방광암세포주의 항암제 반응에 대한 in vivo Hollow Fiber Assay

문기혁,한병규,정성진,홍성규,변석수,이상은 대한비뇨의학회 2008 Investigative and Clinical Urology Vol.49 No.5

Purpose: The National Cancer Institute(NCI)'s Hollow Fiber Assay(HFA) is currently used as an in vivo screening model to quantitatively define anticancer activity. To investigate the use of HFA in a bladder cancer model, we conducted in vitro and in vivo experiments with several anticancer drugs in nude mice. Materials and Methods: The human bladder cancer cell lines(CRL2742, 253JP, SW1710, HTB9) were cultured both in vitro and in vivo in polyvinylidene fluoride(PVDF) hollow fibers. The fibers were implanted intraperitoneally(ip) and subcutaneously(sc) into female athymic nude mice(C57BL/6), and the mice were then treated with gemcitabine 120 mg/kg(bolus), cisplatin(3mg/kg), paclitaxel(15mg/kg) or vehicle only (control) for 4-consecutive days. After 6 days, the fibers were retrieved and the viable cell density was analyzed by MTT assay. Results: The difference between in vitro and in vivo growth was not significant for the CRL2742, 253J-P and SW1710 cell lines; the difference between the ip and sc fibers was also not significant in the CRL2742, SW1710 and HTB9 cell lines. After drug treatment, the percent of growth inhibition revealed constant and effective anticancer activities for the 3 individual drugs. Conclusions: This study demonstrates the possibility of measuring and quantifying the anticancer effect with using in vivo hollow fiber assay in a bladder cancer model. (Korean J Urol 2008;49:392-397) Purpose: The National Cancer Institute(NCI)'s Hollow Fiber Assay(HFA) is currently used as an in vivo screening model to quantitatively define anticancer activity. To investigate the use of HFA in a bladder cancer model, we conducted in vitro and in vivo experiments with several anticancer drugs in nude mice. Materials and Methods: The human bladder cancer cell lines(CRL2742, 253JP, SW1710, HTB9) were cultured both in vitro and in vivo in polyvinylidene fluoride(PVDF) hollow fibers. The fibers were implanted intraperitoneally(ip) and subcutaneously(sc) into female athymic nude mice(C57BL/6), and the mice were then treated with gemcitabine 120 mg/kg(bolus), cisplatin(3mg/kg), paclitaxel(15mg/kg) or vehicle only (control) for 4-consecutive days. After 6 days, the fibers were retrieved and the viable cell density was analyzed by MTT assay. Results: The difference between in vitro and in vivo growth was not significant for the CRL2742, 253J-P and SW1710 cell lines; the difference between the ip and sc fibers was also not significant in the CRL2742, SW1710 and HTB9 cell lines. After drug treatment, the percent of growth inhibition revealed constant and effective anticancer activities for the 3 individual drugs. Conclusions: This study demonstrates the possibility of measuring and quantifying the anticancer effect with using in vivo hollow fiber assay in a bladder cancer model. (Korean J Urol 2008;49:392-397)

Hollowness Variation with Die Wall Thickness in Melt-Spinning of Polypropylene Hollow Fibers

Rebecca Ruckdashel,심은경 한국섬유공학회 2022 Fibers and polymers Vol.23 No.5

A hollow fiber poses great potential as it can provide superior performance at low weight and low cost. Its uniqueproperties come from its geometry, the presence of void and air inclusion, but controlling it is a challenging problem. Thisstudy explores how the geometry of a die influences fiber hollowness. Fibers were extruded from dies with four segmentedarcs, 4-C, which had varying die wall thickness and constant inner diameter. The effects of die wall thickness on wall-shearrate, solidification, spinnability, and hollow fiber geometry are evaluated under various processing conditions. Bothprocessing parameters and die wall thickness influence hollow fiber dimensions and hollowness, but die wall thickness hasthe largest impact. Reduction of die wall thickness decreases fiber wall thickness, increases the outer and inner diameter, andincreases hollowness. It can be explained by higher die hollowness and faster extrudate solidification. However, the thinnestdie shows reduced spinnability.

