Novel Features of Potassium and Sodium Vibrations on Copper Surfaces Observed by High-Resolution Electron-Energy-Loss Spectroscopy

High-resolution electron-energy-loss spectra of alkali metals adsorbed on Cu show three unexpected features: the adsorbate-substrate stretching frequency does not change with coverage, within 1 meV on Cu(111) and Cu(110), in agreement with the covalent picture of chemisorption; the spectra show an unusual overtone which is interpreted as a consequence of a strongly non linear relationship between the surface dipole moment and the adsorbate-substrate distance; the dynamical dipole moment is strongly coverage dependent.

Vibrational States of the Hydrogen Isotopes on Pd(111)

The ground and excited vibrational states for the three hydrogen isotopes on the Pd(111) surface have been calculated. Notable features of these states are the high degree of anharmonicity, which is most prominently seen in the weak isotopic dependence of the parallel vibrational transition, and the narrow bandwidths of these states, which imply that atomic hydrogen is localized on a particular surface site on time scales of 100 picoseconds or more. Experiments to resolve ambiguities concerning the present system are suggested.Comment: Surface Science Letters, 302, L305 (1994

Metabolism within the tumor microenvironment and its implication on cancer progression: an ongoing therapeutic target

Since reprogramming energy metabolism is considered a new hallmark of cancer, tumor metabolism is again in the spotlight of cancer research. Many studies have been carried out and many possible therapies have been developed in the last years. However, tumor cells are not alone. A series of extracellular components and stromal cells, such as endothelial cells, cancer-associated fibroblasts, tumor-associated macrophages and tumor-infiltrating T cells, surround tumor cells in the so-called tumor microenvironment. Metabolic features of these cells are being studied in deep in order to find relationships between metabolism within the tumor microenvironment and tumor progression. Moreover, it cannot be forgotten that tumor growth is able to modulate host metabolism and homeostasis, so that tumor microenvironment is not the whole story. Importantly, the metabolic switch in cancer is just a consequence of the flexibility and adaptability of metabolism and should not be surprising. Treatments of cancer patients with combined therapies including anti-tumor agents with those targeting stromal cell metabolism, anti-angiogenic drugs and/or immunotherapy are being developed as promising therapeutics.Mª Carmen Ocaña is recipient of a predoctoral FPU grant from the Spanish Ministry of Education, Culture and Sport. Supported by grants BIO2014-56092-R (MINECO and FEDER), P12-CTS-1507 (Andalusian Government and FEDER) and funds from group BIO-267 (Andalusian Government). The "CIBER de Enfermedades Raras" is an initiative from the ISCIII (Spain). The funders had no role in the study design, data collection and analysis, decision to publish or preparation of the manuscript

The Static and Dynamic Lattice Changes Induced by Hydrogen Adsorption on NiAl(110)

Static and dynamic changes induced by adsorption of atomic hydrogen on the NiAl(110) lattice at 130 K have been examined as a function of adsorbate coverage. Adsorbed hydrogen exists in three distinct phases. At low coverages the hydrogen is itinerant because of quantum tunneling between sites and exhibits no observable vibrational modes. Between 0.4 ML and 0.6 ML, substrate mediated interactions produce an ordered superstructure with c(2x2) symmetry, and at higher coverages, hydrogen exists as a disordered lattice gas. This picture of how hydrogen interacts with NiAl(110) is developed from our data and compared to current theoretical predictions.Comment: 36 pages, including 12 figures, 2 tables and 58 reference

A HREEL investigation of adsorption and dissociation of NO on a Rh(110) surface

The adsorption and dissociation of NO on a Rh(110) surface in the temperature range from 100 to 300 K has been studied by means of high-resolution electron energy loss (HREEL) spectroscopy. At 100 K only one adsorption state of NO, assigned to bridge-bonded NO species, is observed at the whole NO coverage range. The N-O stretching frequency of this species increases from 1560 to 1710 cm-1 with increasing NO coverage. NO decomposition, which occurs readily at temperatures above 170 K has been studied for NO coverages less than 0.3 of the saturated NO coverage at 100 K. The HREELS data have shown that the fraction of NO molecules which undergo dissociation increases with increasing temperature and with decreasing initial NO coverage. For the highest NO coverages considered (0.3 of saturation at 100 K) all NO molecules decompose at 240 K. A variety of loss features are observed in the HREEL spectra after decomposition of different amounts of NO. These HREEL data are explained on the basis of comparison with the HREEL spectra measured for oxygen, nitrogen and mixed oxygen and nitrogen layers on Rh(110). It has been established that the variety of loss features observed after dissociation of NO is due to different oxygen states on the surface. The observed effect of the dissociation products on the N-O stretching frequencies have heen discussed considering the factors that can account for the blue-shifts observed in the presence of electronegative surface modifiers

Identification of autoantibodies to the I protein of the heterogeneous nuclear ribonucleoprotein complex in patients with systemic sclerosis

Objective. To assess the presence of autoantibodies to the I protein (polypyrimidine-tract binding protein) of the heterogeneous nuclear RNPs (hnRNP) in different connective tissue diseases. Antibodies to other hnRNP proteins (A1, A2, and B) have been previously found in patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and mixed connective tissue disease (MCTD). Methods. Sera from 101 patients with various connective tissue diseases and 25 normal controls were investigated by enzyme-linked immunosorbent assay and immunoblotting, for their reactivity to highly purified recombinant hnRNP I. Moreover, reactivity to cellular hnRNP I protein was investigated by immunoblotting using a partially purified preparation of hnRNP proteins (including A1, A2, B, and I), and by indirect immunofluorescence. For the analysis of the fluorescence pattern, affinity-purified antibodies to hnRNP I, obtained from a selected patient, were tested on HEp-2 cells. Results. By immunoblotting, antibodies reacting to recombinant hnRNP I were found in 22 of 40 patients with systemic sclerosis (SSc), 3 of 32 with RA, 0 of 23 with SLE, and 0 of 6 with MCTD. Antibodies to recombinant hnRNP I were more frequently found in patients with pre-SSc or limited SSc (15 of 24) than in those with intermediate or diffuse SSc (7 of 16). In indirect immunofluorescence studies, affinity-purified anti-hnRNP I autoantibodies gave a diffuse nucleoplasmic staining. Using an hnRNP preparation from nuclear extracts, anti-hnRNP I reactivity was detectable in SSc sera, while it was not detectable in RA, SLE, and MCTD sera reacting with hnRNP A/B proteins. Conclusion. Human autoimmune sera show distinct patterns of anti-hnRNP reactivity, i.e., anti-A/B in SLE and RA sera, and anti-I in SSc sera. This suggests that A/B proteins and the I protein may be involved in different dynamic hnRNP complexes that elicit different autoimmune responses. From a clinical perspective, anti-hnRNP I antibodies are frequently associated with pre-SSc features, suggesting an early appearance of these antibodies during the course of the disease