• Title/Summary/Keyword: reaction route

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Alkylhydridorhodium(Ⅲ) Route for Isomerization and Hydrogenation of Unsaturated Alcohols with Rh(ClO$_4)(CO)(PPh_3)_2$ and [Rh(CO)(PPh$_3)_3]ClO_4$ under Hydrogen

  • Chin, Chong-Shik;Park, Jeong-Han;Kim, Choon-Gil
    • Bulletin of the Korean Chemical Society
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    • v.10 no.4
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    • pp.360-362
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    • 1989
  • Catalytic isomerization of unsaturated alcohols to the corresponding carbonyl compounds with$Rh(ClO_4)(CO)(PPh_3)_2\;(1)\;and\;[Rh(CO)(PPh_3)_3]ClO_4$ (2) is faster under hydrogen (where hydrogenation also occurs to give saturated alcohols) than under nitrogen. The isomerization under hydrogen seems to occur through an alkylhydridorhodium(III) complex which also undergoes reductive elimination to give hydrogenation products, saturated alcohols. The isomerization under hydrogen is faster with 2 than with 1, which is understood by acceleration of the last step, enol formation by $PPh_3$ dissociated from 2 and present in the reaction mixture when 2 is used as catalyst. Relative rates of the isomerization observed for different unsaturated alcohols are interpreted by steric effects of substituted groups and numbers of hydrogens to be abstracted by the rhodium of the intermediate, alkylhydridorhodium(III) to undergo the reductive elimination to give enol which is then rapidly converted into a carbonyl compound. It has been observed that the hydrogenation is relatively significant when reactions occur slowly whereas the isomerization is predominant when reactions proceed rapidly.

Sodium titanate as an infrared reflective material for cool roof application

  • Ullah, Mahboob;Kim, Hee Jung;Heo, Jae Gu;Roh, Dong Kyu;Kim, Dae-Sung
    • Journal of Ceramic Processing Research
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    • v.20 no.spc1
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    • pp.86-91
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    • 2019
  • A solid-state route was used to prepare sodium titanium oxide (NTO, Na2Ti3O7) as a solar heat protecting material with an impressive solar reflectance (TSR = 94.3%) using a high refractive index rutile TiO2. The solar reflectance of the synthesized NTO was measured using UV-Vis-NIR spectrophotometer. Solar reflectance property of the synthesized compound depends on the calcination temperature. The solar reflectance property of the synthesized NTO powder was compared with commercial rutile TiO2. The compound synthesized at 900 ℃ for 24 hrs had remarkable solar reflectance 94.3% than that calcined below 900 ℃. Crystalline nature, structural property, morphology and optical properties of NTO powders were characterized and analyzed using XRD, FE-SEM, EDS and UV-Vis-NIR spectrophotometer. From the results, we guessed that NTO would be a suitable "solar heat protecting candidate" for energy-saving applications in coating industries.

Safety of hydroxyzine in the sedation of pediatric dental patients

  • Taegyeom, Kim;Keoungah, Kim;Seungoh, Kim;Jongbin, Kim
    • Journal of Dental Anesthesia and Pain Medicine
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    • v.22 no.6
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    • pp.395-404
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    • 2022
  • Hydroxyzine is one of the most popular oral sedatives used in pediatric dentistry. This study aimed to investigate the safety and possible side effects of sedation using hydroxyzine in pediatric dentistry. "Hydroxyzine," "Dental sedation," "Child," and "Safety" and their associated synonyms were searched using the Cochrane Library, Embase, PubMed, KISS, KMBASE, and KoreaMed databases. Academic information and portals of DBpia and RISS were also perused. Altogether, 340 papers were found, among which a total of 24 papers were selected according to the detailed criteria. Nine studies used hydroxyzine as monotherapy, and 10 studies compared its safety when hydroxyzine used as multitherapy. In addition, seven studies employed a drug regimen wherein hydroxyzine was one of the components. All these studies revealed that the adverse events specific to hydroxyzine usage were drowsiness and dryness of the mouth, and that there were respiratory complications due to a synergistic reaction of hydroxyzine. Although classified as a histamine blocker, hydroxyzine with its sedative, antiemetic, anticonvulsant, and anticholinergic properties is an oral sedative available without serious adverse events, If the proper dosage of the drug is used and its synergistic effects with other drugs are ascertained in the route of administration.

