• 제목/요약/키워드: N-containing compound

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TiAl에 석출한 질화물의 결정구조와 형태 (Crystal Structure and Morphology of Nitride Precipitates in TiAl)

  • 한창석;구경완
    • 한국재료학회지
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    • 제18권1호
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    • pp.51-56
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    • 2008
  • The crystal structures and morphologies of precipitates in $L1_0$-ordered TiAl intermetallics containing nitrogen were investigated by transmission electron microscopy (TEM). Under aging at an approximate temperature of 1073 K after quenching from 1423 K, TiAl hardens appreciably due to the nitride precipitation. TEM observations revealed that needle-like precipitates, which lie only in one direction parallel to the [001] axis of the $L1_0$-TiAl matrix, appear in the matrix preferentially at the dislocations. Selected area electron diffraction (SAED) pattern analyses showed that the needle-shaped precipitate is perovskite-type $Ti_3AlN$ (P-phase). The orientation relationship between the P-phase and the $L1_0$-TiAl matrix was found to be $(001)_P//(001)_{TiAl}\;and\;[010]_P//[010]_{TiAl}$. By aging at higher temperatures or for longer periods at 1073 K, plate-like precipitates of $Ti_2AlN$ (H-phase) with a hexagonal structure formed on the {111} planes of the $L1_0$-TiAl matrix. The orientation relationship between the $Ti_2AlN$ and the $L1_0$-TiAl matrix is $(0001)_H//(111)_{TiAl}\;and\;_H//_{TiAl}$.

Reaction of Bis(diethylamino)aluminum Hydride in Tetrahydrofuran with Selected Organic Compounds Containing Representative Functional Groups

  • Jin Soon Cha;Oh Oun Kwon;Jong Mi Kim
    • Bulletin of the Korean Chemical Society
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    • 제15권2호
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    • pp.132-138
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    • 1994
  • Bis(diethylamino)aluminum hydride was utilized in a systematic study of the approximate rates and stoichiometry of the reaction of excess reagent with 55 selected organic compounds containing representative functional groups under standardized conditions (THF, $0^{\circ}C$, reagent to compound=4 : 1) in order to define the characteristics of the reagent for selective reductions. The reducing action of BEAH was also compared with that of the parent aluminum hydride. The reducing action of the reagent is quite similar to that of aluminum hydride, but the reducing power is much weaker. Aldehydes and ketones were readily reduced in 1-3 h to the corresponding alcohols. However, unexpectedly, a ready involvement of the double bond in cinnamaldehyde was realized to afford hydrocinnamyl alcohol. The introduction of diethylamino group to the parent aluminum hydride appears not to be appreciably influential in stereoselectivity on the reduction of cyclic ketones. Both p-benzoquinone and anthraquinone utilized 2 equiv of hydride readily without evolution of hydrogen, proceeded cleanly to the 1,4-reduction products. Carboxylic acids and acid chlorides underwent reduction to alcohols slowly, whereas cyclic anhydrides utilized only 2 equiv of hydride slowly to the corresponding hydroxylacids. Especially, benzoic acid with a limiting amount of hydride was reduced to benzaldehyde in a yield of 80%. Esters and lactones were also readily reduced to alcohols. Epoxides examined all reacted slowly to give the ring-opened products. Primary and tertiary amides utilized 1 equiv of hydride fast and further hydride utilization was quite slow. The examination for possibility of achieving a partial reduction to aldehydes was also performed. Among them, benzamide and N,N-dimethylbenzamide gave ca, 90% yields of benzaldehyde. Both the nitriles examined were also slowly reduced to the amines. Unexpectedly, both aliphatic and aromatic nitro compounds proved to be relatively reactive to the reagent. On the other hand, azo- and azoxybenzenes were quite inert to BEAH. Cyclohexanone oxime liberated 1 equiv of hydrogen and utilized 1 equiv of hydride for reduction, corresponding to N-hydroxycyclohexylamine. Pyridine ring compounds were also slowly attacked. Disulfides were readily reduced with hydrogen evolution to the thiols, and dimethyl sulfoxide and diphenyl sulfone were also rapidly reduced to the sulfides.

