PubMed Health⌕ Search

Biomedical subjects

S Benetti

Publications and source records attributed to S Benetti.

9 recordsLinked to original sources
PubMed2000

The Properties of Supernova 1997cy Associated with GRB 970514.

The extraordinary SN 1997cy associated with GRB 970514 has been observed photometrically and spectroscopically for nearly 2 yr. At the time of discovery, SN 1997cy was the brightest supernova (SN) ever observed (MV</=-20.1, vhel=19,140 km s-1, H0=65 km s-1 Mpc-1). Up to the last available observations (600 days after the gamma-ray burst), the total time-integrated flux was equal to or larger than that expected from the complete thermalization of the gamma-rays produced by 2.3 M middle dot in circle of 56Co. However, starting already on day 60 the luminosity decline is slower than the 56Co decay rate, indicating that the SN ejecta was interacting with circumstellar material (CSM). The interaction appeared to weaken around day 550. The spectra of SN 1997cy are dominated at all epochs by Halpha emission, which shows at least three components of different widths, as in SN 1988Z. Several other lines with different widths are also visible, especially at early epochs. The entire light curve of SN 1997cy is reproduced by a model of the interaction of the very energetic (E=3x1052 ergs) ejecta of a massive star (25 M middle dot in circle) with the CSM, with some contribution from radioactive decays. The CSM could have been ejected with a mass-loss rate of M&d2; approximately 4x10-4 M middle dot in circle yr-1 as the progenitor star evolved from a blue to a red supergiant about 104 yr before the explosion. The lack of oxygen and magnesium lines in the spectra at nebular phases poses a problem for models requiring high-mass progenitors. The possibility that most of the core material of the progenitor has fallen onto a massive black hole so that the reverse shock dies at the inner edge of the H/He envelope is discussed.

Journal Article↗
PubMed1995

[Video-assisted atypical resection of peripheral lung nodules localized using CT-guided wires. First clinical experiences].

One of the reasons for the rapidly expanding use of thoracoscopic surgery as an alternative to thoracotomy, is the excision of peripheral lung nodules. Nodules judged too small or too far from the pleural surface to be seen during thoracoscopy, must be localized beforehand. The aim of this study was to evaluate the feasibility and effectiveness of percutaneous placement of needle hook-wires to locate such nodules before surgery. Under Ct guidance 5 nodules were pre-operatively identified in 4 patients. The thoracoscopic resection of the lesions was done without complication, in 1 patient the operation had to be converted into an open one to dislodge of the wire. CT-guided hook-wire localization is easily and safely performed and permits thoracoscopic resection of lung nodules, which otherwise might be impossible.

Aged↗
PubMed1994

[Homogenized thoracic radiography].

The major obstacle to optimal radiographic depiction of the chest has always been its anatomical features and, in particular, the considerable difference in X-ray beam attenuation between pulmonary and mediastinal structures. At least 40% of this region cannot be visualized in an optimal way. Therefore, much technological work was done to overcome this limitation, which has recently led to the development of electronic (Amber) and mechanical (homogenization) filtration systems. This study was aimed at assessing the capabilities of mechanical filtration, in terms of anatomical representation and lower biologic cost, the latter intended as lower exposure and absorbed doses. Therefore, eight radiologists studied 40 negative radiographs, i.e., a homogenized radiograph and a non-homogenized one per patient, twenty patients in all. The statistical analysis of the radiographs demonstrated the homogenized technique to allow better visualization of all the anatomical structures examined, i.e., trachea, carina, right and left main bronchi, aorta, spine and retrocardiac region. In contrast, the two radiographic techniques yielded much the same results in the depiction of the pulmonary pattern. As for dosimetry, good results were also obtained, because the homogenizer made it possible to reduce both exposure and absorbed doses to the lung and thyroid, while in the mediastinal region the absorbed dose remained similar to that measured with the non-homogenized even though exposure dose was increased mildly.

Humans↗
PubMed1981

Azaprostaglandin analogues. Synthesis and biological properties of 11-azaprostaglandin derivatives.

New nitrogen analogues of prostaglandins (11, 11a, 12, and 12a) have been synthesized starting from a 4,5-disubstituted 2-pyrrolidinone nucleus (5 and 5a) containing one side chain and a suitable functionality for elaborating the second one. These analogues had no better activity than natural prostaglandins in vitro [guinea pig ileum and trachea, rat stomach fundus strip, uterus and portal vein, ADP-induced guinea pig platelet-rich plasma (PRP) aggregation]. They similarly lacked any interesting activity in vivo [anesthetized rat blood pressure, stress, and acetylsalycilic acid (ASA) induced gastric lesions in rat].

Animals↗
PubMed1978

Synthesis and prostaglandin-like activity of 2-(trans-3-hydroxy-1-octenyl)-3-indoleheptanoic acid.

The synthesis of 2-(trans-3-hydroxy-1-octenyl)-3-indoleheptanoic acid (1) is described. The title compound appeared to show a weak prostaglandin-like activity in two different systems. It contracted rat stomach fundus strips and guinea-pig ileum preparations only at concentrations about 10(3)- and 10(2)-fold higher, respectively, than PGE1. Moreover, it stimulated adenylate cyclase from rat liver plasma membrane, but the relative potency was 4--5 X 10(2)-fold lower than the natural compound. The title compound showed also a certain degree of PGE1 antagonism.

Animals↗
PubMedDate not supplied

Solid-phase synthesis of indolizidine and quinolizidine derivatives.

An efficient method for the construction of simple indolizidine and quinolizidine derivatives on solid support has been developed. An intramolecular tandem Michael reaction initiated by the nucleophilic attack of a suitably placed amino group on the tethered Wittig condensation products between 4- or 5-aminoaldehydes attached to a trityl chloride resin and 4-[(4-methylphenyl)sulfonyl]-1-(triphenylphosphoranylidene)-2-b utanon e is the key step.

Drug Design↗