Spectroradiometric measurements of tree species in the Caspian forests of Iran

Forest type maps play a significant role in sustainable forest management. For many years aerial photos and satellite data were a primary data source supporting forest type mapping. Recent developments in remote sensing provide opportunities to further enhance forest type maps by introducing variations of spectral, biochemical and biophysical properties at various scales. A structural sampling and collection of the above variables will support an improved interfacing between spatially continuous data, forest type maps and finally will support forward and inverse modeling of advanced forest biochemical, -structural, and other relevant variables. The main objective of this study is to acquire, process and analyze spectral signatures of main forest tree species of the Caspian forest (namely Fagus orientalis, Quercus castaneifolia, Carpinus betulus, Alnus subcordata, and Parrotia persica) located in the Research Forest owned by the University of Tehran on the Northern slopes of the Elburz mountains, Iran. We have sampled 102 spectra each of the afore mentioned tree species using leaf ‘pile’ reflectance and branch pile reflectance. We build a comprehensive database of leaf optical properties, and other measures such as branch and twig reflectance. Field spectroradiometric measurements (350-2500nm) were carried out in the course of summer 2007. Spectral measurements were acquired in altitude gradients between 400-2100m (low, mid and high elevation) of the Elburz mountains. All spectral signatures after preprocessing were analyzed physically and statistically. We select a set of vegetation indices related to optical properties of the leaves and exploit changes of vegetation reflectance signature dependent on illumination conditions (shaded vs. non-shaded leaves) and chlorophyll content. We conclude that the Vogelmann index (R740/R720) is more sensitive to chlorophyll content in comparison with the other indices. It shows that hornbeam (Carpinus betulus) is significantly different in spectral signatures compared to beech (Fagus orientalis), oak, (Quercus castaneifolia) and alder (Alnus subcordata) as well as ironwood (Parrotia persica) with alder and oak being statistically differen

FcγRIIB is a T cell checkpoint in antitumor immunity

In the setting of cancer, T cells upregulate coinhibitory molecules that attenuate TCR signaling and lead to the loss of proliferative capacity and effector function. Checkpoint inhibitors currently in clinical use have dramatically improved mortality from melanoma yet are not effective in all patients, suggesting that additional pathways may contribute to suppression of tumor-specific CD8+ T cell responses in melanoma. Here, we show that FcγRIIB, an inhibitory Fc receptor previously thought to be exclusively expressed on B cells and innate immune cells, is upregulated on tumor-infiltrating effector CD8+ T cells in an experimental melanoma model and expressed on CD8+ T cells in patients with melanoma. Genetic deficiency of Fcgr2b resulted in enhanced tumor-infiltrating CD8+ T cell responses and significantly reduced tumor burden. Adoptive transfer experiments of Fcgr2b–/– tumor antigen-specific T cells into FcγRIIB-sufficient hosts resulted in an increased frequency of tumor-infiltrating CD8+ T cells with greater effector function. Finally, FcγRIIB was expressed on CD8+ memory T cells isolated from patients with melanoma. These data illuminate a cell-intrinsic role for the FcγRIIB checkpoint in suppressing tumor-infiltrating CD8+ T cells