• Title/Summary/Keyword: Sonication effect

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Effect of Pretreatment of Biogenic Titanium Dioxide on Photocatalytic Transformation of Chloroform (Biogenic TiO2 나노입자 전처리가 클로로포름 광분해에 미치는 영향)

  • Kwon, Sooyoul;Rorrer, Greg;Semprini, Lewis;Kim, Young
    • Journal of Korean Society on Water Environment
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    • v.27 no.1
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    • pp.98-103
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    • 2011
  • Photocatalysis using UV light and catalysts is an attractive low temperature and non-energy- intensive method for remediation of a wide range of chemical contaminants like chloroform (CF). Recently development of environmental friendly and sustainable catalytic systems is needed before such catalysts can be routinely applied to large-scale remediation or drinking water treatment. Titanium dioxide is a candidate material, since it is stable, highly reactive, and inexpensive. Diatoms are photosynthetic, single-celled algae that make a microscale silica shell with nano scale features. These diatoms have an ability to biologically fabricate $TiO_2$ nanoparticles into this shell in a process that parallels nanoscale silica mineralization. We cultivated diatoms, metabolically deposited titanium into the shell by using a two-stage photobioreactor and used this biogenic $TiO_2$ to this study. In this study we evaluated how effectively biogenic $TiO_2$ nanoparticles transform CF compared with chemically-synthesized $TiO_2$ nanoparticlesthe and effect of pretreatment of diatom-produced $TiO_2$ nanoparticles on photocatalytic transformation of CF. The rate of CF transformation by diatom-$TiO_2$ particles is a factor of 3 slower than chemically-synthesized one and chloride ion production was also co-related with CF transformation, and 79~91% of CF mineralization was observed in two $TiO_2$ particles. And the period of sonication and mass transfer due to particle size, evaluated by difference of oxygen tention does not affect on the CF transformation. Based on the XRD analysis we conclude that slower CF transformation by diatom-$TiO_2$ might be due to incomplete annealing to the anatase form.

Sonoporation with echogenic liposome: therapeutic effect on a breast cancer cell (약물이 탑재된 미소기포와 결합된 sonoporation: 유방암세포에 대한 치료효과)

  • Park, Juhyun;Lee, Hana;Lee, Yougyeong;Seo, Jongbum
    • The Journal of the Acoustical Society of Korea
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    • v.41 no.5
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    • pp.501-506
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    • 2022
  • Echogenic liposome contains both liquid and gas inside the shell. In ultrasound mediated drug delivery, sonoporation, these new microbubbles can be an attractive drug carrier since they can be loaded water soluble drugs and drug molecules can be unloaded at the specific location with ultrasound sonication. In this paper, the structure of the echogenic liposome was confirmed with EF-TEM and the positive effect of sonoporation with echogenic liposome was comparatively evaluated on MDA-MB-231 cells which is a type of breast cancer cell with Doxorubicin. Control group (Group 1), Doxorubicin only (Group 2), sonoporation with Doxorubicin and hollow microbubbles (Group 3), sonoporation with Doxorubicin loaded echogenic liposome (Group 4) were classified and experiments were conducted. According to the results, Group 4 is at least 1.4 times better in inducing necrosis of cancer cells. Therefore, we conclude echogenic liposome could be one of the most useful form of microbubbles in sonoporation.

Strength of CNT Cement Composites with Different Types of Surfactants and Doses (분산제의 종류 및 사용량에 따른 CNT 보강 시멘트 복합체의 강도변화)

  • Ha, Sung-Jin;Kang, Su-Tae;Lee, Jong-Han
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.2
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    • pp.99-107
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    • 2015
  • This study was aimed to investigate the difference in strength of Carbon Nanotube (CNT) reinforced cement mortars with different types of surfactants and doses. In the experimental program, CTAB, SDBS and TX10 which were common surfactants adopted to improve CNTs dispersion in fabricating CNT composites in many industrial fields were included and superplasticizer which was revealed to be effective to disperse CNTs especially in CNT reinforced cementitious composites were added as well. Superplasticizer presented less strength reduction in cement mortar and more strength gain by adding CNTs among four types of surfactants. Higher dosage of superplasticizer caused lower strength of cement mortar. Adding CNTs of 0.4 wt.% or less to cement didn't show strength enhancement by adding CNTs but 0.8 wt.% of CNTs resulted in strengthening effect after all. Finally, a combination of 0.1 wt.% of CNTs, superplasticizer and sonication treatment could lead to strength improvement by adding CNTs in cement mortar.

