NASA Lidar system support and MOPA technology demonstration

A series of lidar design and technology demonstration tasks in support of a CO2 lidar program is discussed. The first of these tasks is discussed in Section VI of this report under the heading of NASA Optical Lidar Design and it consists of detailed recommendations for the layout of a CO2 Doppler lidar incorporating then existing NASA optical components and mounts. The second phase of this work consisted of the design, development, and delivery to NASA of a novel acousto-optic laser frequency stabilization system for use with the existing NASA ring laser transmitter. The second major task in this program encompasses the design and experimental demonstration of a master oscillator-power amplifier (MOPA) laser transmitter utilizing a commercially available laser as the amplifier. The MOPA design including the low chirp master oscillator is discussed in detail. Experimental results are given for one, two and three pass amplification. The report includes operating procedures for the MOPA system

Neural Nets and Star/Galaxy Separation in Wide Field Astronomical Images

One of the most relevant problems in the extraction of scientifically useful information from wide field astronomical images (both photographic plates and CCD frames) is the recognition of the objects against a noisy background and their classification in unresolved (star-like) and resolved (galaxies) sources. In this paper we present a neural network based method capable to perform both tasks and discuss in detail the performance of object detection in a representative celestial field. The performance of our method is compared to that of other methodologies often used within the astronomical community.Comment: 6 pages, to appear in the proceedings of IJCNN 99, IEEE Press, 199

The recruitment and activation of phosphatidylinositol 4-phosphate 5-kinases α critically regulate CD28-dependent signaling responses

CD28 costimulatory receptor is a crucial determinant of the outcome of T lymphocyte activation. The engagement of CD28 by its natural ligands, B7.1/CD80 or B7.2/CD86, expressed on the surface of professional APC, lowers T cell receptor (TCR) activation threshold, thus leading to the enhancement of early signalling events necessary for efficient cytokine production, cell cycle progression, survival and regulation of T cells effector responses. CD28 is also able to act as a unique signalling receptor and to deliver TCR-independent autonomous signals, which account for its critical role in the regulation of pro-inflammatory cytokine/chemokine production and T cell survival. Most of the CD28-dependent signalling functions are initiated by the recruitment and activation of class IA phosphatidylinositol 3-kinase (PI3K), The intracytoplasmic domain of CD28 contains a N-terminal YMNM motif that following phosphorylation binds the p85 subunit of phosphatidylinositol 3-kinase (PI3K). Once activated, PI3K catalyzes the conversion of phosphatidylinositol 4,5-biphosphate (PIP2) to phosphatidylinositol 3,4,5-triphosphate (PIP3) and generates the docking sites for key signalling proteins. PIP2 plays a critical role in the regulation of both cytoskeleton dynamics and second messenger generation. Indeed, PIP2 is the common source for two major distinct signalling cascades involving PI3K and PLCγ1 that often colocalize in the same signalling complexes competing for the common pool of substrate. Consequently, PIP2 levels decrease following receptor activation, thus suggesting that stimulation of PIP2 synthesis may be an essential regulatory step to sustain the activation of both PI3K and PLCγ1 following CD28 engagement. The main biosynthetic pathway of PIP2 involves phosphorylation of phosphatidylinositol 4-monophosphate (PI4P) at the D5 position of the inositol ring by PIP5K. Three PIP5K isoforms (α, β and γ) have been identified. Several data obtained in different cell systems evidenced differential subcellular localizations of each isoform. PIP5Kα, for instance, is localized at the plasma membrane, where it guarantees the local availability of PIP2. Here we show that CD28 stimulation by both B7.1/CD80 or agonistic Abs induces the recruitment and activation of PIP5Kα in human primary CD4+ T lymphocytes. This event leads to the neo-synthesis of PIP2 that is consumed by CD28-activated PI3K. By either small interference RNA (siRNA)-driven cell silencing or overexpressing a kinase dead mutant, we evidenced that PIP5Kα activation is required for both CD28 autonomous signals regulating IL-8 gene expression as well as for CD28/TCR-induced Ca2+ mobilization, NF-AT nuclear translocation and IL-2 gene transcription. Our findings identify PIP5Kα as a critical mediator of CD28-dependent responses

