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  • 1
    Electronic Resource
    Electronic Resource
    FT-IR photoacoustic depth profiling spectroscopy of enamel (1994)
    Springer
    Calcified tissue international 54 (1994), S. 481-485 
    Details
    ISSN: 1432-0827
    Keywords: Fourier transform infrared spectroscopy ; Photoacoustic spectroscopy ; Depth profile ; Enamel ; Carbonate ; Phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Photoacoustic Fourier transform infrared (PA-FT-IR) depth profiling spectra of the enamel of an intact human tooth are obtained in a completely nondestructive fashion. The compositional and structural changes in the tissue are probed from the enamel surface to a depth of about 200 μm. These changes reflect the state of tissue development. The subsurface carbonate gradient in the enamel could be observed over the range of about 10–100 μm. The carbonate-to-phosphate ratio increases in the depth profile. The depth profile also reveals changes in the substitutional distribution of carbonate ions. Type A carbonates (hydroxyl substituted) increase relative to type B carbonates (phosphate substituted) with increasing thermal diffusion length. In addition to the changes in the carbonate ion distribution and content, the PA-FT-IR depth profile clearly indicates a dramatic increase in the protein content relative to the phosphate content with increased depth. The changes in the carbonate content and distribution, along with the changes in the protein content, may be responsible for the changes observed in the apatitic structure in the depth profile of the enamel.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334328
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  • 2
    Electronic Resource
    Electronic Resource
    Arthritis diagnosis based upon the near-infrared spectrum of synovial fluid (1995)
    Springer
    Rheumatology international 15 (1995), S. 159-165 
    Details
    ISSN: 1437-160X
    Keywords: Near-infrared spectroscopy ; Arthritis ; Diagnosis ; Synovial fluid ; Analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Synovial fluid aspirates have been characterized by measuring their visible/near-infrared spectra (400–2500 nm). The hypothesis tested in this study is that the spectra contain sufficient information to serve as an aid in the diagnosis and/or staging of arthritic disorders. The concentrations of all major constituents are carried implicitly in the spectra, and in this sense this approach is similar in spirit to conventional synovial fluid analysis. The distinguishing feature of this method is that we have not converted the raw data (spectra) explicitly to analytical information. Rather, we have used automated pattern recognition methods to identify significant characteristics of the spectra themselves. A total of 109 spectra were measured and split into three classes according to the disease (osteoarthritis, rheumatoid arthritis, or spondyloarthropathy) affecting the patient from whom the synovial fluid sample was taken. An automated classification method was then trained by correlating features derived from these spectra to the clinical diagnoses. The robustness of the classification was validated using the leave-one-out cross-validation method, i.e., by training on all but one of the spectra and using the resulting model to predict the classification for the spectrum that is left out. The result derived by following this procedure for each of the spectra was that 105 of the 109 predicted classifications correctly matched the clinical diagnosis. These results suggest that the near-infrared spectrum of synovial fluid is sufficient to allow diagnosis of the disease affecting the joint from which the aspirate is drawn.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00301774
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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