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Search Results: 1 - 10 of 14329 matches for " Andrea Remo "
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Genetic and Epigenetic Events Generate Multiple Pathways in Colorectal Cancer Progression
Massimo Pancione,Andrea Remo,Vittorio Colantuoni
Pathology Research International , 2012, DOI: 10.1155/2012/509348
Abstract: Colorectal cancer (CRC) is one of the most common causes of death, despite decades of research. Initially considered as a disease due to genetic mutations, it is now viewed as a complex malignancy because of the involvement of epigenetic abnormalities. A functional equivalence between genetic and epigenetic mechanisms has been suggested in CRC initiation and progression. A hallmark of CRC is its pathogenetic heterogeneity attained through at least three distinct pathways: a traditional (adenoma-carcinoma sequence), an alternative, and more recently the so-called serrated pathway. While the alternative pathway is more heterogeneous and less characterized, the traditional and serrated pathways appear to be more homogeneous and clearly distinct. One unsolved question in colon cancer biology concerns the cells of origin and from which crypt compartment the different pathways originate. Based on molecular and pathological evidences, we propose that the traditional and serrated pathways originate from different crypt compartments explaining their genetic/epigenetic and clinicopathological differences. In this paper, we will discuss the current knowledge of CRC pathogenesis and, specifically, summarize the role of genetic/epigenetic changes in the origin and progression of the multiple CRC pathways. Elucidation of the link between the molecular and clinico-pathological aspects of CRC would improve our understanding of its etiology and impact both prevention and treatment. 1. Background: The Molecular Basis of Colon Carcinogenesis Colorectal cancers (CRCs) arise through a multistep process in which genetic and epigenetic alterations accumulate in a sequential order. Three different pathogenetic pathways have been implicated in the development of these tumors: (1) chromosomal instability (CIN); (2) microsatellite instability (MSI); (3) CpG island methylator phenotype (CIMP). The CIN pathway is associated with the sequential deregulation of tumor suppressor genes (TSGs) and oncogenes such as, APC, KRAS, DCC/SMAD4, and TP53. It generally occurs within inherited tumors, such as familial adenomatous polyposis (FAP), but it has also been associated with the majority of sporadic CRCs. Microsatellite instability is responsible for the Lynch syndrome and sporadic tumors and is mainly caused by inactivation of the DNA mismatch repair genes (hMLH1, hMSH2, hMSH6, and hPMS2). CRCs displaying MSI tend to be rightsided, generally have high histological grades, a mucinous phenotype, and diagnosed at lower pathological stages than CIN cancers. The CpG island methylator
Charged massive particle at rest in the field of a Reissner-Nordstr?m black hole
Donato Bini,Andrea Geralico,Remo Ruffini
Physics , 2006, DOI: 10.1103/PhysRevD.75.044012
Abstract: The interaction of a Reissner-Nordstr\"om black hole and a charged massive particle is studied in the framework of perturbation theory. The particle backreaction is taken into account, studying the effect of general static perturbations of the hole following the approach of Zerilli. The solutions of the combined Einstein-Maxwell equations for both perturbed gravitational and electromagnetic fields at first order of the perturbation are exactly reconstructed by summing all multipoles, and are given explicit closed form expressions. The existence of a singularity-free solution of the Einstein-Maxwell system requires that the charge to mass ratios of the black hole and of the particle satisfy an equilibrium condition which is in general dependent on the separation between the two bodies. If the black hole is undercritically charged (i.e. its charge to mass ratio is less than one), the particle must be overcritically charged, in the sense that the particle must have a charge to mass ratio greater than one. If the charge to mass ratios of the black hole and of the particle are both equal to one (so that they are both critically charged, or "extreme"), the equilibrium can exist for any separation distance, and the solution we find coincides with the linearization in the present context of the well known Majumdar-Papapetrou solution for two extreme Reissner-Nordstr\"om black holes. In addition to these singularity-free solutions, we also analyze the corresponding solution for the problem of a massive particle at rest near a Schwarzschild black hole, exhibiting a strut singularity on the axis between the two bodies. The relations between our perturbative solutions and the corresponding exact two-body solutions belonging to the Weyl class are also discussed.
