• Title/Summary/Keyword: $OH^-$

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Effect of MgO and NH4OH on Formation of 5Mg(OH)2·MgSO4·3H2O Whiskers (침상형 5Mg(OH)2·MgSO4·3H2O 형성에 관한 MgO와 NH4OH 영향)

  • Yu, Ri;Pee, Jae-Hwan;Kim, Hyung-Tae;Kim, Kyung-Ja;Kim, Young-Woong;Kim, Woong;Kim, Yoo-Jin
    • Journal of Powder Materials
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    • 제18권3호
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    • pp.283-289
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    • 2011
  • Magnesium hydroxide sulfate hydrate whiskers ($5Mg(OH)_2{\cdot}MgSO_4{\cdot}3H_2O$, abbreviated 513 MHSH) were prepared using hydrothermal reaction with magnesium oxide (MgO) and magnesium sulfate ($MgSO_4{\cdot}7H_2O$) as the starting materials. The effects of the molar ratio of $MgSO_4$/MgO and amount of $NH_4OH$ were studied. As a result, 513 MHSH whiskers co-existed with hexagonal plate $Mg(OH)_2$ at low concentration of $SO_4^{2-}$. The molar ratio of $MgSO_4{\cdot}7H_2O$/MgO was 7:1, uniform 513 MHSH whiskers were formed without impurity such as $Mg(OH)_2$. Appropriate amount of $NH_4OH$ has affected to formation of high quality MHSH. Their morphologies and structures were determined by powder X-ray diffraction (XRD) scanning electron microscopy (SEM) and thermo-gravimetric analyzer (TGA).

Inhibitory Activity of Flavonoids from Prunus davidiana and Other Flavonoids on Total ROS and Hydroxyl Radical Generation

  • Jung, Hyun-Ah;Jung, Mee-Jung;Kim, Ji-Young;Chung, Hae-Young;Choi, Jae-Sue
    • Archives of Pharmacal Research
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    • 제26권10호
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    • pp.809-815
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    • 2003
  • Since reactive oxygen species (ROS) and hydroxyl radicals ($^-OH$) play an important role in the pathogenesis of many human degenerative diseases, much attention has focused on the development of safe and effective antioxidants. Preliminary experiments have revealed that the methanol (MeOH) extract of the stem of Prunus davidiana exerts inhibitory/scavenging activities on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radicals, total ROS and peroxynitrites ($ONOO^-$). In the present study, the antioxidant activities of this MeOH extract and the organic solvent-soluble fractions, dichloromethane (CH$_2$Cl$_2$), ethyl acetate (EtOAc), and n-butanol (n-BuOH), and the water layer of P. davidiana stem were evaluated for the potential to inhibit $^-OH$ and total ROS generation in kidney homogenates using 2',7'-dichlorodihydrofluorescein diacetate (DCHF-DA), and for the potential to scavenge authentic $ONOO^-$. We also evaluated the inhibitory activity of seven flavonoids isolated from P. davidiana stem, kaempferol, kaempferol 7-Ο-$\beta$-D-glucoside, (+)-catechin, dihydrokaempferol, hesperetin 5-Ο-$\beta$-D-glucoside, naringenin and its 7-Ο-$\beta$-D-glucoside, on the total ROS, $^-OH$ and $ONOO^-$ systems. For the further elucidation of the structure-inhibitory activity relationship of flavonoids on total ROS and 'OH generation, we measured the antioxidant activity of sixteen flavonoids available, including three active flavonoids isolated from P. davidiana, on the total ROS and 'OH systems. We found that the inhibitory activity on total ROS generation increases in strength with more numerous hydroxyl groups on their structures. Also, the presence of an ortho-hydroxyl group, whether on the Aring or S-ring, and a 3-hydroxyl group on the C-ring increased the inhibitory activity on both total ROS and $^-OH$ generation.

Orientational Control of Nano Structures from Block Copolymer Using Homo-Polymer Nano Interface (단일 성분 고분자 나노 계면의 도입을 통한 블락 고분자 박막의 나노 구조 배향 조절)

  • In, Insik
    • Journal of Adhesion and Interface
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    • 제9권4호
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    • pp.30-33
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    • 2008
  • Two polymeric interfaces with single component homo-polymers were prepared to control the orientation of block copolymer thin-film nanostructures. Poly(4-acetoxy styrene) (OH-PAS) and poly(4-methoxy styrene) (OH-PMS) which have the average chemical composition of polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) were precisely synthesized through nitroxide-mediated radical polymerization. After dehydration reactions between above polymers and SiOx layers of silicon wafers, the polymer-modified interface induced partial (30%) vertical orientation of PS-b-PMMA thin film in the case of OH-PMS and wholly parallel orientation in the case of OH-PAS. Chemical compositions of polymeric interface layers are regarded as the key parameter to control the orientation of nanostructures of block copolymer thin film.