Extraction of phenolic compounds from 'Aglianico' and 'Uva di Troia' grape skins and seeds in model solutions: Influence of ethanol and maceration time

The effect of increasing concentration of ethanol (0, 4, 7.5 and 13 %) and contact time (respectively 1, 4, 7 and 10 days) on the extraction of phenolics from berry skins and seeds of the grape, Vitis vinifera 'Aglianico' and 'Uva di Troia', were examined. Two assays of post-fermentative maceration in two hydroalcoholic solutions at 11 and 13 % ethanol, were also performed. Chromatic properties and phenolics of medium were analyzed by HPLC and spectrophotometric methods. The extraction of total phenolics, anthocyanins, proanthocyanidins, and vanilline reactive flavans (VRF) from berry skins reached the maximum on the 4th day of maceration. Quercetin and gallic acid were gradually extracted from grape skins. The maximum release of flavan-3-ols from the skins was achieved on the first day of maceration. Total phenolics, tannins and VRF were gradually extracted from seeds. During the postfermentative maceration, higher the content of ethanol, higher the extraction of total polyphenols and tannins from 'Uva di Troia' skins and the extraction of total polyphenols and tannins from 'Aglianico' seeds. These results clearly indicate that the grape cultivar mainly influences the release of phenolic compounds from the solid parts of berry to the must especially during postfermentative maceration.

A rock physics and seismic tomography study to characterize the structure of the Campi Flegrei caldera

The Campi Flegrei (CF) caldera experiences dramatic ground deformations unsurpassed anywhere in the world. The source responsible for this phenomenon is still debated. With the aim of exploring the structure of the caldera as well as the role of hydrothermal fluids on velocity changes, a multidisciplinary approach dealing with 3-D delay-time tomography and rock physics characterization has been followed. Selected seismic data were modeled by using a tomographic method based on an accurate finite-difference travel-time computation which simultaneously inverts P-wave and S-wave first-arrival times for both velocity model parameters and hypocenter locations. The retrieved P-wave and S-wave velocity images as well as the deduced Vp/Vs images were interpreted by using experimental measurements of rock physical properties on CF samples, to take into account steam/water phase transition mechanisms affecting P-wave and S-wave velocities. Also, modelling of petrophysical properties for site-relevant rocks constrains the role of overpressured fluids on velocity. A flat and low Vp/Vs anomaly lies at 4 km depth under the city of Pozzuoli. Earthquakes are located at the top of this anomaly. This anomaly implies the presence of fractured over-pressured gas-bearing formations and excludes the presence of melted rocks. At shallow depth, a high Vp/Vs anomaly located at 1 km suggests the presence of rocks containing fluids in the liquid phase. Finally, maps of the Vp*Vs product show a high Vp*Vs horse-shoe shaped anomaly located at 2 km depth. It is consistent with gravity data and well data and might constitute the on-land remainder of the caldera rim, detected below sea level by tomography using active source seismic data. For a more exhaustive description of the utilized methodologies, of synthetic tests for spatial resolution and uncertainty assessment and, the interpretation of results, the reader may refer to the paper Vanorio et al. (2005)

Stimulated single-fiber electromyography (sSFEMG) in Lambert-Eaton syndrome

Objective: To report the clinical features and the neurophysiological approach of a patient with Lambert-Eaton myasthenic syndrome (LEMS), highlighting the diagnostic role of the stimulated single fiber electromyography (sSFEMG). Case report: A 60-year-old woman presenting with the LEMS triad (proximal and axial weakness, autonomic dysfunction and areflexia) was evaluated by neurophysiological tests (electroneuromyography, repetitive stimulation test (TSR), voluntary and stimulated SFEMG). We reported: 1) increase of compound muscle action potential (CMAP) amplitude (>60%) following brief isometric exercise compared to the rest (baseline); 2) decremental/incremental response of CMAP amplitude at low- (3 Hz) and high-frequency (30 Hz) repetitive stimulation test (RST), respectively; 3) increased neuromuscular jitter and blocking at voluntary single-fiber electromyography (vSFEMG); 4) stimulation rate-dependent reduction of the neuromuscular jitter and blocking at sSFEMG. Diagnosis was confirmed by serological demonstration of circulating voltage gated calcium channels (VGCC) antibodies. Significance: The present case highlights the role of the sSFEMG in the diagnosis of LEMS, underling the stimulation rate-dependency of both neuromuscular jitter and blocks

