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Development and application of non-invasive drug delivery systems utilizing pulse power, and its application to mouse models (펄스파워를 적용한 비침습 약물 전달기 개발 및 마우스 모델로의 적용)

  • Hwi-Chan Ham;Kyu-Sik Kim;Ji-Hwan Lee;Hyung-Jin Choi;Do-Nyun Kim;Jai-Ick Yoh
    • Journal of IKEEE
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    • v.28 no.1
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    • pp.97-103
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    • 2024
  • Some drugs can offer far better medical effectiveness as it is injected through the intradermal layer of the skin, known as a needle-free injection. However, conventional needle-free devices might deliver a relatively large amount of drug in a just single spot of skin, splitting open the tissue layer structure, which might cause bruising and bleeding. By injecting the small volume with a fast repetition rate in a large surface area of skin, the patient may get much fewer injuries and pain. To achieve that specification, the driving force must be instantaneous and short-pulsed. Such a form of an injection device has been developed but the efficacy of those devices has been rarely examined. Therefore, this study developed the laser-induced microjet device that ejects microjet whose speed is ~310 m/s, during the 400~800 ㎲ of pulse time. The device can eject ~1 µL of the drug at the rate at which each shot repeated 10 shots per second. Using this specification, we evaluated the efficacy of drug injection onto mouse models. After injecting the insulin solution into the mouse model, the blood insulin level is detected, resulting in 20 % of blood insulin level with the ordinary needle syringe injection method.

Economic Effect Analysis of Pyongyang's 50,000 Housing Units Construction Project (평양 5만세대 주택건설계획의 경제적 효과 분석)

  • JooYung Lee
    • Analyses & Alternatives
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    • v.8 no.1
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    • pp.87-109
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    • 2024
  • At the 8th Party Congress in 2021, North Korea announced a plan to build 50,000 housing units in Pyongyang, and this paper analyzes the economic effects and related informal costs of of the project. Currently, Pyongyang is experiencing a significant housing shortage. It is estimated that the number of households in Pyongyang increased by 184,000 between 1994 and 2020, while the estimated new housing supply during the period was only 30,000. Pyongyang's 50,000 housing units construction project is characterized by the goal of improving the living conditions of workers, the application of the new city construction method, and the largest state-led housing construction since the Arduous March. The project is expected to generate economic effects such as increasing workers' motivation to work, increasing tourism resources, and generating income from related industries. On the one hand, a significant portion of the construction cost of the 50,000-unit housing project in Pyongyang is passed on to companies and households in the form of informal cost such as quasi-taxes and manpower mobilization. In addition, there may be congestion in the power supply and sewerage facilities that occur when moving in. If these costs are not taken into account, the feasibility of a housing construction project may not be properly assessed, making it difficult to sustain it in the long term.

Seasonal variation in longitudinal connectivity for fish community in the Hotancheon from the Geum River, as assessed by environmental DNA metabarcoding

  • Hyuk Je Lee;Yu Rim Kim;Hee-kyu Choi;Seo Yeon Byeon;Soon Young Hwang;Kwang-Guk An;Seo Jin Ki;Dae-Yeul Bae
    • Journal of Ecology and Environment
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    • v.48 no.1
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    • pp.32-48
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    • 2024
  • Background: Longitudinal connectivity in river systems strongly affects biological components related to ecosystem functioning, thereby playing an important role in shaping local biodiversity and ecosystem health. Environmental DNA (eDNA)-based metabarcoding has an advantage of enabling to sensitively diagnose the presence/absence of species, becoming an efficient/effective approach for studying the community structure of ecosystems. However, little attention has been paid to eDNA-based biomonitoring for river systems, particularly for assessing the river longitudinal connectivity. In this study, by using eDNA we analyzed and compared species diversity and composition among artificial barriers to assess the longitudinal connectivity of the fish community along down-, mid- and upstream in the Hotancheon from the Geum River basin. Moreover, we investigated temporal variation in eDNA fish community structure and species diversity according to season. Results: The results of species detected between eDNA and conventional surveys revealed higher sensitivity for eDNA and 61% of species (23/38) detected in both methods. The results showed that eDNA-based fish community structure differs from down-, mid- and upstream, and species diversity decreased from down to upstream regardless of season. We found that there was generally higher species diversity at the study sites in spring (a total number of species across the sites [n] = 29) than in autumn (n = 27). Nonmetric multidimensional scaling and heatmap analyses further suggest that there was a tendency for community clusters to form in the down-, mid- and upstream, and seasonal variation in the community structure also existed for the sites. Dominant species in the Hotancheon was Rhynchocypris oxycephalus (26.07%) regardless of season, and subdominant species was Nipponocypris koreanus (16.50%) in spring and Odontobutis platycephala (15.73%) in autumn. Artificial barriers appeared to negatively affect the connectivity of some fish species of high mobility. Conclusions: This study attempts to establish a biological monitoring system by highlighting the versatility and power of eDNA metabarcoding in monitoring native fish community and further evaluating the longitudinal connectivity of river ecosystems. The results of this study suggest that eDNA can be applied to identify fish community structure and species diversity in river systems, although some shortcomings remain still need to be resolved.

