• Journal of Semiconductor Engineering
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• 제1권1호
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• pp.46-56
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• 2020

This article highlights new opportunities of inorganic semiconductor materials for bio-implantable electronics, as a subset of 'transient' technology defined by an ability to physically dissolve, chemically degrade, or disintegrate in a controlled manner. Concepts of foundational materials for this area of technology with historical background start with the dissolution chemistry and reaction kinetics associated with hydrolysis of nanoscale silicon surface as a function of temperature and pH level. The following section covers biocompatibility of silicon, including related other semiconductor materials. Recent transient demonstrations of components and device levels for bioresorbable implantation enable the future direction of the transient electronics, as temporary implanters and other medical devices that provide important diagnosis and precisely personalized therapies. A final section outlines recent bioresorbable applications for sensing various biophysical parameters, monitoring electrophysiological activities, and delivering therapeutic signals in a programmed manner.

• 세라미스트
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• 제21권1호
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• pp.44-54
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• 2018

Oxide semiconductor has been spotlighted as a channel material of TFTs in AMLCD as an alternative to Si, due to high mobility ( > $5cm^2/Vs$). It is also one of the strong candidates for TFTs in AMOLED because of high bias stability at amorphous phase. Beyond the advantages mentioned above, oxide semiconductor has many strengths such as transparency, low fabrication temperature and relatively low fabrication cost. For those reasons, the application of oxide semiconductor is not limited to display but can be extended to new types of electronics, for example, transient electronics for human implantable devices. From this context, oxide materials that have been used as semiconductor and insulator at transient electronics are investigated respectively, and conductor and substrate candidates are also explained, since transient electronics require systematic consideration beyond individual oxide films.

• Journal of Pharmaceutical Investigation
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• 제23권4호
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• pp.207-211
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• 1993

Reservoir type devices were designed for long-term implantable drug delivery system. The reservoir type device was prepared with the polymethacrylic acid gel coated with polyurethane membrane. Release controlling agent (RCA) were employed to control drug release from devices via generation of micropores in the membranes. The polyurethane membrane functioned as a rate controlling barrier. The drug release pattern of hydrogel demonstrated zero order kinetics. The release rate of drugs could be regulated by varying hydrophobicity/hydrophilicity and content of the RCA, as well as the thickness of the polyurethane membrane. The release of drugs from this system was governed by pore mechanism via simple diffusion and osmotic pressure.

• Journal of Pharmaceutical Investigation
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• 제21권4호
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• pp.237-245
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• 1991

Matrix type silicone rubber devices were designed for long-term implantable drug delivery system. Release controlling agents (RCA), i.e., polypropylene glycol, polyethylene glycol, were employed to control drug release from the devices. The release rate of drug from RCA dispersed silicone matrices was mainly dependent on hydrophilicity-hydrophobicity of drug and RCA. In the case of hydrophilic drug, the release from the RCA dispersed matrix was regulated by swelling kinetics. Especially when the relatively hydrophobic polypropylene glycol was used, swelling control mechanism induced zero-order release kinetics. Whereas, the release of hydrophobic drug was resulted from partition mechanism. The effect of RCA was to increase drug diffusivity.

• 대한의용생체공학회:의공학회지
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• 제20권5호
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• pp.625-632
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• 1999

이식형 인공중이에 사용되는 전자트랜스듀서는 압전형 트랜스듀서에 비해 음향특성은 좋으나 부피가 크고 효율이 낮으며 수술시 정밀한 코일-자석 간격 조정이 필요하며, 최근 제안된 FMT 트랜스듀서는 외부 자장의 변화에 민감하다는 문제점이 지적되고 있다. 본 논문에서는 코일-자석 간격조정이 필요 없고 외부자장에 영향을 받지 않는 차동 플로팅메스형 전자 트랜스듀서를 제안하였다. 제안된 방식은 2개의 소형 자석을 같은 극끼리 접합함으로써 외부자장에 대해 영향을 받지 않고 효율이 높은 등의 장점을 가진다. 제안된 트랜스듀서의 진동력 및 효율에 관한 정량적인 해석을 하였으며 기존의 트랜스듀서와 비교분석을 행하였다. 그리고 공급전류에 대해 발생되는 진동력의 크기를 계산함으로서 실제 이식형 인공중이의 제작에 필요한 객관적인 설계데이타를 제시하였다. 한편, 시험 제작된 트랜스듀서의 해석결과 제안한 트랜스듀서는 기존의 FMT 트랜스듀서보다도 효율이 1.5배 정도의 향상됨을 보였으며 무부하시험 및 사체의 이소골 진동실험을 통하여 적절한 진동을 효과적으로 이소골에 전달할 수 있음을 보였다.

