• Journal of Microbiology and Biotechnology
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• v.17 no.7
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• pp.1059-1070
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• 2007

Prion diseases, often called transmissible spongiform encephalopathies (TSEs), are infectious diseases that accompany neurological dysfunctions in many mammalian hosts. Prion diseases include Creutzfeldt-Jakob disease (CJD) in humans, bovine spongiform encephalopathy (BSE, "mad cow disease") in cattle, scrapie in sheep, and chronic wasting disease (CWD) in deer and elks. The cause of these fatal diseases is a proteinaceous pathogen termed prion that lacks functional nucleic acids. As demonstrated in the BSE outbreak and its transmission to humans, the onset of disease is not limited to a certain species but can be transmissible from one host species to another. Such a striking nature of prions has generated huge concerns in public health and attracted serious attention in the scientific communities. To date, the potential transmission of prions to humans via foodborne infection and iatrogenic routes has not been alleviated. Rather, the possible transmission of human to human or cervids to human aggravates the terrifying situation across the globe. In this review, basic features about prion diseases including clinical and pathological characteristics, etiology, and transmission of diseases are described. Based on recently accumulated evidences, the molecular and biochemical aspects of prions, with an emphasis on the molecular interactions involved in prion conversion that is critical during prion replication and pathogenesis, are also addressed.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.21 no.2
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• pp.89-107
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• 2017

In this paper, we have proposed a modified Marker-And-Cell (MAC) method to investigate the problem of an unsteady 2-D incompressible flow with heat and mass transfer at low, moderate, and high Reynolds numbers with no-slip and slip boundary conditions. We have used this method to solve the governing equations along with the boundary conditions and thereby to compute the flow variables, viz. u-velocity, v-velocity, P, T, and C. We have used the staggered grid approach of this method to discretize the governing equations of the problem. A modified MAC algorithm was proposed and used to compute the numerical solutions of the flow variables for Reynolds numbers Re = 10, 500, and 50000 in consonance with low, moderate, and high Reynolds numbers. We have also used appropriate Prandtl (Pr) and Schmidt (Sc) numbers in consistence with relevancy of the physical problem considered. We have executed this modified MAC algorithm with the aid of a computer program developed and run in C compiler. We have also computed numerical solutions of local Nusselt (Nu) and Sherwood (Sh) numbers along the horizontal line through the geometric center at low, moderate, and high Reynolds numbers for fixed Pr = 6.62 and Sc = 340 for two grid systems at time t = 0.0001s. Our numerical solutions for u and v velocities along the vertical and horizontal line through the geometric center of the square cavity for Re = 100 has been compared with benchmark solutions available in the literature and it has been found that they are in good agreement. The present numerical results indicate that, as we move along the horizontal line through the geometric center of the domain, we observed that, the heat and mass transfer decreases up to the geometric center. It, then, increases symmetrically.

• Korean Journal of Veterinary Service
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• v.32 no.4
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• pp.307-314
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• 2009

The aim of the present study was to investigate whether Bovine Spongiform Encephalopathy (BSE) is present in this country and to analyze the Global BSE Risk (GBR) status in Bangladesh. A total of 2,000 brain samples were collected from cattle older than 30 months of age, slaughtered for human consumption in the district slaughter houses from 2005 to 2006. The brainstem (obex), Pyriform lobe, cerebrum and cerebellum were subjected to histopathological study. Samples that showed some nonspecific lesions were subjected to immunohistochemistry and only brain stem to ELISA for the detection of abnormal prion protein $PrP^{sc}$. In passive surveillance, annual overall diseases of cattle, buffalo, sheep and goats in Bangladesh were collected from Department of Livestock Services (DLS), Dhaka to investigate the occurrences of neurological diseases. Import related data were collected from "National Export Promotion Bureau" Kawran Bazar, Bangladesh Bank and DLS to analyze the importing products of animal origin (cattle, buffalo, sheep and goats) from different countries to find whether or not the imported products posed any risk for the BSE. In an actire surveillance conducted in slaughter house, histopathologically BSE specific lesions were not detected in any of the brain samples, but other nonspecific lesions were observed. No $PrP^{sc}$ was detected from the samples by immunohistochemistry and ELISA. DLS report also supported the absence of BSE in cattle and buffalo and scrapie in sheep and goats in Bangladesh. It was also clearly recorded that Bangladesh imported livestock products from countries in GBR level I and II but not from countries in GBR level III and IV. From this study it apparently seems that BSE is not currently present in the indigenous animals in Bangladesh and poses no or negligible risk to human and animal health.

