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Neurotransmitter sensing is currently a challenge in biomedical research, and optoelectronic sensing may play an important role in this field. In particular, miniature visible-light photo-spectrometers can be very useful for molecular detection. In this respect, this work evaluates a new type of spectrometer geometry based on the grism, or grating-prism, which combines an optical grating and an optical prism. The system was first designed in either transmission or reflection geometry, and then adapted to fit commercially available components so that a prototype could be fabricated in the laboratory. The comparison with a more conventional approach shows that the grism-based spectrometer offers superior resolution as well as a smaller footprint.

We measured solar light transmitted through ice and snow cover with fiber optic probes, and examined the benefits and trade-offs of using diffusers and optics to reduce signal variations due to non-uniform illumination.

Human tumors display considerable diversity in their genetic makeup but share common physiologic attributes such as a hypoxic microenvironment that contribute to the malignant phenotype. Hypoxic cells switch from eukaryotic initiation factor 4E (eIF4E) to eIF4E2 cap-dependent translation to synthesize a portion of their proteins. Here, we show that genetically distinct human cancer cells exploit eIF4E2-directed protein synthesis to form cellular masses larger than approximately 0.15 mm, the diffusion limit of oxygen. Cancer cells depleted of eIF4E2 are indistinguishable from control cells under normoxic conditions, but are unable to survive and proliferate in low oxygen conditions. Activation of eIF4E2-directed translation is essential for cancer cells to form a hypoxic tumor core in in vitro spheroids and to form detectable tumors in in vivo xenograft assays. In contrast, the eIF4E-directed protein synthesis pathway alone cannot sustain cellular adaptation to hypoxia in vitro or confer tumorigenic potential in xenograft assays. These data demonstrate that the phenotypic expression of the cancer genome requires translation by the eIF4E2-directed hypoxic protein synthesis machinery. Cancer Res; 74(5); 1379–89. ©2014 AACR.