Tumor markers in T1-T2 laryngeal squamous cell carcinoma:Considerations on a clinical and biological level

Early stage laryngeal cancer is predominantly treated with radiotherapy. However, in 40% of these patients the tumor does not respond or returns after a while. Often an extensive surgical procedure is the only remaining curative option, at a regular basis accompanied by wound complications, a long hospital admittance and even impaired survival. For that reason, lots of research is focused on tumor markers. Tumor markers are proteins in tumor cells with which potentially tumors that will not react well to radiotherapy can be identified. These tumors might need an alternative and more aggressive treatment. Previously, research focusing on tumor markers in early-stage laryngeal cancer of the vocal cords (glottis) demonstrated a predictive value for the efficacy of radiotherapy in the case of, amongst others, HIF-1a, CA-IX, pFADD. Jan Edward Wachters evaluated the predictive value of these markers in a comparable group of patients with early stage laryngeal cancer, originated in the area just above the glottis, the supraglottis. He demonstrated that these tumor markers in this area did not show any predictive significance. On the other side, Wachters demonstrated that the expression of PTEN, a key protein involved in DNA-repair, did have predictive value in early stage cancer of the supraglottis. It has been known that early-stage cancer of the glottis and supraglottis demonstrate clinical and epidemiological differences. Wachters has shown that these 2 types of tumor have molecular and tumor biological differences as well. These findings can have consequences for the interpretation of earlier reported results of tumor marker research and for the study designs, focusing on tumor markers, in the future

Heisenberg exchange enhancement by orbital relaxation in cuprate compounds

We calculate the Heisenberg exchange J in the quasi-2D antiferromagnetic cuprates La2CuO4, YBa2Cu3O6, Nd2CuO4 and Sr2CuO2Cl2. We apply all-electron (MC)SCF and non-orthogonal CI calculations to [Cu2O11]18-, [Cu2O9]14-, [Cu2O7]10- and [Cu2O7Cl4]14- clusters in a model charge embedding. The (MC)SCF triplet and singlet ground states are well characterized by Cu2+ (dx2-y2) and O2-. The antiferromagnetic exchange is strongly enhanced by admixing relaxed (MC)SCF triplet and singlet excited states, in which a single electron is transferred from the central O ion to Cu. We ascribe this effect to orbital relaxation in the charge transfer component of the wave function. Close agreement with experiment is obtained.Comment: publishe

DFT Calculations as a Tool to Analyse Quadrupole Splittings of Spin Crossover Fe(II) complexes

Density functional methods have been applied to calculate the quadrupole splitting of a series of iron(II) spin crossover complexes. Experimental and calculated values are in reasonable agreement. In one case spin-orbit coupling is necessary to explain the very small quadrupole splitting value of 0.77 mm/s at 293 K for a high-spin isomer

A Theoretical Study on a Reaction of Iron(III) Hydroxide with Boron Trichloride by Ab Initio Calculation

We investigate a reaction of boron trichloride (BCl3) with iron(III) hydroxide (Fe(OH)3) by ab initio quantum chemical calculation as a simple model for a reaction of iron impurities in BCl3 gas. We also examine a reaction with water. We find that compounds such as Fe(Cl)(OBCl2)2(OHBCl2) and Fe(Cl)2(OBCl2)(OHBCl2) are formed while producing HCl and reaction paths to them are revealed. We also analyze the stabilization mechanism of these paths using newly-developed interaction energy density derived from electronic stress tensor in the framework of the Regional DFT (Density Functional Theory) and Rigged QED (Quantum ElectroDynamics).Comment: 21 pages, 12 figure

Nuclear Resonance Vibrational Spectroscopy of Iron Sulfur Proteins

Nuclear inelastic scattering in conjunction with density functional theory (DFT) calculations has been applied for the identification of vibrational modes of the high-spin ferric and the high-spin ferrous iron-sulfur center of a rubredoxin-type protein from the thermophylic bacterium Pyrococcus abysii

Ab initio correlation approach to a ferric wheel-like molecular cluster

We present an ab initio study of electronic correlation effects in a molecular cluster derived from the hexanuclear ferric wheel [LiFe6(OCH3)12-(dbm)6]PF6. The electronic and magnetic properties of this cluster have been studied with all-electron Hartree-Fock, full-potential density functional calculations and multi-reference second-order perturbation theory. For different levels of correlation, a detailed study of the impact of the electronic correlation on the exchange parameter was feasible. As the main result, we found that the influence of the bridge oxygen atoms on the exchange parameter is less intense than the influence of the apical ligand groups, which is due to the geometry of the cluster. With respect to the cluster model approach, the experimental value of the exchange parameter was affirmed.Comment: to be published in EPJ