• 한국세라믹학회지
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• 제39권3호
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• pp.286-293
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• 2002

소성온도에 따른 ZnO계 적층형 세라믹 칩 바리스터(약칭 MLV)의 미세구조와 전기적 특성의 변화를 조사하였다. 소성온도 1100$^{\circ}$C에서 Ag/Pd(7:3) 내부전극층의 두께가 불균일하게 변화하면서 부분적인 공극이 발생하기 시작하고, 1150$^{\circ}$C에서는 상당한 전극 패턴의 소멸과 박리가 관찰되었다. 950$^{\circ}$C로 소성한 MLV의 경우 누설전류의 열화가 특히 컸는데 이는 미반응의 pyrochlore상이 잔류하여 액상과 천이원소의 균일한 분포가 일어나지 않았기 때문이라 사료된다. 1100$^{\circ}$C 이상의 온도로 소성한 경우에는 바리스터 특성 및 그 재현성의 저하가 관찰되었는데, 이는 내부전극의 소멸, 전극물질과 소체의 반응, 그리고 $Bi_2O_3$의 휘발에 기인한 것으로 보인다. 한편, 950∼1100$^{\circ}$C의 전 소성온도 범위에 걸쳐 온도가 증가할수록 정전용량과 누설전류는 증가하고 항복전압과 피크전류는 감소하였으나, 비선형계수와 클램핑 비는 각각 ∼30 및 1.4로 거의 일정한 값을 유지하였다. 특히 1000∼1050$^{\circ}$C 소성체의 경우 칩 바리스터에 적합한 바리스터 특성이 재현성 있게 나타났다. 결과적으로 Ag/Pd(7:3) 합금은 1050$^{\circ}$C의 동시 소성 온도이하에서는 $Bi_2O_3$를 함유한 대부분의 ZnO계 MLV의 내부전극으로 충분히 사용가능한 것으로 판단된다.

• Journal of Pharmaceutical Investigation
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• 제25권3호
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• pp.249-264
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• 1995

Although liposome has many advantages as a pharmaceutical dosage form, its application in the industrial field has been limited because of some problems such as preparation method, reproducibility, scale-up, stability and sterilization etc. Liposomes prepared by microemulsification method had defined size, narrow size distribution, reproducibility and high entrapment efficiency. For enhancing the stability, the dry form of liposome was recommended. These types of liposome are proliposome and freeze-dried liposome. The liposome must have some properties for preparing of freeze-dried liposome; small size $(50{\sim}200\;nm)$, narrow size distribution and cryoprotectant. In this experiment, the liposomes containing 5-Fluorouracil(5-FU) and its prodrug(pentyl-5-FU-1-acetate; PFA, hexyl-5-FU-1-acetate; HFA) were made with soybean phosphatidylcholine, cholesterol, stearylamine(SA) and dicetyl phosphate(DCP) employing hydration method or microemulsification method using $Microfluidizer^{TM}$. Both or liposome types were MLV and MEL. After preparation, freeze drying and rehydration were performed. In the process of freezing, trehalose(Tr) was added as a cryoprotectant. Their evaluation methods were as follows; entrapment efficiency, mean particle size and size distribution, dissolution test, retain of entrapment efficiency and turbidity after freeze-drying. The results are summarized as belows. The entrapment efficiency of 5-FU was dependent on total lipid concentration and cholesterol content but that of PFA and HFA was decreased when cholesterol was added. When DCP and SA were added, entrapment efficiency was decreased. As the partition coefficient of drug was increased, entrapment efficiency was increased. Under the same condition, entrapment efficiency of MEL is similar to that of MLV. The mean particle size and size distribution of MEL were smaller than those of MLV. Dissolution rates of drug from both liposome types were comparatively similar. Dissolution rates of drugs with serum and liver homogenate were faster than without these material. After preparation of liposome, free drug was removed efficiency by Dowex 50W-X4. When liposome was freeze-dried and then rehydrated in the presence of Tr, characteristics of liposome were maintained well in MEL than MLV. Tr Was used successfully as a cryoprotectant in the process of freeze drying and the optimal ratio of Tr:Lipid was 4:1(g/g).

