• 제목/요약/키워드: internal reaction rate

검색결과 195건 처리시간 0.032초

중증 또는 비전형적 지역사회획득 폐렴으로 입원한 환자에서 호흡기 바이러스의 검출 빈도 (Respiratory Virus Detection Rate in Patients with Severe or Atypical Community-acquired Pneumonia)

  • 박지원;정선영;은혁수;천신혜;성석우;박동일;박명린;박희선;정성수;김주옥;김선영;이정은
    • Tuberculosis and Respiratory Diseases
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    • 제71권5호
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    • pp.335-340
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    • 2011
  • Background: Community-acquired pneumonia (CAP) is an important cause of morbidity and mortality throughout the world in all age groups. Viral causes of CAP are less well characterized than bacterial causes. We analyzed the characteristics of hospitalized patients with CAP who had a viral pathogen detected by multiplex polymerase chain reaction (PCR). Methods: Multiplex real-time PCR was performed for respiratory viruses in samples collected from 520 adults who developed CAP at Chungnam National University Hospital. Clinical, laboratory, and radiological features at presentation as well as other epidemiological data were analyzed. Results: Of 520 patients with CAP, a viral pathogen was detected in 60 (11.5%), and influenza A was the most common. The virus detection rate in patients with CAP was highest in November. Two or more pathogens were detected in 13 (21.7%) patients. Seven patients had severe disease and were administered in the intensive care unit. Most patients (49/60, 81.7%) had comorbidities. However, nine (15%) patients had no comorbidities, and their age was <60 years. The ground glass opacity pattern was the most common radiological feature. Seven (11.7%) patients died from CAP. Conclusion: Viral pathogens are commonly detected in patients with CAP, and a respiratory virus may be associated with the severity and outcome of pneumonia. Careful attention should be paid to the viral etiology in adult patients with CAP.

Energy- and Time-Dependent Branching to Competing Paths in Coupled Unimolecular Dissociations of Chlorotoluene Radical Cations

  • Seo, Jongcheol;Kim, Seung Joon;Shin, Seung Koo
    • Bulletin of the Korean Chemical Society
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    • 제35권3호
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    • pp.833-838
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    • 2014
  • The energy- and time-dependent branching to the competing dissociation paths are studied by theory for coupled unimolecular dissociations of the o-, m-, and p-chlorotoluene radical cations to $C_7{H_7}^+$ (benzylium and tropylium). There are four different paths to $C_7{H_7}^+$, three to the benzylium ion and one to the tropylium ion, and all of them are coupled together. The branching to the multiple paths leads to the multiexponential decay of reactant with the branching ratio depending on both internal energy and time. To gain insights into the multipath branching, we study the detailed kinetics as a function of time and internal energy on the basis of ab inito/RRKM calculations. The number of reaction steps to $C_7{H_7}^+$ is counted for each path. Of the three isomers, the meta mostly goes through the coupling, whereas the para proceeds with little or no coupling. In the beginning, some reactants with high internal energy decay fast to the benzylium ion without any coupling and others rearrange to the other isomers. Later on all three isomers dissociate to the products via long-lived intermediates. Thus, the reactant shows a multiexponential decay and the branching ratio varies with time as the average internal energy decreases with time. The reciprocal of the effective lifetime is taken as the rate constant. The resulting rate-energy curves are in line with experiments. The present results suggest that the coupling between the stable isomers is thermodynamically controlled, whereas the branching to the product is kinetically controlled.

대구지역 한 대학병원에서 비결핵 항산균의 미생물학적 분포 및 임상적 특성 (Microbiologic distribution and clinical features of nontuberculous mycobacteria in the tertiary hospital in Daegu)

  • 홍경수;안준홍;최은영;진현정;신경철;정진홍;이관호
    • Journal of Yeungnam Medical Science
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    • 제32권2호
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    • pp.71-79
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    • 2015
  • Background: Recent studies have shown that the nontuberculosis mycobacterium (NTM) recovery rate in clinical cultures has increased within Korea. However, another study conducted by a secondary hospital within Daegu reported different results. Therefore, the purpose of this study is to understand and evaluate the microbiological distribution and clinical features of NTM in Daegu. Methods: A retrospective study was conducted on 11,672 respiratory specimens undergoing acid fast bacilli (AFB) culture from 6,685 subjects who visited Yeungnam University Respiratory Center from January 2012 to December 2013. Results: Of the 11,672 specimens undergoing AFB culture, 1,310 specimens (11.2%) showed positive results. Of these specimens, NTM was recovered from 587 specimens, showing a recovery rate of 44.8%. Identification test for NTM was performed on 191 subjects; the results were as follows: M. avium-intracellulare complex (MAC) 123 (64.4%), M. abscessus 20 (10.5%), M. kansasii 12 (6.3%), and 33 other NTM germ strains. Of the 382 subjects with NTM, 167 were diagnosed with pulmonary NTM disease (43.7%), however virulence differed depending on NTM strain. Multivariate analysis showed that nodular bronchiectasis, the nodules, and finding consistent with cavity under imaging study were statistically significant for triggering pulmonary NTM disease. AFB culture showing MAC and M. abscessus was statistically significant as well. Positive predictive value for NTM polymerase chain reaction (NTM-PCR) was 88.6%. Conclusion: Results for NTM recovery rate within the Daegu area were similar to those for the Seoul metropolitan area. We can assume that NTM infection is increasing in our community, therefore AFB-positive subjects (1) should undergo NTM-PCR, (2) should have their culture results checked for differentiation of mycobacterium tuberculosis complex (MTB) from NTM, and (3) undergo NTM identification test to confirm its type. Administration of treatment with the above results should be helpful in improving the patients' prognosis.