Comparative Study of Undoped and Nickel-Doped Molybdenum Oxide Photoanodes for PEC Water Splitting

  • Garcia-Garcia, Matias
    • Journal of Electrochemical Science and Technology
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    • v.13 no.3
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    • pp.377-389
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    • 2022
  • The current global energy supply depends heavily on fossil fuels. This makes technology such as direct water splitting from harvesting solar energy in photoelectrochemical (PEC) systems potentially attractive due to its a promising route for environmentally benign hydrogen production. In this study, undoped and nickel-doped molybdenum oxide photoanodes (called photoanodes S1 and S2 respectively) were synthesized through electrodeposition by applying -1.377 V vs Ag/AgCl (3 M KCl) for 3 hours on an FTO-coated glass substrate immersed in molibdatecitrate aqueous solutions at pH 9. Scanning electron microscopy (SEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) were used for microstructural and compositional characterizations of the photoanodes. In addition, the optical and photoelectrochemical characterizations of these photoanodes were performed by UV-Visible spectroscopy, and linear scanning voltammetry (LSV) respectively. The results showed that all the photoanodes produced exhibit conductivity and catalytic properties that make them attractive for water splitting application in a photoelectrochemical cell. In this context, the photoanode S2 exhibited better photocatalytic activity than the photoanode S1. In addition, photoanode S2 had the lowest optical band-gap energy value (2.58 eV), which would allow better utilization of the solar spectrum.

Surveillance of African swine fever infection in wildlife and environmental samples in Gangwon-do

  • Ahn, Sangjin;Kim, Jong-Taek
    • Korean Journal of Veterinary Service
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    • v.45 no.1
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    • pp.13-18
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    • 2022
  • African swine fever (ASF) is fatal to domestic pigs and wild boars (Sus scrofa) and affects the domestic pig industry. ASF is transmitted directly through the secretions of infected domestic pigs or wild boars, an essential source of infection in disease transmission. ASFV is also very stable in the environment. Thus, the virus is detected in the surrounding environment where ASF-infected carcasses are found. In this study, ASF infection monitoring was conducted on the swab and whole blood samples from wild animals, various hematopoietic arthropod samples that could access infected wild boar carcasses or habitats to cause maintenance and spread of disease, and soil samples of wild boar habitats. ASF viral DNA detection was confirmed negative in 317 wildlife and environmental samples through a real-time polymerase chain reaction. However, ASF occurs in the wild boars and spreads throughout the Korean peninsula. Therefore, it is necessary to trace the route of ASF virus infection by a continuous vector. Additional monitoring of various samples with potential ASF infection is needed to help the epidemiologic investigation and disease prevention.

Bacterins to Prevent the Contamination of Vbrio vulnificus in the Flounder, Paralichthys olivaceus (넙치에서의 Vbrio vulnificus 오염 방지를 위한 백신 연구)

