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A study on Crack Healing of Various Glassy Polymers (part I) -theoretical modeling- (유리질 중합체의 균열 Healing에 관한 연구 (제1보) -이론 모델링-)

  • Lee, Ouk-Sub
    • Journal of the Korean Society for Precision Engineering
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    • v.3 no.1
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    • pp.40-49
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    • 1986
  • Crack, craze and void are common defects which may be found in the bulk of polymeric materials such as either themoplastics or thermosets. The healing phenomena, autohesion, of these defects are known to be a intrinsic material property of various polymeric materials. However, only a few experimental and theoretical investigations on crack, void and craze healing phenomena for various polymeric materials have been reported up to date [1, 2, 3]. This may be partly due to the complications of healing processes and lacking of appropriate theoretical developments. Recently, some investigators have been urged to study the healing phenomena of various polymenic materials since the significance of the use of polymer based alloys or composites has been raised in terms of specific strength and energy saving. In the earlier published reports [1, 2, 3, 4], the crack and void healing velocity, healing toughness and some other healing mechanical and physical properties were measured experimentally and compared with predicted values by utilizing a simple model such as the reptation model under some resonable assumptions. It seems, however, that the general acceptance of the proposed modeling analyses is yet open question. The crack healing processes seem to be complicate and highly dependent on the state of virgin material in terms of mechanical and physical properties. Furthermore, it is also strongly dependent on the histories of crack, craze and void development including fracture suface morphology, the shape of void and the degree of disentanglement of fibril in the craze. The rate of crack healing may be a function of environmental factors such as healing temperature, time and pressure which gives different contact configurations between two separated surfaces. It seems to be reasonable to assume that the crack healing processes may be divided in several distinguished steps like stress relaxation with molecular chain arrangement, surface contact (wetting), inter- diffusion process and com;oete healing (to obtain the original strength). In this context, it is likely that we no longer have to accept the limitation of cumulative damage theories and fatigue life if it is probable to remove the defects such as crack, craze and void and to restore the original strength of polymers or polymer based compowites by suitable choice of healing histories and methods. In this paper, we wish to present a very simple and intuitive theoretical model for the prediction of healed fracture toughness of cracked or defective polymeric components. The central idea of this investigation, thus, may be the modeling of behavior of chain molecules under healing conditions including the effects of chain scission on the healing processes. The validity of this proposed model will be studied by making comparisons between theoretically predicted values and experimentally determined results in near future and will be reported elsewhere.

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A Study on the Network and Space Planning of the Public libraries in Daegu City for Construction of Knowledge-Information infrastructure (지식정보 인프라 구축을 위한 대구시 공공도서관의 지역네트워크 및 공간계획에 관한 연구)

  • Hwang, Mee-Young
    • Korean Institute of Interior Design Journal
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    • v.20 no.5
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    • pp.236-244
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    • 2011
  • As the digital information infrastructure is established for the public library system in the contemporary age, expectations and demands surrounding the public library system are growing rapidly as the place of exchange and enjoyment of information and culture, and as the place of life-long learning. In addition, a new kind of information & culture services are needed to meet the demands of contemporary men and women, who are exploring information as the information environment undergoes rapid changes - from increase in the volume of digital publications, to increase in the usefulness of online information resources, to strides made in the media industry. The public library will continue to play its role and function by providing to all users all available information, whether it's available online or offline, whether it's in a physical format or in a digital format. As such, design and management of a space appropriate as a new information environment are needed. It is deemed that an information infrastructure for Daegu that can improve the quality of life in the region and can increase user accessibility to information in this information age is needed, as well as reorganization of the pertinent environment. Therefore more public libraries have to be built in Daegu as a necessity, and it is urgently needed that the information services be expanded through an organic linkage between local libraries such as between the central library and the branch libraries. This paper aims to provide basic data for building of public libraries in Daegu. To establish an information infrastructure for Daegu, a direction is given for the establishment of a local network of public libraries and ways for improvement are explored. This paper is significant in that, first, it helps in the planning of a local network of public libraries, which plays a crucial role in improving accessibility to information as well as the level of their use; and second, it helps in setting up guidelines for spatial configuration of the user space. As for the method, quantitative review of the information environment is to be done by analyzing the present situation of the public library network in Daegu from the perspectives of region, facility, and space, in order to present a method of user-centered spatial configuration that meets the changes in social roles and forms of information in the contemporary society.

