Library

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
    Time profile of calcium accumulation in hippocampus, striatum and frontoparietal cortex after transient forebrain ischemia in the gerbil (1992)
    Springer
    Acta neuropathologica 84 (1992), S. 400-406 
    Details
    ISSN: 1432-0533
    Keywords: Forebrain ischemia ; Selective vulnerability ; Calcium ; Gerbils ; Hippocampus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The topical and temporal relationship between neuronal injury and calcium loading was investigated in gerbils following bilateral carotid artery occlusion for 5 or 10 min and recirculation times from 15 min to 7 days. The association of histochemically visible calcium deposits with neuronal death was assessed by combining two calcium stains, alizarin red and arsenazo III, with conventional histological techniques. Neuronal calcium accumulation was evaluated morphometrically in the striatum, the frontoparietal cortex and the CA1 and CA4 sectors of the hippocampus. After 5-min ischemia and 1–2 days of recirculation numerous calcium-containing neurons appeared in the CA4 sector but only a few were present in the CA1 sector. After 4 days of recirculation calcium accumulation was visible in the whole CA1 sector and the dorso-lateral part of striate nucleus. After 10-min ischemia calcium accumulation started in these regions, as well as in the cortex, already after 1 day. In the CA1 sector calcium accumulation followed a typical time course: on day 2 only the lateral parts were affected, while on day 4 the whole CA1 neuronal band was calcium positive. The regional distribution of histological lesions matched that of calcium loading and, furthermore, the lesions appeared after a corresponding delay in the respective regions. Morphometric evaluations of calcium staining and histological lesions in the CA1 sector revealed a high correlation, indicating that calcium accumulation and neuronal death are closely associated both topically and temporally. This suggests that disturbances of calcium homeostasis such as those measured by this histochemical technique are the consequence of and not the reason for ischemic cell death.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227667
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Krebsbekämpfung, allgemeine und operative Therapie (1938)
    Springer
    Journal of cancer research and clinical oncology 47 (1938), S. 356-362 
    Details
    ISSN: 1432-1335
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01620583
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Strahlenwirkungen (1938)
    Springer
    Journal of cancer research and clinical oncology 47 (1938), S. 425-432 
    Details
    ISSN: 1432-1335
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01621057
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Microcavity dynamics during laser-induced spallation of liquids and gels (1996)
    Springer
    Applied physics 62 (1996), S. 303-311 
    Details
    ISSN: 1432-0630
    Keywords: 87.00 ; 81.60 ; 43.00
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Photomechanical fracture induced by thermoelastic stress waves is an important mechanism of tissue ablation by short laser pulses. In this study, we present experimental investigations of the fracture process in ductile, water-containing materials and compare the results with a theoretical calculation. The model describes cavitation caused by the negative part of a bipolar thermoelastic stress wave. Pulses from aQ-switched, frequency-doubled Nd:YAG laser with 8 ns duration were used to irradiate dyed water and gelatine with variable absorption coefficient. Cavitation and ablation were observed with various time-resolved methods such as stress detection, video imaging and an optical pump-probe technique for the detection of individual cavities. Quantitative agreement between experiment and simulation could be achieved in the case of cavity lifetimes, especially at low laser fluence where the bubble density is low and no coalescence takes place. An increase of the threshold energy density for ablation with rising absorption coefficient and a distortion of the thermoelastic wave in the presence of cavitation were experimentally observed and could be qualitatively explained by use of the simulation. The results obtained in this study should facilitate the choice of the optimal laser parameters for photomechanical tissue ablation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01594227
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Microcavity dynamics during laser-induced spallation of liquids and gels (1996)
    Springer
    Applied physics 62 (1996), S. 303-311 
    Details
    ISSN: 1432-0630
    Keywords: PACS: 87.00; 81.60; 43.00
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract.  Photomechanical fracture induced by thermoelastic stress waves is an important mechanism of tissue ablation by short laser pulses. In this study, we present experimental investigations of the fracture process in ductile, water-containing materials and compare the results with a theoretical calculation. The model describes cavitation caused by the negative part of a bipolar thermoelastic stress wave. Pulses from a Q-switched, frequency-doubled Nd:YAG laser with 8 ns duration were used to irradiate dyed water and gelatine with variable absorption coefficient. Cavitation and ablation were observed with various time-resolved methods such as stress detection, video imaging and an optical pump–probe technique for the detection of individual cavities. Quantitative agreement between experiment and simulation could be achieved in the case of cavity lifetimes, especially at low laser fluence where the bubble density is low and no coalescence takes place. An increase of the threshold energy density for ablation with rising absorption coefficient and a distortion of the thermoelastic wave in the presence of cavitation were experimentally observed and could be qualitatively explained by use of the simulation. The results obtained in this study should facilitate the choice of the optimal laser parameters for photomechanical tissue ablation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01594227
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Regional Hypometabolism in an Acute Model of Focal Epileptic Activity in the Rat (1995)
    Oxford, UK : Blackwell Publishing Ltd