  • Son Sang Gyu;Kim Myoung Sug;Park Jun Hyo;Yoo Min Ho;Jeong Hyun Do
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.35 no.1
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    • pp.1-7
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    • 2002
  • To study the increased resistance in fish against Vibrio vulnificus known as an important agent of vibrio septicemia in human, we analyzed specific and nonspecific immune response in flounder after administration of V. vulnificus bacterins by oral route. It contained the comparison of antibody concentrations in the sera of flounder after oral administration by two different protocols with uncoated heat killed bacterin of V vulnificus (UHKB, 20 mg/kg body weight), i.e., 4 weeks continuously (group 4W) and taking 2 weeks resting period between the 1st and last week of administration (group 1-2-1W). Even though, 1-2-1W group showed significantly increased level of specific antibody in serum, it did not reach to that of 4W group. Certainly, flounder vaccinated twice a week for four weeks (20 mg/kg b.w.) showed increased concentration of specific antibody against V. vulnificus at week 2 after last administration by oral route and maintained throughout the experimental period. It also was confirmed by the increased numbers of specific antibody secreting cells (SASC) in the leukocytes isolated from the splenocytes of the flounder of 4W group at week 1 after last administration until the end of experimental period. However, enteric, acid-resistant film coated heat killed bacterin (ECHB) did not show both greater immune reaction for antibody production and faster elimination of a challenge dose of V. vulnificus compared with those of the UHKB. These results suggested that UHKB administered by oral route was very effective method to prevent the contamination of V vulnificus in flounder, and did not show the increased antigenicity by coating the surface with acid-resistant film.

Comparison about adverse drug reaction report forms among Asian's countries using herbal medicine (한약을 사용하는 아시아권 국가의 유해사례 보고 양식에 관한 비교 연구)

  • Sun, Seung-Ho;Lee, Eun-Kyoung;Jang, Bo-Hyoung;Park, Sunju;Go, Ho-Yeon;Jeon, Chan-Yong;Ko, Seong-Gyu
    • Journal of Society of Preventive Korean Medicine
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    • v.19 no.3
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    • pp.91-102
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    • 2015
  • Objective : The purpose of this study is to find out the possibility of application to herbal medicine's report form for adverse drug reaction (ADR) by reviewing and analyzing Asian countries's ADR report forms. Method : We investigated, compared, and analyzed ADR report forms (ADR-RF) of Asian countries's ADR institutions (ACAI), such as, Korea institute of drug safety & risk management and Dongguk university Ilsan oriental hospital (DUIOH) in Korea, national center for ADR monintoring (NCAM) in China, pharmaceuticals and medical devices agency (PMDA) in Japan, Ministry of Health and Welfare (MOHW) in Taiwan, and drug office, department of health, the government of the Hong Kong special administrative region (GHKSAR) in Hong Kong. Results : ADR-RF for ACAI included common contents, such as, patients information (name(initial), gender, age, weight), adverse event (AE)'s report information (Recognition and report for AE occurrence, first or follow up report, Severe AE), the detailed information of AE (the title of AE, onset & closing date of AE symptoms, the progress & results detailed test of AE), the information of AE's medicine (the types of medicine, product name, ingredient name, suspected or combination drug, single dose & frequency, dosage form, administration route, dealing for AE-suspected medicine), and AE reporter's information (reporter's information, institution's information). Taiwan had ADR-RF and the department exclusively for herbal medicine (HM), but others (except DUIOH) had not only no ADR report form but also contents for HM. Conclusion : ADR-RF for HM have to include the common contents of ACAI at least, as well as HM information related to ADR, such as the title, composition and types of HM, history related to HM's ADR, and the contents of drug-induced liver injury and so on. In addition, the main department of government for HM's ADR will be needed.

Syntheses and Properties of ZnS:Mn/ZnS Core-Shell Quantum Dots Prepared via Thermal Decomposition Reactions of Organometallic Precursors at Various Reaction Temperatures (다양한 온도 조건에서의 ZnS:Mn/ZnS 코어-쉘 양자점의 합성 및 광 특성에 관한 연구)

