Interstellar travel guide : chronicles of a violent universe

In contrast to observations from our local viewpoint, the universe is extremely violent. Explosions of massive stars, X-ray and gamma-ray binary stars, and active galaxies are related to the presence of compact objects such as neutron stars or black holes. Processes such as matter accretion or the formation and release of relativistic plasma jets are responsible for the generation of large amounts of high-energy radiation, caused by the acceleration of elementary particles, and have a significant impact in their surroundings. Moreover, they are related to the generation of gravitational waves: vibrations in spacetime produced by the acceleration of compact massive objects that produce strong curvatures. These systems are studied within the framework of the general and special relativity theories. In this article, we summarise several of the most well-known astrophysical scenarios, and offer a brief description of what we currently know about them

Purificación y propiedades de una proteina (P8) con afinidad por el DNA obtenida de fibroblastos en cultivo

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Biológicas, leída en 1976.Fac. de Ciencias BiológicasTRUEProQuestpu

Stability of hydrodynamical relativistic planar jets. I. Linear evolution and saturation of Kelvin-Helmholtz modes

The effects of relativistic dynamics and thermodynamics in the development of Kelvin-Helmholtz instabilities in planar, relativistic jets along the early phases (namely linear and saturation phases) of evolution has been studied by a combination of linear stability analysis and high-resolution numerical simulations for the most unstable first reflection modes in the temporal approach. Three different values of the jet Lorentz factor (5, 10 and 20) and a few different values of specific internal energy of the jet matter (from 0.08 to $60.0 c^2$) have been considered. Figures illustrating the evolution of the perturbations are also shown

Influence of internal energy on the stability of relativistic flows

A set of simulations concerning the influence of internal energy on the stability of relativistic jets is presented. Results show that perturbations saturate when the amplitude of the velocity perturbation approaches the speed of light limit. Also, contrary to what predicted by linear stability theory, jets with higher specific internal energy appear to be more stable.Comment: 4 pages, 2 figures. To be published in proceedings of the V Scientific Meeting of the SEA (Highlights of Spanish Astrophysics III), Toledo, Spain, September 9-13, 2002. Ed. J. Gallego, J. Zamorano and N. Cardiel, ASSL, Kluwer. Uploaded version of figure 3 is low resolution due to size problems: available high resolution version on request to Manuel Perucho ([email protected]

Frameshift mutations in Fas, Apaf-1, and Bcl-10 in gastro-intestinal cancer of the microsatellite mutator phenotype

Dear Editor, in a letter to the editor in a recent issue of Cell Death and Differentiation, Abdel-Rahman et al1. reported the absence of mutations in the death pathways gene Fas (Apo-1/CD95) in colorectal carcinomas. From the absence of mutations in 24 colon cancers, 12 of which were classified as replication error positive (RER+), Abdel-Rahman et al1. concluded that such mutations confer no substantial growth advantage in colorectal carcinogenesis. In agreement with this report, we identified Fas mutations in only 10% of colon and gastric cancers of the microsatellite mutator phenotype (MMP), also denominated as RER or microsatellite instability (MSI). Mutations were also found in Apaf-1 and Bcl-10, two other genes involved in the cell death pathways. The mutations were detected in mononucleotide tracts within these three genes (Figure 1). The frequency of these frameshift mutations was low (Table 1) and they appeared to be heterozygous (Figure 2). However, considering the peculiar features of these tumors, we suggest that these frameshift mutations contribute to cancer progression by providing survival advantage

Preservation of fertility in patients with cancer (Review)

Survival rates in oncological patients have been steadily increasing in recent years due to the greater effectiveness of novel oncological treatments, such as radio‑ and chemotherapy. However, these treatments impair the reproductive ability of patients, and may cause premature ovarian failure in females and azoospermia in males. Fertility preservation in both female and male oncological patients is nowadays possible and should be integrated as part of the oncological healthcare. The main objective of this review was to describe the different existing options of fertility preservation in patients undergoing gonadotoxic cancer treatments, as well as the differences in success rates that may appear in the different techniques evaluated. Emerging techniques are promising, such as the cryopreservation in orthotopic models of ovarian or testicle tissues, artificial ovaries, or in vitro culture prior to the autotransplantation of cryopreserved tissues. However, oocyte vitrification for female patients and sperm banking for male patients are considered the first line fertility preservation option at the present time for cancer patients undergoing treatment. Certainly, new fertility preservation techniques will continue to develop in the following years. However, despite the growing advances in the subject, optimal counselling from healthcare professionals should always be present

Emerging roles of macrosatellite repeats in genome organization and disease development

Altres ajuts: Fundación Olga TorresAbundant repetitive DNA sequences are an enigmatic part of the human genome. Despite increasing evidence on the functionality of DNA repeats, their biologic role is still elusive and under frequent debate. Macrosatellites are the largest of the tandem DNA repeats, located on one or multiple chromosomes. The contribution of macrosatellites to genome regulation and human health was demonstrated for the D4Z4 macrosatellite repeat array on chromosome 4q35. Reduced copy number of D4Z4 repeats is associated with local euchromatinization and the onset of facioscapulohumeral muscular dystrophy. Although the role other macrosatellite families may play remains rather obscure, their diverse functionalities within the genome are being gradually revealed. In this review, we will outline structural and functional features of coding and noncoding macrosatellite repeats, and highlight recent findings that bring these sequences into the spotlight of genome organization and disease development