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Experimental Study on Heat Release in a Lean Premixed Dump Combustor Using OH Chemiluminescence Images (희박 예혼합 덤프 연소기에서 OH 자발광을 이용한 열 방출에 관한 실험적 연구)

  • Moon, Gun-Feel;Lee, Jong-Ho;Jeon, Chung-Hwan;Chang, Young-June
    • Transactions of the Korean Society of Mechanical Engineers B
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    • 제28권11호
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    • pp.1368-1375
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    • 2004
  • Measurements of OH chemiluminescence in an atmospheric pressure, laboratory-scale dump combustor at equivalence ratios ranging from 0.63 to 0.89 were reported. The signal from the first electronically excited state of OH to ground state was detected through a band-pass filter with an ICCD. The objectives of this study are two: One is to see the effects of equivalence ratio on global heat release rate and local Rayleigh index distribution. To get the local Rayleigh index distribution, the line-of-sight images were inverted by tomographic method, such as Abel do-convolution. Another aim is to investigate the validity of using OH chemiluminescence acquired with an ICCD as a qualitative measure of local heat release. For constant inlet velocity and temperature, the overall intensities of OH emission acquired at different equivalence ratio showed periodic and higher value at high equivalence ratio. OH intensity averaged over one period of pressure increased exponentially with equivalence ratio. Local Rayleigh index distribution clearly showed the region of amplifying or damping the combustion instability as equivalence ratio increased. It could provide an information/insights on active control such as secondary fuel injection. Finally, local heat release rate derived from reconstructed OH images were presented fur typical locations.

Association of circulating 25-hydroxyvitamin D levels with hypertension and blood pressure values in Korean adults: A Mendelian randomization study on a subset of the Korea National Health and Nutrition Survey 2011-2012 population

  • Kwak, So-Young;Cho, Yoonsu;Oh, Hannah;Shin, Min-Jeong
    • Nutrition Research and Practice
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    • 제13권6호
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    • pp.498-508
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    • 2019
  • BACKGROUND/OBJECTIVES: Lower circulating 25-hydroxyvitamin D [25(OH)D] levels are associated with a higher risk of hypertension (HTN); however, it remains unclear whether the relationship is causal. We aimed to evaluate the causal effects of circulating 25(OH)D levels on the prevalence of HTN in the Korean population using the Mendelian randomization (MR) approach. SUBJECTS/METHODS: Epidemiological data, serum 25(OH)D data, and genomic DNA biospecimens were obtained from 2,591 participants, a subset of the study population in the Korea National Health and Nutrition Survey 2011-2012. Five 25(OH)D-related single nucleotide polymorphisms (SNPs; DHCR7 rs12785878, CYP2R1 rs10741657, CYP2R1 rs12794714, CYP24A1 rs6013897, and GC rs2282679), identified a priori from genome-wide association studies, were used as instrument variables (IVs) for serum 25(OH)D levels. In the MR analysis, we performed IV analyses using the two-stage least squares method. RESULTS: In the observational analysis, circulating 25(OH)D levels were found to be inversely associated with the HTN prevalence in ordinary least squares models (odds ratio: 0.97, 95% confidence interval: 0.96, 0.99) after adjusting for the potential confounders. There were differences in the circulating 25(OH)D levels across genotypes of individual SNPs. In the MR analysis, using individual SNPs as IVs, 25(OH)D levels were not associated with the HTN prevalence. CONCLUSIONS: We found no association between genetically determined circulating 25(OH)D levels and HTN in Korean adults. Our results are listed owing to the relatively small sample size and possible weak instrument bias; therefore, further studies are needed to confirm these results.

