Structure and morphology of low mechanical loss TiO₂-doped Ta₂O₅

The exceptional stability required from high finesse optical cavities and high precision interferometers is fundamentally limited by Brownian motion noise in the interference coatings of the cavity mirrors. In amorphous oxide coatings these thermally driven fluctuations are dominant in the high index layer compared to those in the low index SiO₂ layer in the stack. We present a systematic study of the evolution of the structural and optical properties of ion beam sputtered TiO₂-doped Ta₂O₅ films with annealing temperature. We show that low mechanical loss in TiO₂-doped Ta₂O₅ with a Ti cation ratio = 0.27 is associated with a material that consists of a homogeneous titanium-tantalum-oxygen mixture containing a low density of nanometer sized Ar-filled voids. When the Ti cation ratio is 0.53, phase separation occurs leading to increased mechanical loss. These results suggest that amorphous mixed oxides with low mechanical loss could be identified by considering the thermodynamics of ternary phase formation

Structure and morphology of low mechanical loss TiO₂-doped Ta₂O₅

The exceptional stability required from high finesse optical cavities and high precision interferometers is fundamentally limited by Brownian motion noise in the interference coatings of the cavity mirrors. In amorphous oxide coatings these thermally driven fluctuations are dominant in the high index layer compared to those in the low index SiO₂ layer in the stack. We present a systematic study of the evolution of the structural and optical properties of ion beam sputtered TiO₂-doped Ta₂O₅ films with annealing temperature. We show that low mechanical loss in TiO₂-doped Ta₂O₅ with a Ti cation ratio = 0.27 is associated with a material that consists of a homogeneous titanium-tantalum-oxygen mixture containing a low density of nanometer sized Ar-filled voids. When the Ti cation ratio is 0.53, phase separation occurs leading to increased mechanical loss. These results suggest that amorphous mixed oxides with low mechanical loss could be identified by considering the thermodynamics of ternary phase formation

Deleted in Colorectal Cancer Is a Putative Conditional Tumor-Suppressor Gene Inactivated by Promoter Hypermethylation in Head and Neck Squamous Cell Carcinoma

Deleted in colorectal cancer (DCC) is a candidate tumor-suppressor gene located at chromosome 18q21. However, DCC gene was found to have few somatic mutations and the heterozygous mice (DCC+/−) showed a similar frequency of tumor formation compared with the wild-type mice (DCC+/+). Recently, DCC came back to the spotlight as a better understating of its function and relationship with its ligand (netrin-1) had shown that DCC may act as a conditional tumor-suppressor gene. We evaluated hypermethylation as a mechanism for DCC inactivation in head and neck squamous cell carcinoma (HNSCC). DCC promoter region hypermethylation was found in 75% of primary HNSCC. There was a significant correlation between DCC promoter region hypermethylation and DCC expression (assessed by immunohistochemistry; P = 0.021). DCC nonexpressing HNSCC cell lines JHU-O12 and JHU-O19 with baseline hypermethylation of the DCC promoter were treated with 5-aza-2′-deoxycytidine (a demethylating agent) and reexpression of DCC was noted. Transfection of DCC into DCC-negative HNSCC cell lines resulted in complete abrogation of growth in all cell lines, whereas additional cotransfection of netrin-1 resulted in rescue of DCC-mediated growth inhibition. These results suggest that DCC is a putative conditional tumor-suppressor gene that is epigenetically inactivated by promoter hypermethylation in a majority of HNSCC. (Cancer Res 2006; 66(19): 9401-07

Comprehensive study of amorphous metal oxide and Ta2_2O5_5-based mixed oxide coatings for gravitational-wave detectors