Investigation of Sorption Reaction of Re(VII) onto HDPy- and HDTMA-modified Bentonite (HDPy 및 HDTMA로 개질된 벤토나이트에 대한 Re(VII)의 흡착반응 분석)

  • Jun-Myung Choi;Junhyuk Ha;Ranyeong Choi;Jun-Yeop Lee
    • Journal of Radiation Industry
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    • v.18 no.3
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    • pp.167-171
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    • 2024
  • Technetium-99 (99Tc) is recognized as a critical concern in the disposal of spent nuclear fuel due to its long half-life and remarkable stability, existing predominantly as TcO4- in the natural environment. The anionic form of technetium is highly soluble and mobile, posing significant environmental risks from the viewpoint of nuclear waste management. Thus, developing efficient and cost-effective sorbents for aqueous Tc(VII) is essential for mitigating relevant contamination. In the present work, the adsorption characteristics of Re(VII), a chemical analog of Tc(VII), were investigated using the clay mineral bentonite, modified with two different organic cations: hexadecylpyridinium (HDPy) and hexadecyltrimethylammonium (HDTMA). Sorption experiments were conducted at a liquid-to-solid ratio of 1 g/L with Re(VII) solutions prepared at concentrations from 10-4 mol/L to 10-6 mol/L. The sorption ratio and distribution coefficients were determined with samples collected at reaction times of 10, 50, 100, and 500 minutes after 0.45 ㎛ syringe filtration. In parallel, the modified bentonite samples were further analyzed using the X-ray diffraction (XRD) method to understand the adsorption mechanism of Re(VII) onto the target minerals. According to the quantification analysis results, a rapid equilibrium reaction of aqueous Re(VII) for all modified bentonite samples was identified. Moreover, near-complete adsorption of Re(VII) was observed when the bentonite was modified at 200-400% of its cation exchange capacity (CEC) for both organic cations. For cases of lower modification, the HDTMA-modified bentonite showed relatively higher adsorption efficiency compared with the one modified with HDPy. This result was inferred to be due to the difference in inter-layer spacing based on the characteristics of the organic cations. It is expected that the results obtained through this study will serve as a preliminary case for the synthesis of adsorbents for the retardation of highly mobile anionic radionuclides, such as I and Tc, in the natural environment.

The Persuit of Rationality and the Mathematics Education (합리성의 추구와 수학교육)

  • Kang Wan
    • The Mathematical Education
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    • v.24 no.2
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    • pp.105-116
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    • 1986
  • For any thought and knowledge, its growth and development has close relation with the society where it is developed and grow. As Feuerbach says, the birth of spirit needs an existence of two human beings, i. e. the social background, as well as the birth of body does. But, at the educational viewpoint, the spread and the growth of such a thought or knowledge that influence favorably the development of a society must be also considered. We would discuss the goal and the function of mathematics education in relation with the prosperity of a technological civilization. But, the goal and the function are not unrelated with the spiritual culture which is basis of the technological civilization. Most societies of today can be called open democratic societies or societies which are at least standing such. The concept of rationality in such societies is a methodological principle which completes the democratic society. At the same time, it is asserted as an educational value concept which explains comprehensively the standpoint and the attitude of one who is educated in such a society. Especially, we can considered the cultivation of a mathematical thinking or a logical thinking in the goal of mathematics education as a concept which is included in such an educational value concept. The use of the concept of rationality depends on various viewpoints and criterions. We can analyze the concept of rationality at two aspects, one is the aspect of human behavior and the other is that of human belief or knowledge. Generally speaking, the rationality in human behavior means a problem solving power or a reasoning power as an instrument, i. e. the human economical cast of mind. But, the conceptual condition like this cannot include value concept. On the other hand, the rationality in human knowledge is related with the problem of rationality in human belief. For any statement which represents a certain sort of knowledge, its universal validity cannot be assured. The statements of value judgment which represent the philosophical knowledge cannot but relate to the argument on the rationality in human belief, because their finality do not easily turn out to be true or false. The positive statements in science also relate to the argument on the rationality in human belief, because there are no necessary relations between the proposition which states the all-pervasive rule and the proposition which is induced from the results of observation. Especially, the logical statement in logic or mathematics resolves itself into a question of the rationality in human belief after all, because all the logical proposition have their logical propriety in a certain deductive system which must start from some axioms, and the selection and construction of an axiomatic system cannot but depend on the belief of a man himself. Thus, we can conclude that a question of the rationality in knowledge or belief is a question of the rationality both in the content of belief or knowledge and in the process where one holds his own belief. And the rationality of both the content and the process is namely an deal form of a human ability and attitude in one's rational behavior. Considering the advancement of mathematical knowledge, we can say that mathematics is a good example which reflects such a human rationality, i. e. the human ability and attitude. By this property of mathematics itself, mathematics is deeply rooted as a good. subject which as needed in moulding the ability and attitude of a rational person who contributes to the development of the open democratic society he belongs to. But, it is needed to analyze the practicing and pursuing the rationality especially in mathematics education. Mathematics teacher must aim the rationality of process where the mathematical belief is maintained. In fact, there is no problem in the rationality of content as long the mathematics teacher does not draw mathematical conclusions without bases. But, in the mathematical activities he presents in his class, mathematics teacher must be able to show hem together with what even his own belief on the efficiency and propriety of mathematical activites can be altered and advanced by a new thinking or new experiences.