Airbag Damping of the Hollow Fiber Composite with Different Porosity in the Fiber Wall

Mingjun Li,Guoqun Zhou,Yongwen Xu,Guifang Wang 한국섬유공학회 2019 Fibers and polymers Vol.20 No.2

The inner cavity of the hollow fiber with porosity in its fiber wall constitutes a damping airbag with slow passage of gas. The magnitude of the damping value of the airbag and its damping influencing factors need to be researched, which adds the nonlinear airbag damping to the damping of the raw materials and increases the total damping loss factor of the structure. In this paper, the hollow fiber damping materials with different hollow inside diameters, different fiber wall thicknesses, different wall porosity and different wall pore structure were prepared by adjusting and controlling the technological parameters of the hollow fiber spinning and the formula of spinning casting solution. Meanwhile, we have a comprehensive study on the relationship between the factors and performances. It was found and confirmed that the size of the airbag, the wall pore structure, the wall porosity and the wall thickness of the airbag were the most crucial parameters, which can affect the additional damping of the airbag in the hollow fiber. And the controlling method of the four key parameters was also obtained. Finally, the mechanism and effect of hollow fiber airbag damping was proved.

분리막 접촉기용 Poly(vinylidene fluoride) 중공사막 제조 및 투과특성

박유인 ( Park Yu In ),이기섭 ( Lee Gi Seob ),연순화 ( Yeon Sun Hwa ),서봉국 ( Seo Bong Gug ),임지원 ( Im Ji Won ),이규호 ( Lee Gyu Ho ) 한국공업화학회 2003 공업화학 Vol.14 No.6

상전이 공정을 이용하여 분리막 접촉기용 비대칭 다공성 poly(vinylidene fluoride) (PVDF) 중공사막을 제조하였다. 용매로는 dimethylacetamide (DMAc)를 사용하였으며 기공 형성제로는 LiCl를 사용하였다. 또한 중공사막 제조시 내부 응고제로는 물, 에탄올/물 및 DMAc/물 혼합액 등을 사용하였으며 외부 응고제로는 물을 사용하였다. 상전이 과정에서 기공 형성제 및 내부 응고제(비용매)가 막의 구조에 미치는 영향을 살펴보았다. 제조된 PVDF 중공사막의 구조는 주사전자현미경(SEM)을 이용하여 확인하였으며 기공크기와 유효표면 기공율은 기체 측정법(Gas Permeation Method)을 이용하여 알아보았다. 그 결과 이 중 스킨의 비대칭구조로서 0.02~0.04 ㎛ 범위의 기공크기를 갖는 PVDF 중공사막을 제조하였다. 또한 제조된 PVDF 중공사막에 대해 물리적 흡수제로 물을 사용하여 기체 및 흡수제의 유속에 따른 이산화탄소의 분리효율을 알아보았다. 현재 분리막 접촉기로 많이 사용되어지고 있는 대칭 다공성 구조의 Polypropylene(PP) 중공사막과 본 연구를 통해 제조된 비대칭 다공성 PVDF 중공사막에 대해 이산화탄소 분리효율을 비교ㆍ분석한 결과 비대칭 다공성 PVDF중공사막 접촉기가 단위 표면적당 높은 이산화탄소 흡수효율을 나타내었다. Asymmetric porous polyvinylidene fluoride(PVDF) hollow fiber membranes for membrane contactor were prepared by a wet phase inversion method. In spinning these PVDF hollow fibers. dimethylacetamide (DMAc) and LiCl were used as a solvent and a pore-forming additive. respectively. Pure water, water/ethanol or water/DMAc mixture was used as an internal coagulant, while water was an external coagulant. The characteristics of the phase inversion process were studied during the formation of the PVDF membrane, expecinlly the effect of pore-forming additive and internal coagulants (non-solvent) addition on the membrane structure. The cross- sectional structure of the prepared PVDF hollow fiber membranes was examined by scanning electron microscopy (SEM). The Average pore size and effective surface porosity were determined using the gas permeation method. The pore size the prepared asymmetric PVDF hollow fiber membrane was in the ragne of 0.02-0.04 μm. The carbon dioxide separation performances with the change of flow rates of absorbent and mixed gas were studied, using the PVDF hollow fiber membrane water as a physical absorbent. The performances of the asymmetric porous WDF hollow fiber membrane and a symmetric commercialized one made from PP were compared. As a result, the asymmetric porous PVDF hollow fiber membrane showed higher separation efficiency of CO_(2) per unit surface areas than the symmetric porous PP hollow fiber membrane.