• Microbiology and Biotechnology Letters
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• v.19 no.5
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• pp.433-438
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• 1991

The plasmid pSY130-14 for the high production of phenylalanine is a temperaturecontrollable expression vector composed of the $P_R$ and the $P_L$ promoter and a temperature sensitive repressor, $cI_{857}$ of bacteriophage lambda. Strain AT2471 harbouring plasmid pSY13O- 14 is induced the phenylalanine production by shifting up the incubation temperaure to $38.5^{\circ}C$. Plasmid stability of E. coli AT2471 harbouring pSY130-14 was very low, it was about 30% after 48 h cultivation at $38.5^{\circ}C$ without kanamycin. The plasmid disappeared immediately at $40^{\circ}C$ without kanamycin, and at $40^{\circ}C$ adding kanamycin, the plasmid stability decreased at the beginning, but rose with the extension of the culture time. For the improvement of plasmid stability, the plasmid obtaind was designated as pSY15O-1 by changing origin region (ori) pACYC 177 of pSY130-14 for ori pSC101. E. coli AT2471 harbouring pSY150-1 was stable at $38.5^{\circ}C$ without tetracycline, and the plasrnid stability was about 40% after 48 h cultivation at $40^{\circ}C$.

• Journal of Plant Biotechnology
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• v.33 no.3
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• pp.195-207
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• 2006

Stem cells are the primordial, initial cells which usually divide asymmetrically giving rise to on the one hand self-renewals and on the other hand progenitor cells with potential for differentiation. Zygote (fertilized egg), with totipotency, deserves the top-ranking stem cell - he totipotent stem cell (TSC). Both the ICM (inner cell mass) taken from the 6 days-old human blastocyst and ESC (embryonic stem cell) derived from the in vitro cultured ICM have slightly less potency for differentiation than the zygote, and are termed pluripotent stem cells. Stem cells in the tissues and organs of fetus, infant, and adult have highly reduced potency and committed to produce only progenitor cells for particular tissues. These tissue-specific stem cells are called multipotent stem cells. These tissue-specific/committed multipotent stem cells, when placed in altered environment other than their original niche, can yield cells characteristic of the altered environment. These findings are certainly of potential interest from the clinical, therapeutic perspective. The controversial terminology 'somatic stem cell plasticity' coined by the stem cell community seems to have been proved true. Followings are some of the recent knowledges related to the stem cell. Just as the tissues of our body have their own multipotent stem cells, cancerous tumor has undifferentiated cells known as cancer stem cell (CSC). Each time CSC cleaves, it makes two daughter cells with different fate. One is endowed with immortality, the remarkable ability to divide indefinitely, while the other progeny cell divides occasionally but lives forever. In the cancer tumor, CSC is minority being as few as 3-5% of the tumor mass but it is the culprit behind the tumor-malignancy, metastasis, and recurrence of cancer. CSC is like a master print. As long as the original exists, copies can be made and the disease can persist. If the CSC is destroyed, cancer tumor can't grow. In the decades-long cancer therapy, efforts were focused on the reducing of the bulk of cancerous growth. How cancer therapy is changing to destroy the origin of tumor, the CSC. The next generation of treatments should be to recognize and target the root cause of cancerous growth, the CSC, rather than the reducing of the bulk of tumor, Now the strategy is to find a way to identify and isolate the stem cells. The surfaces of normal as well as the cancer stem cells are studded with proteins. In leukaemia stem cell, for example, protein CD 34 is identified. In the new treatment of cancer disease it is needed to look for protein unique to the CSC. Blocking the stem cell's source of nutrients might be another effective strategy. The mystery of sternness of stem cells has begun to be deciphered. ESC can replicate indefinitely and yet retains the potential to turn into any kind of differentiated cells. Polycomb group protein such as Suz 12 repress most of the regulatory genes which, activated, are turned to be developmental genes. These protein molecules keep the ESC in an undifferentiated state. Many of the regulator genes silenced by polycomb proteins are also occupied by such ESC transcription factors as Oct 4, Sox 2, and Nanog. Both polycomb and transcription factor proteins seem to cooperate to keep the ESC in an undifferentiated state, pluripotent, and self-renewable. A normal prion protein (PrP) is found throughout the body from blood to the brain. Prion diseases such as mad cow disease (bovine spongiform encephalopathy) are caused when a normal prion protein misfolds to give rise to PrP$^{SC}$ and assault brain tissue. Why has human body kept such a deadly and enigmatic protein? Although our body has preserved the prion protein, prion diseases are of rare occurrence. Deadly prion diseases have been intensively studied, but normal prion problems are not. Very few facts on the benefit of prion proteins have been known so far. It was found that PrP was hugely expressed on the stem cell surface of bone marrow and on the cells of neural progenitor, PrP seems to have some function in cell maturation and facilitate the division of stem cells and their self-renewal. PrP also might help guide the decision of neural progenitor cell to become a neuron.