Nefrolitiasi da iperparatiroidismo primitivo: uso del Cinacalcet in pazienti non trattabili con terapia chirurgica

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A comparison of mixed-models for the analysis of non-linear longitudinal data: application to late-life cognitive trajectories

Several mixed-effects models for longitudinal data have been proposed to accommodate the non-linearity of late-life cognitive trajectories and assess the putative influence of covariates on it. No prior research provides a side-by-side examination of these models to offer guidance on their proper application and interpretation. In this work, we examined five statistical approaches previously used to answer research questions related to non-linear changes in cognitive aging: the linear mixed model (LMM) with a quadratic term, LMM with splines, the functional mixed model, the piecewise linear mixed model, and the sigmoidal mixed model. We first theoretically describe the models. Next, using data from two prospective cohorts with annual cognitive testing, we compared the interpretation of the models by investigating associations of education on cognitive change before death. Lastly, we performed a simulation study to empirically evaluate the models and provide practical recommendations. Except for the LMM-quadratic, the fit of all models was generally adequate to capture non-linearity of cognitive change and models were relatively robust. Although spline-based models have no interpretable nonlinearity parameters, their convergence was easier to achieve, and they allow graphical interpretation. In contrast, piecewise and sigmoidal models, with interpretable non-linear parameters, may require more data to achieve convergence.Comment: 34 pages, 7 Figures, 1 Tabl

Increased IGF-1: IGFBP-3 ratio in patients with hepatocellular carcinoma

BACKGROUND: The development of hepatocellular carcinoma in liver cirrhosis is associated with altered synthesis and secretion of several growth factors. AIM: The aim of this prospective study was to investigate the potential implication of IGF-I and its major binding protein (IGFBP-3) in the development of hepatocellular carcinoma. PATIENTS AND METHODS: IGF-I and IGFBP-3 were measured in 150 healthy subjects, 40 patients with liver cirrhosis and 63 with liver cirrhosis and untreated hepatocellular carcinoma. The ratio between IGF-I and IGFBP-3 was also calculated. RESULTS: Serum IGF-I (70 ± 10 and 65 ± 7 vs. 185 ± 6.4 μg/l, P < 0.001) and IGFBP-3 levels (1225 ± 113 and 984 ± 67 vs. 3017 ± 80 μg/l, P < 0.001) were lower in patients with liver cirrhosis, without or with hepatocellular carcinoma, than in controls. Age was negatively correlated with IGF-I levels In patients with liver cirrhosis (r = -0.6; P = 0.0002) as well as in controls (r = -0.8, P < 0.0001), but not in patients with hepatocellular carcinoma (r = -0.2; P = 0.2). Additionally, in patients with liver cirrhosis (r = -0.54; P = 0.0003) and more weakly in those with hepatocellular carcinoma (r = -0.24; P = 0.04) IGF-I levels were negatively correlated with liver failure measured according with Child class. Despite patients with class C hepatocellular carcinoma being older than those in the same functional class with cirrhosis (64 ± 2 vs. 57 ± 2 years, P < 0.01), they had a significantly increased IGF-I : IGFBP-3 ratio (0.18 ± 0.05 vs. 0.41 ± 0.09, P = 0.04), due mostly to increased IGF-I levels (27.1 ± 5.6 vs. 42 ± 6.2 μg/l) as IGFBP-3 levels were similar to patients with cirrhosis (734 ± 81 vs. 679 ± 83 μg/l). CONCLUSIONS: Hepatocellular carcinoma is associated with a higher IGF-I : IGFBP-3 ratio than that found in patients with liver cirrhosis and a similar degree of liver failure

SiPM: Characterizations, modelling and VLSI front-end dedicated development

In this work we describe the results of performance tests and measures of SiPM of several sizes (1×1, 3×3, 5×5) delivered from MEPHI. The SiPMs have been studied both in steady and pulsed stimuli. Aging and temperature behavior are also discussed. Another test has been performed in order to obtain an electrical model of the SiPM to be used in analog simulations. Finally, a design of a pilot chip with 0.35 μm technology implementing a front-end for SiPM aimed to TOF applications with adjustable thresholds and very high dynamical range is described