Changes in CO2 Absorption Efficiency of NaOH Solution Trap with Temperature

  • Park, Se-In;Park, Hyun-Jin;Yang, Hye In;Choi, Woo-Jung
    • Korean Journal of Soil Science and Fertilizer
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    • 제50권6호
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    • pp.554-561
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    • 2017
  • Under the projected global warming, release of carbon as $CO_2$ through soil organic matter decomposition is expected to increase. Therefore, accurate measurement of $CO_2$ released from soil is crucial in understanding the soil carbon dynamics under increased temperature conditions. Sodium hydroxide (NaOH) traps are frequently used in laboratory soil incubation studies to measure soil respiration rate, but decreasing $CO_2$ gas solubility with increasing temperature may render the reliability of the method questionable. In this study, the influences of increasing temperature on the $CO_2$ capture capacity of NaOH traps were evaluated under $5{\sim}35^{\circ}C$ temperature range at $10^{\circ}C$ interval. Two closed-chamber experiments were performed where NaOH traps were used to capture $CO_2$ either released from acidified $Na_2CO_3$ solution or directly injected into the chamber. The sorption of ambient $CO_2$ within the incubators into NaOH traps was also measured. The amount $CO_2$ captured increased as temperature increased within 2 days of incubation, suggesting that increased diffusion rate of $CO_2$ at higher temperatures led to increases in $CO_2$ captured by the NaOH traps. However, after 2 days, over 95% of $CO_2$ emitted in the emission-absorption experiment was captured regardless of temperature, demonstrating high $CO_2$ absorption efficiency of the NaOH traps. Thus, we conclude that the influence of decreased $CO_2$ solubility by increased temperatures is negligible on the $CO_2$ capture capacity of NaOH traps, supporting that the use of NaOH traps in the study of temperature effect on soil respiration is a valid method.

Reaction morphology depending on the amounts of HCl and NH4OH and effect of pH on the preparation of TiO2 nanopowder (TiO2 나노분말 제조시 HCI과 NH4OH의 첨가량에 따른 반응양상과 pH의 영향)

  • Lim, Chang Sung;Oh, Won Chun
    • Analytical Science and Technology
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    • 제20권4호
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    • pp.302-307
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    • 2007
  • The reaction morphology was investigated depending on the amounts of HCl and $NH_4OH$, and the effect of pH was studied on the preparation of $TiO_2$ nanopowders. $TiO_2$ nanopowder was prepared using a titanium tetra-isopropoxide. Subsequently, the effect of pH on the characteristics of the prepared $TiO_2$ nanopowder was evaluated depending on the amounts of the catalysts such as HCl and $NH_4OH$. The morphology and phase transformation of $TiO_2$ powder prepared by hydrolysis of titanium tetra-isopropoxide were strongly influenced by the presence of the catalysts. In the case of using $NH_4OH$, the morphology of the $TiO_2$ powder exhibited powder form. For the HCl catalyst, it showed bulk or granule form. The phase transformations of amorphous $Ti(OH)_4$ to anatase $TiO_2$ and the anatase to rutile was significantly influenced by the kind and amount of thecatalysts.

Dietary Effects of Varying Levels of Calcium and 25-hydroxycholecalciferol on Hatching Egg Production and Eggshell Quality in Aged Egg-Type Breeder Hens (칼슘의 수준별 급여 및 25-hydroxycholecalciferol의 사료 내 첨가가 종란 생산성 및 후기 난각질에 미치는 영향)

  • Kim, Eun-Jib;Ahn, Byoung-Ki;Kang, Chang-Won
    • Journal of Animal Science and Technology
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    • 제51권4호
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    • pp.295-306
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    • 2009
  • This experiment was conducted to investigate the effects of dietary calcium (Ca) and vitamin $D_3$ metabolite on eggshell quality and hatching egg production in aged egg-type breeder hens. A total of five hundred and forty 60-week-old Hy-Line Brown breeder hens were randomly allocated to nine treatments in a $3\times3$ factorial design to determine the effects of dietary Ca levels (3.3, 3.9, and 4.5%), combined with three levels of 25-hydroxycholecalciferol [25-$(OH)D_3$ 0, 75, and $150{\mu}g/kg$], on eggshell quality and egg production for 10 weeks. There were significant Ca and 25-$(OH)D_3$ effects (P<0.01) on egg production rate. There was a linear (P<0.01) increase in eggshell strength and thickness with increasing dietary Ca and 25-$(OH)D_3$ levels. Dietary 25-$(OH)D_3$ had a significant effect (P<0.05) on hatchability of egg although fertility was not influenced by dietarylevels of Ca and 25-$(OH)D_3$. Dietary Ca levels affected Ca content in tibia (P<0.05). These results indicated that relatively high levels of dietary Ca in combination with 25-$(OH)D_3$ had a beneficial effect on improving eggshell quality and reproductive performance in aged egg-type breeder hens.

