2,552 research outputs found
An X-ray study of the SNR G344.7-0.1 and the central object CXOU J170357.8-414302
Aims. We report results of an X-ray study of the supernova remnant (SNR)
G344.7-0.1 and the point-like X-ray source located at the geometrical center of
the SNR radio structure. Methods. The morphology and spectral properties of the
remnant and the central X-ray point-like source were studied using data from
the XMM-Newton and Chandra satellites. Archival radio data and infrared Spitzer
observations at 8 and 24 m were used to compare and study its multi-band
properties at different wavelengths. Results. The XMM-Newton and Chandra
observations reveal that the overall X-ray emission of G344.7-0.1 is extended
and correlates very well with regions of bright radio and infrared emission.
The X-ray spectrum is dominated by prominent atomic emission lines. These
characteristics suggest that the X-ray emission originated in a thin thermal
plasma, whose radiation is represented well by a plane-parallel shock plasma
model (PSHOCK). Our study favors the scenario in which G344.7-0.1 is a 6 x 10^3
year old SNR expanding in a medium with a high density gradient and is most
likely encountering a molecular cloud on the western side. In addition, we
report the discovery of a soft point-like X-ray source located at the
geometrical center of the radio SNR structure. The object presents some
characteristics of the so-called compact central objects (CCO). However, its
neutral hydrogen absorption column (N_{H}) is inconsistent with that of the
SNR. Coincident with the position of the source, we found infrared and optical
objects with typical early-K star characteristics. The X-ray source may be a
foreground star or the CCO associated with the SNR. If this latter possibility
were confirmed, the point-like source would be the farthest CCO detected so far
and the eighth member of the new population of isolated and weakly magnetized
neutron stars.Comment: 9 pages, 8 figures, accepted for publication in Astronomy and
Astrophysics. Higher resolution figures can be seen on A&
Legal evidence: a realistic approach
The issue of the veracity of legal claims and its consequences is based, first and foremost, on the study of legal philosophy. This article explores the substantivity of judicial evidence from the perspective of classical legal realism, as a key mechanism against claims of truth and the different models of truth from different positions. Judicial decisions go through ontological and definitive interpretations of what is fair and right, in relation to judicial evidence, through the exercise of legal science by the jurist.El problema del potencial de verdad de las afirmaciones jurídicas y de sus consecuencias tiene como sustrato primero y primordial los problemas de la filosofía del derecho: su objeto de estudio. Se explora aquí, desde la perspectiva del realismo jurídico clásico, la sustantividad de la prueba judicial como mecanismo decisivo frente a las distintas posiciones respecto a las "pretensiones de verdad" en el derecho y los distintos modelos de verdad. Por ello, la decisión jurídica pasa por una interpretación ontológica y definitiva de lo "justo", lo debido, en relación con la prueba judicial, por medio del ejercicio de la ciencia práctica del "derecho" por parte del jurista
Non-Singlet Structure Functions at Three Loops: Fermionic Contributions
We compute the fermionic (n_f) contributions to the flavour non-singlet
structure functions in unpolarized electromagnetic deep-inelastic scattering at
third order of massless perturbative QCD. Complete results are presented for
the corresponding nf-parts of the three-loop anomalous dimension and the
three-loop coefficient functions for the structure functions F_2 and F_L. Our
results agree with all partial and approximate results available in the
literature. The present calculation also facilitates a complete determination
of the threshold-resummation parameters B_2 and D_2^DIS of which only the sum
was known so far, thus completing the information required for the
next-to-next-to-leading logarithmic resummation. We find that D_2^DIS vanishes
in the MSbar scheme.Comment: 20 pages, LaTeX, 1 eps-figur
¿Qué significa tener derechos?
