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Reduced graphene oxide field-effect transistor for biomolecule detection and study of sensing mechanism

  • Kim, D.J.;Sohn, I.Y.;Kim, D.I.;Yoon, O.J.;Yang, C.W.;Lee, N.E.;Park, J.S.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.431-431
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    • 2011
  • Graphene, two dimensional sheet of sp2-hybridized carbon, has attracted an enormous amount of interest due to excellent electrical, chemical and mechanical properties for the application of transparent conducting films, clean energy devices, field-effect transistors, optoelectronic devices and chemical sensors. Especially, graphene is promising candidate to detect the gas molecules and biomolecules due to the large specific surface area and signal-to-noise ratios. Despite of importance to the disease diagnosis, there are a few reports to demonstrate the graphene- and rGO-FET for biological sensors and the sensing mechanism are not fully understood. Here we describe scalable and facile fabrication of rGO-FET with the capability of label-free, ultrasensitive electrical detection of a cancer biomarker, prostate specific antigen/${\alpha}1$-antichymotrypsin (PSA-ACT) complex, in which the ultrathin rGO sensing channel was simply formed by a uniform self-assembly of two-dimensional rGO nanosheets on aminated pattern generated by inkjet printing. Sensing characteristics of rGO-FET immunosensor showed the highly precise, reliable, and linear shift in the Dirac point with the analyte concentration of PSA-ACT complex and extremely low detection limit as low as 1 fg/ml. We further analyzed the charge doping mechanism, which is the change in the charge carrier in the rGO channel varying by the concentration of biomolecules. Amenability of solution-based scalable fabrication and extremely high performance may enable rGO-FET device as a versatile multiplexed diagnostic biosensor for disease biomarkers.

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Nonlinear behavior of axially loaded back-to-back built-up cold-formed steel un-lipped channel sections

  • Roy, Krishanu;Ting, Tina Chui Huon;Lau, Hieng Ho;Lim, James B.P.
    • Steel and Composite Structures
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    • v.28 no.2
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    • pp.233-250
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    • 2018
  • Back-to-back built-up cold-formed steel un-lipped channel sections are used in cold-formed steel structures; such as trusses, wall frames and portal frames. In such built-up columns, intermediate fasteners resist the buckling of individual channel-sections. No experimental tests or finite element analyses have been reported in the literature for back-to-back built-up cold-formed steel un-lipped channel sections and specially investigated the effect of screw spacing on axial strength of such columns. The issue is addressed in this paper. The results of 95 finite element analyses are presented covering stub to slender columns. The finite element model is validated against the experimental tests recently conducted by authors for back-to-back built-up cold-formed steel lipped channel sections. The verified finite element model is then used for the purposes of a parametric study to investigate the effect of screw spacing on axial strength of back-to-back built-up cold-formed steel un-lipped channel sections. Results are compared against the built-up lipped channel sections and it is shown that the axial strength of un-lipped built-up sections are 31% lesser on average than the built-up lipped channel sections. It was also found that the American Iron and Steel Institute (AISI) and the Australian and New Zealand Standards were over-conservative by around 15% for built-up columns failed through overall buckling, however AISI and AS/NZS were un-conservative by around 8% for built-up columns mainly failed by local buckling.

Human Security Dimension Israel-Hamas War and Security Policy Implications (인간안보 차원 이스라엘-하마스 전쟁과 안보정책적 함의)

  • Il Soo Bae;Hee Tae Jeong
    • The Journal of the Convergence on Culture Technology
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    • v.10 no.4
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    • pp.17-22
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    • 2024
  • The war that broke out on October 7, 2023 is prolonging and expanding into the Middle East. Although the damage from war is increasing, humanitarian aid to the Gaza Strip has been halted due to UNRWA's deviant actions. Powerful countries have suspended support, and the UN is appealing for support for the Gaza Strip. All damage is borne by civilians in the Gaza Strip, especially women, children, and the elderly. Israel has selected an evacuation zone and evacuation route in the Gaza Strip and established a humanitarian aid route in the border area. However, Hamas's resistance in underground tunnels, using civilian-dense areas and civilian facilities such as hospitals and schools as shields, further amplified civilian casualties. This Israel-Hamas war requires the international community to approach it from a human security perspective. We must strengthen the UN's functions and roles to ensure that humanitarian supplies reach the field and humanitarian intervention forces ensure human dignity and basic rights. We must restore the credibility of the UN's role through the Israel-Hamas war. In addition, Korea should urge the introduction of humanitarian aid and goods, and provide humanitarian goods such as daily necessities and medicine. We must also prepare for deployment as a member of the UN peacekeeping force in the future. These activities will help Korea develop into a model country that fulfills its role as a 'global pivotal nation' and will have a virtuous cycle of international support in the event of a future crisis on the Korean Peninsula.