폴리카보실란으로부터 제조된 탄화규소 중공사의 미세구조제어

신동근,공은배,조광연,권우택,김영희,김수룡,홍준성,류도형,Shin, Dong-Geun,Kong, Eun-Bae,Cho, Kwang-Youn,Kwon, Woo-Tek,Kim, Younghee,Kim, Soo-Ryong,Hong, Jun-Sung,Riu, Doh-Hyung 한국세라믹학회 2013 한국세라믹학회지 Vol.50 No.4

SiC hollow fiber was fabricated by curing, dissolution and sintering of Al-PCS fiber, which was melt spun the polyaluminocarbosilane. Al-PCS fiber was thermally oxidized and dissolved in toluene to remove the unoxidized area, the core of the cured fiber. The wall thickness ($t_{wall}$) of Al-PCS fiber was monotonically increased with an increasing oxidation curing time. The Al-PCS hollow fiber was heat-treated at the temperature between 1200 and $2000^{\circ}C$ to make a SiC hollow fibers having porous structure on the fiber wall. The pore size of the fiber wall was increased with the sintering temperature due to the decomposition of the amorphous $SiC_xO_y$ matrix and the growth of ${\beta}$-SiC in the matrix. At $1400^{\circ}C$, a nano porous wall with a high specific surface area was obtained. However, nano pores grew with the grain growth after the thermal decomposition of the amorphous matrix. This type of SiC hollow fibers are expected to be used as a substrate for a gas separation membrane.

PVDF와 PP 중공사막 접촉기를 이용한 Alkanolemine 수용액의 이산화탄소 흡수 분리 특성

연순화 ( Sun Hwa Yeon ),서봉국 ( Bong Kuk Sea ),이기섭 ( Ki Sub Lee ),박유인 ( You In Park ),이규호 ( Kew Ho Lee ) 한국공업화학회 2002 공업화학 Vol.13 No.8

중공사막 접촉기를 기존의 흡수장치에 흡수기로 도입하여 구축한 hybrid 시스템을 이용하여 이산화탄소의 분리효율과 흡수제에 대한 중공사막의 물리ㆍ화학적 안정성에 관한 연구를 수행하였다. 서로 다른 구조적 특성을 지니는 PVDF 중공사막과 PP 중공사막을 사용하여 흡수제 MEA, TEA, MDEA 수용액의 이산화탄소 분리효율을 측정하였다. 또한 위의 흡수제에 대한 막의 물리적 그리고 화학적 안정성을 막의 젖음성(wettibility)과 IR 분석을 통해 분석한 결과, MEA와 MDEA 수용액의 경우 PVDF 막에서 물리ㆍ화학적 불안정성을 보였다. 각 흡수제에 대한 long-term 실험을 실시한 결과 3급 아민인 TEA 수용액의 경우 가장 오랜 시간 동안 steady-state 상태를 유지하였다. TEA 수용액에 소량의 MEA를 첨가한 혼합 흡수제의 경우 상당한 분리효율의 상승을 기대할 수 있으며, 막의 pore 내에서 안정적 기-액 계면의 형성으로 인하여 장기간 안정적 운전이 가능하므로 중공사막의 적합한 흡수제로 기대된다. A hollow fiber membrane contactor-stripper hybrid process was used to recover CO_2 from the flue gas, and the physical and chemical stability test of hollow fibers against alkanolamine-based absorbents was conducted. The CO_2 removal efficiency of the polyvinylidenefluoride (PVDF) and polypropylene (PP) hollow fiber membrane contactor was tested with aqueous monoethanolamine (MEA), triethanolamine (TEA) and methyl-diethanolamine (MDEA) absorbents. For MEA, the hollow fibers showed a high CO_2 removal efficiency, but poor chemical and physical stability because the MEA absorbent chemically attacked fibers or physically well penetrated into fiber`s pores. For TEA, the hollow fibers showed a low CO_2 removal efficiency, but good chemical and physical stability. In the case of mixed absorbent adding MEA to aqueous TEA solution, CO_2 removal efficiency of the hollow fiber membrane contactor was enlargd, and this mixed absorbent made it possible to operate this system under long term steady-state conditions due to creating stable liquid-gas interface among the fiber`s pores.

