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Dynamic mechanical analysis (DMA) measurements have been used for determining the viscoelastic behaviour of polystyrene (PS) nanocomposites containing a 1 wt.% of single- or multi-walled carbon nanotubes, both pristine (SWCNT and MWCNT) and modified by previous treatment with a room-temperature ionic liquid (SWCNTm and MWCNTm). Two sets of multiple frequency tests have been carried out. The Arrhenius relationship has been used to estimate the apparent activation energies for the glass transition. Master curves have been generated using the time–temperature superposition principle. The nanocomposites show an increase of the activation energy up to an 8% with respect to PS, in the order PS + MWCNT > PS + MWCNTm > PS + SWCNTm > PS + SWCNT > PS. The nanophases also induce a displacement of the onset of the storage modulus to longer times following the order PS + SWCNTm > PS + SWCNT > PS + MWCNT > PS + MWCNTm > PS, at 40 °C. At higher temperatures, the storage modulus onset is very similar for all materials. In the case of PS + SWCNTm, the period of time for the onset of the storage modulus is multiplied by a factor of 28 with respect to PS. The surface modification of the SWCNT by the ionic liquid could improve the interfacial compatibility. The results described here show that a very low proportion of carbon nanotubes can effectively improve the long-term stability of PS under service temperature conditions.

Multi-walled carbon nanotubes, both neat (MWCNT) and modified (MWCNTm) by the room-temperature ionic liquid (IL) 1-octyl-3-methylimidazolium tetrafluoroborate ([OMIM]BF4), were added in a 1 wt% to polystyrene (PS) to obtain the new nanocomposites (PS + MWCNT and PS + MWCNTm). Friction coefficients and abrasive wear from instantaneous penetration depth, residual depth and viscoelastic recovery were determined for compression-moulded materials as a function of applied normal load and of the number of successive scratches. The new nanocomposites improve the abrasion resistance of neat PS and of the analogous PS nanocomposites containing neat and IL-modified single-walled carbon nanotubes. The lowest friction coefficient and residual depth values, after 15 scratches, under the whole range of applied loads are obtained for PS + MWCNTm, with maximum reduction under the most severe conditions. The influence of sliding direction with respect to flow was studied for injection-moulded PS + MWCNTm under multiple scratching. The most severe surface damage is observed in the transverse direction to injection flow, while the lowest friction coefficient and the highest abrasion resistance and viscoelastic recovery values are obtained in the direction parallel to injection flow, due to the higher mobility of the polymer chains and the additives. Thermal analysis (DSC and TGA), Raman spectroscopy, transmission electron microscopy, X-ray diffraction and XPS surface analysis have been used as characterization techniques. XPS shows that the IL molecules are present on the nanotube surface. According to TGA, the IL content in MWCNTm can be estimated to be of a 12 wt%. Mechanisms of surface damage are discussed upon scanning electron microscopy, 3-D surface topography, surface roughness and profilometry observations.

Pristine single-walled carbon nanotubes (CNTs) were dispersed in the room-temperature ionic liquid (IL) 1-octyl, 3-methylimidazolium tetrafluoroborate ([OMIM]BF4) by grinding and ultrasounds. Excess IL was removed to obtain single-walled carbon nanotubes modified by [OMIM]BF4 (mCNTs). mCNTs were added in a 1 wt.% to polystyrene (PS), polymethylmethacrylate (PMMA) and polycarbonate (PC) to obtain PS + mCNT, PMMA + mCNT and PC + mCNT. The dry tribological performance of the new nanocomposites was studied against AISI 316L stainless steel pins and compared with that of the neat polymers and with the nanocomposites containing pristine carbon nanotubes without IL (PS + CNT; PMMA + CNT and PC + CNT). The maximum wear rate and friction coefficient reduction is obtained for PS + mCNT. Results are discussed upon the basis of optical, SEM and TEM microscopy, thermogravimetric analysis (TGA), Raman spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS).

