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  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 113 (2000), S. 6107-6112 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The photodissociation of CF2(Double Bond)CFCl at 193 nm has been studied by product translational spectroscopy. Results show that the molecule undergoes competing dissociation into three pairs of products: (1) CFCl+CF2, (2) C2F2Cl+F, and (3) C2F3+Cl with a relative yield of 1.0:∼0.1:1.4. When photolyzed with polarized laser light, reactions (1) and (3) were detected with fragments recoiling anisotropically, indicating that dissociation occurs primarily on the excited potential energy surface. From the maximum kinetic energy derived for reactions (2) and (3), a upper limit of 110 and 90 kcal/mol was determined for the C–F bond and the C–Cl bond dissociation energy, respectively. In addition to these primary dissociation channels, we have observed the secondary products, CF+CF2 and F+C2F2 from the primary fragment C2F3 by absorbing an additional photon. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 115 (2001), S. 3195-3200 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The photodissociation of 1,2-C2H2Br2 at 248 nm has been studied by product translational spectroscopy. The results show that the molecule dissociates exclusively into the products (1) Br2+C2H2 and (2) Br (fast)+Br (slow)+C2H2 with a branching ratio ∼0.2:0.8. While the cleavages of the C–Br bonds are not symmetric, producing the Br atoms at unequal velocities, the anisotropy of the products indicates that both reactions occur in a fraction of a rotational period. Following an asynchronous concerted reaction, the triple products were simulated with the P(Et) distributions coupled by asymmetric angular distributions. A mechanism consistent with the measured results is proposed that the Br2 elimination is a result of a fast intersystem crossing from the ππ* pumped state while the triple products occur via a simultaneous asymmetric scission of the C–Br bonds along the nσ* state. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 113 (2000), S. 5331-5338 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The photodissociation of CH2(Double Bond)CClF at 193 nm has been studied by product translational spectroscopy. A total of five primary dissociation channels was detected for the products of Cl (fast), HCl, HF, Cl (slow), and F in the decreasing order of relative yield. Product translational energy distributions have been measured for these reaction products. While a thermal-like distribution was detected for the slow Cl and F atoms, a nonthermal distribution was determined for the fast Cl atom and the molecular elimination of HCl and HF. Apart from the fast Cl atom with anisotropy parameter β=0.5, the remaining products recoil isotropically following photolysis with linearly polarized light. By analogy with the photodissociation of chloroethylenes, these products are found to originate from two potential energy surfaces. In addition to the primary dissociation channels, we have detected the secondary products of F+C2H2 from the internally excited α-fluorovinyl radical through a fast fragment isomerization. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1365-2044
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In order to improve arterial oxygenation and venous admixture during one lung ventilation, the effect of selective infusion of prostaglandin Ei into the pulmonary artery of the ventilated lung was investigated in 12 adult patients undergoing thoracotomy. Patients’bronchi were intubated with a Mallinckrodt bronchial tube and ventilated with 66% oxygen in air. Cardiopulmonary factors such as systemic and pulmonary arterial pressures, pulmonary vascular resistance, blood gas analyses, cardiac output and airway pressure were measured before and during one-lung ventilation; venous admixture (Qs/Qt) was calculated. Serial blood samples were taken from the pulmonary artery of the ventilated lung for endothelin-1 estimation. One lung ventilation reduced the mean Pao2 from 42.1 (2.3)kPa to 11.8 (1.4)kPa (p 〈 0.001) and increased Qs/Qt from 10.8 (3.2)% to 39.2(4.7)% (p 〈 0.001). Pulmonary vascular resistance also increased from 167 (24) dyne.s.cm-5 to 262 (38) dyne.s.cm-5 (p 〈 0.05) with a corresponding increase of plasma endothelin-1 (p 〈 0.05). After 30min of one lung ventilation, PGE, was infused continuously into the pulmonary artery of the ventilated lung at a rate which increased incrementally from 0.04–0.10 μg.kg-1.min-1. Pao2 increased to 20.7 (2.6) kPa (p 〈 0.01) and Qs/Qt decreased to 30.6 (3.5)% (p 〈 0.05). During the infusion, pulmonary vascular resistance reduced to 173 (30) dyne.s.cm-5 (p 〈 0.01). The plasma endothelin-1 concentration reached a plateau between the end of one lung ventilation (before closing the thorax) and 6h postoperatively. This correlated inversely with the pre-operative forced expiratory volume in one second (r =— 0.68, p 〈 0.005), declining to normal values 72 h after operation. The selective infusion of PGEi into the pulmonary artery of the ventilated lung corrected pulmonary vasoconstriction and improved both arterial oxygenation and venous admixture during one lung ventilation for thoracotomy.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Clinical & experimental allergy 34 (2004), S. 0 