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Effect of titanium powder on the bond strength of metal heat treatment (티타늄 파우더가 금속의 열처리 시 결합강도에 미치는 영향)

  • Kim, Sa-Hak;Kim, Wook-Tae
    • Journal of Dental Rehabilitation and Applied Science
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    • v.33 no.2
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    • pp.71-79
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    • 2017
  • Purpose: Ni-Cr alloy does not contain Beryllium, causing the metal compound to form oxides in the furnace but by using Titanium as a chemical catalyst the forming of the oxides can be controlled, and by controlling the impurities formed on the metal surface, the possibility of the Ni-Cr alloy bond strength being increased can be analysed. Materials and Methods: Titanium was used as a chemical catalyst in the porcelain for the oxidation of beryllium-free metal (Ni-Cr) alloy. The T1 group, which does not use Titanium power as a chemical catalyst is a reference model for comparison. The T2 group and T3 group used 10 g and 20 g of Titanium power, respectively. They are fabricated to observe the shear bond strength and surface properties. There was no significance when One-way ANOVA analysis/Tukey Honestly Significant Difference Test was conducted for statistical analysis among groups (P > 0.05). Results: Results of measuring the three-point flexural bond strength of the Ni-Cr alloy and thickness of the oxide film. Experiment T3 using 20 g Titanium chemical catalyst: $39.22{\pm}3.41MPa$ and $6.66{\mu}m$, having the highest bond strength and thinness of oxide film. Experiment T2 using 10 g Titanium chemical catalyst: $34.65{\pm}1.39MPa$ and $13.22{\mu}m$. Experiment T1 using no Titanium chemical catalyst: $32.37{\pm}1.91MPa$ and $22.22{\mu}m$. Conclusion: The T2 and T3 experiments using Titanium chemical catalyst showed higher bond strength for the Ni-Cr alloy and lower thickness of oxide film than experiment T1, and the titanium catalyst being able to increase bond strength was observed.

Simultaneous Separation and Determination of $^{l4}C\;and\;^3H$ in Spent Resins from PWR Nuclear Power Plants (가압경수로형 원전에서 발생된 폐수지의 $^{14}C$$^3H$ 동시 분리 및 측정)

