ABSTRACT
INTRODUCTION: Prison inmates are known to be more exposed to various lung cancer risk factors, and some studies have shown that lung cancer is the most common cancer in prisoners. However, no study has particularly focused on lung cancer features in this population. METHOD: Charts of patients with lung cancer hospitalized in one of the French secured hospital units between 1997 and 2012 were reviewed. Data from this cohort were then compared to those of two large observational studies conducted in 2000 and 2010 (KBP studies). RESULTS: Thirty-two cases were included. All were men. The mean age was 52.2 ± 11.5 years, which was significantly lower than in the KBP-2000 (64.4 years) and KBP-2010 (65.5 years; both p < 0.0001) studies. The percentage of current smokers was much higher in prisoners (87.1 vs. 52.2 and 49.2%, respectively; both p < 0.001). Ninety percent of prisoners presented with at least one comorbidity. Lung cancer clinical presentation did not differ between prisoners and the reference populations. The median overall survival was 5.8 months (range 0-15.1) for all stages and 4.7 months (range 2.8-6.6) for stage IIIB/IV. CONCLUSION: Although our study suffers from limitations, prisoners seem to develop lung cancer at a younger age and their prognosis is poor.
Subject(s)
Lung Neoplasms/mortality , Adult , Aged , Humans , Lung Neoplasms/pathology , Male , Middle Aged , Neoplasm Staging , Prisoners , Prognosis , Retrospective StudiesABSTRACT
We report on the first simultaneous observations of both electronic and structural temperature-induced insulator-to-metal transition (IMT) in VO2 ultrathin films, made possible by the use of broad range transmission infrared spectroscopy. Thanks to these techniques, the infrared phonon structures, as well as the appearance of the free carrier signature, were resolved for the first time. The temperature-resolved spectra allowed the determination of the temperature hysteresis for both the structural (monoclinic-to-rutile) and electronic (insulator-to-metallic) transitions. The combination of these new observations and DFT simulations for the monoclinic structure allows us to verify the direct transition from monoclinic (M1) to rutile and exclude an intermediate structural monoclinic form (M2). The delay in structural modification compared to the primer electronic transition (325 K compared to 304 K) supports the role of free charges as the transition driving force. The shape of the free charge hysteresis suggests that the primer electronic transition occurs first at 304 K, followed by both its propagation to the heart of the layer and the structural transition when T increases. This study outlines further the potential of VO2 ultrathin films integrated on silicon for optoelectronics and microelectronics.
ABSTRACT
We have performed ab initio linear combination of atomic orbitals-density functional theory calculations on biperiodic supercells to model the electronic and geometrical involvements of Ti intercalated atom in either octahedral or tetrahedral sites of the (001) TiS2 surfaces. For each type of defect, both the relaxed atomic structure and the electronic properties of the defect states were carefully analyzed. For the titanium atom in the van der Waals gap, the partial filling of the conduction band is in agreement with the metallic behavior reported by experimental studies and the last filled states in the bottom of the conduction band--mainly developed on titanium 3d orbitals--permit us to explain the dark defects observed on the scanning tunneling microscopy image of the (001) TiS2 surfaces. On the other hand, the intercalated titanium atom in the tetrahedral site which is just below the top sulfur atom plane governs the electronic density detected by the tip. It permits us to explain the triangular defect with a clear maximum of intensity in its center and dark sides.
ABSTRACT
Various defects--either bright or dark triangular defects--are observed on the (001) titanium disulfide surface by ultrahigh vacuum scanning tunneling microscopy. The experimental interpretations of the images available in the literature suggest that a fraction of Ti atoms could be displaced from the octahedral site they occupied to vacant sites of the crystal structure, leading to more or less correlated defects. In this paper, the authors have performed ab initio periodic linear combination of atomic orbitals-generalized gradient approximation (LCAO-GGA) calculations on (5x5) and (4x4) biperiodic supercells to model the electronic and geometrical involvements of Ti vacancy. The relaxed atomic structures of each system and the wave-function character of the defect states are carefully analyzed before the theoretical scanning tunneling microscopy images are generated within the Tersoff-Hamann approximation. The relaxed structure of the Ti vacancy shows an inward movement of the neighboring sulfur atoms at the surface. However, the occupied electronic states of the vacancy at the Fermi level are mainly developed on the atomic orbitals of the first sulfur neighbors at the surface, leading to bright triangular zones on the simulated image.