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Polymorphisms at the glutathione S-transferase (GST) P1 locus were associated with asthma-related phenotypes and bronchial hyper-responsiveness.Objective This study investigated whether GSTP1 genotypes and outdoor air pollution were interactive risk factors on childhood asthma.Methods Four hundred and thirty-six subjects were recruited for oral mucosa samplings from 2853 fourth- to ninth-grade schoolchildren from three districts with different air pollution levels in southern Taiwan. PCR-based assays were performed by oral mucosa DNA to determine GSTP1 genotypes. We also conducted a nested case–control study comprising 61 asthmatic children and 95 controls confirmed by International Study of Asthma and Allergies in Childhood questionnaire results and methacholine challenge test. Multiple logistic regression was used to adjust for potential confounding factors.Results All participants were homozygous at the Ala-114 locus. Although only a marginally significant association existed between the frequency of homozygosity at the Ile-105 locus and asthma when air pollution was not considered, we found a significant gene–environmental interaction between GSTP1–105 alleles and air pollution after adjusting for confounders (P=0.035). Specifically, we found that compared with participants carrying any Val-105 allele in low air pollution, those who are Ile-105 homozygotes in high air pollution district had a significantly increased risk of asthma (adjusted odds ratio (AOR)=5.52, 95% confidence interval (CI)=1.64–21.25). Compared with participants carrying any Val-105 allele, in high air pollution district, children with Ile-105 homozygotes had a significantly increased risk of asthma (AOR=3.79, 95% CI=1.01–17.08), but those who carried two Ile-105 alleles in low or moderate air pollution districts did not show similar tendencies. The risk of asthma also revealed a clear dose–response relationship with outdoor air pollution in children with Ile-105 homozygotes.Conclusion Our result suggests a gene–environmental interaction between GSTP1–105 genotypes and outdoor air pollution on childhood asthma.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 3534-3540 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We investigated the effects of surface roughness and grain boundary diffusion (GBD) at elevated temperatures on the Auger-electron-spectroscopy sputter depth profiles of Co–Ag bilayers and the GBD process of Ag atoms in Co. The Ag layer in the Ag/Co bilayer is transformed from a uniform layer to discrete islands by heat treatment. Enhanced mobility during sputtering at elevated temperatures makes Ag atoms migrate continually from islands to cover neighboring exposed Co, which reduces the size of Ag islands. On the other hand, the surface morphological modification of Co/Ag bilayer does not occur by heat treatment, and the depth profile at 340 °C resembles that from a uniformly intermixed film, which shows a drastic difference from that of Ag/Co. This is explained with a very thin and stable accumulation of Ag on the Co layer by GBD. A model of structural changes in Co/Ag subjected to ion sputtering at elevated temperatures is proposed on the basis of the results. The activation energy and pre-exponential factor for GBD of Ag in Co are found to be 0.46±0.06 eV and ∼1×10−8 cm2/s, respectively. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1617-4623
    Keywords: Key words Brevibacterium albidum  ;  Arginine tRNACCG  ;  Escherichia colirnpA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Escherichia colirnpA gene encodes C5 protein, the protein component of RNase P. The rnpA49 mutation renders the C5 protein thermosensitive, which results in thermosensitivity of RNase P function. The chromosomal DNA region from Brevibacterium albidum that complements the rnpA49 mutation was analysed. The gene capable of complementing the growth defect of an rnpA49 mutant strain at nonpermissive temperature was identified as the gene for an arginine tRNA with anticodon CCG by a deletion analysis combined with complementation assays. Transcription of the arginine tRNA gene carried on a multicopy plasmid was correlated with the complementation of the rnpA49 mutation, indicating that the gene product is indeed responsible for complementation of the rnpA49 mutation.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Accounts of chemical research 28 (1995), S. 321-327 
    ISSN: 1520-4898
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Biochemistry 23 (1984), S. 3569-3575 
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Biochemistry 23 (1984), S. 6437-6444 
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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