• Journal of Korean Theatre Studies Association
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• no.52
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• pp.117-157
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• 2014

Cette ${\acute{e}}tude$ est pour l'objectif de rechercher sur $l^{\prime}{\acute{e}}criture$ $th{\acute{e}}{\hat{a}}trale$ de la mort et le deuil dans les $th{\acute{e}}{\hat{a}}tres$ chez Young-sun Yun(1954-2007) ${\grave{a}}$ travers des textes dramatiques ${\acute{e}}crits$ par $lui-m{\hat{e}}me$, qui ${\acute{e}}tait$ aussi le metteur en $sc{\grave{e}}ne$ depuis 1994 dans le $th{\acute{e}}{\hat{a}}tre$ contemporain en $Cor{\acute{e}}e$. Cette $th{\grave{e}}se$ est $commenc{\acute{e}}$ ${\grave{a}}$ ${\acute{e}}crire$ pas pour apprendre ses textes mais pour comprendre la ralation entre les textes et les ${\exp}{\acute{e}}riences$ de l'auteur. Ici, pour cela, j''ai $analys{\acute{e}}$ ses 4 $pi{\grave{e}}ces$ $th{\acute{e}}{\hat{a}}trales$ produites ${\grave{a}}$ cette ${\grave{e}}poque$, dont (1994), (2000), $d{\acute{e}}biteur$, mon $p{\grave{e}}re$ est $progress{\acute{e}}$ de cancer>(1996), (2005), en referrant les rapports entre $l^{\prime}{\acute{e}}criture$ dramatique et de la mort et le deuil de $p{\grave{e}}re$. Cette ${\acute{e}}tude$ $pr{\acute{e}}suppose$ un certain situation psychologue de l'auteur sur la mort et le deuil de personnage '$p{\grave{e}}re$'. L'auteur dramatique et le metteur en $sc{\grave{e}}ne$ du $th{\acute{e}}{\hat{a}}tre$ Young-sun Yun propose certaines orientations de la mort de son $p{\grave{e}}re$ dans ses texts dramatiques: le sentiment de victime sous le pouvoir absolu de son $p{\grave{e}}re$. Chez lui, ${\acute{e}}crire$ le texte dramatique, c'est transmettre les amertumes d'esprit et une forme de $r{\acute{e}}flextion$ vis-${\grave{a}}$-vis de la relation avec son $p{\grave{e}}re$ surtout le $probl{\grave{e}}me$ $inachev{\acute{e}}$ de deuil. c'est-${\grave{a}}$-dire fournir des sentiments coupables et des $anxi{\acute{e}}t{\acute{e}}s$ qui $r{\acute{e}}sident$ au fond de son coeur, tout au long de sa vie. Pour cette objecif, il est ${\acute{e}}vident$ qu'il faudra toujours partir du texte et y revenir. J'ai $essay{\acute{e}}$ de ne pas $r{\acute{e}}duiser$ $l^{\prime}{\acute{e}}tude$ des textes au respect myope des paroles des personnage et rester la $r{\acute{e}}flextion$ pshchologique sur la mort et le processu de deuil. J'ai $essay{\acute{e}}$ d'appuyer mes remarques sur les sources $autoris{\acute{e}}es$: psychanalytiques en la $mati{\grave{e}}re$. C'est pourquoi j'ai cru devoir $pr{\acute{e}}senter$ cette recherche de l'analyse sous la forme d'une $synth{\grave{e}}se$ des principaux concepts de la $th{\acute{e}}orie$ de la pshchologie moderne qui permettent l'analyse des textes dramatiques.(Dany Nobus, David K. Switzer, Fritz Riemann, Giles Deleuze, Sigmund Freud, Julia Kristeva) Et auiss j'ai $essay{\acute{e}}$ de explorer l'imaginaire des paroles dans les textes en ses rapports avec l'auteur et les personnages et entre les personnages. Ainsi conçu, j'ai $analys{\acute{e}}$ les formes de paroles en ce qui concerne la mort de $p{\grave{e}}re$ et le deuil. Cette $mani{\grave{e}}re$ s'est $r{\acute{e}}v{\acute{e}}l{\acute{e}}e$ efficace pour montrer comment des traces de sentiment se transforment dans des textes. Dans les pluparts des personnages chez les textes de Young-sun Yun, on peut voir si $d{\acute{e}}finitivement$ leur cicatrices personnelles, $sensibilit{\acute{e}}s$ $m{\hat{e}}l{\acute{e}}s$, ce 'je-ne-pourrai-rien-contre-mon-$p{\grave{e}}re$' ou 'je-ne-sais-quoi-et-presque-$apr{\grave{e}}s$-la mort-de-mon pere'. Pour $d{\acute{e}}pouiller$ cet aspect, j'ai $montr{\acute{e}}$ qu'il n'y avait pas de $v{\acute{e}}rit{\acute{e}}s$ objectives, mais que la $subjectivit{\acute{e}}$ doit trouver le jeu triangulaire entre l'inconscient de l'auteur par les paroles des textes et par les rapports entre le symbolisant et le $symbolis{\acute{e}}$ dans les $repr{\acute{e}}sentation$ socio-culturelle en $Cor{\acute{e}}e$ d'aujourd'hui.