Use of In vitro Gas Production Technique to Investigate Interactions between Rice Straw, Wheat Straw, Maize Stover and Alfalfa or Clover

  • Tang, S.X.;Tayo, G.O.;Tan, Z.L.;Sun, Z.H.;Wang, M.;Ren, G.P.;Han, X.F.
    • Asian-Australasian Journal of Animal Sciences
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    • v.21 no.9
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    • pp.1278-1285
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    • 2008
  • Measurement of gas produced during in vitro fermentation was used to investigate the fermentation characteristics and interactions of rice straw, wheat straw or maize stover mixed with alfalfa or clover at proportions of 100:0, 75:25, 50:50, 25:75 and 0:100, respectively. Cumulative gas production was recorded at 2, 4, 8, 12, 16, 24 and 48 h of incubation, and the Gompertz function was used to describe the kinetics of gas production. In vitro dry matter and organic matter disappearances (IVDMD and IVOMD) were determined after 48 h incubation. The rate of gas production of clover was higher (p<0.05) than that of rice straw, wheat straw, maize stover and alfalfa when straws and hays were incubated separately. Increasing the proportion of alfalfa in the straw-alfalfa mixtures increased (p<0.05) the rates, but not the maximum volume of gas production. However, both rate and the maximum volume of gas production were increased (p<0.01) as the proportions of clover increased in the straw-clover mixtures. The cumulative gas production at 48 h, IVDMD and IVOMD showed no consistent interaction effects between different mixtures of cereal straws and hays. The extent of interactive effects was affected by the types of cereal straw, legume hay and their proportions in the mixture. The appropriate combination for the mixture of rice straw or maize stover with leguminous hays was 75:25 and 25:75, respectively. The better combination occurred at a proportion of 50:50 for the mixture of wheat straw and alfalfa. We conclude that the suitable proportion of low-quality straw and high quality legume hay combination should be considered in the ration formulation system of ruminants according to the extent of positive interactive effects.

Inhibition of Transient Receptor Potential Melastain 7 Enhances Apoptosis Induced by TRAIL in PC-3 cells

  • Lin, Chang-Ming;Ma, Ji-Min;Zhang, Li;Hao, Zong-Yao;Zhou, Jun;Zhou, Zhen-Yu;Shi, Hao-Qiang;Zhang, Yi-Fei;Shao, En-Ming;Liang, Chao-Zhao
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.10
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    • pp.4469-4475
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    • 2015
  • Transient receptor potential melastain 7 (TRPM7) is a bifunctional protein with dual structure of both ion channel and protein kinase, participating in a wide variety of diseases including cancer. Recent researches have reported the mechanism of TRPM7 in human cancers. However, the correlation between TRPM7 and prostate cancer (PCa) has not been well studied. The objective of this study was to investigate the potential the role of TRPM7 in the apoptosis of PC-3 cells, which is the key cell of advanced metastatic PCa. In this study, we demonstrated the influence and potential function of TRPM7 on the PC-3 cells apoptosis induced by TNF-related apoptosis inducing-ligand (TRAIL). The study also found a novel up-regulated expression of TRPM7 in PC-3 cells after treating with TRAIL. Suppression of TRPM7 by TRPM7 non-specific inhibitors ($Gd^{3+}$ or 2-aminoethoxy diphenylborate (2-APB) ) not only markedly eliminated TRPM7 expression level, but also increased the apoptosis of TRAIL-treated PC-3 cells, which may be regulated by the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway accompany with up-regulated expression of cleaved Caspase-3, (TRAIL-receptor 1, death receptors 4) DR4, and (TRAIL-receptor 2, death receptors 5) DR5. Taken together, our findings strongly suggested that TRPM7 was involved in the apoptosis of PC-3 cells induced by TRAIL, indicating that TRPM7 may be applied as a therapeutic target for PCa.

