• Korean Journal of Poultry Science
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• v.26 no.3
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• pp.149-170
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• 1999

Protozoa of the genus Eimeria are the etiologic agents of avian coccidiosis, the most economically important Parasitic disease for the poultry industry. Coccidia multiply in intestinal epithelial cells of a wide range of hosts, including livestock in addition to poultry. Chemotherapy is extensively used to control coccidiosis. However, development of drug resistance by Eimeria parasites, the intensive cost and labor involved in the identification of new anticoccidial compounds and public awareness of drug residues in foods warrant alternative methods to prevent coccidiocic in the fast growing poultry industry. For these reasons, there is a great interest in developing vaccines against avian coccidiosis. Live Eimeria vaccines confer protective immunity, however a significant disadvantage of using these types of vaccines is their pathogenicity. Live parasites with attenuated pathogenicity also usually produce immunity but may revert back to a pathogenic form and may be contaminated with other pathogenic organisms. Killed Eimeria vaccines are safer but, unlike live attenuated vaccines, are not able to generate cytotoxic T lymphocyte responses. Recombinant vaccines are biochemically purified proteins produced by genetic engineering that consist of particular epitopes or metabolites of Eimeria. Unlike live attenuated organisms, recombinant vaccines do not possess as much risk and generally are able to induce both humoral and cell mediated immunity. DNA vaccines consist of genes encoding immunogenic proteins of pathogens that are directly administered into the host in a manner that the gene is expressed and the resulting protein generates a protective immune response. Although all of these different types of vaccines have been applied to coccidiosis, this disease continues to cause substantial morbidity and mortality in the poultry industry. Future development of an effective vaccine against coccidiosis will depend on further investigation of protective immunity to Eimeria infection and identification of important immundgenic parasite molecules.

• Development and Reproduction
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• v.2 no.1
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• pp.69-74
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• 1998

The early gonadal development and sexual differentiation of Rhynchocypris oxycephalus are described from the stage of hatching to 150 days after hatching. During this peroid, the average length of the body grew from 0.64 cm to 5.96 cm. the primordial germ cells (PGCs), which could be recognized at the time of hatching, began to protrude into peritoneal cavity at a standard total length of 1.91 cm. At a standard total length of 2.29cm, initial ovarian differentiation wasidentified by the transformation of PGCs to meiotic oocytes. Finally, at the standard total length of 5.96 cm, the female gonads gradually developed towards migratory nucleus oocytes, characterisiing the maturation. Oocytes proliferated rapidly after sex differentiation while the testis entered a period of quiescence, as they continued to multiply but did not undergo growth until the standard total length of 4.00 cm. At a standard total length of 4.00 cm, spermatocytes arrested in thephase of interkinesis, Sertoli-like cells and sperm duct formation, with signs of meiotic activity, were observed. Therefore it may be concluded that R. oxycephalus belongs to the differentiated type of gonochoristic teleosts.

• Journal of Food Hygiene and Safety
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• v.3 no.1
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• pp.19-26
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• 1988

