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  • 1990-1994  (17)
  • 1975-1979  (8)
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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Langmuir 9 (1993), S. 2921-2925 
    ISSN: 1520-5827
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0630
    Keywords: 81.15 ; 82.80 ; 42.62
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Laser-ionization Time-Of-Flight (TOF) mass-spectrometric studies have been carried out on the 532 nm and 1064 nm laser ablation products from a nitrogen-rich polymer. The polymer used had an elemental composition of C6.0N8.9H3.4 and consisted of C=N, C-N, and N-H chemical bonds. The TOF mass spectra observed were composed of various peaks (≤150 amu) depending on the ablation laser wavelength. The primary peaks were assigned to C+, CN+, CHnN+ 2 (n=1−3) and C2H2N+ 3 for 532 nm ablation, and C+, C+ 3, HCN+, HCCN+, CH2NH+, HNCN+, H3NCN+, and C4H4N+ 7 for 1064 nm ablation. The flight velocity distributions with peak velocities ranging from ≈8.6×103 cm/s to ≈3.8×104 cm/s were measured for these products. The distinct velocity distributions observed between small and large products indicate the presence of two origins in the fragment ejection process from the polymer for both 532 nm and 1064 nm ablation. Furthermore, we suggest an importance of the translational energy of the fragments for the product generation in the laser plume.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 105-110 (Jan. 1992), p. 1229-1232 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 93 (1990), S. 8703-8708 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Reactions of N(4S) atoms with NO and H2 have been investigated using direct detection of N atoms by the atomic resonance absorption technique in a shock tube apparatus, where N(4S) is generated by photodecomposition of NO by 193 nm laser radiation behind reflected shock waves. The rate constant of the reaction, N+NO→N2+O (1) has been determined using pseudo first-order kinetic analysis to be k1=(1.3±0.3)×1013 (cm3 mol−1 s−1) over 1600–2300 K temperature range, which agrees very well with the estimation by Baulch et al. [Evaluated Kinetic Data for High Temperature Reactions (Butterworths, London, 1973), Vol. 2]. No (or very small) activation energy of this process was confirmed. Also, the rate constant of the reaction, N+H2→NH+H (2) has been decided by adding H2 to NO–Ar mixtures; it is k2=(2.8±0.2)×1014 exp(−Ea/RT) (cm3 mol−1 s−1), where Ea =33±7 kcal/mol. A quantum mechanical calculation performed in order to determine the mechanism of this reaction suggests that the reaction N(4S)+H2→NH+H proceeds via a direct abstraction of H atom from H2, and it gives calculated activation energy which is in good agreement with the present experiment.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 92 (1990), S. 4077-4092 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Ultraviolet photoelectron spectroscopy (UPS) has been applied to the investigation of the electronic structure of oligothiophenes with 4–8 thiophene rings. In a series of α-linked oligomers (αn with n being the number of rings), a systematic evolution of the π band is observed. Several peaks which correspond to the π band are observed in the region of 0.7–3 eV below the Fermi level (EF), and the bandwidth becomes broader with increasing n. The nonbonding π band is observed at 3.5 eV below EF and its energy is almost independent of the number of thiophene units. UPS spectra of α7 and α8 are fairly similar to the spectra of polythiophene, showing that these oligomers are good model compounds of the polymer. The ionization threshold energy of α7 and polythiophene was observed to be 5.3 eV. The effect of irregularity on the π-electron system was also studied by using oligomers which contain a β linkage or a vinylene group at the middle of the molecule. The UPS spectra showed that the β linkages significantly affect the electronic structure of polythiophene, while the vinylene group does not. In order to analyze the UPS spectra and to investigate the electronic structures of oligomers, the orbital energies and the geometries of these oligomers are calculated by the semiempirical MNDO-SCF-MO (modified neglect of diatomic overlap self-consistent-field molecular orbital) method. Theoretically simulated spectra of these oligothiophenes derived from the obtained orbital energies by Gaussian broadening are compared with the observed ones. The agreement between the observed and calculated spectra is very good, particularly in the π region. It is shown from the optimized geometry that (1) αn 's have planar structure and π electrons are delocalized, (2) the oligomer with β linkages has nonplanar structure leading to limited delocalization of π electrons, and (3) the oligomers with a vinylene group are almost planar and the disturbance by the vinylene group on the delocalization is small.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    238 Main Street, Cambridge, Massachusetts 02142, USA : Blackwell Scientific Publications
    International journal of gynecological cancer 3 (1993), S. 0 
    ISSN: 1525-1438
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Using anti-p53 (PAb1801 and PAb240), anti-DNA polymerase α and Ki-67 monoclonal antibodies, the expression of p53 was studied in 11 normal endometria, 14 endometrial hyperplasias and 27 endometrial carcinomas and its relationship to the proliferative activity of the tumors was examined. Normal endometria and simple hyperplasias were completely negative for p53. The PAb1801 indices of complex hyperplasias and complex atypical hyperplasias were 2.5±1.8% and 5.0±3.2%, respectively. The PAb1801 indices of grade 1, grade 2 and grade 3 endometrial carcinomas were 10.2±14.2%, 44.4±29/0% and 45.0±32.5%, respectively. These results indicate a progressively enhanced p53 expression in the sequence from normal endometrium, through hyperplasia to carcinoma. A significant correlation between p53 expression and labeling indices of Ki-67 and DNA polymerase α was observed in endometrial carcinomas. The endo-metrial carcinomas with p53 overexpression developed mainly in post-menopausal patients and were frequently high-grade tumors with deep myometrial invasion. These findings may indicate that overexpression of p53 protein contributes to the proliferative activity of the tumor cells.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Three Cambridge Center, Suite 208, Cambridge, MA 02142, USA : Blackwell Scientific Publications Inc.
    International journal of gynecological cancer 1 (1991), S. 0 
    ISSN: 1525-1438
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A differential assessment by colposcopy of three subgroups of stage I in the new FIGO classification of cervical cancer was attempted. Colposcopic findings in invasive cancer were atypical white epithelium, atypical mosaic, papillary punctation, atypical vessels, abnormal ‘rock-like’ projection, papillomatous growth and ulcer. Ulcer and abnormal ‘rock-like’ projection were more suggestive of a frank invasive carcinoma than a microinvasive carcinoma. While 89% of the cases in stage Ib were correctly predicted, only about 50% of those in stage Ia were correctly predicted. We propose that a colposcopic assessment be included in the armamentarium to decide the method of treatment for cervical cancer patients.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1439-0523
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Plant regeneration was achieved through anther culture of three wild species of Hordeum (H. murinum, H. marinum and H, bulbosum). Calli or embryoids were formed from microspores in anthers cultured on a medium containing 6-benzylammopurine (BAP) and ficoll. These calli or embryoids regenerated green or albino shoots and roots after transfer to regeneration media. Green plantlets which developed on regeneration media were transferred to soil where they showed further growth.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 583-584 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A new method of adjusting the bias current of dc superconducting quantum interference device (SQUID) is described. It is shown that the signal-to-noise ratio of a SQUID magnetometer connected in a flux-locked loop configuration is proportional to the second harmonic of the output signal from the SQUID. A circuit configuration that can automatically optimize a SQUID's bias current by measuring this second harmonic and adjusting the bias current accordingly is proposed.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Industrial and engineering chemistry 17 (1978), S. 243-248 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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