First muography of Stromboli volcano.

Muography consists in observing the differential absorption of muons - elementary particles produced through cosmic-ray interactions in the Earth atmosphere - going through the volcano and can attain a spatial resolution of tens of meters. We present here the first experiment of nuclear emulsion muography at the Stromboli volcano. Muons have been recorded during a period of five months by a detector of 0.96 m2 area. The emulsion films were prepared at the Gran Sasso underground laboratory and were analyzed at Napoli, Salerno and Tokyo scanning laboratories. Our results highlight a significant low-density zone at the summit of the volcano with density contrast of 30-40% with respect to bedrock. The structural setting of this part of the volcanic edifice controls the eruptive dynamics and the stability of the "Sciara del Fuoco" slope, which is affected by recurrent tsunamigenic landslides. Periodical imaging of the summit of the Stromboli volcano such as that provided by muography can become a useful method for studying the evolution of the internal structure of the volcanic edifice.

The Continuous Motion Technique for a New Generation of Scanning Systems.

In the present paper we report the development of the Continuous Motion scanning technique and its implementation for a new generation of scanning systems. The same hardware setup has demonstrated a significant boost in the scanning speed, reaching 190 cm2/h. The implementation of the Continuous Motion technique in the LASSO framework, as well as a number of new corrections introduced are described in details. The performance of the system, the results of an efficiency measurement and potential applications of the technique are discussed.

Kinetic characterization of the photosynthetic reaction centres in microalgae by means of fluorescence methodology.

The kinetic characterization of the photosynthetic activity in autotrophic microalgae plays a key role in the design of optimized photobioreactors. This paper presents a procedure to assess kinetic parameters of a three-state photosynthetic reaction centres model. Four kinetic parameters of the model were assessed by processing the time-series measurements of pulse-amplitude modulation fluorimetry. The kinetic parameters were assessed for several microalgal strains (Stichococcus bacillaris, Scenedesmus vacuolatus, Chlamydomonas reinhardtii, Chlorella vulgaris) growth in vertical and inclined bubble columns and irradiated by white-light or red/blue light. The procedure was successfully applied to the investigated strains. The assessed parameters allow identifying the irradiance range under which: the photochemical process is controlled by the photons capture; the photoinhibition competes with the photochemical quenching. The analysis of the time-scale of the photosynthetic reaction centres as a function of the irradiance allows interpreting the performances of photobioreactors characterized by non-homogeneous irradiance.

NMR (¹H) analysis of crude extracts detects light stress in Beta vulgaris and Spinacia oleracea leaves.

In highlight stress conditions, the mechanism of non-photochemical quenching (NPQ) of chlorophyll fluorescence is triggered at the chloroplast level. This process allows thermal quenching of the excessive excitation energy and it is strictly related to the efficiency of the xanthophyll cycle. Nowadays, the utilization of the nuclear magnetic resonance (NMR) spectroscopy provides a powerful complementary way for the identification and quantitative analysis of plant metabolites either in vivo or in tissue extracts. Seeing that the oxidative damage caused by light stress in plants and the consequent involvement of pigments are widely studied, NMR spectroscopy can be utilized to compare crude leaf extract at different levels of light stress, allowing an analysis of these compounds. In this paper, the identification of possible relationships between light stress and ¹H NMR signal variations is discussed. The analysis of the ¹H NMR (1D) spectra of two agronomic species (Spinacia oleracea and Beta vulgaris) exposed to different light intensities is presented. In particular, change in carotenoids and xanthophylls signals are analyzed.

Total body water in health and disease: Have anthropometric equations any meaning?

BACKGROUND: The accurate measurement of total body water (TBW) requires isotopic dilution techniques that are not easily applicable to the clinical setting. Therefore, indirect methods of estimating TBW are commonly employed, such as bioelectrical impedance analysis (BIA) and anthropometry. In the human body, >90% of the measured impedance is composed of resistance (R). METHODS: The aim of the present study was to compare TBW estimated by means of two anthropometric equations (by Watson and Hume) with TBW obtained by BIA (equations proposed by Sun et al.) in a group of white disease-free individuals (n = 3625, 1860 men and 1765 women) and white haemodialysis (HD) patients (n = 688, 443 men and 245 women). They underwent one single-frequency BIA measurement, on the nondominant side of the body, injecting an 800-muA and 50-kHz alternating sinusoidal current with a standard tetrapolar technique. The BIA variable measured was R. RESULTS: Among them, a selection of disease-free individuals (n = 481) and HD patients (n = 270), pair-matched by age, body weight and height, after stratification by gender, was made. When comparing the four pair-matched groups, it was found that (1) TBW was not different (disease-free men versus HD men; disease-free women versus HD women) when using anthropometric equations, which utilize quite identical parameters (age, body weight and height); (2) R was statistically significantly different in the four groups (511 +/- 58 SD Omega in disease-free men versus 558 +/- 80 in HD men, P < 0.0001; 593 +/- 70 Omega in disease-free women versus 615 +/- 100 in HD women, P < 0.02) and (3) therefore, TBW was statistically significantly different only when applying BIA equations (P < 0.0001 and 0.05, respectively). CONCLUSIONS: The present study demonstrates that anthropometric equations for the estimation of TBW can be used only within a specific population in order to assess individual differences; they cannot be used in order to compare two different populations.

Development and validation of bioimpedance analysis prediction equations for dry weight in hemodialysis patients.

BACKGROUND: Accurate assessment of hydration status and specification of dry weight (DW) are major problems in the clinical treatment of hemodialysis (HD) patients. Bioelectrical impedance analysis (BIA) has been recognized as a noninvasive and simple technique for the determination of DW in HD patients. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: This study was designed to develop and validate BIA prediction equations for DW in HD patients. It included white adults (1540 disease-free adults with normal body mass index [BMI] and 456 prevalent and 27 incident HD patients). All participants underwent at least one single-frequency BIA measurement (800 muA and 50 kHz alternating sinusoidal current with a standard tetrapolar technique). The BIA variable measured was resistance (R). Data of 1463 (95% of the cohort) disease-free individuals with normal BMI (prediction sample) were used to establish best-fitting BIA prediction equations of body weight. The latter were cross-validated in the residual 5% subset (77 individuals) of the same cohort (validation sample). RESULTS: Multiple regression analysis showed a significant relationship among body weight, R, age, and height in 739 men (R(2) = 0.82, P < 0.0001) and among body weight, R, and height in 724 women (R(2) = 0.68, P < 0.0001) in the prediction sample. The Bland Altman analysis showed a mean difference between predicted and measured body weight of 0.3 +/- 1.0 kg (95% confidence interval +/- 2.0 kg) in the validation sample. The BIA prediction equations that were obtained in disease-free individuals with normal BMI were applied to a cohort of 456 prevalent HD patients: The mean difference between achieved and estimated DW was 0.1 +/- 1.0 kg (P = 0.53) in men and -0.3 +/- 1.0 (P = 0.76) in women. Finally, BIA prediction equations were tested in a cohort of 27 incident HD patients. The mean difference between predicted and achieved DW was -0.6 +/- 1.0 kg (P = 0.76) in men and 0.6 +/- 1.0 (P = 0.50) in women. CONCLUSIONS: This study was able to develop and validate BIA prediction equations for DW in HD patients. They seem to be a promising tool; however, they still need external validation.