ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Long-range fluorescence quenching of ethidium ion by cationic porphyrins in the presence of DNA (1991)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 113 (1991), S. 6835-6840 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00018a019
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Nonadiabatic electronic interactions in the ion-pair states of NeICl (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 4171-4181 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Nonadiabatic interactions in the NeICl van der Waals complex have been explored in the lowest energy triad of ICl ion-pair states (∼39 000 cm−1). Dispersed fluorescence measurements reveal emission characteristic of multiple ion-pair electronic states, with the relative contributions from the E(0+), β(1), and D'(2) states changing with the initial ICl vibrational excitation (vICl). Emission directly from NeICl (vICl=0) complexes indicates that the initially prepared NeICl levels have mixed electronic character and that the ICl electronic parentage changes with the initial van der Waals vibrational level selected. NeICl complexes prepared with 1–4 quanta of ICl stretch undergo rapid vibrational predissociation with a strong propensity for ΔvICl=−1 relaxation. The electronic state(s) populated in the ICl fragments differ from the mixed electronic character of the initially prepared level, demonstrating that vibrational predissociation is accompanied by nonadiabatic electronic state changing processes. The observed final state selectivity may be attributed to the relative strength of the nonadiabatic couplings between the initial NeICl bound state and the final ICl states or a momentum gap rationale based on the overlap between the NeICl bound state wave function and the highly oscillatory continuum wave function of the separating fragments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.460650
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Fragment energy and vector correlations in the overtone-pumped dissociation of HN3 X˜ 1A' (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 250-261 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: NH stretching overtone and combination states in HN3 X˜ 1A' were excited by IR–visible double resonance pumping and by direct overtone pumping in the range 6ν1 (17 670 cm−1) to 7ν1 (20 070 cm−1). NH fragments in the a 1Δ and X 3Σ− states were detected by laser induced fluorescence with sub-Doppler resolution to determine branching ratios, correlated fragment rotational state and kinetic energy distributions, and fragment vector correlations. The spin-forbidden triplet channel was accessible to all states excited, while the threshold for the singlet channel was determined to lie in the range 18 190 to 18 755 cm−1. The measured energy release places limits on the HN–NN bond energy, and the heights of barriers to reaction. The barrier in the singlet exit channel is at least 540 cm−1. The singlet channel accessed by 7ν1 dissociation is characterized by a Boltzmann-like NH rotational distribution (〈J NH〉≈3.5), highly excited N2 rotations (〈JN2〉 ≥ 20), and total translational energy release peaked away from zero (〈ET〉≈1350 cm−1). Vector correlations and Λ-doublet propensities indicate that nonplanar dissociation processes influence the NH rotations, but become less important for higher NH rotational states. The principal correlations are a strong positive recoil anisotropy (β≈0.6), a weak positive v–J correlation (βvJ≈0.17), and a JNH-dependent Λ-doublet propensity. A model using parent vibrational motion projected onto fragment rotation is suggested to explain these observations. The triplet channel exhibits similar NH and N2 rotational state distributions, with most of the available energy (substantially greater than in the singlet channel) appearing as fragment kinetic energy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.460392
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Subpicosecond transient infrared spectroscopy of adsorbates. Vibrational dynamics of CO/Pt(111) (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 95 (1991), S. 5403-5418 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The vibrational dynamics of excited CO layers on Pt(111) were studied using infrared (IR) pump–probe methods. Resonant IR pulses of 0.7 ps duration strongly pumped the absorption line (ν≈2106 cm−1 ) of top-site CO. Weak probe pulses delayed a time tD after the pump were reflected from the CO-covered Pt(111) surface, and dispersed in a monochromator to determine the absorption spectrum of the vibrationally excited CO band, with time resolution 〈1 ps and monochromator resolution 〈1 cm−1. Transient spectra were obtained as a function of CO coverage, surface temperature, and laser fluence. Complex spectra for tD〈0 show features characteristic of a perturbed free induction decay, which are expected based on multiple-level density-matrix models. For tD≥0, the CO/Pt absorption exhibits a shift to lower frequency and an asymmetric broadening which are strongly dependent on fluence (1.3–15 mJ/cm2 ). Spectra return to equilibrium (unexcited) values within a few picoseconds. These transient spectral shifts and the time scale for relaxation do not depend (within experimental error) on coverage for 0.1≤aitch-thetaCO≤0.5 ML or on temperature for 150≤Ts≤300 K. A model for coupled anharmonic oscillators qualitatively explains the tD〉0 spectra in terms of a population-dependent decrease in frequency of the one-phonon band, as opposed to a transition involving a true CO(v=2) two-phonon bound state. The rapid relaxation time and its insensitivity to Ts and aitch-thetaCO are consistent with electron–hole pair generation as the dominant decay mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.461657
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Laboratory experiments on turbulent mixing across sheared density interfaces (1991)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 3 (1991), S. 1461-1461 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An experimental study was carried out to investigate turbulent mixing and entrainment across a density interface subjected to velocity shear. The flow configuration consisted of a salinity (stably) stratified two-fluid system with a driven upper turbulent layer and a quiescent lower layer. The experiments were performed in an Odell–Kovasznay tank and the mean flow in the upper layer was generated by using a conventional disk pump. The velocity and salinity measurements were made using a laser-Doppler anemometer and conductivity probes, respectively, and (quantitative) flow visualization was performed using the laser-induced fluorescence LIF technique. The refractive indices of upper and lower layers were matched, using salt and alcohol, to facilitate the use of laser-based flow diagnostic techniques. The measurements show that the rms velocity