Reconsideration of the Roles of Libraries for Sustainable Development (지속가능한 발전을 위한 도서관의 역할 재고찰)

  • Lee, Seungmin
    • Journal of the Korean Society for Library and Information Science
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    • v.54 no.1
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    • pp.29-49
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    • 2020
  • Through the UN 2030 Agenda adopted by the United Nations, sustainable development is bringing about many changes around the world. While discussions continue on the roles of libraries in supporting sustainable development in library communities, specific discussions on this have not been made enough. This study reconsidered the roles and functions of libraries to support sustainable development and discussed approaches to which libraries can perform in terms of informational, social, cultural, and environmental aspects. It also proposed a plan to allow libraries and librarians to lay the groundwork for supporting the sustainable development of society by reconsidering the roles of librarians as the core of all library activities to support sustainable development.

Tele-operation of A Low-cost Un-autonomous Mobile Robot Using A New Fuzzy Command Smoothing Concept (새로운 퍼지 명령 스무딩 개념을 이용한 저가형 비자율주행 이동로봇의 원격제어)

  • Yoo Bong-Soo;Joh Joongseon
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.9
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    • pp.809-815
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    • 2004
  • Researches on mobile robots have been mainly focused on the autonomous navigation and a lot of interesting results have been published so far. Most of applications are, however, fancy, unpractical, and very expensive to be used for 'UN-expensive' purpose. Well-known soccer robot may be an example of unpractical application. Un-autonomous mobile robot has, however, potential for a lot of practical applications. Especially, tele-operation of the un-autonomous mobile robot may the central issue of research. Major research topics for the tele-operated un-autonomous mobile robot include development of a force reflecting joystick for tele-operation and development of a sophisticated algorithm for smooth tele-operation. A new concept named fuzzy command smoothing algorithm is proposed in this paper in order to provide smooth motion to a tele-operated mobile robot. It gives smooth motion command to the mobile robot from possibly abrupt quick turn motion command of the joystick using fuzzy logic. Simulation results verify the usefulness of the proposed algorithm.

Evaluation of the Effect of Sedimentation Basin Structure on Hydrodynamic Behavior using CFD(I): The Effect of Longitudinal Baffle (CFD를 이용한 침전지 구조가 수리거동에 미치는 영향 평가(I): 도류벽의 영향)

  • Park, Se-Jin;Park, No-Suk;Lim, Jae-Lim;Kim, Sun-Kyu;Kim, Sug-Goo;Mun, Yong-Taek;Bang, Ki-Woong
    • Journal of Korean Society of Water and Wastewater
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    • v.20 no.5
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    • pp.667-676
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    • 2006
  • This study was conducted to evaluate the effect of longitudinal baffle on hydrodynamic behavior within a certain full-scale sedimentation basin (flow rate per basin; $1,000m^3/d$). Comparative experimental investigations have been carried out on the sediment removal efficiencies and the sludge deposit distribution in the baffled and un-baffled sedimentation basin, respectively. From the results derived in the baffled and un-baffled sedimentation, the turbidity removal rate in the baffled sedimentation basin is about 38% higher than that in un-baffled. Also, the height of sludge deposit in the baffled sedimentation basin is approximately 20% lower, and the sludge concentration is 10% higher than those in un-baffled sedimentation basin. In order to explain the experimental results and investigate the effect of longitudinal baffle in more detail, we conducted Computational Fluid Dynamics (CFD) simulation. From the results of CFD simulation, the flow, especially in the near of outlet orifice, was more stable in the case of longitudinal baffled sedimentation basin than that in un-baffled basin. Also, it could be concluded that the longitudinal baffle made a fully developed flow more effective for sedimentation.

