Search for Dark Matter with GLAST

The detection of exotic cosmic rays due to pair annihilation of dark matter particles in the Milky Way halo is a viable techniques to search for supersymmetric dark matter candidates. The study of the spectrum of gamma-rays, antiprotons and positrons offers good possibilities to perform this search in a significant portion of the Minimal Supersymmetric Standard Model parameter space. In particular the EGRET team have seen a convincing signal for a strong excess of emission from the Galactic center that has no simple explanation with standard processes. We will review the limits achievable with the experiment GLAST taking into accounts the LEP results and we will compare this method with the antiproton and positrons experiments.Comment: 8 pages, 12 figures, Invited talk at the First International Workshop on Fundamental and Particle Physics in Space, Space Part, May 14-19 2002, Isola d'Elba. V2: one figure updated, references adde

The large area detector onboard the eXTP mission

The Large Area Detector (LAD) is the high-throughput, spectral-timing instrument onboard the eXTP mission, a flagship mission of the Chinese Academy of Sciences and the China National Space Administration, with a large European participation coordinated by Italy and Spain. The eXTP mission is currently performing its phase B study, with a target launch at the end-2027. The eXTP scientific payload includes four instruments (SFA, PFA, LAD and WFM) offering unprecedented simultaneous wide-band X-ray timing and polarimetry sensitivity. The LAD instrument is based on the design originally proposed for the LOFT mission. It envisages a deployed 3.2 m2 effective area in the 2-30 keV energy range, achieved through the technology of the large-area Silicon Drift Detectors - offering a spectral resolution of up to 200 eV FWHM at 6 keV - and of capillary plate collimators - limiting the field of view to about 1 degree. In this paper we will provide an overview of the LAD instrument design, its current status of development and anticipated performance

Influence of isoenzyme patterns on commutability in enzyme determinations.

The use of recommended methods has very much improved the precision and accuracy of enzymatic determinations. The use of 'enzyme reference materials' allows us to overcome the remaining difficulties. The possibility of extending standardization by using calibration materials to convert results obtained by different methods requires an essential property: 'commutability'. The relationship between patients' specimens and reference materials are conditioned by analytical causes (relative to the used methods) and clinical causes (relative to the condition of the human samples to be examined). Among the clinical causes, the different isoenzyme content of patients sera, induced by different pathologies, was considered. The effect of this influence has been investigated with an analytical approach of the isoenzymes in the individual clinical samples. The results obtained on determination of alkaline phosphatase (ALP), creatine kinase (CK), and lactate dehydrogenase (LD), are discussed according to a model of investigation which can be utilized for the experimental protocols in the assessment of commutability

Decreased serum leptin levels during prolonged high altitude exposure

Circulating leptin concentrations are shown to be influenced not only by hormones, but also by body weight and energy balance. High altitude (HA) exposure induces a daily negative energy balance and stress hormone activation. The aim of our study was to evaluate leptin concentration during both acute and prolonged HA exposure and its correlations with some metabolic and hormonal parameters. Twelve males were studied during a stay at HA (15–20 days at 5,050 m). Blood samples for serum leptin, plasma insulin and 24-h urinary epinephrine (E) and norepinephrine (NE) were collected at sea level (SL), at the arrival at HA (A) and after 12–16 days (C) of stay. Symptoms of Acute Mountain Sickness (AMS) were evaluated using the Lake Louise score and the results showed there was no relationship with leptin concentrations. During the stay, both body mass index and leptin levels significantly decreased in both groups [leptin from 1.88 (1.12) to 1.21 (1.04) ng/ml, P<0.008, in A; and to 1.06 (0.74) ng/ml, P<0.003, in C]. Acute HA exposure induced a clear-cut significant increase of NE (P<0.001 in A, P<0.003 in C) while E and insulin levels were unchanged in both phases. Moreover, a significant correlation between leptin and NE absolute values, and leptin and insulin variations was found (r 0.359, P<0.034 and r=0.560, P<0.007, respectively). Exposure to HA induces a decrease in fasting serum leptin concentrations in men. These changes are not linked to symptoms of AMS but to hormonal and energy balance variations, suggesting that leptin is involved in the endocrine and metabolic adaptations occurring during HA exposure

Immunoturbidimetric assay of glycated hemoglobin.

We investigated the performances of HbA1c determination by a latex enhanced turbidimetric immunoassay using the specific monoclonal antibodies (Unimate, Roche) against the beta-N-terminal fragments. The coefficients of variation ranges from 1.7 to 3.8% within assay (n = 30) and from 3.9 to 4.9% between assay (n = 20). The assay was linear from 2.5 to 14.9% of HbA1c. No interferences was found from fetal, carbamylated, or variant (S) hemoglobins and from labile Schiff adduct with glucose. The following relationship was derived from fresh sample comparison between HPLC (Diamat-BioRad) (x) and immunoassay (y) method: y = 0.971 x + 0.87%, r=0.98, n = 115. The immunoassay provides a highly precise and specific method for HbA1c