fluctuation u in bulk of the mixed layer scales well with the mean velocity jump Δu across the interface. The Thorpe, buoyancy, overturning, and integral length scales, as well as the maximum Thorpe displacement in the mixed layer, were also found to be proportional to the depth h of the upper mixed layer.The structure of the entrainment interface was found to depend strongly on the bulk Richardson number Ri (=Δb h/u2), where Δb is the buoyancy jump across the interfacial layer. At lower Ri, the entrainment occurred rapidly, as in a nonstratified fluid, but as Ri increases, the entrainment rate becomes a strong function of Ri: under the latter conditions, the interfacial wave breaking and Kelvin–Helmholtz instabilities were common features. At still higher Ri, the entrainment rate becomes vanishingly small and the interfacial mixing events were found to be controlled by the molecular diffusive effects. The measurement of the interfacial-layer thickness using LIF shows that it is much thinner than that measured using less-accurate techniques such as traversing probes. The nondimensional rms amplitude of the interfacial distortions at moderate and high Ri was found to be a strong function of Ri. The interfacial instabilities cause the formation of isolated mixing patches within the interface, which, when collapsed, form horizontal intrusions. The experimental measurements were in agreement with theoretical formulations based on scaling arguments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.857995
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Observation of speckle by diffraction with coherent X-rays (1991)
    [s.l.] : Nature Publishing Group
    Nature 352 (1991), S. 608-610 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] To obtain a speckle pattern, the incident beam must be sufficiently coherent. With visible light this is typically achieved with a laser source, but it is possible to use an incoherent source, such as a mercury arc lamp2 or, as in our case, an X-ray wiggler, provided that it is suitably collimated ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/352608a0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Importance of energetic solar protons in ozone depletion (1991)
    [s.l.] : Nature Publishing Group
    Nature 352 (1991), S. 137-139 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Although terrestrial sources exist for nitric oxide in the stratosphere2, it can be generated by both solar protons and galactic cosmic rays3'5. Solar protons of energies 〉10MeV enter the stratosphere at high geomagnetic latitudes (60°) and can penetrate to altitude ranges where ozone is ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/352137a0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    A comparative study of microsomal and cytosolic S6 phosphatase activities in rat liver (1991)
    Springer
    Molecular and cellular biochemistry 107 (1991), S. 103-110 
    Details
    ISSN: 1573-4919
    Keywords: ribosomal protein ; hepatectomy ; cycloheximide ; insulin ; phosphopeptide mapping ; phosphoprotein phosphatases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary Spontaneous S6 phosphatase activities dephosphorylating Ser(P)-235 and Ser(P)-236 of the ribosomal protein S6 were measured and compared in microsomes and cytosol of rat liver. The substrate used, small (40S) ribosomal subunits 32P-labelled in vitro by protein kinase A, contained phosphorylated S6 (mainly in the dephosphorylated form) and some minor phosphorylated species. The microsomal and cytosolic S6 phosphatase activities displayed a number of distinct properties. The microsomal activity, representing ca 20% of the S6 phosphatase activity in the post-mitochondrial supernatant, was mainly due to a type-1 phosphatase and dephosphorylated only S6. The remaining post-mitochondrial S6 phosphatase activity, which was fully recovered in the cytosol, and appeared to result from a combination of type-1 (43%) and type 2 (57%) phosphatases, acted on S6 as well as on the minor phosphorylated species. The microsomal activity was 50% inhibited by MgCl2 (l0 mM) and was stimulated at least 4.3 fold by MnCl2 (1 mM), while the cytosolic activity was inhibited only 18% by Mg2+ (10 mM) and was increased 2.2 fold by Mn2+ (1 mM). The microsomal activity was increased 10% (P 〈 0.06) by lower doses of insulin (25 U/Kg) and 14% (P 〈 0.05) by vanadate, but was not significantly (P 〉 0.10) affected by larger doses of insulin (100 U/kg), hepatectomy or cycloheximide. By comparison the cytosolic S6 phosphatase activity was unresponsive to insulin and vanadate, but was decreased 14% and 17% (P 〈 0.05) by hepatectomy and cycloheximide. It is concluded that (i) there. are clear differences between the microsomal and cytosolic S6 phosphatase activities, which may be relevant to their specific functions in the cell, and (ii) the inhibition of cytosolic S6 phosphatase activity by hepatectomy and cycloheximide may contribute to the increase in hepatic S6 phosphorylation induced by these treatments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225513
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    [(C5Me5)(Et2NCS2)Rh(μ-Ph2PCH2CH2PPh2)Rh(Et2NCS2)(C5Me5)]2+.2BPh4− (1991)
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 47 (1991), S. 648-650 
    Details
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0108270190009684
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Effects of chronic exposure to sublethal concentrations of lead acetate on heme synthesis and immune function in red-tailed hawks (1991)
    Springer
    Archives of environmental contamination and toxicology 21 (1991), S. 72-77 
    Details
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract Red-tailed hawks were exposed to sublethal levels of lead acetate for periods of 3 or 11 weeks. Alterations in the heme biosynthetic pathway were demonstrated after the first week of exposure to 0.82 mg lead per kilogram body weight per day. Activity of erythrocyte porphobilinogen synthase (aminolevulinic acid dehydratase) was depressed significantly and did not return to normal levels until 5 weeks after the termination of lead treatments. A rapid and relatively brief increase in erythrocyte free protoporphyrin and a slower but more prolonged increase in its zinc complex were also demonstrated with exposure to this dose of lead for 3 weeks. Less substantial decreases in hematocrit and hemoglobin levels occurred but only in the longer experiment with exposure to higher lead levels. Short term, low level lead exposure did not effect immune function significantly in the hawks, as measured by antibody titers to foreign red blood cells or by the mitogenic stimulation of T-lymphocytes. Increased lead exposure produced a significant decrease in the mitogenic response but had no effect on antibody titers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01055559
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...