• 대한수의학회지
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• 제58권2호
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• pp.73-79
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• 2018

Outbreaks of porcine reproductive and respiratory syndrome virus (PRRSV) in vaccinated sow herds from occurrence to stabilization were monitored and analyzed in terms of serology and reproductive performance. Three different conventional pig farms experienced severe reproductive failures with the introduction of a type 1 PRRSV. These farms had adopted mass vaccination of sows using a type 2 PRRSV modified live vaccine (MLV). Therefore, to control the type 1 PRRSV, an alternative vaccination program utilizing both type 1 and type 2 MLV was undertaken. Following whole herd vaccinations with both types of MLV, successful stabilization of PRRS outbreaks was identified based on serological data (no viremia and downward trends in ELISA antibody titers in both sows and suckling piglets) and recovery of reproductive performance. Additionally, through comparison of the reproductive parameters between outbreak and non-outbreak periods, it was identified that PRRSV significantly affected the farrowing rate and the number of suckling piglets per litter at all three pig farms. Comparison of reproductive parameters between periods when the different vaccination strategies were applied revealed that the number of piglets born in total and born dead per litter were significantly increased after the introduction of the type 1 PRRS MLV.

• 대한화장품학회지
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• 제21권2호
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• pp.1-21
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• 1995

본 연구는 세포 간지질이 주성분인 세라마이즈, 콜레스테롤, 콜레스테롤 에스텔, 스쿠알란, 레시친, 왁스 지방산을 팽윤 반응에 의하여 다중라멜라 소구체를 제조하였다. AHAsomes과 마이크로 플루다이저를 사용하여 MLV 형성에 대한 특성을 조사 하였다. 다중라멜라 소구체는 Polyol과 수상을 서서히 첨가하고, 마이크로 플루다이저를 사용함에 의해 자연스럽게 형성된다. 실제적으로 이 AHAsomes system의 형성은 방부제가 필요하지 않고, 활성 미용 성분을 침투시켰다. 친수성 활성 성분인 말릭산, 타타릭산, 락틱산, 알란토인, 우레아 그리고 소수성 미용 성분인 비타민-E 아세테이트, 비타민-A 팔미테이트를 캡슐화시켰다. MLV형성 조건은 마이크로플루다이저에 3회 통과하였으며, 베지클의 입자크기의 범위는 50-523nm이었다. 응용으로, 일반적인 O/W 에멀젼과 AHAsomes 크림을 사용하여 발바닥의 각질제거 효과를 비교하였다. 3개월동안 사용하여 주름은 15.8%, 피부 탄력은 3배정도 회복되었다. 이것을 Image Analyzer와 Cutometer로 확인하였다.

• 전기학회논문지
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• 제56권4호
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• pp.745-750
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• 2007

In this paper, we propose a new gate modification method using the input vector maximizes the number of gates in WLS within the optimum range of the minimum leakage power. We prove that MLV is not always the optimal solution, and that the leakage power and area can decrease when modifying the gates using the input vector for which the number of gates in WLS is maximized within the optimum range of the minimum leakage power for the circuits applying the IVC technique and gate modification method. Using the proposed method, the gate-level description circuit can be converted to the modified circuit which reduces the leakage power by chip designer, and the modified circuit can be applied without any modification in design flow.

• Toxicological Research
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• 제17권
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• pp.157-166
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• 2001

Almost all currently available retroviral vectors based on murine leukemia virus (MLV) contain one or more viral coding sequences. Because these sequences are also present in the packaging genome, it has been suggested that homologous recombination may occur between the same nucleotide sequence in the packaging genome and the vector, resulting in the production of replication competent retrovirus (RCR). Up until now, it has been difficult to completely remove viral coding sequences since some were thought to be involved in the optimum function of the retroviral vector. For example, the gag coding sequence present in almost all available retroviral vectors has been believed to be necessary for efficient viral packaging, while the pol coding sequence present in the highly efficient vector MFG has been thought to be involved in achieving the high levels of gene expression. However, we have now developed a series of retroviral vectors that are absent of any retroviral coding sequences but produce even higher levels of gene expression without compromising viral titer. In these vectors, the intron and exon sequences from heterologous cellular or viral genes are present. When compared to the well known MLV-based vectors, some of these newly developed vectors have been shown to produce significantly higher levels of gene expression for a longer period. In an experimental system that can maximize the production of RCR, our newly constructed vectors produced an absence of RCR. These vectors should prove to be safer than other currently available retroviral vectors containing one or more viral coding sequences.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2000년도 추계 학술대회
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• pp.31-50
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• 2000

