alpha mRNA levels were higher in the HIMG than in the LIMG, and levels were higher in both groups than in the normal group; there was no difference in mRNA levels between the edge and center of the tumor. VEGF-A and HIF-1alpha protein levels were higher in the HIMG than in the LIMG, and protein levels in both groups were higher than in the normal group; there was a significant difference in protein expression between the edge and center of the tumor. Correlation analysis showed that the key miRNAs (miR-20a and miR-20b) negatively correlated with the target proteins (VEGF-A and HIF-1alpha). Conclusions: Our data suggest that miR-20a and miR-20b are differentially distributed in breast cancer, while VEGF-A and HIF-1alpha mRNA had coincident distributions, and VEGF-A and HIF-1alpha proteins had uneven and opposing distributions to the miRNAs. It appears that one of the most important facets underlying metastatic heterogeneity is the differential distribution of miR-20a and miR-20b and their regulation of target proteins.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3431-3436
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• 2016

Background: Carcinogenesis is a multifaceted intricate cellular mechanism of transformation of the normal functions of a cell into neoplastic alterations. Metastasis may result in failure of conventional treatment and death Hence, research on metastatic suppressors in cancer is a high priority. The metastatic suppressor gene CD82, also known as KAI1, is a member of the transmembrane 4 superfamily which was first identified in carcinoma of prostate. Little work has been done on this gene in breast cancer. Herein, we aimed to determine the gene and protein level expression of CD82/KAI1 in breast cancer and its role as a prognosticator. Materials and Methods: In this study, 83 histologically proven cases of breast cancer and a similar number of controls were included. Patient age ranged from 18-70 years. Quantitative Real Time Polymerase Chain Reaction (q-RT PCR) and immunohistochemistry (IHC) were used to investigate KAI1 expression at gene and protein levels, respectively. Statistical analysis was done to correlate expression of KAI1 and clinicopathological parameters. Results: It was revealed that: (i) KAI1 was remarkably diminished in metastatic vs non metastatic breast cancer both at the gene and the protein levels (P < .05); (ii) KAI1 expression levels were strongly correlated with TNM staging, histological grade and advanced stage (p<0.001) and no association was found with any other studied parameter; (iii) Lastly, a significant correlation was observed between expression of KAI1 and overall median survival of BC patients (P = 0.04). Conclusions: Our results suggest that lack of expression of the KAI1 might indicate a more aggressive form of breast cancer. Loss of KAI1 may be considered a significant prognostic marker in predicting metastatic manifestation. When evaluated along with the clinical and pathological factors, KAI1 expression may be beneficial to tailor aggressive therapeutic strategies for such patients.

• Journal of Distribution Science
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• v.13 no.3
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• pp.69-77
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• 2015

Purpose - The purpose of this study is to examine whether the cash policies of retail firms listed on Korean stock markets are consistent with the evidence provided in the study of Almeida et al. (2004). Liquidity management is an important issue for financially constrained firms relative to financially unconstrained firms. Because there are few sources of external funding, the optimal liquidity policies of financially constrained firms should reflect their own earnings or cash inflows to create opportunities for current and future real investments. According to this simple idea, we estimate the sensitivity of cash to cash flows and simply check whether the estimated sensitivity to cash flows of the cash retained by constrained retail firms is greater than that of the cash retained by unconstrained retail firms. Through this work, we aim to explain why the cash policies of the retail firms listed on the Korean stock markets differ from those of listed manufacturing enterprises. Research design, data, and methodology - To explain a firm's cash holdings, we use only three explanatory variables: earnings before interest and taxes (EBIT), Tobin's q, and size. All the variables are defined as the value of the numerator divided by aggregate assets. Thanks to this definition, it is possible to treat all the sample firms as a single large firm. The sample financial data for this study are collected from the retail enterprises listed on the KOSPI and KOSDAQ markets from 1991 to 2013. We can obtain these data from WISEfn, the financial information company. This study's methodology has its origin in Keynes's simple idea of precautionary liquidity demand: When a firm faces financial constraints, cash savings from earnings or cash inflows become important from the corporate finance perspective. Following this simple idea, Almeida et al. (2004) developed their theoretical model and found empirical evidence that the sensitivity of cash to cash flows varies systematically according to different types of financing frictions. To find more empirical evidence for this idea, we examined the cash flow sensitivity of the cash held by Korean retail firms. Results - Through several robustness tests, we empirically showed that financially constrained Korean retail firms display significant positive propensity to save cash from earnings before interest and taxes, while the estimated cash flow sensitivity of the cash held by unconstrained retail firms is not significant. Despite the relatively low earnings of retail firms, their sensitivity is three times greater than that of manufacturing enterprises. This implies that Korean retail firms have greater intentions of facilitating future investments rather than current investments. Conclusions - The characteristics of the cash policies of Korean retail firms differ from those of manufacturing firms. This contrast may be attributable to industry-oriented policy planning, regulations, and institutional differences. However, the industrial policymakers should observe signals of the long-term growth options of retail firms based on their high propensity to save from their cash inflows.