Study on Anti-obesity and Hypoglycemic Effects of Lycium chinense Mill Extracts (구기자 추출물의 항비만 및 혈당강하 효과)

  • Hwang, Eun-Young;Hong, Jung-Hee;Choi, Jun-Hyeok;Choi, Eun-Jung;Lee, In-Seon
    • Journal of the Korean Society of Food Science and Nutrition
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    • 제38권11호
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    • pp.1528-1534
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    • 2009
  • This study was designed to evaluate the anti-obesity and hypoglycemic effects of Gugija (Lycium chinense Mill) extracts in 3T3-L1 adipocytes. We investigated the $\alpha$-amylase and $\alpha$-glucosidase inhibitory activities of extracts from Gugija. Gugija was extracted by 70% EtOH and 80% MeOH and aqueous, respectively. A single oral dose of Gugija extract inhibited the increase of blood glucose levels significantly at 0, 30, 60, 90 and 120 min and decreased incremental response areas under the glycemic response curve. These results suggest that Gugija 70% EtOH extracts may delay carbohydrate digestion and reduce postprandial hyperglycemia. In addition, triglyceride content in 3T3-L1 adipocytes decreased at higher concentrations of Gugija 70% EtOH extract. Free fatty acid content in 3T3-L1 adipocytes was increased at higher concentrations of Gugija 70% EtOH extract. Also, glucose transporter 4 (GLUT4), the key insulin signaling pathway transcription factor, was remarkably increased by the Gugija 70% EtOH extract when compared to those of control cells in protein expression levels. Therefore, Gugija can be developed as an effective anti-obesity and hypoglycemic agent.

In vitro Antioxidant and Anti-Inflammatory Activities of Ethanol Extract and Sequential Fractions of Flowers of Prunus persica in LPS-Stimulated RAW 264.7 Macrophages (복숭아꽃 에탄올 추출물과 분획물의 in vitro 항산화 효과 및 RAW 264.7 대식세포에서의 항염증 효과)

  • Kwak, Chung Shil;Choi, Hye-In
    • Journal of the Korean Society of Food Science and Nutrition
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    • 제44권10호
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    • pp.1439-1449
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    • 2015
  • Prunus persica Flos (PPF) were investigated for their antioxidant and anti-inflammatory activities to find a natural functional food resource preventing degenerative diseases associated with excessive oxidative stress and chronic inflammation. PPF was extracted using ethanol (EtOH) and then sequentially fractioned by hexane (Hx), dichloromethane (DM), ethyl acetate (EA), n-butanol (BtOH), and water (DW). Contents of total phenolics and flavonoids, as well as 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities were measured. Anti-inflammatory effects in terms of nitric oxide (NO), prostaglandin (PG) E2, and pro-inflammatory cytokines such as interleukin (IL)-6 and tumor necrosis factor (TNF)-${\alpha}$ production were also measured using LPS-treated RAW 264.7 macrophages. EtOH extract showed relatively high antioxidant activity with high total phenolic (78.1 mg tannic acid/g) and flavonoid contents (55.3 mg rutin/g). EA fraction contained the highest total phenolic and flavonoid contents (394.6 mg tannic acid/g, 253.7 mg rutin/g), followed by BtOH (128.3 mg tannic acid/g, 93.1 mg rutin/g). EA and BtOH fractions and EtOH extract showed higher DPPH radical and ABTS radical scavenging activities than the others (P<0.05). In LPS-treated RAW 264.7 macrophages, EtOH extract ($200{\mu}g/mL$) showed significantly reduced (P<0.05) NO, PGE2, and TNF-${\alpha}$ production levels to 38.5%, 32.3%, and 48.9% of the control, respectively, as well as reduced iNOS and COX-2 protein expression. DM fraction ($50{\mu}g/mL$) showed significantly reduced (P<0.05) NO, PGE2, IL-6, and TNF-${\alpha}$ production levels to 43.5%, 13.3%, 38.7%, and 41.3% of the control, respectively, and EA fraction ($50{\mu}g/mL$) showed significantly reduced NO, PGE2, IL-6, and TNF-${\alpha}$ production levels to 44.8%, 22.4%, 45.7%, and 62.0% of the control, respectively. Taken together, EtOH extract of PPF showed potent antioxidant and anti-inflammatory activities, and EA and BtOH fractions showed comparatively stronger antioxidant activities while DM and EA fractions showed stronger anti-inflammatory activities. It can be concluded that EtOH extract of PPF and its fractions are good candidates as natural resources for the development of anti-oxidative and anti-inflammatory functional food products.