En el presente trabajo daremos a conocer el concepto y la importancia de los derechos humanos en la vida de cada persona desde un punto de vista reflexivo y analítico, tomando como referencia los aportes de algunos filósofos y escritores influyentes de diferentes épocas, los cuales serán de gran ayuda para tener una percepción más clara de estos términos y comprender las raíces de estos. El punto de partida al abarcar temas como la realidad jurídica en el derecho no siempre será la razón, por lo que para definir “derecho” encontramos diferentes alternativas; si nos ubicamos en el concepto de derecho natural logramos observar una gran cantidad de tesis contradictorias las cuales nos introducen en un debate, partiendo de las diferentes posturas que toman los autores que serán citados. Por otra parte, los derechos humanos, hacen referencia a aquellos principios o normas que tienen la intención de proteger e identificar el valor humano y a consecuencia de esto son parte de la dignidad intrínseca e inherente del ser humano. El Estado actúa sobre las personas, por lo que tiene el deber de asegurar que toda la sociedad goce de estos y que en ninguna circunstancia se vean vulnerados. Es esencial tener en cuenta la interpretación que le daremos a los derechos humanos, lo cual es fundamental para no abusar en ningún momento de dichos privilegios; sin una buena interpretación se incrementarían las problemáticas sociales. La interpretación va ligada a la comprensión, por lo que se requiere un razonamiento lógico para entender en qué momento termina la libertad de un individuo para iniciar la de otro, así como lo deja claro el filósofo Jean Paul-Sartre “Mi libertad se termina dónde empieza la de los demás”
Intercellular Trafficking of Gold Nanostars in Uveal Melanoma Cells for Plasmonic Photothermal Therapy
Efficient plasmonic photothermal therapies (PPTTs) using non-harmful pulse laser irradiation at the near-infrared (NIR) are a highly sought goal in nanomedicine. These therapies rely on the use of plasmonic nanostructures to kill cancer cells while minimizing the applied laser power density. Cancer cells have an unsettled capacity to uptake, retain, release, and re-uptake gold nanoparticles, thus offering enormous versatility for research. In this work, we have studied such cell capabilities for nanoparticle trafficking and its impact on the effect of photothermal treatments. As our model system, we chose uveal (eye) melanoma cells, since laser-assisted eye surgery is routinely used to treat glaucoma and cataracts, or vision correction in refractive surgery. As nanostructure, we selected gold nanostars (Au NSs) due to their high photothermal efficiency at the near-infrared (NIR) region of the electromagnetic spectrum. We first investigated the photothermal effect on the basis of the dilution of Au NSs induced by cell division. Using this approach, we obtained high PPTT efficiency after several cell division cycles at an initial low Au NS concentration (pM regime). Subsequently, we evaluated the photothermal effect on account of cell division upon mixing Au NS-loaded and non-loaded cells. Upon such mixing, we observed trafficking of Au NSs between loaded and non-loaded cells, thus achieving effective PPTT after several division cycles under low irradiation conditions (below the maximum permissible exposure threshold of skin). Our study reveals the ability of uveal melanoma cells to release and re-uptake Au NSs that maintain their plasmonic photothermal properties throughout several cell division cycles and re-uptake. This approach may be readily extrapolated to real tissue and even to treat in situ the eye tumor itself. We believe that our method can potentially be used as co-therapy to disperse plasmonic gold nanostructures across affected tissues, thus increasing the effectiveness of classic PPTT
A gene signature derived from the loss of cdkn1a (P21) is associated with CMS4 colorectal cancer
The epithelial–mesenchymal transition (EMT) is associated with tumor aggressiveness and increased invasion, migration, metastasis, angiogenesis, and drug resistance. Although the HCT116 p21-/- cell line is well known for its EMT-associated phenotype, with high Vimentin and low E-cadherin protein levels, the gene signature of this rather intermediate EMT-like cell line has not been determined so far. In this work, we present a robust molecular and bioinformatics analysis, to reveal the associated gene expression profile and its correlation with different types of colorectal cancer tumors. We compared the quantitative signature obtained with the NanoString platform with the expression profiles of colorectal cancer (CRC) Consensus Molecular Subtypes (CMS) as identified, and validated the results in a large independent cohort of human tumor samples. The expression signature derived from the p21-/- cells showed consistent and reliable numbers of upregulated and downregulated genes, as evaluated with two machine learning methods against the four CRC subtypes (i.e., CMS1, 2, 3, and 4). High concordance was found between the