241 research outputs found
Electronic properties of guanine-based nanowires
We present a first-principle study of the electronic and conduction
properties of a few classes of nanowires constituted of guanine (G) molecules,
self-assembled in different geometries. We first analyze the effect of the
vertical - interaction in model G-stack columns. Then, we exploit the
results obtained from those models to interpret the features of realistic
stacked and hydrogen-bonded structures, namely the guanine quadruple helices
and the planar ribbons. With respect to natural DNA, the different structures
as well as the inclusion of metal cations, drastically affect the bonding
pattern among the bases, introducing novel features in the electronic
properties of the systems. These supramolecular G-aggregates, alternative to
DNA, are expected to show intersting properties for molecular elec tronics
applications.Comment: 30 pages (preprint format), 8 figures. To appear in Solid State
Communications - Special Issue on "New advances on collective phenomena in
one-dimensional systems
Chemotherapy-induced ileal crypt apoptosis and the ileal microbiome shape immunosurveillance and prognosis of proximal colon cancer
The prognosis of colon cancer (CC) is dictated by tumor-infiltrating lymphocytes, including follicular helper T (TFH) cells and the efficacy of chemotherapy-induced immune responses. It remains unclear whether gut microbes contribute to the elicitation of TFH cell-driven responses. Here, we show that the ileal microbiota dictates tolerogenic versus immunogenic cell death of ileal intestinal epithelial cells (IECs) and the accumulation of TFH cells in patients with CC and mice. Suppression of IEC apoptosis led to compromised chemotherapy-induced immunosurveillance against CC in mice. Protective immune responses against CC were associated with residence of Bacteroides fragilis and Erysipelotrichaceae in the ileum. In the presence of these commensals, apoptotic ileal IECs elicited PD-1+ TFH cells in an interleukin-1R1- and interleukin-12-dependent manner. The ileal microbiome governed the efficacy of chemotherapy and PD-1 blockade in CC independently of microsatellite instability. These findings demonstrate that immunogenic ileal apoptosis contributes to the prognosis of chemotherapy-treated CC
Cost-effectiveness analysis of neonatal hearing screening program in china: should universal screening be prioritized?
Catalytic activity of nickel sulfide catalysts supported on Al-pillared montmorillonite for thiophene hydrodesulfurization
Glial contribution to excitatory and inhibitory synapse loss in neurodegeneration
Synapse loss is an early feature shared by many neurodegenerative diseases, and it represents the major correlate of cognitive impairment. Recent studies reveal that microglia and astrocytes play a major role in synapse elimination, contributing to network dysfunction associated with neurodegeneration. Excitatory and inhibitory activity can be affected by glia-mediated synapse loss, resulting in imbalanced synaptic transmission and subsequent synaptic dysfunction. Here, we review the recent literature on the contribution of glia to excitatory/inhibitory imbalance, in the context of the most common neurodegenerative disorders. A better understanding of the mechanisms underlying pathological synapse loss will be instrumental to design targeted therapeutic interventions, taking in account the emerging roles of microglia and astrocytes in synapse remodeling
Modelling human choices: MADeM and decision‑making
Research supported by FAPESP 2015/50122-0 and DFG-GRTK 1740/2. RP and AR are also part of the Research, Innovation and Dissemination Center for Neuromathematics FAPESP grant (2013/07699-0). RP is supported by a FAPESP scholarship (2013/25667-8). ACR is partially supported by a CNPq fellowship (grant 306251/2014-0)
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