Roles of CYP1A1 and CYP2E1 Gene Polymorphisms in Oral Submucous Fibrosis

  • Yaming, Punyo;Urs, Aadithya Basavaraj;Saxena, Alpana;Zuberi, Mariyam
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.7
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    • pp.3335-3340
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    • 2016
  • Background: Oral submucous fibrosis (OSF) is a precancerous condition with a 4 to13% malignant transformation rate. Related to the habit of areca nut chewing it is mainly prevalent in South-east Asian countries where the habit of betel quid chewing is frequently practised. On chewing, alkaloids and polyphenols are released which undergo nitrosation and give rise to N-nitrosamines which are cytotoxic agents. CYP450 is a microsomal enzyme group which metabolizes various endogenous and exogenous chemicals including those released by areca nut chewing. CYP1A1 plays a central role in metabolic activation of these xenobiotics, whereas CYP2E1 metabolizes nitrosamines and tannins. Polymorphisms in genes that code for these enzymes may alter their expression or function and may therefore affect an individuals susceptibility regarding OSF and oral cancer. The present study was therefore undertaken to investigate the association of polymorphisms in CYP1A1 m2 and CYP2E1 (RsaI/PstI) sites with risk of OSF among areca nut chewers in the Northern India population. A total of 95 histopathologically confirmed cases of OSF with history of areca nut chewing not less than 1 year and 80, age and sex matched controls without any clinical signs and symptoms of OSF with areca nut chewing habit not less than 1 year were enrolled. DNA was extracted from peripheral blood samples and polymorphisms were analyzed by PCR-RFLP method. Gene polymorphism of CYP1A1 at NcoI site was observed to be significantly higher (p = 0.016) in cases of OSF when compared to controls. Association of CYP1A1 gene polymorphism at NcoI site and the risk of OSF (Odd's Ratio = 2.275) was also observed to be significant. However, no such association was observed for the CYP2E1 gene polymorphism (Odd's Ratio = 0.815). Our results suggest that the CYP1A1 gene polymorphism at the NcoI site confers an increased risk for OSF.

A Study on the Optimum-Path for Traffic of Road Using GIS (GIS를 이용한 도로교통(道路交通)의 최적경로(最適經路) 선정(選定)에 관한 연구)

  • Oh, Myoung-Jin
    • Journal of Korean Society for Geospatial Information Science
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    • v.5 no.2 s.10
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    • pp.131-144
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    • 1997
  • Traffic jam densified day by day is phenomenon to occur lack of the road capacity in comparison with traffic density, but lack of the road cannot be concluded by main cause of traffic ism. Because the central function of a city would be concentrated upon the downtown and traffic demand would not be evenly distributed by the classification of an hour. Therefore, this study based on the fact that each driver will select the route generating traffic delay very low when path choice from origin to destination in travel plan estimating the quality of passage could be maintained the speed he want will approach to a characteristic grasp of a road, traffic, driver changing every moment by traffic-demand of road increased as a geometrical series with analysis a classification of a street, a intersection along the path on traffic density and highway capacity analysis the path using GIS techniques about complex street network, also will get the path of actual optimum for traffic delay trend creating under various condition the classification per a hour, a day of week and an incident through network such as analysis for traffic generation zone adjacent about street, intersection, afterward will expect the result increasing efficiency of the road-use through a good distribution of traffic by optimum-path choice, accordingly will prepare the scientific, objective, appropriate basis to decide the reasonable time of a road-widen and expansion through section analysis along a rate of traffic volume vs. road capacity.

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A case of encephalitis in a juvenile rheumatoid arthritis patient treated with etanercept (소아기 류마티스모양 관절염 환자에서 etanercept 사용 후 발생한 뇌염 1예)

  • Kwon, Ah Reum;Park, Eun Jung;Kim, Ki Hwan;Kim, Dong Soo
    • Clinical and Experimental Pediatrics
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    • v.53 no.2
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    • pp.262-266
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    • 2010
  • Tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$) is a major proinflammatory cytokine involved in the pathophysiology of juvenile rheumatoid arthritis. Etanercept is an effective inhibitor of $TNF-{\alpha}$ and has shown a beneficial effect in patients with JRA. However, the most important cause of concern related to etanercept administration is infection. We report a case of encephalitis in a JRA patient receiving long-term treatment with etanercept. The patient was a 4-year-old boy with refractory JRA, and he received etanercept subcutaneously at a dose of $0.4\;mg\;kg^{-1}\;day^{-1}$ twice a week for 14 months, along with non-steroidal anti-inflammatory drugs, methotrexate, oral steroids, and sulfasalazine. The patient presented with sudden fever, headache, vomiting, a generalized tonic seizure, and changes in mental status. We suspected a central nervous system infection, and simultaneously administered antibiotics, an antiviral agent, and steroids. After 2 days of hospitalization, his mental function returned to normal, and he showed no further seizure-like movements. Brain magnetic resonance imaging scan of the patient showed a multifocal cortical lesion on both sides of the temporoparietooccipital lobe, which indicated encephalitis. Although we were unable to identify the causative organism of encephalitis, we think that the encephalitis may be attributed to infection, and the use of etanercept may have increased the risk of severe infection. Therefore, etanercept was discontinued and the patient recovered shortly after. To the best of our knowledge, this is the first case of encephalitis in a juvenile rheumatoid arthritis patient treated with etanercept.