High finesse optical cavities of current interferometric gravitational-wave detectors are significantly limited in sensitivity by laser quantum noise and coating thermal noise. The thermal noise is associated with internal energy dissipation in the materials that compose the test masses of the interferometer. Our understanding of how the internal friction is linked to the amorphous material structure is limited due to the complexity of the problem and the lack of studies that span over a large range of materials. We present a systematic investigation of amorphous metal oxide and Ta$_2$O$_5$-based mixed oxide coatings to evaluate their suitability for low Brownian noise experiments. It is shown that the mechanical loss of metal oxides is correlated to their amorphous morphology, with continuous random network materials such as SiO$_2$ and GeO$_2$ featuring the lowest loss angles. We evaluated different Ta$_2$O$_5$-based mixed oxide thin films and studied the influence of the dopant in the optical and elastic properties of the coating. We estimated the thermal noise associated with high-reflectance multilayer stacks that employ each of the mixed oxides as the high index material. We concluded that the current high index material of TiO$_2$-doped Ta$_2$O$_5$ is the optimal choice for reduced thermal noise among Ta$_2$O$_5$-based mixed oxide coatings with low dopant concentrations

La patria grande insurgente : dignidad soberana del pensamiento plebeyo. Selección de ponencias del I Congreso de Pensamiento Político Latinoamericano

Los días 7 y 8 de octubre de 2011, el Centro de Investigaciones en Pensamiento Político Latinoamericano (CIPPLA), dependiente de la Secretaría de Investigación de la Universidad Popular Madres de Plaza de Mayo, organizó el I Congreso de Pensamiento Político Latinoamericano. Éste contó con la participación de más de trescientas personas, y a lo largo de sus dos jornadas se organizaron casi treinta foros de debate y cinco paneles de conferencias, a cargo de destacados intelectuales, dirigentes sociales, funcionarios públicos y profesionales de diversas disciplinas: Hugo Biagini, Zulma Palermo, Inés Vázquez, Florencia Saintout, Hugo Trinchero, Roberto Caballero, Norberto Galasso y Hebe de Bonafini, entre otros. Se presentaron a su vez más de cien ponencias, que abordaron variadas temáticas relacionadas con el pensamiento emancipador, los derechos humanos, el poscolonialismo, la descolonialidad, la comunicación y la educación. Este volumen reúne una selección de esos trabajos en los que, desde diversas perspectivas, se sostiene la dignidad del pensamiento plebeyo y su rol fundamental en la construcción de una Patria Grande Latinoamericana.5. Introducción 12. Fundamentación del CIPPLA 23. Frantz Fanon, los espectros y lo trágico por Alejandro De Oto & María Marta Quintana 35. La universalización de los derechos del Hombre. El ideario político de los esclavos rebeldes de Haití por Juan Francisco Martínez Peria 55. La trinidad filosófica Pueblo-Cultura-Liberación, entre la herejía y el dogma por Martín S. Forciniti 73. Descolonizar los corazones: discutiendo el modelo traumático para investigar un pasado genocida desde un presente militante por Diego Benegas Loyo 79. Polémicas culturales de los años sesenta en Cuba: historia, contextos y actualidad por María Ximena Vergara 91. Pretorianismo y femeneidad: un discurso fallido por Lilián Fernández del Moral 99. Cultura, política y modernización técnica en Kusch. Algunas observaciones por Daniel Eduardo Gutiérrez 111. La celebración del Bicentenario de México: Las razones para releer la historia por Juan José Carrillo Nieto 117. Aproximaciones históricas a los planteamientos políticos de la insugerencia colombiana por Sandra Díaz, Jenny Cristina Perdomo, Diana Ortiz y Mauricio Viloria 137. Acumulación por desposesión y democracia participativa: Excursus de una interrelación compleja en las antinomias del extractivismo argentino por Nicolás Di Genaro 145. Aproximación al pensamiento político de Agustín García Calvo por Marta Nogueroles Jové 155. Contribuciones del movimiento de los trabajadores rurales sin tierra (MTS, Brasil) en la re-conceptualización del desarrollo por Gabriel Rodrigues Lopes 169. Lecturas fanonianias sobre el armado de cuerpos por Cedriani Juan Pablo 177. Desarrollo y colonialidad: Vigencia estructural de la colonialidad en el discurso del desarrollo por Facundo Zorzoli 189. El bisturí y el megáfono por Juan Manuel Spinelli 195. Emancipaciones, resistencias y autonomías por Rebeca Peralta Mariñelarena 207. ¿Es posible, y es deseable, una ontología del oprimido? por Ezequiel Pinacchio 217. Filosofía política del movimiento obrero por Andrés Fortunato 225. La historia como discurso político por Martín López 233. Manuela Sáenz: Mujer y emancipación en el siglo XIX por Facundo Bindi 241. Des(bordes) institucionales por Mariana Serbent 253. Heterogeneidad espitémica y movimientos sociales latinomericanos por María Mercedes Palumbo y Laura Celina Vacca 275. Inflexiones de la comunidad nacional: las posiciones de la particularidad en el pensamiento de Carlos Astrada por Juan Antonio Delgado de la Rosa 283. Las dos caras de la dignidad por Diego Adrián Perez Sosa 287. ¿La Vida de quién? por Nayibe Agudelo Piza 295. Unfluencia de Esteban Echeverría en el diseño global imperial. Reflexiones desde el pensamiento descolonial por Soledad Ramati y María Mercedes Palumbo 303. La revolución boliviana de 1952 por Federico Li Rosi 311. El lenguaje y el derecho por Liliana Lisanti 319. Notas sobre el derecho por rodolfo Enrique Peláez 327. Nación y otredad: apuntes sobre la invención de lo extraño y peligroso en la Argentina moderna por Martín e. Díaz 337. La integración regional desde el pensamiento latino americano por Lucila Melendi 347. Pensar desde América Latina: arte y política por Carolina Wajnerma

