1.

Record Nr.

UNINA9910367756903321

Autore

Stratta Giulia

Titolo

Observations and Theory of Short GRBs at the Dawn of the Gravitational Wave Era / Giulia Stratta, Maria Giovanna Dainotti, Andrea Rossi

Pubbl/distr/stampa

MDPI - Multidisciplinary Digital Publishing Institute, 2019

Basel, Switzerland : , : MDPI, , 2019

ISBN

9783039215898

3039215892

Descrizione fisica

1 electronic resource (86 p.)

Lingua di pubblicazione

Inglese

Formato

Materiale a stampa

Livello bibliografico

Monografia

Sommario/riassunto

The book starts with a review of the established facts on the numerical simulations of binary neutron star mergers and simulations of short GRB jets that highlights the issues that need to be revised and further clarified, as the need to understand how the relativistic outflow was launched, what the initial structure of the outflow is, and how it evolved through its interaction with the binary ejecta. Constraints on a local population of faint short duration GRBs are then provided in light of the GW170817/GRB 170817A event at d~40 Mpc by considering statistical limits on a d < 200 Mpc population. Using past and current GRB detectors, results suggest that GRB 170817A-like events are likely to be rare in existing short GRB catalogues and, if binary neutron star merger rates are at the high end of current estimates, then at most a few percent will be accompanied by detectable gamma-ray flashes in the forthcoming LIGO/Virgo science runs. Indirect information on the nature of short GRBs can be obtained from their host galaxy. The host galaxies of most short GRBs are found to be star-forming, but an important fraction, ∼1/5, are elliptical with negligible star formation. Short bursts often occur at very large off-sets from their hosts, in regions where there is little or no underlying host light. These results provide evidence of progenitors associated with merger of compact



object binaries with kick velocities of a few tens of km/s and merger times of ∼1 Gyr. The last two issues of the book tackle the physics of the short GRB radiative processes. Interestingly, it was already noted in the past that the prompt emission for short GRBs and the initial 2 s of long-duration GRBs show similarity in the low energy photon index. This result has been further confirmed using a larger sample of Fermi Gamma-ray burst monitor data. In particular, it has been found that for 25% of GRBs, the photon index is shallower than −2/3,  challenging the standard synchrotron emission scenario. The extent up to which the reverse shock component is detectable for short GRBs in radio wavelengths is analyzed. Results show that early, radio bright reverse shock is expected in many cases, but more rapid follow-up observational campaigns are required in order to test these predictions.]

2.

Record Nr.

UNINA9910367753703321

Autore

Bachmeier Beatrice

Titolo

Curcumin in Health and Disease / Beatrice Bachmeier

Pubbl/distr/stampa

MDPI - Multidisciplinary Digital Publishing Institute, 2019

Basel, Switzerland : , : MDPI, , 2019

ISBN

9783039214501

3039214500

Descrizione fisica

1 electronic resource (274 p.)

Soggetti

Chemistry

Lingua di pubblicazione

Inglese

Formato

Materiale a stampa

Livello bibliografico

Monografia

Sommario/riassunto

The plant-derived polyphenol curcumin has been used in promoting health and combating disease for thousands of years. Its therapeutic effects have been successfully utilized in Ayurvedic and Traditional Chinese Medicine in order to treat inflammatory diseases. Current results from modern biomolecular research reveal the modulatory



effects of curcumin on a variety of signal transduction pathways associated with inflammation and cancer. In this context, curcumin's antioxidant, anti-inflammatory, anti-tumorigenic, and even anti-metastatic activities are discussed. On the cellular level, the reduced activity of several transcription factors (such as NFkB or AP-1) and the suppression of inflammatory cytokines, matrix degrading enzymes, metastasis related genes and even microRNAs are reported. On functional levels, these molecular effects translate into reduced proliferative, invasive, and metastatic capacity, as well as induced tumor cell apoptosis. All these effects have been observed not only in vitro but also in animal models. In combination with anti-neoplastic drugs like Taxol, kinase inhibitors, and radiation therapy, curcumin potentiates the drugs' therapeutic power and can protect against undesired side effects.  Natural plant-derived compounds like curcumin have one significant advantage: They do not usually cause side effects. This feature qualifies curcumin for primary prevention in healthy persons with a predisposition to cancer, arteriosclerosis, or chronic inflammatory diseases. Nonetheless, curcumin is considered safe, although potential toxic effects stemming from high dosages, long-term intake, and pharmacological interactions with other compounds have yet to be assessed.  This Special Issue examines in detail and updates current research on the molecular targets, protective effects, and modes of action of natural plant-derived compounds and their roles in the prevention and treatment of human diseases.