Sonochemical Grafting of Poly(vinyl alcohol) onto Multiwall Carbon Nanotubes in Water (초음파를 이용한 PVA에 의한 다중벽 탄소나노튜브의 수상 그래프팅)

  • Kim, Yeongseon;Baeck, Sung Hyeon;Shim, Sang Eun
    • Polymer(Korea)
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    • v.38 no.3
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    • pp.378-385
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    • 2014
  • Multiwall carbon nanotubes (MWCNTs) were modified with a water soluble polymer, poly(vinyl alcohol), PVA, using a simple ultrasonic wave in water. Under the irradiation of ultrasound, PVA chains were severed as macroradicals and instantly grafted onto the surface of MWCNTs due to the radical scavenging effect of MWCNTs. To control the grafting PVA onto MWCNTs, the ultrasonication power and irradiation time were changed from 300 to 500 W and from 10 to 50 min, respectively. The grafted PVA onto MWCNTs was confirmed by FTIR, TGA, SEM, and TEM. Dispersion stability of the modified MWCNTs was monitored by Turbiscan. The amount of grafted PVA on MWCNTs increased with the increase in the sonication power and irradiation time. The grafted PVA on MWCNTs induced the improved dispersion stability of the modified MWCNTs in water. These findings exhibit that ultrasound can be readily used for the grafting polymer chains on MWCNTs.

Prediction Method of Dispersion Condition for Reinforced Epoxy in Nano SiC Particles Using Capacitance Measurement (Capacitance 측정법을 이용한 나노 SiC 에폭시 복합재료의 내부 강화재 분산 예측방법)

  • Kwon, Dong-Jun;Wang, Zuo-Jia;Kim, Je-Jun;Jang, Key-Wook;Park, Joung-Man
    • Composites Research
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    • v.26 no.6
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    • pp.337-342
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    • 2013
  • The good dispersion of nano-materials in epoxy matrix was important parameter for the reinforcement effect, and the evaluation of dispersion degree was to prove it. This work was studied to predict the dispersion condition of nano-SiC powders in SiC/epoxy composites using capacitance measurement. Capacitance was defined to be the electric capacity in proportional to electron charge of the measuring section. In case of nano-SiC powders, the electron charge of SiC/epoxy composites was higher than that of neat epoxy resin. Capacitance was evaluated for each section of SiC/epoxy composites. The prediction of dispersion condition was verified by using capacitance measurement. Dispersion condition of nano-SiC powders in epoxy matrix was evaluated with two different dispersion methods, i.e., sonication and stirring methods. The dispersion degree was also verified with the tensile strength correlating to capacitance.

Improvement of an hydroxyapatite bead adherence assay for streptococcus sanguis (Streptococcus sanguis의 구형 Hydroxyapatite 비드에의 부착 Assay 방법의 개량)

  • 최선진;이시영;송요한
    • Korean Journal of Microbiology
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    • v.27 no.1
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    • pp.48-55
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    • 1989
  • The purpose of the present investigation was to improve several procedures being used in the adherence assay of Streptococcus sanguis cells to hydroxyapatite (HA) beads and to study the effect of the beads on the counting of radioactivity. The standard adhere assay involved the adherence of radiolabeled bacteria to 40mg of HA beads. The beads were mixed with ['H]thymidine-labeled bacterial cells and incubated for 60 minutes at room temperature. Unadsorbed cells were removed, the beads with adsorbed cells were dried, and the radioactivity was monitered in a scintillation spectrometer. The 30 seconds sonication of cells in a form of long chains appeared to be adequate for obtaining mostly singlet or doublet cells. Unlike the counting of S. sanguis cell suspension, bacterial cells adhered to HA or saliva-coated HA(SHA) required smaller volume (2.5ml) of scintillaton fluid for better counting. Eighteen percent quenching of counts could be attributed to the beads. Among 3 procedures commonly used to equilibrate the beads for adherence assay, no differences were found in their effectiveness. The HA beads on which the bacteria remained attached in scintillant during the counting were found to be the source of sample self-absorption representing 34.5% of the total radioactivity counts resulting from the beads dissolved in HCl solution.

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Change of the Protection Efficiency in Each Part of Developed Pesticide-Proof Clothes by Repeated Washings (개발 과수용 농약방제복의 반복세탁에 따른 부위별 농약 방호성능의 변화)

  • Shin, Jeoung-Hwa;Hwang, Kyoung-Sook;Lee, Hyo-Hyeon
    • The Korean Journal of Community Living Science
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    • v.22 no.4
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    • pp.615-621
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    • 2011
  • This study was conducted to evaluate of the protection efficiency in each part of developed pesticide-proof clothes by repeated washings. We investigated the effect of repeated laundering on mechanical properties of pesticide-proof clothes (not washed vs 5 times washed). We also examined pesticide infiltration rate into the pesticide-proof clothes by repeated laundering. The patches(TCL paper, surface area 50cm2)were attached to the inside of pesticide-proof clothes(head, chest, right upper-arm, right forearm, left thigh, left calf, back) which subjects had dressed in during pesticide spraying. The patches were detached from working clothes after work. For the extraction of pesticide in pesticide-proof clothes, sonication was applied for 30 min with methanol. The gas chromatography/mass spectrometry (GC/MS) was applied to identify the pesticide component. The results of this study are as follows: The force strength, water-vapour resistance and surface wetting resistance of pesticide-proof clothes decreased 5 times more in washed clothes. The concentration of pesticide was the highest in the head area of pesticide-proof clothes. In seven parts of TLC paper attached to the pesticide proof clothes, the concentration of pesticide was higher in the left thigh. The penetration part and concentration of pesticide increased as washing was repeated. Therefore the conclusion which can be drawn from this study is this: protection efficiency of pesticide-proof clothes decrease by repeated washings.

