• Title/Summary/Keyword: Host materials

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Infection and Innate Immunityi (감염과 선천면역)

  • Oh, Moo-Young
    • Clinical and Experimental Pediatrics
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    • v.48 no.11
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    • pp.1153-1161
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    • 2005
  • As known by other name(natural immunity), the innate immune system comprises all those mechanisms for dealing with infection that are constitutive or built in, changing little with age or with experience of infection. Though in some ways less sophisticated than adaptive immunity, innate immunity should not belittled, since it has evidently protected thousands of species of invertebrates sufficiently to survive for up to 2 billion years. In the innate immune system, molecules of both cellular and humoral types are involved, corresponding to the need to recognize and dispose of different types of pathogen, to promote inflammatory responses and to interact to the adaptive immune system. A major features of innate immunity are the presence of the normal gut flora, complements, macrophages, dendritic cells, natural killer cells and many cytokines that can block the establishment of infection. Both phagocytic cells and complement system have tremendous potential for damaging host cells, but fortunately they are normally only triggered by foreign materials, and usually most of their destructive effects are focussed on the surface of these or in the safe environment of the phagolysosome. This article addreses the comprehensive mechanisms of the major components of the innate immune system to prevent the infection.

Electron Microscopy Studies on the Formation of Polyhedra Occlusion Bodies of Autographa californica Nuclear Polyhedrosis Virus (미생물 살충제인 Autographa californica Nuclear Polyhydrosis Virus의 Polyhydra 형성 과정의 전자현미경적 연구)

  • Lee Hyung-Hoan
    • Applied Microscopy
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    • v.11 no.1
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    • pp.51-57
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    • 1981
  • The process of the formation of polyhedra occlusion bodies and occlusion of viral nucleocapsids of Autographa californica Nuclear Polyhedrosis Virus in Spodoptera frugiperda cell were photomicrographed and described. Progeny viral nucleocapsids were observed in the nuclei of the host cells, bundled and then enveloped. The nucleoapsids were mainly accumulated near the membrane-like profiles. The nuclear membrane were hypertophied up to the cytoplasmic membrane. Prepolyhedral bodies were observed and they were growing with the accumulations of thread-like materials(polypeptides) produced by viral genes. The bundled and enveloped nucleocapsids were occluded into the growing polyhedra.

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Photodegradation stability study of PVDF- and PEI-based membranes for oily wastewater treatment process

  • Ong, C.S.;Lau, W.J.;Al-anzi, B.;Ismail, A.F.
    • Membrane and Water Treatment
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    • v.8 no.3
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    • pp.211-223
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    • 2017
  • In this work, an attempt was made to compare the effects of UV irradiation on the intrinsic and separation properties of membranes made of two different polymeric materials, i.e., polyvinylidene fluoride (PVDF) and polyetherimide (PEI). The changes on membrane structural morphologies and chemical characteristics upon UV-A exposure (up to 60 h) were studied by FESEM and FTIR, respectively. It was found that cracks and fractures were detected on the PVDF-based membrane surface when the membrane was exposed directly to UV light for up to 60 h. Furthermore, the mechanical strength and thermal stability of irradiated PVDF-based membrane was reported to decrease with increasing UV exposure time. The PEI membrane surface meanwhile remained almost intact throughout the entire UV irradiation process. Filtration experiments showed that the permeate flux of UV-irradiated PVDF membrane was significantly increased from approximately 11 to $16L/m^2.h$ with increasing UV exposure time from zero to 60 h. Oil rejection meanwhile was decreased from 98 to 85%. For the PEI-based membrane, oil rejection of >97% was recorded and its overall structural integrity was marginally affected throughout the entire UV irradiation process. The findings of this work showed that the PEI-based membrane should be considered as the host for photocatalyts incorporation if the membrane was to be used for UV-assisted wastewater treatment process.