Rhodosporidium toruloides를 이용한 Hollow-fiber 반응기에서의 광학활성 Phenyl Oxirane 생산

김희숙,박성훈,이은열 한국생명과학회 2003 생명과학회지 Vol.13 No.6

Rhodosporidium toruloides SJ-4의 epoxide hydrolase의 입체선택적 가수분해 반응을 이용하여 hollow-fiber 반응기에서 라세믹 phenyl oxirane 기질로부터 광학활성 phenyl oxirane을 생산하였다. 라세믹 에폭사이드 기질의 수용액 상에서의 낮은 용해도로 인한 저농도 반응의 문제점을 극복하기 위하여 dodecane 유기용매에 용해시켜 lumen 부위로 공급하였으며, 생촉매인 R. toruloides 세포 현탁액은 수용액강인 shell 부위에 위치시킴으로써 유기용매 사용에 따른 생촉매 활성 저하를 줄인 1단계 반응기 시스템에서는 200 mM의 고농도에서 (S)-phenyl oxirane을 생산할 수 있었다. 또한, 반응 산물로 생성되는 diol에 의한 생촉매 활성저해효과를 감소시키기 위하여 2단계 hollow-fiber 반응기에서는 완충용액을 이용하여 diol을 제거시킨 결과 300 mM에서 EH 활성을 이용한 입체선택적 가수분해반응을 수행할 수 있었으며, 200∼300 mM의 고농도 라세믹 기질로부터 99% ee 이상의 광학순도를 가진 (S)-phenyl oxirane을 이론 수율 대비 12∼35% 수율로 얻을 수 있었다. Production of chiral phenyl oxirane by Rhodosporidium toruloides SJ-4 was investigated. Racemic phenyl oxirane was kinetically resolved by enantioselective hydrolysis reaction by epoxide hydrolase of R. toruloides in two-phase hollow-fiber reactor system. Dodecane with high concentration of the racemic substrate passed through the lumen side and cell suspension was recirculated through the shell side of the hollow fiber reactor For the removal of phenyl-1, 2-ethandiol to reduce the product inhibition to biocatalysts, another hollow-fiber reactor was employed to extract the diol. Racemic phenyl oxirane up to 300 mM was enantioselectively resolved with high enantiopurity (>99% ee) in hollow-fiber reactor system.

Phase Sensitivity to Acoustic Pressure of Microstrustured Optical Fibers : A comparison Study

Adel Abdallah,Zhang Chaozhu,Zhong Zhi 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.2

Recently, photonic crystal fibers (PCFs) have attracted many researchers because of their unique properties, and design flexibility that can’t be realized by conventional fibers. One of the fruitful areas of research is the optical fiber hydrophone. In this paper, the finite element solver (FES), COMSOL multiphysics, is used to study and compare the response to acoustic pressure of a hollow-core photonic band gap fiber (HC-PBF), a solid-core photonic crystal fiber (SC-PCF), and a conventional single-mode fiber (SMF) for different acoustic pressures in the frequency range from 10 kHz to 50 kHz. The key structural factors affect the sensitivity to acoustic pressure (S) of the microstructured fibers are studied and a mathematical formula describes the relation of S and the dominant structural factor is proposed. Simulation results of the investigated optical fibers show that the normalized responsivity (NR) of the HC-1550, LMA-5, and SMF are -344 dB, -367.5 dB, and -366 dB, respectively. The proposed simulation results are in good agreement with published theoretical and experimentally measured results. The proposed results indicate the significance of the HC-PBFs in the future hydrophone systems and are useful for the design of microstrustured optical fibers for sensing applications.