Most of meat spoilage bacteria area Gram negative, which are very sensitive to freezing ; for instance , 90% of E. coli cells are killed or sub-lethally injured by freezing at -3$0^{\circ}C$, and the freeze-injury rate is dependent upon freezing rate. Since the injured bacterial cells are sensitive to selective agents, they fail to multiply in selective media. Injured bacterial cells are, however, capable of spontaneous repair at appropriate environmental and nutritional conditions . Enumeration of injured bacterial cells involves artificial induction of repair at these conditions. Cubic beef samples(3$\times$3$\times$3cm) were frozen at -6$0^{\circ}C$, -4$0^{\circ}C$, or -18$^{\circ}C$. The samples frozen at each temperature were thawed at 4$^{\circ}C$, 2$0^{\circ}C$, or by microwave . After these respective freezing an thawing treatments, the percentage of sub-lethally injured total coliforms out of total surviving ones was measured and compared. The results were as follows: 1. The interaction between freezing and thawing on injury rate was not significant. 2. The injury rates(as means of all three thawing treatments post-freezing) by freezing at -6$0^{\circ}C$, -4$0^{\circ}C$, or -18$^{\circ}C$ were 32.2$^{\circ}C$ and 19.2$^{\circ}C$ respectively . 3. The injury rates(as means of all three freezing treatments)by thawing at 4$^{\circ}C$, 2$0^{\circ}C$, or by microwave were 49.3%, 11.7% and 21.0% respectively. The highest injury rate was caused by freezing at -6$0^{\circ}C$ and subsequent thawing at 4$^{\circ}C$. However since the injury rates by freezing treatment were not significantly different, freezing at -18$^{\circ}C$ and subsequent thawing at 4$^{\circ}C$ can also be recommended , from an economic perspective.

• The Journal of the Korean Society for Microbiology
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• v.35 no.3
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• pp.239-250
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• 2000

Sixty-eight clinical isolates of Stenotrophomonas maltophilia from inpatients of 2 university hospitals in Taegu were epidemiologically analyzed by using the minimum inhibitory concentrations of 25 antimicrobial drugs, biochemical reaction, pulsed-field gel elctropgoresis (PFGE), and PCR with enterobacterial repetitive intergenic consensus sequences as primer (ERIC-PCR). 1. All the strains were susceptible to minocycline. More than 57% were susceptible to sulfisomidine (Su), ciprofloxacin (Ci), Ofloploxacin (Of), nalidixic acid (Na), and chloramphenicol (Cm), and $19{\sim}35%$ to ceftazidime (Cd), trimethoprim (Tp), Ticacillin-clavulanic acid, and cefoperazone-sulbactam. Most isolates were resistant to ${\beta}$-lactam antibiotics such as ampicillin (Ap), carbenicillin (Cb), cefotaxim (Ct), cefoxitin (Cx), and aminoglycosides including gentamicin (Gm), tobramycin (Tb), amikacin (Ak). 2. All the isolates were multiply resistant of 5 to 17 drugs and showed 40 different resistance pattern types. 3. All the strains showed very similar biochemical reactions except ${\beta}$-galactosidase and nitrate reduction test. Fourteen strains selected randomly were classified 10 different pattern type by PFGE and ERIC-PCR. These two methods showed identical result. Four strains isolated from wound in 1994 showed similar MIC pattern and identical API 20NE profile, PFGE, and ERIC-PCR pattern indicating episodes of cross-infection among patients. These results indicate that PFGE or ERIC-PCR profile has comparable discriminatory power for epidemiological typing of S. maltophilia.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.87-93
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• 2014

For n/m=qm+r, there is no simple divisibility rule for simple m=7 such that is the n multiply by m? This problem can be more complex for two or more digits of m. The Dunkels method has been known for generalized divisibility test method, but this method can not compute very large digits number that can not processed by computer. This paper suggests simple and exact divisibility method for m completely irrelevant n and m of digits. The proposed method sets $r_1=n_1n_2{\cdots}n_l(mod m)$ for $n=n_1n_2n_3{\cdots}n_k$, $m=m_1m_2{\cdots}m_l$. Then this method computes $r_i=r_{i-1}{\times}10+n_i(mod m)$, $i=2,3,{\cdots}k-l+1$ and reduces the digits of n one-by-one. The proposed method can be get the quotient and remainder with easy, fast and correct for various n,m experimental data.