Enhancing Lifetime of White OLED Device by Minimizing Operating Voltage Increase

  • Lee, Sung-Soo;Choi, Jun-Ho;Ha, Jae-Kook;Lee, Sang-Pil;Kim, Seong-Min;Choi, Ji-Hye;Lee, Soo-Yeon;Kim, Hyo-Seok;Chu, Chang-Woong;Shin, Sung-Tae;Kim, Chi-Woo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08b
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    • pp.1658-1660
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    • 2007
  • We fabricate green device having unique life time characteristics of operating voltage reduction with time, ${\Delta}V_{op}$ <0. A green device needs lower voltage than initial voltage for sustaining constant current as life time goes on. It means there are two possible reasons; one is interface modification between anode and HIL due to oxygen plasma treatment and the other is bulk property modification due to combination of new green host and new green dopant. From these materials and oxygen plasma treatment, we can make white OLED device having the characteristics of low ${\Delta}V_{op}$ increasing.

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Biophysical therapy and biostimulation in unfavorable bony circumstances: adjunctive therapies for osseointegration

  • Kim, Yong-Deok
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.38 no.4
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    • pp.195-203
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    • 2012
  • Dental implants using titanium have greatly advanced through the improvement of designs and surface treatments. Nonetheless, the anatomical limits and physiological changes of the patient are still regarded as obstacles in increasing the success rate of implants further, even with the enhancement of implant products. So there have been many efforts to overcome these limits. The intrinsic potential for bone regeneration can be stimulated through adjuvant treatments with the continuous improvement of implant properties, and this can play an important role in achieving optimum osseointegration toward peripheral bone tissue and securing ultimate long-term implant stability in standard surgical procedures. For this purpose, various chemical, biological, or biophysical measures were developed such as bone grafts, materials, pharmacological agents, growth factors, and bone formation proteins. The biophysical stimulation of bone union includes non-invasive and safe methods. In the beginning, it was developed as a method to enhance the healing of fractures, but later evolved into Pulsed Electromagnetic Field, Low-Intensity Pulsed Ultrasound, and Low-Level Laser Therapy. Their beneficial effects were confirmed in many studies. This study sought to examine bone-implant union and its latest trend as well as the biophysical stimulation method to enhance the union. In particular, this study suggested the enhancement of the function of cells and tissues under a disadvantageous bone metabolism environment through such adjunctive stimulation. This study is expected to serve as a treatment guideline for implant-bone union under unfavorable circumstances caused by systemic diseases hampering bone metabolism or the host environment.

Preparation and Characterization of White Phosphorescence Polymer Light Emitting Diodes Using PFO:Ir(ppy)3:MDMO-PPV Emission Layer

  • Park, Byung-Min;Chang, Ho-Jung
    • Journal of the Microelectronics and Packaging Society
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    • v.18 no.4
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    • pp.79-83
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    • 2011
  • White phosphorescence polymer light emitting diodes (WPhPLEDs) with a glass/ITO/PEDOT:PSS/PFO:$Ir(ppy)_3$:MDMO-PPV/TPBI/LiF/Al structure were fabricated to investigate the effects of $Ir(ppy)_3$ doping concentrations on the optical and electrical properties of the devices. PFO, $Ir(ppy)_3$ and MDMO-PPV conjugated polymers as host and guest materials in the emission layer were spin coated at various concentrations of $Ir(ppy)_3$ ranging from 0.0 to 20.0 vol.%. As the concentration of $Ir(ppy)_3$ increased from 5.0 to 20.0 vol.%, the luminance and current efficiency values of the devices decreased clearly, which are attributable to the quenching effect at a high doping concentration. The maximum luminance and current density were 2850 $cd/m^2$ and 741 $mA/cm^2$, respectively for a WPhPLED with an $Ir(ppy)_3$ concentration of 5.0 vol.%. The CIE color coordinates were about x=0.33 and y=0.34 at 11V, showing a good white color.

Luminance Characteristics of a Novel Red-Light-Emitting Device Based on Znq2 and Dye

  • Cho, min-Jeong;Park, Wan-Ji;Lee, Jeong-Gu;Lim, In-Su;Lim, Kee-Joe;Kim, Hyun-Hoo
    • Transactions on Electrical and Electronic Materials
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    • v.3 no.2
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    • pp.16-19
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    • 2002
  • In this study, a novel red emitting organic electroluminescent (EL) device was fabricated with the bis(8-oxyquinolino)zinc II (Znq2) doped dye as an emitting layer. The Znq2 was synthesized successfully from zinc chloride (ZnC1$_2$) as an initial material. Then, we fabricated the red organic EL device with a dye (DCJTB) doped and inserted Znq2 between emission layer and cathode for increasing EL efficiency. The hole transporting layer is a N,N'-diphenyl-N,N'-bis-(3-methylphenyl)-1,1'-diphenyl-4,4-diamine (TPD), and the host material of emission layer is Znq2. And the electrical and luminance characteristics of the device were measured. We found that the EL device with Znq2 inserting layer results in the increasing luminance efficiency.