  • Park, Soon-Dal;Kim, Jung-Suck;Kim, Jong-Goo;Han, Sun-Ho;Jee, Kwang-Yong
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.5 no.3
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    • pp.179-188
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    • 2007
  • In this work $^{14}C\;and\;^3H$ distribution characteristics of spent resins from nuclear power plants(NPPs), pressurized water reactors(PWRs), was investigated. It was found that the recovery percent of $^{14}C$ by the wet oxidation-acid stripping was $81%{\sim}100%$ for the added activity range of $^{14}C,\;0.72\;Bq{\sim}460\;Bq$, and it was not affected by the kinds of stripping acids, 3N-HCl, $3\;N-HNO_3\;and\;3\;N-H_2SO_4$. And the recovery percent of $^3H$ by distillation using the same apparatus was $81%{\sim}101%$ for the added activity range of $^3H,\;0.60\;Bq{\sim}435\;Bq$. Among the tested stripping acids, 3\;N-HCl, $3\;N-HNO_3\;and\;3\;N-H_2SO_4$, only the trapped $^3H$ solution by distillation in $3\;N-H_2SO_4$ was compatible with the 3H scintillator, Ultimagold XR. Neither of the $^{14}C\;and\;^3H$ trapping solutions from the spent ion exchange resin samples by the wet oxidation-3 $N-H_2SO_4$ stripping contained gamma nuclides. However, some gamma nuclides, $^{60}Co,\;^{134}Cs,\;^{137}Cs\;and\;^{54}Mn$, were found in the trapped $^3H$ solutions of the spent resins by the wet oxidation-3 N-HCl stripping. It was the same for the $^3H$ trapping solutions of the spent resins by Sample Oxidizer(PACKARD MODEL 307). Meanwhile only two nuclides, $^{134}Cs,\;and\;^{134}Cs$, were found in the $^{14}C$ trapping solutions of the spent resins by Sample Oxidizer(PACKARD MODEL 307). It was found that most of the $^{14}C$ in the spent resins existed as inorganic carbon form, more than about 70% of the total $^{14}C$ content. Among the analyzed 30 spent ion exchange resin samples, the average concentration of $^{14}C$ and $^3C$ for the high radioactive samples, 8 samples, was $19000\;Bq/g{\pm}41000\;Bq/g,\;670\;Bq/g{\pm}460\;Bq/g$ and that for the low radioactive samples, 22 samples, was $4.2\;Bq/g{\pm}4.3\;Bq/g,\;6.0\;Bq/g{\pm}5.3\;Bq/g$, respectively. And the average $^{14}C/^3H$ ratio for the high radioactive samples, was higher, 28, than that of low radioactive samples, 0.70. Some linear relationship trend was found between the activity concentrations of $^{14}C\;and\;^3H$.

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American Culture at the Crossroad : Debates over NEA(National Endowments for the Arts) (미국 문화, 그 기로에 서서 - NEA(국립예술진흥기금)를 둘러싼 논쟁 중심으로)

  • Kim, Jin-A
    • The Journal of Art Theory & Practice
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    • no.4
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    • pp.33-56
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    • 2006
  • The cultural debates between conservatives and liberals at the end of the 1980s and in the early 1990s were termed as "culture wars." The "culture wars" involved a diverse range of controversial issues, such as the introduction of multicultural curricula in educational institutions, prayers in schools, whether to allow gays to serve openly in the military, and whether abortion should be permitted. The most heated debates of the "culture wars" regarding art raged over the NEA and the question of whether Andres Serrano's works should have been publicly funded, in addition to the exhibition "Robert Mapplethorpe: The Perfect Moment" which were charged as projecting "obscene" or "blasphemous" images. This paper examines the development of culture wars in art and focuses on several issues invoked by the NEA debates. However, it is not a detailed chronological investigation. Rather it pays attention to the several phases of the debates, analyzing and criticizing the clashes of the political and esthetical points of views between conservatives and liberals. How could NEA funding, a mere fraction of the federal budget, have become so critical for both sides(conservative and liberal), for politicians and artists' groups, and for academics and the general public? The art community was astounded by this chain of events; artists personally reviled, exhibitions withdrawn and under attack, the NEA budget threatened, all because of a few images. For conservative politicians, the NEA debate was not only a battle over the public funding of art, but a war over a larger social agenda, a war for "American values and cultures"based on the family, Christianity, the English language, and patriarchy. Conservative politicians argued the question was not one of "censorship" but of "sponsorship," since the NEA charter committed it to "helping museums better serve the citizens of the United States."Liberals and art communities argued that the attempt to restrict NEA funding violated the First Amendment rights of artists, namely "free speeches." "No matter how divided individuals are on matters of taste," Arthur C. Danto wrote, "freedom is in the interest of every citizen." The interesting phase is that both sides are actually borrowing one another's point of view when they are accompanied by art criticism. Kramer, representative of conservative art critic, objected the invasion of political contents or values in art, and struggled to keep art's own realm by promoting pure aesthetic values such as quality and beauty. But, when he talked about Mapplethorpe's works, he advocated political and ethical values. By contrast, art experts who argued for Mapplethorpe's works in the Cincinnati trial defended his work, ironically by ignoring its manifest sexual metaphor or content although they believed that the issues of AIDS and homosexuality in his work were to be freely expressed in the art form. They adopted a formalistic approach, for example, by comparing a child nude with putti, a traditional child-angel icon. For a while, NEA debates made art institutions, whether consciously or unconsciously, exert self-censorship, yet at the same time they were also producing positive aspects. To the majority of people, art was still regarded as belonging to the pure aesthetic realm away from political, economical, and social ones. These debates, however, were expanding the very perspective on the notion of what is art and of how art is produced, raising questions on art appreciation, representation, and power. The interesting fact remains: had the works not been swiped in NEA debates, could the Serrano's or Mapplethorpe's images gain the extent of power and acceptance that it has today?

