Attenuated total reflection (ATR) spectroscopy is now the most popular sampling technique for the measurement of infrared spectra of condensed phase samples. Most practitioners of ATR spectroscopy use the equation for depth of penetration, d(p), to estimate the path length of the evanescent wave through the sample. However, the effective path length, d(e), of the evanescent wave in an ATR measurement, i.e., the equivalent path length in a transmission measurement that would lead to an absorption band of the same intensity, is a more accurate metric than d(p). In measurements designed to obtain the absorptivity of bands in the spectrum of a strongly absorbing viscous liquid, we have shown that the refractive index used in the expressions for d(e) must be modified to take into account the effect of anomalous dispersion before accurate effective path lengths and band absorptivities can be measured.

Background. The authors previously have shown by gas chromatography‐mass spectrometry that the hydroxyl radical (.OH) induces alterations in the DNA base structure of the female breast, which are premalignant markers of breast cancer. Fourier transform‐infrared (FT‐IR) spectroscopy also has a high potential for revealing a broad array of structural changes in DNA that may provide important new insight into breast cancer etiology and prediction. Methods. DNA from normal reduction mammoplasty tissue, invasive ductal carcinoma, and nearby microscopically normal tissue was analyzed by FT‐IR spectroscopy. Statistical models based on DNA spectral properties were developed and compared with a statistical model previously used with base modifications. Results. Substantial differences were found in the spectral properties of DNA from women with normal and cancerous breast tissue, indicating an ability to discriminate cancerous tissue from noncancerous tissue with a sensitivity and specificity of 83%. Most importantly, the normal population was divided into subgroups in which a nonrandom progression was identified and a cancer‐like DNA phenotype that was highly correlated (r ⩾ 0.90) with that of the patients with cancer was exhibited in 59% of the women. The spectral data, which also were highly correlated with the base‐model data, were used to establish a model for predicting the probability of breast cancer. Consistent with the high cancer reoccurrence rate in the ipsilateral breast, 8 of 10 of the microscopically normal tissue specimens remaining after tumor excision were classified as cancerous using this model. Conclusions. Progressive structural changes in the DNA of the normal female breast, leading to a premalignant cancer‐like phenotype in a high proportion of women, are the basis for a new paradigm for understanding the etiology of breast cancer and predicting its occurrence at early stages of oncogenesis. The results also suggest therapeutic strategies for potentially reversing the extent of DNA damage, which may be useful in disease prevention and treatment. Cancer 1995;75:503‐17.

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We present far-ultraviolet (FUV) spectral imaging observations of the Vela supernova remnant (SNR) obtained with the SPEAR/FIMS instrument. The Vela SNR extends ∼8Њ in the FUV, and its global spectra are dominated by shock-induced emission lines. We find that the global FUV line luminosities can exceed the 0.1-2.5 keV soft X-ray luminosity by an order of magnitude. The global O vi : C iii ratio shows that the Vela SNR has a relatively large fraction of slower shocks compared with the Cygnus Loop.

A B S T R A C T The membrane organization of the erythrocytes from patients with Duchenne muscular dystrophy was studied by means of electron spin resonance. The fluiidity of the membrane near the polar region of Duchenine muscular dystrophy ervthrocytes was similar to that of normal erythrocytes. The membrane environment in the nonpolar region, however, was quite different from that of normal erythrocytes, judged by the spectra with 2-(14-carboxytetradecyl) -2 -ethyl -4,4 -dimethyl -3 -oxazolidinvloxyl as probe. The temperature dependence of the ratio of the line height of central field to that at the low field showed two inflection points in normal erythrocytes at pH 7.4 (13.5°-16.5°and 37.5°-40.5°C, respectively) but the inflection point in the lower temperature range was not detected in Duchenne muscular dystrophy erythrocytes. When pH was varied, an abrupt decrease in the ratio was observed at pH 5.9-5.6 in normal erythrocytes whereas there was a gradual decrease over the range of pH from 6.6 to 5.0 in Duchenne muscular dystrophy erythrocytes.The rate of reduction of the radical 2-(3-carboxypropyl)-4,4-dimethyl-2-tridecyl-3-oxazolidinyloxyl by ascorbate in normal erythrocytes was faster than that in Duchenne muscular dystrophy erythrocytes. Treatment of both erythrocytes with phloretin markedly reduced the rate of reduction by ascorbate and eliminated the difference in the two types of erythrocyte. These results indicate that in Duchenne muscular dystrophy the erythrocyte membrane is involved as well as the muscle cell.

The SPEAR (or 'FIMS') instrumentation has been used to conduct the first large-scale spectral mapping of diffuse cosmic far ultraviolet (FUV, 900-1750 AA) emission, including important diagnostics of interstellar hot (10^4 K - 10^6 K) and photoionized plasmas, H_2, and dust scattered starlight. The instrumentation's performance has allowed for the unprecedented detection of astrophysical diffuse far UV emission lines. A spectral resolution of 550 and an imaging resolution of 5' is achieved on-orbit in the Short (900 - 1175 AA) and Long (1335 - 1750 AA) bandpass channels within their respective 7.4 deg x 4.3' and 4.0 deg x 4.6' fields of view. We describe the SPEAR imaging spectrographs, their performance, and the nature and handling of their data

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Polarized reflectance spectra of the organic superconductors protonated and deuterated~-(BEDT-TTF)2[Cu(NCS)2] (H and D salts) [BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene] were measured over the range from 500 to 28000 cm ' at room temperature with light polarizations parallel to the crystallographic b and c axes which lie on the two-dimensional conducting plane. Polarized reflectance spectra of the organic superconductor P-(BEDT-TTF)2I3 and the organic metal P"-(BEDT-TTF)2AuBr2 were also measured in order to discuss the influence of different molecular arrangements and hydrogen-anion contacts on the electronic and vibrational properties of these salts. Frequency-dependent conductivities were calculated by a Kramers-Kronig transforrnation. By comparison of the infrared conductivity spectra of the H and D salts, the vibrational transitions induced by electronmolecular-vibration {EMV) coupling were clearly distinguished from the carbon-hydrogen bending modes of the BEDT-TTF moiety. A Drude-Lorentz dielectric function was used to evaluate the optical transport parameters and an excitation frequency of the charge-transfer {CT) band superimposed on a plasma-edge-like dispersion which was observed for each compound. The EMV-coupling energies are semiquantitatively estimated to be ca. 70 meV for both the H and D salts from the frequencies of the EMV coupling transition and the CT band in terms of the dimer charge-oscillation model. By use of the coupling energy, various parameters describing the superconducting state were evaluated and discussed on the basis of the BCS theory in a weak-coupling limit. Finally, the magnitudes of hydrogen-anion interaction were estimated from the frequency shifts of the C -H bending modes of the BEDT-TTF moiety.