Investigation of Immunostimulatory Effects of Heat-Treated Lactiplantibacillus plantarum LM1004 and Its Underlying Molecular Mechanism

  • Bae, Won-Young;Jung, Woo-Hyun;Shin, So Lim;Kwon, Seulgi;Sohn, Minn;Kim, Tae-Rahk
    • Food Science of Animal Resources
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    • v.42 no.6
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    • pp.1031-1045
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    • 2022
  • Postbiotics are defined as probiotics inactivated by heat, ultraviolet radiation, sonication, and other physical or chemical stresses. Postbiotics are more stable than probiotics, and these properties are advantageous for food additives and pharmacological agents. This study investigated the immunostimulatory effects of heat-treated Lactiplantibacillus plantarum LM1004 (HT-LM1004). Cellular fatty acid composition of L. plantarum LM1004 isolated form kimchi was analyzed by gas chromatography-mass spectrometry detection system. The nitric oxide (NO) content was estimated using Griess reagent. Immunostimulatory cytokines were evaluated using enzyme-linked immunosorbent assay. Relative protein expressions were evaluated by western blotting. Phagocytosis was measured using enzyme-labelled Escherichia coli particles. L. plantarum LM1004 showed 7 kinds of cellular fatty acids including palmitic acid (C16:0). The HT-LM1004 induced release of NO and upregulated the inducible NO synthase in RAW 264.7 macrophage cells. Tumor necrosis factor-α and interleukin-6 levels were also increased compared to control (non-treated macrophages). Furthermore, HT-LM1004 modulated mitogen-activated protein kinase (MAPK) subfamilies including p38 MAPK, extracellular signal-regulated kinase 1/2, and c-Jun N-terminal kinase. Therefore, these immunostimulatory effects were attributed to the production of transcriptional factors, such as nuclear factor kappa B (NF-κB) and the activator protein 1 family (AP-1). However, HT-LM1004 did not showed significant phagocytosis of RAW 264.7 macrophage cells. Overall, HT-LM1004 stimulated MAPK/AP-1 and NF-κB expression, resulting in the release of NO and cytokines. These results will contribute to the development of diverse types of food and pharmacological products for immunostimulatory agents with postbiotics.

Stripping of High-Dose Ion-Implanted Photoresist Using Co-solvent and Ultra-sonication in Supercritical Carbon Dioxide (초임계이산화탄소 내에서 공용매 및 초음파를 이용한 고농도이온주입 포토레지스트의 제거)

  • Kim, Seung-Ho;Lim, Kwon-Taek
    • Clean Technology
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    • v.15 no.2
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    • pp.69-74
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    • 2009
  • A high-dose ion-implanted photoresist (HDIPR) was stripped off from the surface of a semiconductor wafer by using a mixture of supercritical carbon dioxide and a co-solvent. The additional ultrasonication improved the stripping efficiency remarkably and thus reduced the stripping time by supplying physical force to the substrate. We investigated the effect of co-solvents, co-solvent concentration, and stripping temperature and pressure on the stripping efficiency. The wafer surfaces before and after stripping were analyzed by scanning electron microscopy and by an energy dispersive X-ray spectrometer. The HDIPR could be stripped off completely in 3 min with 10%(w/w) acetone/sc$C0_2$ mixture at 27.6 MPa and 343 K.

Effect of Ultrasonic Pretreatment on Analysis of Potassium Ion in Human Urine Using 15-Crown-5-Anthracene-based Membrane (15-Crown-5-Anthracene 막을 이용한 요 중의 칼륨이온 분석에 미치는 초음파 전처리의 효과)

  • Lee, Ji-Young;Chang, Hye-Young;Bae, Zun-Ung
    • Journal of the Korean Chemical Society
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    • v.47 no.1
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    • pp.13-18
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    • 2003
  • The effect of ultrasonic decomposition was introduced to develop a pretreatment method for the analysis of potassium ion in human urine by potentiometry. N-(4’-benzo-15-crown-5)-anthracene-9-imine, which has a good selectivity coefficient for potassium against ammonium, was used as an ion-selective material for the determination of potassium in urine with relatively high concentration of $NH_4{^+}$. Protenis in urine be removed by 85.1% when the sample acidified with 1.0 M $HNO_3$ was preteated for 100 s by sonication. Potential response of the membrane electrode in the pretreated urine had a slope of 54.6(${\pm}0.2,\;n=5$) mV/decade over the linear range of log $[K^+]$=-5~-1(r=0.9997). When an oxidant, $H_2O_2$, was addwd to the urine sonicated with $HNO_3$, the deproteinization increased 10% more than that in case if only $HNO_3$ and then the maximum ratio of ca. 95% was obtained. Moreover, the Nernstian slope for $K^+$ added to the urinary sample increased to 56.7(${\pm}0.1,\;n=3$) mV/decade. When the calibration curves were measured, the slopes did not vary even after the electrode was successively used 20 times with ultrasonic cleaning. The results showed that an ultrasonic pretreatment method provides simplicity in use, reduced treatment time and improved potentiometric characteristics of the membrane as the method effectively removes ca. 95% of proteins in urine.