FRIDA has been conceived as the first science instrument for the adaptive optics system of the Gran Telescopio Canarias (GTC). It is designed to be installed at the Nasmyth A platform, behind the GTC adaptive optics system. FRIDA will be a diffraction limited, near infrared imager and integral field spectrograph sensitive from 0.9 to 2.5 μm. It may also include provisions for future upgrades such as coronographic masks and long slits. FRIDA is a collaborative project between the Instituto de Astronomia, UNAM, Mexico, the Instituto de Astrofisica de Canarias, Spain, and the Astronomy Department of the University of Florida, USA.

LIF is a pleiotropic cytokine that can act as an immunomodulatory factor in different biological processes, such as embryo implantation, organ transplantation tolerance and multiple sclerosis. Here, we have observed that in tumors expressing LIF, its blockade inhibits tumor growth, and that the anti-tumor effect of LIF neutralization is mediated by the polarization of tumor-associated myeloid cells (TAMCs). LIF sustains the expression of CCL22, MRC1 and CD163 in human healthy monocytes and in TAMCs from mouse syngeneic (non-small cell lung cancer, ovarian cancer and colorectal cancer) models, patient-derived xenograft models and organotypic cultures from glioblastoma. We show that LIF blockade down-regulates CCL22 secretion by TAMCs preventing regulatory T cell and inducing effector T and NK cell tumor infiltration, leading to an increase in tumor cell apoptosis and an anti-tumor response. A positive correlation between M2-like markers and LIF expression has been observed in glioblastoma patients, and high levels of these factors confer poor prognosis. Moreover, we have studied one of the multiple mechanisms through which LIF could modulate the inhibition of effector T and NK cells: the regulation of PD-1/PDL1 axis. We have seen that after anti-LIF treatment of tumor-bearing mice, the expression of PDL1 decreases in tumor cells and in TAMCs. Furthermore, a positive correlation between PDL1 and LIF expression has been observed in glioblastoma patients, and both proteins also correlate with CD44 expression, a marker for cancer-initiating cell (CIC) population. High levels of these three factors confer poor prognosis. Thus, we have found that LIF acts as an immune-suppressor in cancer recapitulating its normal function in other biological processes. LIF is a bridge between the innate and adaptive immune responses through the induction of CCL22 in TAMCs and subsequent regulation of regulatory and effector T and NK cells. Our results identify LIF as a promising immuno-oncology therapeutic target and establish the translational potential of anti-LIF agents.

Patients with multiple sclerosis (MS) suffer with age an early immunosenescence process, which influence the treatment response and increase the risk of infections. We explored whether lipid-specific oligoclonal IgM bands (LS-OCMB) associated with highly inflammatory MS modify the immunological profile induced by age in MS. This cross-sectional study included 263 MS patients who were classified according to the presence (M+, n=72) and absence (M-, n=191) of LS-OCMB. CSF cellular subsets and molecules implicated in immunosenescence were explored. In M- patients, aging induced remarkable decreases in absolute CSF counts of CD4+ and CD8+ T lymphocytes, including Th1 and Th17 cells, and of B cells, including those secreting TNF-alpha. It also increased serum anti-CMV IgG antibody titers (indicative of immunosenescence) and CSF CHI3L1 levels (related to astrocyte activation). In contrast, M+ patients showed an age-associated increase of TIM-3 (a biomarker of T cell exhaustion) and increased values of CHI3L1, independently of age. Finally, in both groups, age induced an increase in CSF levels of PD-L1 (an inductor of T cell tolerance) and activin A (part of the senescence-associated secretome and related to inflammaging). These changes were independent of the disease duration. Finally, this resulted in augmented disability. In summary, all MS patients experience with age a modest induction of T-cell tolerance and an activation of the innate immunity, resulting in increased disability. Additionally, M- patients show clear decreases in CSF lymphocyte numbers, which could increase the risk of infections. Thus, age and immunological status are important for tailoring effective therapies in MS., This work was supported by grants FIS-PI15/00513, FIS-PI18/00572 and RD16/0015/0001 from the Instituto de Salud Carlos III. Ministerio de Ciencia e Innovación, Spain and FEDER: "Una manera de hacer Europa".