• Microbiology and Biotechnology Letters
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• v.32 no.2
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• pp.142-148
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• 2004

Erythropoietin is a main regulator of human erythropoiesis. Recombinant human erythropoietin (rhEPO) is one of the glycoproteins produced in animal cells, and it has oligo saccharides chains which comprise about 40％ of its molecular mass. Because the content of sialic acid can extend circulatory lifetime, the high degree of sialylation is often a desirable feature of therapeutic glycoproteins. In this study, the sialylation of rhEPO produced by chinese hamster ovary cell culture was maximized by supplementing the culture medium with N-acetylm-annosamine (ManNAc), a direct intracellular precursor for sialic acid synthesis and 2-deoxy-2,3-dehydro-N-acetylneuraminic acid (NeuAc2en), a sialidase inhibitor. Feeding of 20 mM ManNAc/0.5 mM NeuAc2en into culture medium increased the sialic acid content by nearly tenfold compared with unsupplemented medium. This effect was achieved without affecting the cell growth or product yield. Six erythropoietin fractions differing in sialic acid content, ranging from 11∼15％ of EPO, were identified from chinese hamster ovary cell-derived rhEPO by mono Q column chromatography. It was found that, at 20 mM ManNAc/0.5 mM NeuAc2en feeding, productivity of hyper-glycosylated EPO increased up to 50％, compared with the unsupplemented medium.

• Journal of Korea Multimedia Society
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• v.7 no.7
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• pp.944-955
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• 2004

The modern society as a high-level information-oriented society lays a great emphasis on lifelong education. It emphasizes all the learners' creative learning ability and various teaching-learning methods as well. We need the self-directed learning to meet these requirements, and one of the solutions is the self-directed teaching-learning process employing the web. Though many educators, so far, developed a number of teaching materials, they are no more than web-based teaching materials for simple learning activities or simple item-bank systems. So, this paper suggests an problem-solving based and self-directed learning system on web in order to overcome such simplicities, and it shows design and implementation of the system. Suggested learning system enables learners to get thinking skill though self-directed control of learning level after they learn the basic concepts and principles on the web as self-directed learning. For example, the system was applied to mathematics education for a middle school students. It supports a test of questions chosen from the item bank in a self-directed way, and helps learners to understand their learning levels for themselves and to solve their questions through on-line discussions with their instructor. The system can also be helpful in improving the learners' learning effects by sharing mutual information through the data room or the Q&A between learners and learners or between learners and instructors.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.4
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• pp.210-217
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• 2015

Fluoride removal by acid and heat treated red mud were studied in batch and column system regarding contact time, initial concentration, pH, adsorbent dose, and filter depth. The results showed that acid treated with 0.8 M HCl, had highest adsorption capacity of fluoride and adsorption capacity decreased as heat treatment temperature increased. Sorption equilibrium reached in 30 min at a initial concentration of 50 mg-F/L but 1 h was required to reach the sorption equilibrium at the initial concentration of 500 mg-F/L by 0.8 M acid treated red mud (0.8 M-ATRM). Equilibrium adsorption data were fitted well to Langmuir isotherm model with maximum fluoride adsorption capacity of 23.162 mg/g. The fluoride adsorption decreased as pH increased due to the fluoride competition for favorable adsorption site with $OH^-$ at higher pH. Removal percentage was increased but the amount of adsorption per unit mass decreased by adding the amount of 0.8 M-ATRM. It was concluded that the 0.8 M-ATRM could be used as a potential adsorbent for the fluoride removal from aqueous solutions because of its high fluoride adsorption capacity and low cost.

• Fisheries and Aquatic Sciences
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• v.22 no.11
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• pp.25.1-25.9
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• 2019

Background: Due to the continuous demand for fish coupled with decline in capture fisheries, there is the need to increase aquaculture production to meet the demand. Aquaculture is faced with high cost of feeding since fish oil and fish meal are expensive. In view of this, there are calls to explore alternatives that are cheap and reliable. Objectives: This study on Oreochromis niloticus was conducted to evaluate the effects of replacing fish oil (FO) with palm oil (PO) at 0%, 25%, 50%, 75%, and 100% on muscle fatty acid and proximate composition as well as growthrelated enzyme activities and mRNA expression. Methods: Oreochromis niloticus were fed five experimental diets (33% crude protein and 10% crude lipid) for 8 weeks. Feed had variation in fish oil and palm oil contents. After the 8 weeks feeding trial, five fish were sampled from each tank (15 from each treatment) and euthanized using an excess dose of tricaine methane sulfonate (MS-222 at 200 mg/L). Fatty acid and enzyme activities were analyzed using standard protocols. Also, RT-qPCR was used to quantify the expression levels of selected growth-related genes. Results: Fish fed 25% PO recorded the least muscle protein content and was significantly lower than the group fed 100% PO. Paired box protein 7 (Pax-7) enzyme activity was significantly higher in the group fed 50% PO compared to the groups fed 25% PO and 100% PO, while caplain-3 (Capn-3) was significantly lower in the group fed 0% PO compared to all other groups. There was a significant difference among treatments with respect to mRNA expression of Pax-7 and Capn-3. Group fed 25% PO had significantly lower mRNA expression of Pax-7, while the group fed 75% PO recorded significantly higher mRNA expression of Capn-3 compared to groups fed 0% PO, 25% PO, and 100% PO. Pearson's correlation analysis revealed that Igf-I and Igf-II mRNA expression have significant correlation with n-3 polyunsaturated fatty acids content in muscle. Conclusion: The results suggest muscle protein content could be modified if FO is replaced with PO. Also, mRNA expression of Pax-7 and Capn-3 is affected by replacing FO with PO.