An Experimental Study on the Transient Behavior of Vehicle Rollover (차량 롤전복의 과도거동에 관한 시험적 연구)

  • Lee, Myung-Su;Kim, Sang-Sup
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.3
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    • pp.113-121
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    • 2011
  • Rollover accident is one of the serious traffic accident and rollover accident takes high portion of all accident. The most common type of rollover is a tripped rollover which occupy 95% of all type of single-vehicle rollover. Tripped rollover occurs when a vehicle leaves normal road way and tripped by loose gravel, soil of fixed object such as guard rail, curbs and ditches. And the rest of the type of rollover is un-tripped rollover. An un-tripped rollovers that occurs during high-speed collision avoidance maneuvers. In this paper, presents the explanation of the un-tripped rollover test method and procedure, additionally this paper deals with various occurrence in the un-tripped test such as occurring excessive tire camber in the un-tripped test, tire side-wall contact with road surface and roll oscillation. And this paper analyzes the analysis of the roll rate amplitude in specific frequency through the FFT (Fast Fourier Transform) and the roll angle at the steering reverse timing which is the Fishhook test roll rate feedback time. Finally, this paper analyzes the relations between the estimated steady state roll gain and rollover stability.

Inhibition of $N^{+}-K^{+}$ Adenosine Triphosphatase Activity in Fisher Rats by Uranyl Nitrate

  • Lee, Kee-Ho;Lee, Je-Ho;Lee, Soo-Yong;Park, Sang-Yoon;Lee, Seung-Hoon;Yun, Taik-Koo;Ryu, Young-Wun;Lim, In-Kyoung
    • Journal of Radiation Protection and Research
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    • v.15 no.2
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    • pp.1-6
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    • 1990
  • An attempt was made to test the possibility of a major role for the $Na^{+}-K^{+}$ adenosine triphosphatase (ATPase)system in the diuresis induced by uranyl nitrate(UN). Fisher 344 rats were intravenously injected with UN(5 mg/kg, 15 mg/kg and 30 mg/kg). Urinary excretion of $Na^{+}\;and\;K^{+}$ significantly increased in 24 h exposure on the UN and then decreased below the normal level 3 days after the treatment. $Na^{+}-K^{+}$ ATPase activity of kidney was significantly inhibited in high dosages of UN 15mg/kg and UN 30 mg/kg 3-5 days after injection. And then the recovery of the enzyme activity was observed within 5-10 days after injection, at which the regeneration of the tubular cells occurred.

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Management of Irq-Un-Nasa (Sciatica) by Fasd (Venesection): A Case Report

  • Khan, Fatima;Nayab, Mohd;Ansari, Abdul Nasir
    • CELLMED
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    • v.12 no.2
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    • pp.6.1-6.5
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    • 2022
  • Objectives: Sciatica is a musculoskeletal pain sensed in the leg along with the distribution of the sciatic nerve, which is sometimes accompanied by low back pain and is most commonly caused by a disc herniation. In the Unani system of Medicine, Irq-un-Nasa (Sciatica) is defined as the pain which starts from the hip joint and descends towards the foot. It is a type of Waja-ul-Mafasil which is developed due to the accumulation of Khilt-e-Dam or Khilt-e-Balgham ghaleez in the hip joint. The conventional system of Medicine offers several medications and surgeries to manage sciatica with limited clinical evidence of effectiveness. These cases aim to provide insight into the effects of Fasd (Venesection) in Irq-un-Nasa. Case Presentation: Fasd was performed in the saphena minor vein of two clinically diagnosed patients with sciatica after the initial assessment. Two sittings of Fasd, once a week in each patient, were performed, followed by telephonic assessments for two months. The intensity of sciatic pain reduced with subsequent sittings of Fasd, and there was no recurrence of any symptoms and signs again during complete follow-up. Conclusion: Based on the results of the present case report, it appears that such cases of Irq-un-Nasa can be managed with Fasd, and the quality of life of such patients can also be improved.