• Composites Research
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• v.27 no.6
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• pp.225-230
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• 2014

In this study, a novel microwave absorber which consists of a structural part, a resistive sheet, and a low dielectric layer is proposed. Unlike the conventional Salisbury screen, a newly proposed absorber is capable of a range of absorbing performance, from narrowband to broadband. In the case of the narrowband absorber, the fabricated absorber with optimized design parameters has a strong resonance at 9.25 GHz and reflection loss of -44 dB with satisfying the -10 dB absorption in whole X-band (8.2 GHz~12.4 GHz). For the broadband absorber design, the reflectivity was minimized in the considered frequency ranges. The designed absorber showed two weak resonances near 6.5 GHz and 16.5 GHz and satisfied the -10 dB absorption from C-band to Ku-band (4 GHz~18 GHz). The measured reflection loss of fabricated absorber was well matched with simulation results, though the measurement was only performed on X-band. For the Salisbury screen to be capable of broadband absorption, it should be stacked multiply in a structure known as the Jaumann absorber. However, for the microwave absorber presented here, broadband as well as narrowband capabilities can be implemented without a change of the structure.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.2
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• pp.121-126
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• 2018

The purpose of this study was to assess bacteriological hazards in the following 7 kinds of minimally processed shellfish products purchased from Korean seafood retail outlets: raw oysters stored with seawater in polyethylene bags, frozen oysters, raw mussels, frozen mussels, boiled mussels, raw short-necked clam, and frozen short-necked clams, obtained from Korean seafood retail outlets. The total coliform and Escherichia coli counts determined in all samples were detected below regulation limit of the Korean government guidelines (Food Code). In addition, the high-risk bacterial pathogens, Listeria monocytogenes, Salmonella spp., and E. coli O157:H7 were not detected in any samples. Low-risk pathogens such as Staphylococcus aureus and Vibrio parahaemolyticus were detected at levels above $1.0{\times}10^2$ colony forming unit (CFU)/g in some minimally processed shellfish products. Notably, S. aureus was detected in all samples. Raw oysters stored with seawater in polyethylene bags, frozen oysters, and boiled blue mussels are commonly ingested without heating, and therefore these minimally processed shellfish products pose bacteriological hazards. The detection of S. aureus in all shellfish products, an organism indicative of poor personal hygiene, which can grow and multiply during distribution, indicates the necessity of improving the food safety of minimally processed shellfish products.

• Korean Journal of Human Ecology
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• v.5 no.2
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• pp.1-16
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• 1996

This study has examined multiple influences of several variables on parenting behavior by looking into illustrative studies. This study provides support to the view that various factors influence parenting and that parenting behavior is multiply determined. Characteristics of parents, children and the context in which parent-child relations occur cause different childrearing patterns among parents. This study can be summarized as follows: 1) Parental behavior is influenced to a large degree by what the parent brings to the situation. In other words, characteristics of the parent including personality characteristics, interpersonal skills, problem-solving skills, level of maturity, values and childrearing beliefs contribute to individual differences in parenting. 2) The parent's relationship history influences the personality characteristics that the parent brings to his or her adult roles. To understand who the parent is today, we have to look at who the parent was, and what the parent was doing in the years prior to parenthood. That is, we need to see the life course of the individual before parenthood. 3) Contextual variables including the immediate context and the larger context have proved to influence parental behaviors. Characteristics of the immediate context such as the quality of marital rationship can influence the parent's psychological well-being and his or her behavior toward the childen while characteristics of the larger context such as the economic situation and the neighborhood can influence the level of stress experienced by the parent and cosequently how the parent relates to his or her child. 4) In order to understand the development of the parent-child relationship we need to look at the characteristics of the child. Children may elicit positive behaviors from their parents, or they may possess characteristics that the parents find aversive thus leading to difficulties in the relationship. Therefore, much depends on the fit beween the characteristics of the parents and characteristics of the child. By examining multiple contemporaneous influences on parenting, this study could deepen the understanding of why parents have different childrearing patterns, why some parents fail to meet their children's demands and why parents act in certain ways. What we ultimately hope is that as we learn more about parenting and the development of parent-child relationships, we will be better able to provide parents with the supports they need to achieve their parenting goals.