GULP1, a potential tumor suppressor gene in ovarian tumors and its utility as a biomarker

Identification of tumor suppressor genes (TSGs) silenced by CpG methylation uncovers the molecular mechanism of tumorigenesis and potential tumor biomarkers. GULP1, a molecule not previously related to cancer, is a cytoplasmic adaptor protein with a phosphotyrosine binding domain that plays a role in one of two partially redundant pathways that lead to the engulfment and clearance of apoptotic cells, according to several genetic studies performed in Caenorhabditis elegans. Performing a pharmacologic unmasking technique we observed that this molecule is downregulated in ovarian tumor tissues when compared to normal ovary. Ovarian cancer is the leading cause of death among gynaecological cancers worldwide, this due to the fact that women are diagnosed with advanced stage disease and because of the lack of truly sensitive/specific screening techniques and unavailability of individualized therapy. We performed an expression microarray on 15 ovarian tumor samples, 10 ovarian normal surface epithelium, 3 ovarian cancer cell lines and 3 normal cell lines. All cells have been treated with a demethylating agent which comprehensively uncovers genes silenced by promoter hypermethylation. The selection of the best candidates was based upon the differential expression between normal and tumor samples (or cell lines), them being downregulated in cancer when compared to normal, and finally the re-activation after the treatment with the demethylating agent. One of these promising genes was GULP1, which expression pattern was then assessed by Reverse Transcriptase PCR and Western Blot and compared to its methylation status in the same six ovarian cell lines and showed correlation between absence of expression and presence of methylation (or the opposite situation). We developed quantitative fluorogenic methylation specific PCR (QMSP) for GULP1 and profiled 437 ovarian tumor samples, 17 borderline tumors, 19 cystadenoma samples and 13 normal ovarian samples, finding 34.7% (151/437), 11.7% (2/17), 10.5% (2/19) and 0% (0/13) of methylation frequency, respectively, (establishing an empiric cutoff). Using fisher´s exact test, we observe a significant increase in methylation when comparing tumors with cystadenomas and normals (p=0.0439 and p=0.0131, respectively). Late stage tumors also showed a higher frequency of methylation versus early stage (p=0.004). So far, we have demonstrated reduced log growth rates after transiently overexpressing GULP1 in one ovarian cell line (IGROVCP). To assess its potential as a TSG, we have ongoing experiments to assess its biological function as ectopic overexpression of this gene in ovarian cancer cell lines as well as creating knock downs using shRNAs. These preliminary data indicate that GULP1 may be an ovarian cancer biomarker. Further studies on the biology of this gene are needed to evaluate its potential as a TSG and its role in ovarian cancer carcinogenesis