Emission Properties of Red OELD with $Znq_2$ and dye (Znq2와 dye에 의한 적색 유기 전계 발광 소자의 발광특성)

  • Cho, M.J.;Choi, W.J.;Park, C.H.;Lim, K.J.;Park, S.K.;Kim, H.H.
    • Proceedings of the KIEE Conference
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    • 2001.07c
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    • pp.1466-1468
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    • 2001
  • For the full color organic electro-luminescent device, essentially, red, green, and blue emissions are required. But red emission is not to reach minimum level of practical use 31[lm/W]. In order to optimize color purity and power consumption requirements, it is important for the materials development efforts to search for improvements in red emission effisiency. In this study, the bis(8-oxyquinolino)zinc II ($Znq_2$) were synthesized successfully from zinc chloride($ZnCl_2$) as a initial material. Then, we fabricated red organic electroluminescent device with a dye(DCJTB)-doped and inserted $Znq_2$ between emission layer and cathode layer for increasing EL efficiency. The hole transfer layer is a N,N'-diphenyl-N,N'-bis-(3-methyl phenyl) -1,1'-diphenyl-4.4'-diamine(TPD), and the host material of emission layer is $Znq_2$. For the inserting of $Znq_2$, efficiency increased.

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A Kr öger-Vink Compatible Notation for Defects in Inherently Defective Sublattices

  • Norby, Truls
    • Journal of the Korean Ceramic Society
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    • v.47 no.1
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    • pp.19-25
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    • 2010
  • Traditional Kr$\ddot{o}$ger-Vink (K-V) notation defines sites in ionic crystals as interstitial or belonging to host ions. It enables description and calculations of combinations of native and foreign defects, including dopants and substituents. However, some materials exhibit inherently disordered partial occupancy of ions and vacancies, or partial occupancy of two types of ions. For instance, the high temperature disordered phases of $Bi_2O_3$, $Ba_2In_2O_5$, $La_2Mo_2O_9$, mayenite $Ca_{12}Al_{14}O_{33}$, AgI, and $CsHSO_4$ are all good ionic conductors and thus obviously contain charged point defects. But traditional K-V notation cannot account for a charge compensating defect in each case, without resorting to terms like "100% substitution" or "Frenkel disorder". the former arbitrary and awkward and the latter inappropriate. Instead, a K-V compatible nomenclature in which the partially occupied site is defined as the perfect site, has been proposed. I here introduce it thoroughly and provide a number of examples.

Improvement in the Stabilities of White Organic Light Emitting Diodes Using a Partially Doped Emission Layer

  • Jeon, Hyeon-Sung;Oh, Hwan-Sool;Yoon, Seok-Beom
    • Transactions on Electrical and Electronic Materials
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    • v.11 no.3
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    • pp.145-148
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    • 2010
  • White organic light emitting devices were fabricated to improve the stability through a structural change using the two peak emission method. The fabricated devices were composed of indium tin oxide (100 nm)/ $\alpha$-NPD (30 nm)/4,40-bis(2,20-diphenylvinyl)-1,10-biphenyl (DPVBi, d: variable)/DPVBi: Rubrene (40 nm)/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline(5 nm)/ $Alq_3$(5 nm)/ Al (100 nm). A DPVBi for blue emissions was used as the host material in the emitters. The doping concentration of the Rubrene was fixed at 2.0% (by weight). The white emission with Commission Internationale De L'Eclairage coordinates of (0.3342, 0.3439) occurred at 14 V with a thickness d of 1 nm. It was insensitive to the drive voltage, and the devices had a maximum luminance of $211\;cd/cm^2$. At 19 V, the current density and maximum external quantum efficiency were $173\;mAcm^2$ and 0.478%, respectively.