• Journal of Microbiology
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• v.43 no.2
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• pp.133-143
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• 2005

Shigellosis is a global human health problem. Four species of Shigella i.e. S. dysenteriae, S. flexneri, S. boydii and S. sonnei are able to cause the disease. These species are subdivided into serotypes on the basis of O-specific polysaccharide of the LPS. Shigella dysenteriae type 1 produces severe disease and may be associated with life-threatening complications. The symptoms of shigellosis include diarrhoea and/or dysentery with frequent mucoid bloody stools, abdominal cramps and tenesmus. Shigella spp. cause dysentery by invading the colonic mucosa. Shigella bacteria multiply within colonic epithelial cells, cause cell death and spread laterally to infect and kill adjacent epithelial cells, causing mucosal ulceration, inflammation and bleeding. Transmission usually occurs via contaminated food and water or through person-to-person contact. Laboratory diagnosis is made by culturing the stool samples using selective/differential agar media. Shigella spp. are highly fragile organism and considerable care must be exercised in collecting faecal specimens, transporting them to the laboratories and in using appropriate media for isolation. Antimicrobial agents are the mainstay of therapy of all cases of shigellosis. Due to the global emergence of drug resistance, the choice of antimicrobial agents for treating shigellosis is limited. Although single dose of norfloxacin and ciprofloxacin has been shown to be effective, they are currently less effective against S. dysenteriae type 1 infection. Newer quinolones, cephalosporin derivatives, and azithromycin are the drug of choice. However, fluoroquinolone-resistant S. dysenteriae type 1 infection have been reported. Currently, no vaccines against Shigella infection exist. Both live and subunit parenteral vaccine candidates are under development. Because immunity to Shigella is serotype-specific, the priority is to develop vaccine against S. dysenteriae type 1 and S. flexneri type 2a. Shigella species are important pathogens responsible for diarrhoeal diseases and dysentery occurring all over the world. The morbidity and mortality due to shigellosis are especially high among children in developing countries. A recent review of literature (KotIoff et al.,1999) concluded that, of the estimated 165 million cases of Shigella diarrhoea that occur annually, $99\%$ occur in developing countries, and in developing countries $69\%$ of episodes occur in children under five years of age. Moreover, of the ca.1.1 million deaths attributed to Shigella infections in developing countries, $60\%$ of deaths occur in the under-five age group. Travellers from developed to developing regions and soldiers serving under field conditions are also at an increased risk to develop shigellosis.

• Journal of Preventive Medicine and Public Health
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• v.38 no.4
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• pp.457-464
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• 2005

Objectives : An outbreak of salmonellosis occurred among the student s and staff of D primary school in Yeongcheon-si, 2004. This investigation was carried out to prevent any recurrence of this outbreak and to study the infection source and transmission of the salmonellosis. Methods : The authors conducted a questionnaire survey among 1,205 students and staff members from D primary school about the ingestion of the school lunch and drinking water, and the manifestation of their symptoms. The author examined rectal swabs, the tap water and microorganism cultures, and we also investigated the dining facility and water supply facility. Results : The diarrheal cases were defined as the confirmed cases or the persons who had diarrhea more than one time with symptoms such as fever, vomiting and tenesmus. The diarrheal attack rate was 28.0%. Ingestion of fried bean curd with egg had a significantly high association with the diarrheal attack rate (p<0.05), and the relative risk of the fried bean curd with egg was 10.68 (95% CI=3.88-29.41), as was determined by logistic regression analysis. The bacterial counts in the tap water of the food preparation room and toilet (first floor) exceeded the maximum permissible counts. S. Enteritidis bacteria were only cultured from the fried bean curd with egg of all the supplied foods on September 3, 2004. Conclusions : The major cause of salmonellosis was presumed to be the contaminated bean curd via contaminated tap water due to a water leak of a school water pipe. This contaminated bean curd was under prepared, which allowed the S. Enteritidis to survive and multiply prior to its ingestion.