Disruption of Established Bacterial and Fungal Biofilms by a Blend of Enzymes and Botanical Extracts

  • Gitte S. Jensen;Dina Cruickshank;Debby E. Hamilton
    • Journal of Microbiology and Biotechnology
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    • 제33권6호
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    • pp.715-723
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    • 2023
  • Microbial biofilms are resilient, immune-evasive, often antibiotic-resistant health challenges, and increasingly the target for research into novel therapeutic strategies. We evaluated the effects of a nutraceutical enzyme and botanical blend (NEBB) on established biofilm. Five microbial strains with known implications in chronic human illnesses were tested: Candida albicans, Staphylococcus aureus, Staphylococcus simulans (coagulase-negative, penicillin-resistant), Borrelia burgdorferi, and Pseudomonas aeruginosa. The strains were allowed to form biofilm in vitro. Biofilm cultures were treated with NEBB containing enzymes targeted at lipids, proteins, and sugars, also containing the mucolytic compound N-acetyl cysteine, along with antimicrobial extracts from cranberry, berberine, rosemary, and peppermint. The post-treatment biofilm mass was evaluated by crystal-violet staining, and metabolic activity was measured using the MTT assay. Average biofilm mass and metabolic activity for NEBB-treated biofilms were compared to the average of untreated control cultures. Treatment of established biofilm with NEBB resulted in biofilm-disruption, involving significant reductions in biofilm mass and metabolic activity for Candida and both Staphylococcus species. For B. burgdorferi, we observed reduced biofilm mass, but the remaining residual biofilm showed a mild increase in metabolic activity, suggesting a shift from metabolically quiescent, treatment-resistant persister forms of B. burgdorferi to a more active form, potentially more recognizable by the host immune system. For P. aeruginosa, low doses of NEBB significantly reduced biofilm mass and metabolic activity while higher doses of NEBB increased biofilm mass and metabolic activity. The results suggest that targeted nutraceutical support may help disrupt biofilm communities, offering new facets for integrative combinational treatment strategies.

석회와 질소원이 버어리종 담배의 수량과 품질에 미치는 영향 I. 생육, 수량 및 품질에 미치는 영향 (Effects of Liming and Nitrogen Sources on the Yield and Quality of Burley Tobacco. I. On the Growth Characteristics, Yield and Quality.)

  • 김상범;한철수;김대송
    • 한국작물학회지
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    • 제32권3호
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    • pp.310-316
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    • 1987
  • 버어리종 담배의 생육과 수량에 미치는 석회시용량(토양 pH)과 질소원에 따른 효과를 알아보기 위하여, 석회시용량은 석회무시용, pH 5.5 적정양, pH6.5 적정양의 3수준으로, 질소원은 연초용복합비료(3.9%의 NH$_4$-N와 6.1%의 NH$_2$-N 함유), NaNO$_3$,(NH$_2$)$_2$CO, (NH$_4$)$_2$SO$_4$의 4종을 두어 포장에서 시험한 바, 그 결과를 요약하면 다음과 같다. 1. 본포기생육은 석회다량구가 알칼리 장해로 불진하였으나, 적심후에는 만회되었다. 2. 초산태질소구는 본포기에는 생육이 불진하였고, 성숙기에는 하위엽의 황화가 빨랐다. 3. 수량 및 대금은 석회시용량 증가에 따라 증가하였으며, 질소원별로는 유의성있는 차이가 나타나지 않았다. 4. 토양 pH 상승에 따른 수량의 증가정도는 류안구가 제일 컸다.

