2,310 research outputs found
ROLE OF FERROPORTIN-MEDIATED IRON RELEASE FROM MACROPHAGES IN TISSUE HOMEOSTASIS AND REPAIR
Macrophages are essential in the inflammatory response and also have
a critical function in body iron homeostasis. Moreover, it is known that
iron metabolism is important in the context of inflammation. Indeed, it
has been demonstrated that, in line with their functions, distinct
macrophage populations, such as M1 and M2 polarized cells, differ in
the expression of genes involved in iron homeostasis as well as in the
expression of immunoregulatory genes. The functional significance of
these differencies are not completely understood: we hypotized that iron
released by M2 macrophages could promote cell proliferation and
extracellular matrix deposition in the resolution phase of inflammation.
Moreover, in line with the increasing awareness that macrophages have
an important trophic role in addition to their immunological function,
macrophages may play a role of \u201clocal iron redistributors\u201d in tissues,
where they would manage iron availability for neighbouring cells.
Therefore, the major aim of this project was to exploit a mouse model of
impaired iron release from macrophages, caused by deletion of
Ferroportin (Fpn), to understand the functions of macrophage iron in two
situations of tissue repair: cutaneous wound healing and liver fibrosis.
The characterization of mice with loss of macrophage Fpn showed that
they are affected by transient alopecia caused by impaired hair follicle
growth. The local impairment of iron distribution due to macrophage Fpn
inactivation was accompanied by cellular iron deprivation and
decreased proliferation in adjacent epithelial cells. By exposing mice to
an iron-restricted diet we concluded that hair loss was not related to
hypoferremia/anemia. Taken together, these results suggest that iron
retention in resident macrophages has detrimental effects on tissue
homeostasis by inhibiting the proliferation of hair follicle cells.
We observed a considerable delay in the closure of excisional skin
wounds of Fpnfl/flLysCre/- mice compared to controls, with defective
granulation tissue formation and diminished fibroplasia. Moreover, the
development of both lymphatic and blood vascular network was
impaired. Conversely, inactivation of Fpn in macrophages had no
impact on inflammatory processes accompanying wound healing, such
as production of inflammatory molecules, content of leukocyte subsets
and macrophage polarization. Altogether, these results indicate that,
though it does not interfere with immune cells recruitment and local
activation, Fpn deletion in macrophages impairs blood vessels formation
and stromal cells proliferation, leading to delayed skin repair.
Fpn inactivation in macrophages had no impact on inflammation,
steatosis and fibrosis associated with exposition to the MCD diet, a model
of non-alcoholic steatohepatitis. Levels of inflammatory and fibrogenic
markers did not show significant differences between Fpnfl/flLysCre/- mice
and controls. Interestingly, the levels of transaminases were significantly
lower in mice with Fpn inactivation in macrophages, suggesting a
different susceptibility to liver damage. These data suggest that, in this
model, Fpn deletion in macrophages does not affect the inflammatory
response to liver damage and fibrogenesis. The different susceptibility to
liver damage and the different results we observed in the cutaneous
wound healing and in the process of hepatic fibrosis should be further
explored, perhaps using another model of fibrosis.
In conclusion, the results reported in this thesis indicate that the
macrophage trophic function in skin homeostasis and healing is iron and
Fpn-dependent
Automated efficiency loss analysis by luminescence image reconstruction using generative adversarial networks
Identifying solar cell efficiency shortfalls in production lines is crucial to troubleshoot and optimize manufacturing processes. With the adoption of luminescence imaging as a key end-of-line characterization tool, a wealth of information is available to evaluate cell performance and classify defects, suitable for user input-free deep-learning analysis. We propose an automated reconstruction method, based on state-of-the-art generative adversarial networks, to remove defective regions in luminescence images. The reconstructed and original images are compared to estimate the efficiency loss. The method is validated on intentionally damaged cells by reconstructing defect-free images and then predicting the efficiency loss. The method can differentiate between different types of defects and pinpoint the defects that lead to the highest efficiency shortfall, enabling manufacturers to troubleshoot production lines in a fast and cost-effective manner. The proposed approach unlocks the potential of luminescence imaging as an effective end-of-line characterization tool
Finding the trigger to Iapetus' odd global albedo pattern: Dynamics of dust from Saturn's irregular satellites
The leading face of Saturn's moon Iapetus, Cassini Regio, has an albedo only
one tenth that on its trailing side. The origin of this enigmatic dichotomy has
been debated for over forty years, but with new data, a clearer picture is
emerging. Motivated by Cassini radar and imaging observations, we investigate