upregulated gene signature of HCT116 p21-/- cells and the signature of the CMS4 mesenchymal subtype. At the same time, the upregulated gene signature of the native HCT116 cells was similar to that of CMS1. Using a multivariate Cox regression model to analyze the survival data in the CRC tumor cohort, we selected genes that have a predictive risk power (with a significant gene risk incidence score). A set of genes of the mesenchymal signature was proven to be significantly associated with poor survival, specifically in the CMS4 CRC human cohort. We suggest that the gene signature of HCT116 p21-/- cells could be a suitable metric for mechanistic studies regarding the CMS4 signature and its functional consequences in CRC. Moreover, this model could help to discover the molecular mechanisms of intermediate EMT, which is known to be associated with extraordinarily high stemness and drug resistance.R.S.-S. was supported by the Emerging Fields Initiative ‘Cell Cycle in Disease and Regeneration’ (CYDER) of the Friedrich Alexander University (Erlangen-Nürnberg, Germany). This article is partly based upon work from COST Action CA17118 TRANSCOLONCAN, supported by COST (European Cooperation in Science and Technology, www.cost.eu, last accessed 20 December 2021). The JDLR research group is supported by the Spanish Government, Instituto de Salud Carlos III (ISCiii, AES project PI18/00591) co-funded by FEDER/ERDF (European Regional Development Fund)
Detection of EGFR mutations with mutation-specific antibodies in stage IV non-small-cell lung cancer
<p>Abstract</p> <p>Background</p> <p>Immunohistochemistry (IHC) with mutation-specific antibodies may be an ancillary method of detecting EGFR mutations in lung cancer patients.</p> <p>Methods</p> <p>EGFR mutation status was analyzed by DNA assays, and compared with IHC results in five non-small-cell lung cancer (NSCLC) cell lines and tumor samples from 78 stage IV NSCLC patients.</p> <p>Results</p> <p>IHC correctly identified del 19 in the H1650 and PC9 cell lines, L858R in H1975, and wild-type EGFR in H460 and A549, as well as wild-type EGFR in tumor samples from 22 patients. IHC with the mAb against EGFR with del 19 was highly positive for the protein in all 17 patients with a 15-bp (ELREA) deletion in exon 19, whereas in patients with other deletions, IHC was weakly positive in 3 cases and negative in 9 cases. IHC with the mAb against the L858R mutation showed high positivity for the protein in 25/27 (93%) patients with exon 21 EGFR mutations (all with L858R) but did not identify the L861Q mutation in the remaining two patients.</p> <p>Conclusions</p> <p>IHC with mutation-specific mAbs against EGFR is a promising method for detecting EGFR mutations in NSCLC patients. However these mAbs should be validated with additional studies to clarify their possible role in routine clinical practice for screening EGFR mutations in NSCLC patients.</p
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Andean orogeny and the diversification of lowland neotropical rain forest trees:A case study in Sapotaceae
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordUnderstanding how species diversify and evolve in species-rich areas like the lowland rain forest in the Neotropics is critical for conservation in times of unprecedented threats. To determine how the Andean uplift, the formation of the Panama land bridge, and Pleistocene climatic fluctuations affected dispersal and diversification in the Sapotaceae subfamily Chrysophylloideae, we collected 146 Chrysophylloideae accessions in previously under-explored areas, generating one of the most geographically complete data sets for neotropical Sapotaceae. Sapotaceae is a good model to test diversification hypotheses in lowland neotropical rain forests as it predominantly occurs <1000 m altitude, and it is an abundant and species-rich group in this biome. We generated a time calibrated phylogeny of 123 Sapotaceae species based upon the nuclear ribosomal internal transcribed spacer region that suggests migration between lineages to the east and the west Andean Cordilleras occurred before and after periods of major uplift, indicating that the Andes did not represent a significant barrier to dispersal for Sapotaceae, although it may have promoted vicariance in some cases. Dispersal between South and Central America occurred mainly prior to the formation of the Panama land bridge, suggesting that this event did not affect migration patterns in Chrysophylloideae. We inferred diversification rates and detected three shifts in the phylogeny, but they are not congruent with tectonic movements during the middle Miocene and climatic changes during the Pleistocene. Finally, some species with restricted distributions appear to be phylogenetically nested within species with broader ranges, suggesting ancestor descendent relationships and insights into patterns of speciation in rain forest trees.Natural Environment Research Council (NERC)National Science Foundation (NSF)Geological Society of Americ
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