Vigorous star formation hidden by dust in a galaxy at $z=1.4$
Andrea Cimatti,Paola Andreani,Huub R?ttgering,Remo Tilanus
Physics , 1998, DOI: 10.1038/31872
Abstract: Near-infrared surveys have revealed a substantial population of enigmatic faint galaxies with extremely red optical-to-near-infrared colours and with a sky surface density comparable to that of faint quasars. There are two scenarios for these extreme colours: (i) these distant galaxies have formed virtually all their stars at very high redshifts and, due to the absence of recently formed stars, the colours are extremely red and (ii) these distant galaxies contain large amounts of dust, severely reddening the rest-frame UV--optical spectrum. HR10 ($z = 1.44$) is considered the archetype of the extremely red galaxies. Here we report the detection of the continuum emission from HR10 at 850$\mu$m and at 1250$\mu$m, demonstrating that HR10 is a very dusty galaxy undergoing a major episode of star formation. Our result provides a clear example of a high-redshift galaxy where the star formation rate inferred from the ultraviolet luminosity would be underestimated by a factor up to 1000, and shows that great caution should be used to infer the global star formation history of the Universe from optical observations only.
Extremely Red Galaxies: Old or Dusty ?
Andrea Cimatti,Paola Andreani,Huub R?ttgering,Remo Tilanus
Physics , 1998,
Abstract: The nature of the extremely red galaxies is poorly known, the critical issue being whether they are old ellipticals at $z>1.5$ or distant star-forming galaxies strongly reddened by dust extinction. Here we review the little we know about them, and we present recent and preliminary results from our ongoing submillimeter -- millimeter observations.
The Stagger-grid: A grid of 3D stellar atmosphere models - IV. Limb darkening coefficients
Zazralt Magic,Andrea Chiavassa,Remo Collet,Martin Asplund
Physics , 2014, DOI: 10.1051/0004-6361/201423804
Abstract: We compute the emergent stellar spectra from the UV to far infrared for different viewing angles using realistic 3D model atmospheres for a large range in stellar parameters to predict the stellar limb darkening. We have computed full 3D LTE synthetic spectra based on 3D radiative hydrodynamic atmosphere models from the Stagger-grid. From the resulting intensities at different wavelength, we derived coefficients for the standard limb darkening laws considering a number of often-used photometric filters. Furthermore, we calculated theoretical transit light curves, in order to quantify the differences between predictions by the widely used 1D model atmosphere and our 3D models. The 3D models are often found to predict steeper limb darkening compared to the 1D models, mainly due to the temperature stratifications and temperature gradients being different in the 3D models compared to those predicted with 1D models based on the mixing length theory description of convective energy transport. The resulting differences in the transit light curves are rather small; however, these can be significant for high-precision observations of extrasolar transits, and are able to lower the residuals from the fits with 1D limb darkening profiles. We advocate the use of the new limb darkening coefficients provided for the standard four-parameter non-linear power law, which can fit the limb darkening more accurately than other choices.
Extremely Red Galaxies
Paola Andreani,Andrea Cimatti,Huub Roettgering,Remo Tilanus
Physics , 1999,
Abstract: Preliminary results of a project aiming at unveiling the nature of the extremely red galaxies (ERGs) (objects with colours R-K>6 and I-K>5) found in deep optical-NIR surveys are presented. Very little is known about these objects, the critical issue being whether they are old ellipticals at z>1 or distant star-forming galaxies strongly reddened by dust extinction. We expect to shed light onto the unknown nature of these galaxies by completing our three-step project: (1) the construction of two very deep optical/NIR surveys to select ERGs, (2) subsequent VLT/NIR spectroscopy; (3) observations in the sub-mm region with SCUBA at the JCMT and with MPIfRbolo at the IRAM 30m antenna.
