Search results for "Photon"

International workshop on next generation gamma-ray source

2022

Journal of physics / G 49(1), 010502 (2022). doi:10.1088/1361-6471/ac2827

A Hard X-Ray View of Scorpius X-1 with INTEGRAL : Nonthermal Emission?

2006

We present here simultaneous INTEGRAL/RXTE observations of Sco X-1, and in particular a study of the hard X-ray emission of the source and its correlation with the position in the Z-track of the X-ray color-color diagram. We find that the hard X-ray (above about 30 keV) emission of Sco X-1 is dominated by a power-law component with a photon index of ~3. The flux in the power-law component slightly decreases when the source moves in the color-color diagram in the sense of increasing inferred mass accretion rate from the horizontal branch to the normal branch/flaring branch vertex. It becomes not significantly detectable in the flaring branch, where its flux has decreased by about an order of…

INTEGRAL observations of the peculiar BeX System SAX J2103.5+4545

2004

We present an INTEGRAL data analysis of the X-ray transient \object{SAX J2103.5+4545} during two outbursts detected in December 2002. The INTEGRAL coordinates and error circle agree with the position of the recently proposed optical counterpart. A power-law plus cut-off model provided a good fit to the 4-150 keV spectrum yielding a photon index of 1.0+-0.1, a cut-off energy E_cut=7.6+-2.0 keV and a folding energy E_fold=30.9+-2.5 keV. The X-ray luminosity in the 4-150 keV energy range was found to be 6.0x10^36 erg/s, assuming a distance of 6.5 kpc. This luminosity, together with the derived photon index, indicate that the source is in a bright state. A 354.9$+-0.5 second pulse period is mea…

Steam sterilization processes affect the stability of clinical thermometers: Thermistor and prototypal FBG probe comparison

2020

Abstract Temperature is one of the most frequently measured physical quantities in clinical environment and a good biomarker of illness. The need for reusable probes, which have to be sterilized to prevent infections, requires the metrological qualification of thermometer probes in response to ageing effects induced by several sterilization processes. In this study, we investigated the effect of repeated sterilizations on both a commonly-used autoclavable thermistor probe and a prototypal Fiber Bragg Gratings (FBG) probe for temperature measurements. Findings highlighted a greater reliability of the proposed FBG probe than the commercial thermistor. Specifically, the FBG probe was able to w…

Surface plasmon-polariton amplifiers

2012

Propagation of surface plasmons at metal surfaces is receiving much interest nowadays because of its broad range of potential applications, like subwavelength photonics or biosensing. Although plasmonic devices achieve unique properties, surface plasmons suffer from high attenuation because of the absorption losses in the metal. This limitation can be overcome by providing the material adjacent to the metal with optical gain. Under these conditions, absorption losses are compensated and the propagation length of the plasmon is significantly increased. In this work, a review of plasmonic amplifiers is presented. To this end, the state of the art of such devices and the propagation characteri…

Contribution of thallium-201-SPECT to the grading of tumorous alterations of the brain

1992

Single photon emission computed tomography (SPECT) with thallium-201-chloride (201Tl) was used in 22 patients to assess the grade of malignancy of brain tumors. Low- and high-grade malignant gliomas could be well differentiated by calculating the Grade Index (GI), i.e., 201Tl uptake in the tumor area relative to a contralateral brain region. Low-grade gliomas (WHO-grade I-II) usually showed a GI of1.5. Tumors classified histologically as high-grade malignant (WHO-grade III-IV) had GI values greater than 1.42 and a mean value of 1.89. Until labelled amino-acid tracers for gamma-cameras become commercially available, thallium-201 brain-SPECT can provide an independent and complementary method…

Abdominal fat quantity and distribution in women with polycystic ovary syndrome and extent of its relation to insulin resistance.

2007

Composizione corporea in relazione alla sindrome dell'ovaio policistico. Increased abdominal fat has been linked to insulin resistance and increased cardiovascular risk. Because many patients with polycystic ovary syndrome (PCOS) present abdominal obesity, it may be the cause of insulin resistance in this disorder.Setting: Fat quantity and distribution were evaluated by dual x-ray absorptiometry at the Departments of Clinical Medicine at the University of Palermo and the University of Naples, Italy.Patients: A total of 110 patients with PCOS and 112 weight-matched controls were studied. Anthropometric data, blood glucose, serum insulin, and testosterone were evaluated. Total, trunk, and cen…

Usefulness of N-terminal pro-B-type natriuretic peptide levels in predicting residual myocardial ischemia in patients with ST elevation acute myocard…

2007

N-terminal pro-b-type natriuretic peptide (NT pro-BNP) is a neurohormone synthesized predominantly in ventricular myocardium. In patients with symptoms of heart failure, elevation in NT pro-BNP accurately identifies ventricular dysfunction. However, NT pro-BNP levels are not specific for ventricular dysfunction in patients who do not have overt symptoms of heart failure, suggesting that other cardiac processes such as myocardial ischemia may also cause elevation in NT pro-BNP. The study was aimed to determine whether NT pro-BNP elevations are associated with myocardial ischemia.One hundred and thirty patients (104 males, 26 females, mean age 61+12 years), with ST elevation acute myocardial …

Myopia, the challenge of Ophthalmology and its worldwide “explosive epidemic”

2018

Prolonged breast-feeding protects mothers from later-life obesity and related cardio-metabolic disorders

2011

AbstractObjectiveTo investigate the long-term effects of duration of postpartum lactation on maternal body composition and risk for cardio-metabolic disorders in later life.DesignRetrospective study. Body composition was measured using dual-energy X-ray absorptiometry and serum glucose, insulin and lipids were analysed using enzymatic photometric methods 16–20 years after the last pregnancy. Medical history and lifestyle factors were collected via a self-administered questionnaire. Detailed information regarding weight change patterns during each pregnancy was obtained from personal maternity tracking records.SettingCity of Jyväskylä and surroundings in Central Finland.SubjectsTwo hundred a…