Effects of lycopene on number and function of human peripheral blood endothelial progenitor cells cultivated with high glucose

  • Zeng, Yao-Chi;Mu, Gui-Ping;Huang, Shu-Fen;Zeng, Xue-Hui;Cheng, Hong;Li, Zhong-Xin
    • Nutrition Research and Practice
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    • v.8 no.4
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    • pp.368-376
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    • 2014
  • BACKGROUND/OBJECTIVES: The objectives of this study were to investigate the effects of lycopene on the migration, adhesion, tube formation capacity, and p38 mitogen-activated protein kinase (p38 MAPK) activity of endothelial progenitor cells (EPCs) cultivated with high glucose (HG) and as well as explore the mechanism behind the protective effects of lycopene on peripheral blood EPCs. MATERIALS/METHODS: Mononuclear cells were isolated from human peripheral blood by Ficoll density gradient centrifugation. EPCs were identified after induction of cellular differentiation. Third generation EPCs were incubated with HG (33 mmol/L) or 10, 30, and $50{\mu}g/mL$ of lycopene plus HG. MTT assay and flow cytometry were performed to assess proliferation and apoptosis of EPCs. EPC migration was assessed by MTT assay with a modified boyden chamber. Adhesion assay was performed by replating EPCs on fibronectin-coated dishes, after which adherent cells were counted. In vitro vasculogenesis activity was assayed by Madrigal network formation assay. Western blotting was performed to analyze protein expression of both phosphorylated and non-phosphorylated p38 MAPK. RESULTS: The proliferation, migration, adhesion, and in vitro vasculogenesis capacity of EPCs treated with 10, 30, and $50{\mu}g/mL$ of lycopene plus HG were all significantly higher comapred to the HG group (P < 0.05). Rates of apoptosis were also significantly lower than that of the HG group. Moreover, lycopene blocked phosphorylation of p38 MAPK in EPCs (P < 0.05). To confirm the causal relationship between MAPK inhibition and the protective effects of lycopene against HG-induced cellular injury, we treated cells with SB203580, a phosphorylation inhibitor. The inhibitor significantly inhibited HG-induced EPC injury. CONCLUSIONS: Lycopene promotes proliferation, migration, adhesion, and in vitro vasculogenesis capacity as well as reduces apoptosis of EPCs. Further, the underlying molecular mechanism of the protective effects of lycopene against HG-induced EPC injury may involve the p38 MAPK signal transduction pathway. Specifically, lycopene was shown to inhibit HG-induced EPC injury by inhibiting p38 MAPKs.

The Question of 'State and Art' with regard to Soviet Socialist Realism (소련 사회주의 리얼리즘에 관하여: '국민과 예술'의 문제)