Antinutritive Compounds in Twelve Camelina sativa Genotypes  [PDF]
Roberto Russo, Remo Reggiani
American Journal of Plant Sciences (AJPS) , 2012, DOI: 10.4236/ajps.2012.310170
Abstract: Camelina sativa is an oilseed crop becoming important in North America and Europe for biodiesel production. The use of Camelina flours in animal diet may be limited by antinutritive compounds. The content of glucosinolates, phytic acid, sinapine and condensed tannins was evaluated in twelve accessions of Camelina sativa. All compounds showed significant differences among genotypes. Only the concentration of glucosinolates in the flour deserves attention, while the content of phytic acid, sinapine and condensed tannins are to acceptable levels. Camelina showed the presence of three different glucosinolates (GSL1, GSL2 and GSL3) in the flour, with differences among genotypes regarding the relative abundance of each glucosinolate. The content of glucosinolates is inversely correlated with that of sinapine. The glucosinolate content in Camelina flour has to be reduced to increase the use of this flour in animal diet, but avoiding altering the sinapine content.
Variation in the Content of Cyanogenic Glycosides in Flaxseed Meal from Twenty-One Varieties  [PDF]
Roberto Russo, Remo Reggiani
Food and Nutrition Sciences (FNS) , 2014, DOI: 10.4236/fns.2014.515159
Abstract:

Flaxseed meal from twenty-one varieties has been evaluated for content of cyanogenic glycosides (linamarin, linustatin and neolinustatin). Varieties belonging to three different groups of productive attitude (oil, fiber and intermediate) were considered. The total content of cyanogenic glycosides ranged from 0.74 to 1.60 g?Kg?1 CN?. As expected, linamarin was a minority component accounting for only 2% - 14% of total glycosides. Linustatin resulted statistically lower in the intermediate group than that in the other groups and, in particular, it was the lowest in the Festival variety. Neolinustatin resulted lower in the fiber group although the variety Ventimiglia (belonging to oil group) showed a negligible level of this compound. Neolinustatin was positively correlated to total cyanogenic glycosides (r = 0.709) and inversely correlated to linustatin (r = ?0.326). The variability observed in the content of the various forms of glycosides could be exploited in breeding programs to reduce the content of these toxic compounds in flaxseed meal.

Evaluation of Protein Concentration, Amino Acid Profile and Antinutritional Compounds in Hempseed Meal from Dioecious and Monoecious Varieties  [PDF]
Roberto Russo, Remo Reggiani
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.61003
Abstract: Hempseed meal from three dioecious and three monoecious varieties has been evaluated for content and quality of the protein and for the concentration of antinutritional compounds. Hemp seeds were obtained from plants grown in two experimental fields for two consecutive years (2011-2012). For all the varieties, hempseed meal resulted in a rich source of protein (34% mean content) with an amino acid profile extremely rich in arginine and slightly poor in lysine. Differences between dioecious and monoecious varieties were observed in the content of antinutritional compounds. They were more concentrated in monoecious varieties in comparison with those dioecious. The concentration of phytic acid in hempseed meal deserves attention in both groups, being 63 and 75.4 g·kg-1 of dry matter in dioecious and monocieous varieties, respectively. The results show that, besides the recognized value of hemp oil, also the hempseed cake could find application in animal feed as a substitute of other cakes (soybean, rapeseed). From this point of view, the dioecious varieties showing lower contents of antinutritional compounds with respect to the monoecious varieties would be preferred.
Glucosinolates and Sinapine in Camelina Meal  [PDF]
Roberto Russo, Remo Reggiani
Food and Nutrition Sciences (FNS) , 2017, DOI: 10.4236/fns.2017.812078
Abstract:
Forty seven accessions of camelina (Camelina sativa L. Crantz) were analyzed for glucosinolates (GSLs) and sinapine in defatted meal. These antinutritional compounds are undesirable in camelina meal for use in animal feeding and therefore we show their variability to identify the best varieties for future breeding programs. Total GSLs ranged from 19.6 to 40.3 mmol Kg-1 dry weight (DW) with an average of 30.3 mmol kg-1 DW. Great variability has also been observed in the levels of individual GSLs (GSL1, GSL2 and GSL3), so that the content of GSL1 and GSL3 were not correlated to each other in the accessions of camelina. Five out of six winter forms of camelina showed low content of GSLs. Sinapine ranged from 1.09 to 4.75 g Kg-1 DW with an average of 2.57 g kg-1 DW. The sinapine content was not correlated with that of GSLs. The use of camelina meal is only limited by the presence of GSLs while sinapine content can be ignored in camelina varieties.
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