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Design and Synthesis of p-hydroxybenzohydrazide Derivatives for their Antimycobacterial Activity

  • Bhole, Ritesh.P.;Borkar, Deepak.D.;Bhusari, Kishore.P.;Patil, Prashant.A.
    • 대한화학회지
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    • 제56권2호
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    • pp.236-245
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    • 2012
  • The main mycobacterial infection in human is tuberculosis caused by Mycobacterium tuberculosis. Tuberculosis is the leading infectious cause of death in the world. Therefore there is continuing and compelling need for new and improved treatment for tuberculosis. The entire logic towards design of new compounds containing 4-hydroxy-N'-(1,3-thiazoldin- 2-yldene)benzohydrazide moiety is basically for superior antimycobacterial activity. The recent advances in QSAR and computer science have provided a systematic approach to design a structure of any compound and further, the biological activity of the compound can be predicted before synthesis. The 3D-QSAR studies for the set of 4-hydroxy-N'-(1,3-thiazoldin- 2-yldene)benzohydrazide and their derivatives were carried out by using V-life MDS (3.50). The various statistical methods such as Multiple Linear Regression (MLR), Partial Least Square Regression (PLSR), Principle Component Regression(PCR) and K nearest neighbour (kNN) were used. The kNN showed good results having cross validated $r^2$ 0.9319, $r^2$ for external test set 0.8561 and standard error of estimate 0.2195. The docking studies were carried out by using Schrodinger GLIDE module which resulted in good docking score in comparison with the standard isoniazid. The designed compounds were further subjected for synthesis and biological evaluation. Antitubercular evaluation of these compounds showed that (4.a), (4.d) and (4.g) found as potent inhibitor of H37RV.

플라즈마질화 및 침질탄화처리한 탄소강의 경도와 내마모특성 (Characteristics of Hardness and Wear-Resistance of Plasma-Nitrided and Nitrocarburized Carbon Steels)

  • 김무길;정병호;박화순;이병찬;신성하;이재식
    • 열처리공학회지
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    • 제12권2호
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    • pp.166-173
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    • 1999
  • Commercial carbon steels containing 0.2~0.55 wt.----C were plasma-nitrided or plasma nitrocarburized at $550^{\circ}C$ for 21.6Ks using $H_2-N_2$ or $H_2-N_2$-CO mixed gas respectively. The characteristics of hardening and wear-resistance of each treatment were studied and compared. And also microstructure of nitrided layer and nitrides formed in compound layer near surface were studied. All plasma-nitrided steels investigated showed remarkable increase of surface hardness with the increase of carbon content. But nitrocarburized steels resulted in higher surface-hardness than plasma-nitrided steels, which means that nitrocarburized has higher surface-hardening effect. Plasma-nitrided steels showed hardness increase in through-thickness direction near surface. And also nitrocarburized steels showed similar hardness distribution in through-thickness direction to that of plasma-nitrided steel. However, nitrocarburized steels had higher cross-sectional maximum-hardness than plasma-nitrided steels as much as 100Hv. Wear test showed that the amount of specific wear was reduced by both plasma-nitriding and nitrocarburized, showing that the amount of specific wear was not related to the hardness. But non-treated specimen showed that the amount of specific wear was related to the hardness.

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THE SYNTHESIS, PHYSICAL PROPERTY, AND THE BIOLOGICAL ACTIVITY OF NOVEL NEO-CERAMIDES

  • Kim, Duck-Hee;Lee, Bo-Seaub;Koo, Myeong-Soo;Kim, Hyun-Jun;Lee, Hae-Kwang;Park, Moon-Jae;Lee, Ok-Sub
    • 대한화장품학회지
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    • 제24권3호
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    • pp.6-16
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    • 1998
  • Ceramides are currently emerging as the major skin care ingredients due to !heir barrier properties in the stratum corneum of the human skin. Thus, major cosmetic companies have developed synthetic ceramide analogs for their own use. In this study, several ceramide mimic compounds , new skin barrier lipids, were designed and synthesized, and their physical and biological properties were investigated to evaluate their skin care capability. Several structures were designed from the variation of hydrophobic alkyl chain and hydrophilic moiety by the use of molecular modeling software. The selected targets were synthesized, and their properties and activities were studied as the pure form, in the emulsion, or in the lamellar mixture containing cholesterol and fatty acid. Some compounds, such as 1,3-bis(N-(2-hydroxyethyl)-palmitoylamino)-2-hydroxypropane, enhanced the restoration of skin barrier damaged by SDS(sodium dodecyl sulfate), and by acetone treatment. The rate of restoration was comparable to that of natural ceramides. The synthesized compounds alleviated SDS induced skin irritation and facilitated lamellar phase liquid crystal formation. The treatment of 1,3-Dis(N-(2-hydroxyethyl)-palmitoylam ino)-2-hyd roxypropane on the acetone damaged skin revealed that the compound promoted the recovery of intercellular lipid lamellar structure of stratum corneum layer. The replacement of palmitoyl groups of the compound with shorter alkyl chain gave lower emulsion viscosity and liquid crystal density, suggesting easier formulation and poorer barrier activity. Most of the synthesized compounds were non-irritable in various toxicological tests proving that they can be safely introduced to the skin care formulations.