재생 셀룰로스/MWCNT 중공 탄소섬유 제조 및 특성

장한진,김완진,정용식,Jang, Han-Jin,Kim, Wan-Jin,Chung, Yong-Sik 한국섬유공학회 2016 한국섬유공학회지 Vol.53 No.1

Cellulose consists of a linear-chain polymer from 1-4-glucoside bond linked 1,4 carbon of ${\beta}$-D-glucose. Unmodified cellulose does not dissolve in water or in common organic solvents due to the presence of inter- and intra-chain hydrogen bonds. Ionic liquids, particularly, 1-ethyl-3-methylimidazolium acetate, dissolve cellulose more easily when compared to traditionally used solvents for cellulose because of directly broken of hydrogen bonds in intra and inter molecular. In addition, CNTs can also be easily dispersed in imidazolium-based ionic liquids by simple mechanical mixing. Cellulose hollow fibers filled with MWCNT were used as a precursor for carbon fibers. The cellulose/MWCNT precursor solution in the ionic liquid was prepared by air-gap spinning to improve the carbon yield and also to optimize the mechanical properties of the final cellulose-based carbon fiber. The cellulose/MWCNT hollow fibers was pyrolyzed by heating in air at $350^{\circ}C$ for 1 h 35 min. The pyrolyzed cellulose/MWCNT hollow fibers were carbonized by heating at $900^{\circ}C$ in an inert atmosphere (nitrogen). Thus-prepared cellulose/MWCNT-based carbon hollow fibers were analyzed to confirm the suitability of the carbon hollow fiber as a substitute for silicon wafer in solar cells and in semiconductor devices.

Ultrathin zeolitic-imidazolate framework ZIF-8 membranes on polymeric hollow fibers for propylene/propane separation

Lee, Moon Joo,Abdul Hamid, Mohamad Rezi,Lee, Jongmyeong,Kim, Ju Sung,Lee, Young Moo,Jeong, Hae-Kwon Elsevier 2018 Journal of membrane science Vol.559 No.-

<P><B>Abstract</B></P> <P>Polymer hollow fibers have great potential as cost-effective scalable substrates for the practical applications of highly propylene-selective ZIF-8 membranes. We report ultrathin ZIF-8 membranes supported on porous Matrimid® polymer hollow fibers via microwave-assisted seeding and microfluidic secondary growth. Densely-packed ZIF-8 seed layers were rapidly prepared on polymeric hollow fibers under microwave heating. The seed layers were then secondarily grown into well-intergrown ZIF-8 membranes under the continuous flow of the growth solution. The effects of synthesis parameters on the microstructures of ZIF-8 seed crystals were systematically studied. The resulting ZIF-8 membranes were characterized with XRD and SEM, showing well-intergrown ZIF-8 films formed on the bore of hollow fibers. The unique nature of the current technique enables facile formation of ultrathin ZIF-8 membranes on either the bore or shell side of hollow fibers with a thickness of ~ 800 nm. Propylene/propane binary gas permeation measurements showed an average separation factor of ~ 46 and propylene permeance of ~ 55 GPU.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Porous Matrimid® hollow fibers were used as ZIF-8 membrane substrates. </LI> <LI> High-quality ZIF-8 seed layers were rapidly formed under microwave. </LI> <LI> Ultrathin ZIF-8 membranes were formed under microfluidic secondary growth. </LI> <LI> Propylene/propane separation performance was measured. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>