    European journal of neuroscience 7 (1995), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Focal epileptic activity can be expected to influence distant brain areas via far reaching connections. To investigate such interactions the effects of focal epileptic activity on the metabolism of the brain were investigated in the rat cortex. Focal epileptic activity was induced by the application of penicillin onto the motor cortex. The focus, and to a lesser extent homotopic contralateral brain areas, showed an increase in the regional cerebral metabolic rate of glucose (rCMRGIc) as measured by [14C]deoxyglucose autoradiography. This focal hypermetabolism was accompanied by widespread hypometabolism lateral to the focus. The decrease of rCMRGIc occurred in somatosensory cortical areas but not in the motor cortex behind or in front of the focus, the perirhinal cortex or the occipital cortex. It was associated with an increase in metabolic rate in the ventrolateral, ventroposteromedial, ventroposterolateral and, in particular, posterior nuclei of the thalamus. It is hypothesized that the widespread reduction of rCMRGIc in the somatosensory cortical areas is due to inhibition via thalamic nuclei caused by activity in the motor cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.1995.tb01055.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Pulsed optoacoustic characterization of layered media (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 1624-1631 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Thermoelastic waves generated by absorption of short laser pulses are used to characterize the layer structure of materials. The method is based on the analysis of the distribution of absorbed laser energy from temporal profiles of recorded acoustic signals. Particularly in view of noninvasive medical applications, optoacoustic front surface transducers are investigated in this study, where irradiation of the surface and detection of the acoustic wave take place on the same side of the sample. Front surface detection of optoacoustic waves is studied theoretically and experimentally, with special emphasis on acoustic diffraction and the differences between measurements in the acoustic near and far field. In the experiments, samples with stepwise and continuously varying depth profiles of absorption coefficient were irradiated with laser pulses of 6–8 ns duration. For the detection of the acoustic waves either an optical ultrasound sensor or an annular piezoelectric film was used. Generating the optoacoustic waves with a flat top laser beam profile and detecting the signals in the acoustic near field yields optimal conditions for direct measurements of the distribution of absorbed energy and the absorption coefficient in the medium. Far field measurements are advantageous for detecting and imaging layer boundaries at large depths in the sample. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.373863
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Investigation of the probabilistic behavior of laser-induced breakdown in pure water and in aqueous solutions of different concentrations (1989)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 66 (1989), S. 4149-4153 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this paper we report on experiments to investigate the laser-induced breakdown properties of saline solutions of different concentrations and of highly deionized water, using a Q-switched Nd:YAG laser. The observation of the dependence of the breakdown probability on the pulse energy gives information about the influence of the ion concentration on the breakdown occurrence. It has turned out that the generation of initial electrons for the avalanche by the ions determines the breakdown threshold in saline solutions. In extremely pure water, with no ions as electron donors, the first free electrons have to be produced by multiphoton ionization of the water molecules, which leads to a very sharp threshold. The region of pulse energies, where breakdown occurs only with a certain probability, has its minimum width in pure water, shows its maximum extension in low concentrated solutions and is again getting narrower with increasing concentrations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.343999
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Time-resolved investigations of laser-induced shock waves in water by use of polyvinylidenefluoride hydrophones (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 63 (1988), S. 46-51 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Laser light from a Q-switched Nd:yttrium-aluminum-garnet laser (λ=1064 nm; pulse duration=20 ns; pulse energies up to 150 mJ) focused into water creates shock waves by rapidly expanding microplasmas. Using piezoelectric, thin-film polyvinylidenefluoride (PVDF) as a transducer, a broadband hydrophone (100-MHz bandwidth) was developed to investigate underwater shock waves. The electrical signal is analyzed with respect to reflections of the shock wave within the transducer and the input impedance of the measuring device. The shock waveform is determined, its peak pressure ranging to kbars (108 Pa), decreasing with r−1.12 and increases by the square root of the laser pulse energy. The time resolution of the hydrophone (4 ns) is sufficient to determine the plasma dimensions and the number of shock waves generated by a single laserpulse. Both vary statistically, primarily because of contaminations in the fluid. Because of the length of the region containing plasmas, different peak pressures are found in the direction of the laser beam and perpendicular to it.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.340461
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Optical method for two-dimensional ultrasonic detection (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 1048-1050 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Two-dimensional detection of ultrasonic waves is based on pressure-induced changes of optical reflectance at a glass–liquid interface, imaged with a time-gated video camera. The method is used to record optoacoustic waves generated after irradiation of optically absorbing targets with 6 ns long laser pulses. Measurements of absolute pressure values with high temporal and spatial resolution (in the range of 10 ns and 10 μm, respectively) is demonstrated. The sensitivity is varied between 0.19% and 0.81% gray level modulation per bar. The detector plane is optically transparent, making it possible to irradiate the sample through the detector without disturbing the acoustic measurement. Two-dimensional recording of ultrasonic waves is ideally suited for the analysis of acoustic emission from small sources and for optoacoustic imaging of optical absorption differences in an opaque material. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.124592
    Library Location Call Number Volume/Issue/Year 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...