Almost all currently available retroviral vectors based on murine leukemia virus (MLV) contain one or more viral coding sequences Because these sequences are also present in the packaging genome, it has been suggested that homologous recombination may occur between the same nucleotide sequence in the packaging genome and the vector, resulting in the production of replication competent retrovirus (RCR). Up until now, it has been difficult to completely remove viral coding sequences since some were thought to be involved in the optimum function of the retroviral vector. For example, the gag coding sequence present in almost all available retroviral vectors has been believed to be necessary for efficient viral packaging, while the pol coding sequence present in the highly efficient vector MFG has been thought to be involved in achieving the high levels of gene e(pression. However, we have now developed a series of reroviral vectors that are absent of any retroviral coding sequences but produce even higher levels of gene expression without compromising viral titer. In these vectors the intron and exon sequences from heterologous cellular or viral genes are present, When compared to the well blown MLV-based vectors, some of these newly developed vectors have been shown to produce significantly higher levels of gene expression for a longer period. In an experimental system that can maximize the production of RCR, our newly constructed vectors produced an absence of RCR. These vectors should prove to be safer than other currently available retroviral vectors containing one or more viral coding sequences

• 대한화장품학회지
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• 제23권3호
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• pp.48-74
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• 1997

Retinlyl Palmitate, the skin normalizerm is useful to promote greater skin elasticity, to diminish lipid peroxidation and skin roughness following UV exposure, and promote a youthfulgeneral skin appearance. In manufacturing creams, Retinyl Palmitate, which is a derivative of retinol, is used since reionol is easily oxidized by heat and light. However, only a small mount of retinol, is used since using a large amount of it may be harmful to its stability. In this study, thermal stability and UV stability of W/O-, W/S-, O/W-, and MLV-type creams containing 5% of retinyl palmitate and 10% of tocopheryl acetate are measured by Chroma Meters, and the content of RP is quantitatively analyzed by HPLC at 25 $^{\circ}C$ and 45 $^{\circ}C$. Also, how RP has been changed by heat, light, etc. is measured by HPLC, and toxicity of the changed substance is studied. Particle size of each type of the cream if measured, cellular renewal is measured by using DHP and Chroma Meters in order to study their efficacy and effect, moisture content is measured by using Corneometer and Tewameter, and how much wrinkles are improved is studied by using Image Analyzer. Development of MLV-type cream containing 5% of RP and 10% of TA, and satisfying conditions for better creams has been successful.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 제5회 영호남 학술대회 논문집
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• pp.126-129
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• 2003

The electrical properties of a ZnO-based multilayered chip varistor (abbreviated as MLV) were studied as functions of firing condition and the degree of lamination. The fundamental varistor characteristics such as nonlinear coefficient and breakdown voltage were independent of the degree of lamination. As the number of the laminated ceramic sheets increased, however, not only the energy handling capability but also the capacitance and the leakage current which are relevant to delayed response to the voltage surge and the pre-breakdown energy loss, respectively, increased. With the increase of firing temperature between $950^{\circ}C$ and $1150^{\circ}C$, both the capacitance and the leakage current of the MLV increased due mainly to the grain growth of ZnO and the volatilization of $BiO_2O_3$. High performance MLVs with clear electrode pattern were obtained at the firing temperature range of $l000{\sim}1050^{\circ}C$ in this experiment.

• Molecules and Cells
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• 제40권5호
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• pp.339-345
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• 2017

Retroviral and lentiviral vectors are mostly pseudotyped and often purified and concentrated via ultracentrifugation. In this study, we quantified and compared the stabilities of retroviral [murine leukemia virus (MLV)-based] and lentiviral [human immunodeficiency virus (HIV)-1-based] vectors pseudotyped with relatively mechanically stable envelope proteins, vesicular stomatitis virus glycoproteins (VSVGs), and the influenza virus WSN strain envelope proteins against ultracentrifugation. Lentiviral genomic and functional particles were more stable than the corresponding retroviral particles against ultracentrifugation when pseudotyped with VSVGs. However, both retroviral and lentiviral particles were unstable when pseudotyped with the influenza virus WSN strain envelope proteins. Therefore, the stabilities of pseudotyped retroviral and lentiviral vectors against ultracentrifugation process are a function of not only the type of envelope proteins, but also the type of viral internal core (MLV or HIV-1 core). In addition, the fraction of functional viral particles among genomic viral particles greatly varied at times during packaging, depending on the type of envelope proteins used for pseudotyping and the viral internal core.