사과의 삼투압농축과 열품건조시 갈색화 반응에 미치는 효과 (Osmotic Concentration of Apples and Its Effect on Browning Reaction during Air Dehydration)

  • 김명환
    • 한국식품영양과학회지
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    • 제19권2호
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    • pp.121-126
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    • 1990
  • Internal mass transfer during osmotic concentration of apples in sugar solutions was exami-ned as a function of concentration temperature and immersion time of those solutions using moisture loss sugar gain molality and rate parameter. Influence of osmotic concentration processes on browning reaction was also evaluated compared to control In creasin the concen-tration and temperature of sugar solutions increased moistrue loss sugar gain molality and rate parameter. Water loss was rapid early in the process and then levelled off, The same phenomena were occurred on sugar gain only in higher concentration(60$^{\circ}$ brix). IN lower concentration (30$^{\circ}$brix) sugar gain was gradually increased during whole process. Moisture loss during osmotic concentration using a sugar solution(60$^{\circ}$ brix 6$0^{\circ}C$) with 180min immer-sion time was 45.79% Effect of osmotic concentration befor air dried to 4% M.C(wet basis) on browning reaction was significant. Minimum browning reaction during air drying was carried out using a pretreatment such as osmotic concentration in sugar solution(60$^{\circ}$brix 45$^{\circ}C$) with 150min immersion time(O.D=0.01) compared to control(O.D=0.17)

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중풍 후 딸꾹질의 한약치료에 대한 임상 연구 동향 - 중의학 저널을 중심으로 (Review of Clinical Research about the Treatment of Hiccup After Stroke with Herbal Medicine - Based on Traditional Chinese Medicine Journals)

  • 강은진;류혜랑;김영균;김경민
    • 대한한방내과학회지
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    • 제39권3호
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    • pp.323-337
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    • 2018
  • Objective: The purpose of this research is to investigate Chinese clinical studies of the treatment of hiccup after stroke with herbal medicine. Methods: We used the China National Knowledge Infrastructure (CNKI) database to search for clinical studies about using herbal medicine to treat hiccup after stroke. Results: Nineteen clinical articles Until August 31, 2017 were analyzed. The most commonly used herbal prescription was Xuanfudaizhe-tang (旋覆代?湯). According to analysis, the most commonly used medical herbs were Haematitum (代?石), Inulae Flos (旋覆花), and Pinelliae Tuber (半夏). Clinical symptoms, total incidence rate of adverse reaction, recurrence rate, symptom improvement time, patient satisfaction comparison, and dietary status improvement were used to evaluate the treatments. The effective rate of the treatment group was 86.0-97.8%, significantly higher than control group in all papers. Side effects occurred much less frequently in the treatment group than in the western medicine control group. Conclusion: The treatment of hiccup after stroke with herbal medicine was shown to be highly effective in 19 studies. Additional well-designed clinical trials are needed; this study can be used as a basis for further research regarding the treatment of hiccup after stroke.

Safety and outcomes of subconjunctival allogenic mesenchymal stem cell transplantation in canine experimental corneal defects

  • Kim, Ju-Won;Lee, So-Young;Park, Hee-Myung
    • 대한수의학회지
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    • 제52권3호
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    • pp.157-162
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    • 2012
  • Corneal injury is very common clinical condition in veterinary medicine and delayed or incomplete corneal healing has the potential of vision loss due to the loss of corneal transparency. For the reconstruction of corneal epithelium, tissue graft and cell transplantation have been prosperously investigated. The purpose of this study was to evaluate the clinical value and short-term safety of application of cultured allogenic mesenchymal stem cells (MSCs) in the treatment of canine experimental corneal defect. Corneal defects were surgically generated in the central corneas of healthy beagle dogs and cultured canine allogenic MSCs were transplanted via subconjunctival injection. Although mean healing time, the rate of epithelial regeneration, and the degree of corneal transparency were not significantly improved after MSC transplantation, significant immune reaction or incompatibility reaction was not detected except transient local irritation. These results propose the possibility of MSC application as a new regenerative medicine in canine ocular disorders.