  • Alexander, Morozov
    • The Journal of Art Theory & Practice
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    • no.7
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    • pp.125-163
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    • 2009
  • The artworks of Socialist Realism of the former Soviet Union, with the beginning of the 21st century, are gaining a new attention from art collectors. One reason for this might consist in the fact that relevant art pieces exemplify the ways in which they visualize ideas on the basis of their high-profile art tradition and also in which they integrate their utopian ideals with mysticism. These aspects of the Soviet art goes far beyond the wide-spread assumption that their art, as a means of propaganda, principally represents a political allegiance to the system. With Stalin coming into power in the 1930s, the artistic trend of Socialist Realism obtained a nationwide sympathy and support from people, giving birth to a new art which essentially corresponded to the demands of the political power. An official art current of the USSR over the period from the 1930s to 1950s, Socialist Realism was in tandem with the Communist commitment to the party and popularity, symbolizing a loyalty to the cause. It was thus characterized by plainness and lucidity so that ordinary people could gain easy access to art. Its salient feature, over an entire range of art, was an optimistic pursuit of a utopian dream. Therefore, it tallied with the popular sentiment for a Communist paradise, giving form to their beliefs in human agency working at the materialist world and also to such abstract concepts as force, fitness, and beauty by adding even mythical ideals. Its main subject matter includes harvest feasts of collective farms, imaginary socialist cities, grand marches of heroic laborers and in this way it served as a propaganda for a sacred utopia of socialist totalitarianism. On the other end of the spectrum, however, rose the second camp of art, which put an emphasis on bona-fide artistic activities of plastic art and on an artist's personal expression and freedom, as opposed to the surface optimism of Socialist Realism. Central to the Russian Avant Garde art, which prized the above-mentioned values, were Malevich's Geometric Abstraction and A. Rodchenko's Constructivism. Furthermore, in the transitional era of the late 20th century and the 21st century it was recognized that film art or electronic media art, rather than traditional genre of paintings, would function as a more efficient way of propaganda. These new genres were made possible by ridiculing the stereotypes of the Russian lifestyle and also by ignoring ethical or professional dimensions of artworks. That is, they reinvented themselves into a sort of field art, seemingly degrading the quality of artworks and transforming them into artifacts or simulacres in the very sense of post-modernism. The advent of the new era brought about the formation and occupation of pop culture of the younger generations, calling into question the idea of art as the class-determined. It also increased the attention to field art, which extensively found way to modern art centers, galleries, and exhibition projects. It can be stated that this was a natural outcome of human nature.

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A Study for Dose-Reduction of Antipsychotics in Chronic Schizophrenics (만성 정신분열병 환자에서 항정신병약물 감량에 관한 연구)

  • Hwang, Tae-Yeon;Lee, Min Soo;Kim, Hyeong-Seob
    • Korean Journal of Biological Psychiatry
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    • v.5 no.2
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    • pp.263-277
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    • 1998
  • Conventional high-dose antipsychotics tend to result in more side effects, negative symptoms and dysphoria, and at the same time lower the cognitive function which is already impaired in most schizophrenics. Florid psychotic symptoms, negative symptoms and cognitive impairment greatly impede psychosocial performance and eventual reintegration into society. The reduction of symptom and the improvement of cognitive funtions and social skills are therefore central to the psychiatric rehabilitation process. The purpose of this study was to evaluate the dose-reduction effects of antipsychotics on chronic schizophrenics prescribed conventional high-dose antipsychotics more than 1,500mg equivalent of chlorpromazine. Fifty-one chronic schizophrenics who maintained high-dose antipsychotics for more than three months were randomly assigned to two groups : 20 patients comprised the dose-maintaining group and 31 patients made the dose-reduction group. Over a sixteen weekperiod Positive and Negative Syndrome Scale(PANSS), Extrapyramidal Symptom(EPS), Nurses' Observation Scale for Inpatient Evaluation(NOSIE-30), Continuous Performance Test(CPT), Quality of Life(QOL), and haloperidol/reduced haloperidol blood levels were determined at the base line and after 2, 4, 6, 8, 12, 16 weeks to evaluate the dose reduction effects of high-dose antipsychotics. The results were as follows : 1) Dose-reduction is highly effective in reducing positive and negative symptoms, and general psychopathology. Effects were most prominent at 8, 12, 16 weeks. Among the dose reduction group, positive symptoms in positive symptom group and negative symptoms in negative symptom group were more reduced. 2 Extrapyramidal symptoms showed no significant difference between two groups. But the EPS was reduced time after time within two groups. 3) Hit rates of Continuous Performance Test, which indicate attentional capacity, increased significantly after dose reduction. 4) Haloperidol and reduced haloperidol blood levels decreased until the 4th week, after which they were constant. 5) Total scores of Nurses' Observation Scale for Inpatient Evaluation were unchanged between the two groups. But among the indices, social interest and personal neatness were improved in the dose-reduction group and retardation was aggrevated in the dose-maintaining group. 6) Total quality of life scores were unchanged between two groups. But in the dose maintaining group, satisfaction scores of attention, autonomy, and interpersonal relationship decreased progressively. These findings suggest that the dose reduction of antipsychotics for chronic schizophrenics on programs of high-dose antipsychotics were effective. Dose reduction should therefore be implemanted to spread the rehabilitation and improve quality of life for chronic schizophrenics.

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