• Economic and Environmental Geology
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• v.56 no.6
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• pp.745-764
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• 2023

In the Republic of Congo, Banded iron formations (BIFs) occur in two areas: the Chaillu Massif and the Ivindo Basement Complex, which are segments of the Archean Congo craton outcropping in the northwestern and southwestern parts of the country. They show interesting potential with significant mineral resources reaching 2 Bt and grades up to 60% Fe. BIFs consist mostly of oxide-rich facies (hematite/magnetite), but carbonate-rich facies are also highlighted. They are found across the country within the similar geological sequences composed of amphibolites, gneisses and greenschists. The Post-Archean Australian Shale (PAAS)-normalized patterns of BIFs show enrichment in elements such as SiO₂, Fe₂O₃, CaO, P₂O₅, Cr, Cu, Zn, Nb, Hf, U and depletion in TiO₂, Al₂O₃, MgO, Na₂O, K₂O, Sc, Th, Ba, Zr, Rb, Ni, V. REE diagrams show slight light REEs (rare earth elements; LREEs) compared to heavy REEs (HREEs), and positive La and Eu anomalies. The lithological associations, as well as the very high (Eu/Eu^*)_SN ratios> 1.8 shown by the BIFs, suggest that they are related to Algoma-type BIFs. The positive correlations between Zr and TiO₂, Al₂O₃, Hf suggest that the contamination comes mainly from felsic rocks, while the absence of correlations between MgO and Cr, Ni argues for negligeable contributions from mafic sources. Pr/Pr^* vs. Ce/Ce^* diagram indicates that the Congolese BIFs were formed in basins with redox heterogeneity, which varies from suboxic to anoxic and from oxic to anoxic conditions. They were formed through hydrothermal vents in the seawater, with relatively low proportions of detrital inputs derived from igneous sources through continental weathering. Some Congolese BIFs show high contents in Cr, Ni and Cu, which suggest that iron (Fe) and silicon (Si) have been leached through hydrothermal processes associated with submarine volcanism. We discussed their tectonic setting and depositional environment and proposed that they were deposited in extensional back-arc basins, which also recorded hydrothermal vent fluids.

• Korean Journal of Poultry Science
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• v.33 no.3
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• pp.225-231
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• 2006

To investigate the effect of feeding rare earth (RE) on the performance of breeder hens a feeding trial with sixteen thousands of 158 day old Ross broiler breeder hens was conducted for thirty weeks. A mixture of RE- chlorides containing mainly La, Ce, and Pr was mixed into corn-soy based diet at two levels, 300 and 600 mg/kg, All the hens were housed in flat layer houses and the ratio of male to female was maintained at one to ten. Dietary supplementation of the of RE at a level of 300 mg/kg made the hens reach egg production peak higher by about 6% and earlier by about two weeks. As a result, it made higher hatchable egg production by 3.5%. It also reduced dramatically the mortality of both male and female breeders(P<0.05). Egg weight was slightly increased but egg qualify was not much influenced by dietary supplementation of RE. Egg albumin hight and Haugh unit were significantly improved while egg shell thickness, egg breaking strength and yolk color were similar to those of the control. Experimental results appeared to show a good possibility that egg fertility and hatchability were improved by feeding RE. Dietary supplementation of RE at a level of 300 mg/kg should be acceptable but not the 600 mg/kg level for breeder hens. Further studies on the effect of RE on egg fertility and hatchability appears to be necessary.