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Quantitative analyses of ricinoleic acid and ricinine in Ricinus communis extracts and its biopesticides

  • Choi, Geun Hyoung;Kim, Leesun;Lee, Deuk Yeong;Jin, Cho long;Lim, Sung-Jin;Park, Byung Jun;Cho, Nam-Jun;Kim, Jin-Hyo
    • Journal of Applied Biological Chemistry
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    • 제59권2호
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    • pp.165-169
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    • 2016
  • The quantitative analytical method for the bioactive substance, 3-cyano-4-methoxy-N-methyl-2-pyridone (ricinine) and an index compound, ricinoleic acid in castor plant (Ricinus communis) extract or oil was developed. For the determination of a pyridone alkaloid compound, ricinine, successive cartridge cleanup method combined with ultra-performance liquid chromatography was set up with $ENVI-Carb^{TM}$ (0.5 g) and $C_{18}$ SPE cartridges. Accuracy and precision were evaluated through fortification studies of one biopesticide (PE) at 10 and $100mg\;kg^{-1}$. Mean recoveries of ricinine were 98.7 and 96.0 % associated with less than 10 % RSD, respectively. For the determination of ricinoleic acid in castor extract and oil, saponification and methylation were optimized using gas chromatography-time of flight mass spectrometry. Recovery was more than 84.8 % associated with 6.2 % RSD after derivatization procedure. Both methodologies developed were applied to analyze real samples including three castor oil products and six commercially available biopesticides containing R. communis, collected at Korean market. The contents of ricinine and ricinoleic acid in most commercial biopesticides were less than the oil or extract contents indicated by label.

Development of Novel Small Chemical Inhibitors for Lck SH Domain with in vitro T-cell Inhibitory Activity

  • Park, See-Hyoung;Kang, Mi-Ae;Shim, Hyeong-Soo;Cho, Hyeong-Jin;Won, Jong-Hwa;Lee, Keun-Hyeung
    • Bulletin of the Korean Chemical Society
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    • 제27권9호
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    • pp.1353-1358
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    • 2006
  • We investigated in vitro T-cell inhibitory activity and bioavailability of small chemical inhibitors for Lck SH2 domain, which had a different scaffold such as an amide bond, reduced amide bond, N-methyl amide bond, thioamide bond, and urethane bond. Each of these compounds, with its particular scaffold, showed a different logP value, stability against serum enzyme, stability in buffer solution, and in vitro T-cell inhibitory activity. Overall results indicated that the SH2 inhibitor containing urethane bond can be a new lead compound because of its superior bioavailability, potent in vitro T-cell inhibitory activity, and facile synthesis.

Antibradykinin Effects of the Non-peptide Antagonists of Mixture Libraries Prepared by Solution-phase Combinatorial Synthesis

  • KAM Yoo Lim;CHOO Hea-Young P.
    • Biomolecules & Therapeutics
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    • 제13권3호
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    • pp.181-184
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    • 2005
  • The solution-phase combinatorial synthesis of iminodiacetic acid triamide libraries linked to 1-(4-chlorobenzhydryl)piperazine has been reported. Ten mixture libraries, each containing 5 components, were synthesized in 4 steps from N-BOC-iminodiacetic acid anhydride. Antibradykinin effects of the mixture and individual libraries were compared using guinea-pig ileum smooth muscle. The changes in the inhibition were also observed by testing the combination of two different compounds from the same library. We found out the correlation between the inhibition of mixtures and that of individual libraries. It is possible to choose the mixtures with relatively high inhibitory effects to find out the most effective individual compound for further synthesis.