• Journal of Electrical Engineering and Technology
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• 제7권2호
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• pp.193-199
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• 2012

Worldwide cardiovascular diseases are the major cause of death. Aside from heart transplants, which are limited due to the availability of human donor hearts, artificial hearts are the only therapy available for terminal heart diseases. For various reasons, a total implantable artificial heart is desirable. But the limited space in the human thorax sets rigorous restrictions on the weight and dimensions of the device. Nevertheless, the appropriate functionality of the artificial heart must be ensured and blood damage must be prevented. These requirements set further restrictions to the drive of this device. In the this paper, two optimization methods, namely, the manual parameter variation and Differential Evolution algorithm, are presented and applied to match the specifications of an artificial heart.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2009년도 공동학술대회
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• pp.496-497
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• 2009

This paper describes about the realization of a remote RF sensor system and its applications. RF Sensor System was designed and realized on DSP over the range of high frequency such as about 200[KHz]. It should be "wireless", "implantable" and "batteryless". Futhermore, the system should be consist of passive components such as R, Land C. The measurement was given using the inductive coupling principle between primary source part and secondary sensor part. This newly developed parameter estimation system can be easily applied to the Ambient Intelligent System including the ubiquitous computing and the sensitive environmental changes.

• Journal of Yeungnam Medical Science
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• 제22권2호
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• pp.131-140
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• 2005

Heart failure is a clinical syndrome comprised of a number of symptoms and signs associated with congestion and/or hypoperfusion. Specific pharmacologic therapies have been developed to slow disease progression from early to more advanced stages. Once symptoms have developed, aggressive multimodality interventions are instituted to alleviate symptoms and improve clinical status and quality of life; especially in those patients that present symptoms. Recently, an evolving adjunctive therapeutic modality, that involves using implanted electrical devices: cardiac resynchronization with or without implantable cardioverter defibrillators (ICD). has been used for management. Cardiac resynchronization therapy (CRT) is a proven treatment for selected patients with heart failure-induced conduction disturbances and ventricular dyssynchrony. When used in combination with stable, optimal medical therapy, CRT is designed to reduce symptoms and improve cardiac function by restoring the mechanical sequence of ventricular activation and contraction. This review summarizes the rationale, procedure, clinical trials, and clinical indications for CRT.

• Journal of Semiconductor Engineering
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• 제1권3호
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• pp.88-98
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• 2020

As biosensors are widely used in the medical field, flexible devices compatible with live animals have aroused great interest. Especially, significant research has been carried out to develop implantable or skin-attachable devices for real-time bio-signal sensing. From the device point of view, various biosensor types such as field-effect transistors (FETs) and multi-electrode arrays (MEAs) have been reported as diverse sensing strategies. In particular, the flexible FETs and MEAs allow semiconductor engineering to expand its application, which had been impossible with stiff devices and materials. This review summarizes the state-of-the-art research on flexible FET and MEA biosensors focusing on their materials, structures, sensing targets, and methods.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.235.1-235.1
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• 2003

With an aim of obtaining high efficacy in cartilage regeneration, implantable polymeric rods were fabricated. These rod-type matrices were anticipated to perform structural tissue supporting activity and enhance extracellular matrix (ECM) formation by releasing specific agent, DHEA-S, in controlled manner. It is expected that application for the drilling operation on the articular cartilage of OA patients as the implants may promote regeneration of their cartilage. Osteoarthritis (OA) is a degenerative joint disease characterized by progressive loss of articular cartilage, subchondral bone remodeling, spur formation, and synovial inflammation. (omitted)