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These data confirm the presence of increased oxidative stress and immune activation in ALS patients. HNE is also suggested as a possible biomarker of disease.

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New 3.3-3.6 µm spectra were obtained of nine young stellar objects embedded in molecular clouds. An absorption feature at ∼3.47 µm (2880 cm −1 ) with FWHM∼0.09 µm (80 cm −1 ), first identified by Allamandola et al. (1992), was definitively detected toward seven objects, and marginally in the other two. The feature is better correlated with H 2 O ice than with the silicate dust optical depth in the data obtained to date. Assuming the feature is due to a C-H stretch absorption, the abundance of the C-H bonds averaged along the lines of sight is closely related to that of H 2 O ice. We interpret the correlation with H 2 O ice as indicating that the C-H bonds form together with H 2 O ice on grain surfaces in the molecular clouds, though other formation mechanisms are not ruled out. A second absorption feature at 3.25 µm (3080 cm −1 ) was detected toward NGC7538/IRS 1 and S140/IRS 1; this feature was first detected in spectra of MonR2/IRS 3 (Sellgren, Smith, & Brooke 1994;Sellgren et al. 1995). There is as yet insufficient data to tell whether this feature is better correlated with H 2 O ice or silicates.

A marker of lipid peroxidation 4-hydroxynonenal (HNE) was elevated in the cerebrospinal fluid (CSF) of a patient with sporadic amyotrophic lateral sclerosis (sALS) compared with that of most patients with other neurological diseases. Such elevations of HNE were sufficient to kill cyclic adenosine monophosphate (cAMP)-differentiated motor neuron hybrid cells in vitro, and anti-oxidants prevented this HNE-dependent cell death. These data suggest that oxidative stress and lipid peroxidation are associated with and may promote motor neuron degeneration in sALS.

A new 3.2-3.5 µm spectrum of the protostar Mon R2/IRS-3 confirms our previous tentative detection of a new absorption feature near 3.25 µm. The feature in our new spectrum has a central wavelength of 3.256 µm (3071 cm −1 ) and has a full-width at half maximum of 0.079 µm (75 cm −1 ). We explore a possible identification with aromatic hydrocarbons at low temperatures, which absorb at a similar wavelength. If the feature is due to aromatics, the derived column density of C-H bonds is ∼1.8 × 10 18 cm −2 . If the absorbing aromatic molecules are of roughly the same size as those responsible for aromatic emission features in the interstellar medium, then we estimate that ∼9% of the cosmic abundance of carbon along this line of sight would be in aromatic hydrocarbons, in agreement with abundance estimates from emission features.

ContributorsGIW wrote and revised the manuscript in response to co-author comments. He finalized all the figures and tables, performed the literature search, and assisted with data interpretation. HJK critically reviewed the manuscript and made important suggestions to improve it. He assisted with data interpretation. IBA performed the data analysis, constructed the figures and tables, and made important suggestions to improve the manuscript. H-CK assisted with the data analysis and also reviewed the manuscript. GRC critically reviewed the manuscript and made important suggestions to improve it. He assisted with data interpretation. All other authors were given the opportunity to review the manuscript and make suggestions which GIW received, either revising the paper or providing explanations. All who are not deceased were involved with approval of the manuscript.

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