  • Lee, Jae-Woog;Hwang, Cheong-Soo
    • Journal of the Korean Chemical Society
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    • v.53 no.6
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    • pp.677-682
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    • 2009
  • ZnS:Mn/ZnS core-shell quantum dots (QDs), were synthesized via a thermal decomposition reaction of organometallic precursors in a hot solvent mixture. The synthetic conditions of the quantum dots were monitored at various reaction temperatures for the core formation, while the shell formation temperature was fixed at 135$^{\circ}C$. The obtained colloidal nanocrystals at corresponding temperatures were characterized by UV-Vis, solution photoluminescence (PL) spectroscopies, and further obtained powders were characterized by XRD, HR-TEM, and EDXS analyses. The synthetic temperature condition to obtain the best PL emission intensity for the core-shell QD was 135$^{\circ}C$, for both core and shell formation. At this temperature, solution PL spectrum showed a narrow emission peak at 583 nm with a relative PL quantum efficiency of 42.15%. In addition, the measured spherical particle sizes for the ZnS:Mn/ZnS nanocrystals via HR-TEM were in the range of 4.0 to 5.4 nm, while ellipsoidal particles were obtained at 150$^{\circ}C$.

The Methane Reforming by $CO_2$ Using Pelletized Co-Ru-Zr-Si Catalyst (성형 Co-Ru-Zr-Si 촉매를 이용한 이산화탄소에 의한 메탄 리포밍)

  • Nam, Jeong-Kwang;Lee, Ji-Hye;Song, Sang-Hoon;Ahn, Hong-Chan;Chang, Tae-Sun;Suh, Jeong-Kwon;Kim, Seong-Bo
    • Applied Chemistry for Engineering
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    • v.23 no.2
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    • pp.176-182
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    • 2012
  • The methane dry reforming has received the considerable attention in recent years, mainly as an attractive route to produce synthesis gas (CO, $H_2$) from green-house gases ($CH_4$, $CO_2$) for resources. However, this process has not been commercialized due to the high temperature and catalyst deactivation. In this study, Co-Ru-Zr catalysts supported on $SiO_2$ were studied for the characterization of methane dry reforming reaction and the preliminary data for process development were achieved. The crystal structure of catalysts was measured by XRD, the surface area and pore size were analyzed by BET, and the element composition of catalyst were analyzed by EDS. Conversions of methane and carbon dioxide were analyzed by GC. In addition, reaction rate constants were obtained from the reaction kinetic study and the optimum catalyst size that does not affect mass transfer from reactants was also determined. The selected pellet-type catalyst maintained activation for 720 h at $850^{\circ}C$.

Process of Coping with Domestic Violence of Marriage Immigrant Women (결혼 이주 여성의 가정폭력 대처과정에 관한 근거이론 접근)

  • Ko, Ki-Sook;Jeong, Mee-Kyung
    • The Journal of the Korea Contents Association
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    • v.12 no.10
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    • pp.254-279
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    • 2012
  • This research aims to suggest a practical solution in order to make marriage immigrant women free from violence and stand on their own. The suggestion could be made by developing Substantive theory in terms of marriage immigrant women's coping with domestic violence. The research question is; How marriage immigrant women cope with domestic violence. The research used a route theory approach, and 11 of marriage immigrant women who have ever suffered from domestic violence participated in it. The research question used semi-structured open questions. As a result of paradigm model analysis, "mental and physical devastation" is defined as a core phenomenon, and causative conditions are "wheel of pain" and "helpless victims of violence". Besides, context conditions are "period growth with solitariness", "irrational marriage" and "indifferent reality". "Mental and physical devastation", the core phenomenon act and interact with effect of mediatory conditions; which are "social help", "cultural difference" and "helplessness". Here the action and reaction appear as "adaptation", "resistance", "self-protection" and "self-reinforcement", and the outcomes show up as "maintaining reality", "decision making" and "beginning a new life". "Coping with mental and physical devastation and standing on one's own feet" could be introduced as a core category. Process of coping with domestic violence presents its levels as; shocks ${\rightarrow}$ endurance ${\rightarrow}$ regret ${\rightarrow}$ overcoming. There are three patterns of coping, which are; "preserving realities", "returning", and "groping for the future".