자동차용 가스 스프링의 반력 특성에 관한 연구 (A Study on the Reaction Force Characteristics of the Gas Spring for the Automotive)

  • 이춘태
    • 드라이브 ㆍ 컨트롤
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    • 제12권4호
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    • pp.35-40
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    • 2015
  • A gas spring provides support force for lifting, positioning, lowering, and counterbalancing weights. It offers a wide range of reaction force with a flat force characteristic, simple mounting, compact size, speed controlled damping, and cushioned end motion. The most common usage is as a support on a horizontally hinged automotive tail gate. However, its versatility and ease of use has been applied in many other industrial applications ranging from office equipment to off-road vehicles. The cylinder of a gas spring is filled with compressed nitrogen gas, which is applied with equal pressure on both sides of the piston. The surface area of the rod side of the piston is smaller than the opposite side, producing a pushing force. The magnitude of the reaction force is determined by the cross-sectional area of the piston rod and the internal pressure inside the cylinder. The reaction force is influenced by many design parameters such as initial chamber volume, diameter ratio, etc. In this paper, we investigated the reaction force characteristics and carried out parameter sensitivity analysis for the design parameters of a gas spring.

${\gamma}-Alumina$에 담지된 산화구리에 의한 $SO_x$가스의 제거 특성 (Removal Characterics of $SO_x$ by CuO Impregnated ${\gamma}-Alumina$)

  • 이창선;윤용수
    • 환경위생공학
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    • 제11권3호
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    • pp.29-35
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    • 1996
  • Numerical solutions were obtained to the model equations for various parameters characterizing the pore structure, effective internal diffusion and the chemical reaction constant. The conversion was decreased with the cause of pore closure at the surface of reacting particles, reduction of porosity, surface area of reaction and effective diffusion coefficient in the solid with the progress of reaction. Total conversion was strongly depend on the local conversion at surface. According to the decreasing of impregnated concentration of the copper oxide and the increase of the flue gases concentration, total conversion was increased. And the conversion were affected by gas flow rate and pore size distribution of the reacting solid.

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SHS 합성에 의한 몰리브덴계 용사용 복합분말의 제조 (Fabrication of Mo based Thermal Spray Composite Powder by Self- propagating High- temperature Synthesis)

  • 박제신;심건주
    • 한국재료학회지
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    • 제11권9호
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    • pp.763-768
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    • 2001
  • Molybdenum-based thermal spray powder is widely used for coating the moving parts of the internal combustion engines due to its excellent wear resistance. A composite powder of the $Mo_{40}(Al_{1-x}Si_x)_{60}$ system was synthesized using the SHS method. The synthesized bulk was pulverized and specially treated to produce thermal spray powder. It was found that the synthesis reaction consisted of two-steps: the formation of $Al_8/Mo_3$ and the formation of Mo(Al,Si)$_2$. Both the temperature and the rate of the SHS reaction linearly increased with the increase of the value of x in $Mo_{40}(Al_{1-x}Si_x)_{60}$, The temperature and the rate of the reaction were also affected by the compacting density of the specimens, exhibiting the maximum valves at 62% and 60%, respectively. Since spherical shape is advantageous to the thermal spraying process, shape-control of the powder was attempted with PVA as a binding additive, resulting in the successful production of almost perfectly spherical powder of 80 $\mu\textrm{m}$ Ø$(d_{50})$ mean particle size.

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Optimization fluidization characteristics conditions of nickel oxide for hydrogen reduction by fluidized bed reactor

  • Lee, Jae-Rang;Hasolli, Naim;Jeon, Seong-Min;Lee, Kang-San;Kim, Kwang-Deuk;Kim, Yong-Ha;Lee, Kwan-Young;Park, Young-Ok
    • Korean Journal of Chemical Engineering
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    • 제35권11호
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    • pp.2321-2326
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    • 2018
  • We evaluated the optimal conditions for fluidization of nickel oxide (NiO) and its reduction into high-purity Ni during hydrogen reduction in a laboratory-scale fluidized bed reactor. A comparative study was performed through structural shape analysis using scanning electron microscopy (SEM); variance in pressure drop, minimum fluidization velocity, terminal velocity, reduction rate, and mass loss were assessed at temperatures ranging from 400 to $600^{\circ}C$ and at 20, 40, and 60 min in reaction time. We estimated the sample weight with most active fluidization to be 200 g based on the bed diameter of the fluidized bed reactor and height of the stocked material. The optimal conditions for NiO hydrogen reduction were found to be height of sample H to the internal fluidized bed reactor diameter D was H/D=1, reaction temperature of $550^{\circ}C$, reaction time of 60 min, superficial gas velocity of 0.011 m/s, and pressure drop of 77 Pa during fluidization. We determined the best operating conditions for the NiO hydrogen reduction process based on these findings.