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The Study of Operating Conditions by Establishing Density Currents Generator for Improving of Water Quality on Lake Water - With Focus on DO and Water Temperature - (호소수의 수질개선을 위한 DCG 설치시 운전조건에 관한 연구 - DO와 수온을 중심으로 -)

  • Lee, Young-Shin;Han, Kyung-Hee;Kim, Young-Kyu;An, Hyung-Chul;Shin, Sung-Woo
    • Journal of Korean Society of Environmental Engineers
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    • v.36 no.4
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    • pp.286-294
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    • 2014
  • The purpose of this study is to investigate the effects of applying density current generator (hereafter referred to as DCG to large lakes on the operating conditions of DCG, de-stratification, water quality improvement and inhibition of algae occurrence. As a result of a survey conducted to derive the optimum operating parameters of DCG in a condition to minimize eco-toxicity, the following conclusions were obtained. During the survey period, a marked stratification appeared in September to October 2011 and May 2012. At this time, the average depth of water to form thermocline was found to be $5{\pm}2$ m, so the location of discharge port for the operation of DCG was determined to be about 5 m below from the surface. To minimize the adverse effects of benthos and obtain the effect of water mixture at the time of water circulation, the mixing ratio of surface water and deep water was designed to be 3:1 by means of ecotoxicological assessment on the DCG operating characteristics. To select the appropriate operating hours for DCG, DCG was operated by 12 hr, 24 hr, 36 hr and 48 hr. As its result, the formation of thermocline did not occur during the operation of 36 hr. Also, It was effected that start reoperating from 3rd day after stop 2days under the condition of operated during 36 hr with calculated power consumption. Under the above conditions, the results of DO and water temperature analysis during the operation of DCG showed that the stratification, which was distinct previously, appeared to be weak, and relatively lower levels than those before operation were found as a result of water quality analysis on COD and chlorophyll-a, which leads to the conclusion that the water body is maintained at a stable condition due to the circulation of water by the occurrence of density current resulting from the operation of DCG.

A FEM comparison study about the force, displacement and initial stress distribution on the maxillary first molars by the application of Asymmetric Head-Gears with the different traction forces (Asymmetric Head-Gear의 견인력의 차이에 따른 상악 제 1 대구치에 나타나는 힘과 변위 및 초기 응력분포에 관한 유한요소법적 비교 연구)

  • Cha, Kyung-Suk
    • The korean journal of orthodontics
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    • v.31 no.3 s.86
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    • pp.311-323
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    • 2001
  • One of the various mechanics used to treat unilateral Class II malocclusion is head gear with asymmetric face bow. We made the finite element models of unilateral Class II maxillary dental arch and power arm asymmetric face bow. We designed this experiment to observe stress distribution of periodontal ligament, reaction force, and displacement and to understand force system, so to predict the therapeutic effect. On the basis of computerized tomograph of maxillary dental arch of 25 years old male with normal occlusion without extraction and orthodontic treatment history, we made finite element models of maxillary dental arch and periodontal ligament. Then we modified that model to unilateral maxillary Class II malocclusion model of which maxillary left molar displaced mesially. Also, We made finite element model of asymmetric face bow of which right outer bow shorter than left by 25mm(RMO, Penta-FormTM/Medium size, 0.045 inch iner bow, 0.072 inch outer bow). After that, retraction force of 250g, 300b, 350g were applied to maxillary first molar. We concluded as follow. 1. The Net force that both maxillary first molars were received increased as the retraction force increased. Mesially positioned tooth received more force than normally positioned tooth. But, both tooth were received distal force, so distal movement occured. 2. Both tooth received buccal lateral force. In analysis of force element, as the retraction force were increased, force of X-axis at mesially positioned tooth decreased, and force of X-axis at normally positioned tooth increased. so lateral force component moved to the side received less force from more force. 3. There were rotation, tipping with distal movement in maxillary first molar. As retraction force were increased, rotation and tipping also increased. More tipping and rotation occured at the side received more force, that is, mesially positioned tooth. Though it Is small change, displacement of same pattern occur in normally positioned tooth

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