Optical links from a spacecraft at planetary distances to a ground-based receiver presume a cloud-free line of sight (CFLOS

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Background: Central nervous system involvement is uncommon in patients with sarcoidosis. It remains a diagnostic challenge for clinicians, as there is a broad differential diagnosis that matches the presenting neurological signs. Often, the imaging findings also overlap with other disease entities. One understudied finding in patients with neurosarcoidosis is the presence of medullary vein engorgement on SWI imaging, termed the “medullary vein sign”, which has been postulated to be a specific sign for neurosarcoidosis. This study aims to provide an understanding of the diagnostic potential of the medullary vein sign. Methods: Thirty-two patients who presented with neurologic signs concerning for possible neurosarcoidosis were analyzed retrospectively for the presence of the medullary vein sign. Results: Out of these cases, 7 cases of definitive neurosarcoidosis cases were found based on other imaging signs, biopsy and CSF analysis; the remaining were classified into groups as possible (16), probable (5) and (4) cases of other infectious meningoencephalitis including 2 cases of autoimmune encephalitis. Seven patients among all of these cases were found to have the medullary vein sign on imaging, with five cases with confirmed and two cases from possible neurosarcoidosis. The sensitivity of the medullary vein sign in this study was 71.4%, and the specificity was 92.3%. Discussion: The benefits of improving diagnostic criteria for neurosarcoidosis include more rapid diagnosis leading to more prompt treatment, less exposure to potentially harmful antibiotics or antifungals, and less long-term neurological effects. Our results support that the medullary vein sign will potentially fill in the diagnostic gaps that have challenged the timely diagnosis of neurosarcoidosis. Conclusions: Our findings support that the medullary vein sign has a high specificity and should be included in the diagnostic criteria for neurosarcoidosis.

We report direct evidence of living anions of 2‐vinylpyridine and 4‐vinylpyridine for the first time to the authors' knowledge on the basis of in situ Raman spectral observations during a living anionic polymerization reaction. The former is characterized by a band at 1607 cm−1 and the latter at 1622 cm−1. A titration experiment was carried out by adding multiple aliquots of 4‐vinylpyridine into a solution containing 2‐vinylpyridine anions. Systematic spectral changes for the aforementioned bands provided convincing evidence for such spectral assignments. These assignments are supported by electronic structure calculations of the monomers and anions. Both anions showed large Raman cross sections, which allowed them to be detected at relatively low concentrations. Such Raman bands will enable facile in situ monitoring of the anionic species and thus can be useful for process development and optimization. Copyright © 2017 John Wiley & Sons, Ltd.

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