University of Naples Federico II

About: University of Naples Federico II is a education organization based out in Naples, Campania, Italy. It is known for research contribution in the topics: Population & Cancer. The organization has 29291 authors who have published 68803 publications receiving 1920149 citations. The organization is also known as: Università degli Studi di Napoli Federico II & Naples University.

A gravitational-wave standard siren measurement of the Hubble constant

Abstract: On 17 August 2017, the Advanced LIGO1 and Virgo2 detectors observed the gravitational-wave event GW170817—a strong signal from the merger of a binary neutron-star system3. Less than two seconds after the merger, a γ-ray burst (GRB 170817A) was detected within a region of the sky consistent with the LIGO–Virgo-derived location of the gravitational-wave source4, 5, 6. This sky region was subsequently observed by optical astronomy facilities7, resulting in the identification8, 9, 10, 11, 12, 13 of an optical transient signal within about ten arcseconds of the galaxy NGC 4993. This detection of GW170817 in both gravitational waves and electromagnetic waves represents the first ‘multi-messenger’ astronomical observation. Such observations enable GW170817 to be used as a ‘standard siren’14, 15, 16, 17, 18 (meaning that the absolute distance to the source can be determined directly from the gravitational-wave measurements) to measure the Hubble constant. This quantity represents the local expansion rate of the Universe, sets the overall scale of the Universe and is of fundamental importance to cosmology. Here we report a measurement of the Hubble constant that combines the distance to the source inferred purely from the gravitational-wave signal with the recession velocity inferred from measurements of the redshift using the electromagnetic data. In contrast to previous measurements, ours does not require the use of a cosmic ‘distance ladder’19: the gravitational-wave analysis can be used to estimate the luminosity distance out to cosmological scales directly, without the use of intermediate astronomical distance measurements. We determine the Hubble constant to be about 70 kilometres per second per megaparsec. This value is consistent with existing measurements20, 21, while being completely independent of them. Additional standard siren measurements from future gravitational-wave sources will enable the Hubble constant to be constrained to high precision.

Macrocortin: a polypeptide causing the anti-phospholipase effect of glucocorticoids

Abstract: Anti-inflammatory glucocorticoids inhibit prostaglandin (PG) biosynthesis by preventing arachidonic acid release from phospholipids rather than inhibiting the cyclooxygenase. As in other cells, this steroid action depends on receptor occupation and de novo protein/RNA biosynthesis. We have previously shown in guinea pig perfused lungs and rat peritoneal leukocytes that the effect of steroids in PG generation is mediated by an uncharacterized 'second messenger'. Now, we report that this factor (which we have named 'macrocortin') is an intracellular polypeptide whose release and synthesis are stimulated by steroids. Macrocortin derived from rat peritoneal leukocytes is very similar to that released from guinea pig lungs.

Comet 81P/Wild 2 under a microscope.

Abstract: The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study. The preliminary examination of these samples shows that the nonvolatile portion of the comet is an unequilibrated assortment of materials that have both presolar and solar system origin. The comet contains an abundance of silicate grains that are much larger than predictions of interstellar grain models, and many of these are high-temperature minerals that appear to have formed in the inner regions of the solar nebula. Their presence in a comet proves that the formation of the solar system included mixing on the grandest scales.

Peginterferon alfa-2b and ribavirin for 12 vs. 24 weeks in HCV genotype 2 or 3.

Abstract: background We hypothesized that in patients with hepatitis C virus (HCV) genotype 2 or 3 in whom HCV RNA is not detectable after 4 weeks of therapy, 12 weeks of treatment is as effective as 24 weeks. methods A total of 283 patients were randomly assigned to a standard 24-week regimen of peginterferon alfa-2b at a dose of 1.0 µg per kilogram weekly plus ribavirin at a dose of 1000 mg or 1200 mg daily, on the basis of body weight. Of these, 70 patients were assigned to the 24-week regimen (standard-duration group) and 213 patients to a variable regimen (variable-duration group) of 12 or 24 weeks, depending on whether tests for HCV RNA were negative or positive at week 4. The primary end point was HCV that was not detectable by polymerase-chain-reaction (PCR) assay 24 weeks after the completion of therapy. results In the standard-duration group, 45 (64 percent) patients had HCV that was not detectable by PCR assay at week 4, as compared with 133 (62 percent) in the variable-duration group (difference [the rate in the standard-duration group minus that in the variableduration group], 2 percent; 95 percent confidence interval, i11 to 15 percent). Fiftythree patients (76 percent) in the standard-duration group and 164 patients (77 percent) in the variable-duration group had a sustained virologic response (difference, i1 percent; 95 percent confidence interval, i13 to 10 percent). Fewer patients in the variableduration group receiving the 12-week regimen had adverse events and withdrew than in the group receiving the 24-week regimen (P=0.045). The rate of relapse (defined as HCV not detectable at the end of treatment but detectable at the end of follow-up) was 3.6 percent in the standard-duration group and 8.9 percent in the variable-duration group (P=0.16). Overall, the rate of sustained virologic response was 80 percent among patients with HCV genotype 2 and 66 percent among those with genotype 3 (P<0.001). conclusions A shorter course of therapy over 12 weeks with peginterferon alfa-2b and ribavirin is as effective as a 24-week course for patients with HCV genotype 2 or 3 who have a response to treatment at 4 weeks.