Soter's model of dark exogenous dust striking an originally brighter Iapetus by
modeling the dynamics of the dark dust from the ring of the exterior retrograde
satellite Phoebe under the relevant perturbations. In particular, we study the
particles' probabilities of striking Iapetus, as well as their expected spatial
distribution on the Iapetian surface. We find that, of the long-lived particles
(greater than about 5 microns), most particle sizes (greater than about 10
microns) are virtually certain to strike Iapetus, and their calculated
distribution on the surface matches up well with Cassini Regio's extent in its
longitudinal span. The satellite's polar regions are observed to be bright,
presumably because ice is deposited there. Thus, in the latitudinal direction
we estimate polar dust deposition rates to help constrain models of thermal
migration invoked to explain the bright poles (Spencer & Denk 2010). We also
analyze dust originating from other irregular outer moons, determining that a
significant fraction of that material will eventually coat Iapetus--perhaps
explaining why the spectrum of Iapetus' dark material differs somewhat from
that of Phoebe. Finally we track the dust particles that do not strike Iapetus,
and find that most land on Titan, with a smaller fraction hitting Hyperion. As
has been previously conjectured, such exogenous dust, coupled with Hyperion's
chaotic rotation, could produce Hyperion's roughly isotropic, moderate-albedo
surface.Comment: Accepted for publication in Icaru
Saturn's icy satellites and rings investigated by Cassini - VIMS. III. Radial compositional variability
In the last few years Cassini-VIMS, the Visible and Infared Mapping
Spectrometer, returned to us a comprehensive view of the Saturn's icy
satellites and rings. After having analyzed the satellites' spectral properties
(Filacchione et al. (2007a)) and their distribution across the satellites'
hemispheres (Filacchione et al. (2010)), we proceed in this paper to
investigate the radial variability of icy satellites (principal and minor) and
main rings average spectral properties. This analysis is done by using 2,264
disk-integrated observations of the satellites and a 12x700 pixels-wide rings
radial mosaic acquired with a spatial resolution of about 125 km/pixel. The
comparative analysis of these data allows us to retrieve the amount of both
water ice and red contaminant materials distributed across Saturn's system and
the typical surface regolith grain sizes. These measurements highlight very
striking differences in the population here analyzed, which vary from the
almost uncontaminated and water ice-rich surfaces of Enceladus and Calypso to
the metal/organic-rich and red surfaces of Iapetus' leading hemisphere and
Phoebe. Rings spectra appear more red than the icy satellites in the visible
range but show more intense 1.5-2.0 micron band depths. The correlations among
spectral slopes, band depths, visual albedo and phase permit us to cluster the
saturnian population in different spectral classes which are detected not only
among the principal satellites and rings but among co-orbital minor moons as
well. Finally, we have applied Hapke's theory to retrieve the best spectral
fits to Saturn's inner regular satellites using the same methodology applied
previously for Rhea data discussed in Ciarniello et al. (2011).Comment: 44 pages, 27 figures, 7 tables. Submitted to Icaru
Characterization of Whole Grain Pasta: Integrating Physical, Chemical, Molecular, and Instrumental Sensory Approaches
The consumption of whole-grain foodincluding pastahas been increasing steadily. In the case of whole-grain pasta, given the many different producers, it seems important to have some objective parameters to define its overall quality. In this study, commercial whole-grain pasta samples representative of the Italian market have been characterized from both molecular and electronic-senses (electronic nose and electronic tongue) standpoint in order to provide a survey of the properties of different commercial samples. Only 1 pasta product showed very low levels of heat damage markers (furosine and pyrraline), suggesting that this sample underwent to low temperature dry treatment. In all samples, the furosine content was directly correlated to protein structural indices, since protein structure compactness increased with increasing levels of heat damage markers. Electronic senses were able to discriminate among pasta samples according to the intensity of heat treatment during the drying step. Pasta sample with low furosine content was discriminated by umami taste and by sensors responding to aliphatic and inorganic compounds. Data obtained with this multidisciplinary approach are meant to provide hints for identifying useful indices for pasta quality.
Practical ApplicationAs observed for semolina pasta, objective parameters based on heat-damage were best suited to define the overall quality of wholegrain pasta, almost independently of compositional differences among commercial samples. Drying treatments of different intensity also had an impact on instrumental sensory traits that may provide a reliable alternative to analytical determination of chemical markers of heat damage in all cases where there is a need for avoiding time-consuming procedures
- …