Emissione di corpo nero e applicazioni astrofisiche

Questo elaborato si propone di descrivere il modello teorico per la radiazione termica di Corpo Nero, e di illustrarne alcune applicazioni astrofisiche. Nel primo capitolo verrà discusso il concetto teorico di Corpo Nero: partendo dal teorema di Kirchhoff, che dimostra come per questo modello si stabilisca un ben definito spettro di energia. A seguire si esporranno brevemente le leggi empiriche di Stefan-Boltzmann e Wien. Dopodiché si passerà alla determinazione dello spettro di Corpo Nero. Prima analizzando la trattazione classica proposta da Rayleigh e Jeans, e successivamente quella quantistica proposta da Planck. Quest’ultima garantisce una soluzione al problema della catastrofe ultravioletta prevista dal modello classico, e getta le basi per la nascita della Teoria Quantistica. Infine si dimostra come la legge ricavata la Planck soddisfi le sopracitate leggi empiriche. Nel secondo capitolo saranno esposte le principali applicazioni astrofisiche del modello teorico di Corpo Nero. In particolare per quanto riguarda gli spettri delle stelle, e la Radiazione Cosmica di Fondo (CMB)

Flesh qualitative traits of tub gurnard (Chelidonichthys lucerna L.), a promising species candidate for aquaculture, captured in the middle Adriatic Sea in different seasons

The quality traits of the fillets from tub gurnard (Chelidonichthys lucerna L.) fished in the mid-Adriatic Sea were investigated. Forty fishes per season were sampled to evaluate the proximate composition, cholesterol content and fatty acid profile of fillets. Seasons significantly affected the quality traits of flesh. The protein content ranged from 19.39% in winter to 19.67% in summer, without significant differences. Lipid content was notably higher in spring (2.28%) and summer (2.32%), compared to autumn (1.72%) and winter (1.31%). Energy content was significantly higher in spring (416.45 kJ/100 g) and summer (417.97 kJ/100 g) compared to autumn (391.35 kJ/100 g) and winter (372.79 kJ/100 g). Saturated fatty acid content was highest in spring (35.88%), whereas monounsaturated acid content was not influenced by season. The n-3 polyunsaturated fatty acid content exceeded 37% of total fatty acid content during summer. The n-6/n-3 ratio remained favourably low across all seasons (from 0.16 to 0.18), with a slight significant increase in autumn (0.31). In conclusion, this study indicates that the flesh of tub gurnard has high nutritional value year-round, with the best results (in terms of n-3 polyunsaturated fatty acids) being obtained in summer

The ovarian reserve as target of insulin/IGF and ROS in metabolic disorder-dependent ovarian dysfunctions

It is known for a long time that metabolic disorders can cause ovarian dysfunctions and affect a woman's fertility either by direct targeting follicular cells and/or the oocytes or by indirect interference with the pituitary-hypothalamic axis, resulting in dysfunctional oogenesis. Such disorders may also influence the efficiency of the embryo implantation and the quality of the embryo with permanent effects on the fertility and health of the offspring. Thanks to the expanding knowledge on the molecular mechanisms governing oogenesis and folliculogenesis in mammals, we are beginning to understand how such disorders can negatively affect this process and consequently fertility in women. In the present review, we point out and discuss how the disturbance of insulin/IGF-dependent signalling and increased reactive oxygen species (ROS) level in the ovary typically associated to metabolic disorders such as type II diabetes and obesity can dysregulate the dynamics of the ovarian reserve and/or impair the survival and competence of the oocytes

Suitability of artisanal fishery discards as feed for juvenile tub gurnard (chelidonichthys lucerna L.) reared in sea bottom cages in the mid Adriatic Sea

The suitability of using discards from artisanal fisheries as feed for wild-caught Chelidonichthys lucerna (L.) reared in submerged cages in the Adriatic Sea was investigated. Three-hundred juvenile tub gurnard (72.9 ± 11 g, 18 ± 1 cm) were captured and separated into four circular 35.3 m3 submerged cages. Two stocking densities were used: two cages contained 60 fish each (1.7 fish m-3; CG-L) and two cages contained 90 fish each (2.55 fish m-3; CG-H). Growth performance and survival rates were recorded over a 240 day period during which tub gurnard were fed with a variety non-target fishery discards, including common crab, sardine, Atlantic chub mackerel, anchovy, and salema. The survival rate was approximately 90% in both groups (CG-L = 91% and CG-H = 90%), with final stocking densities of 0.32 kg m-3 and 0.49 kg m-3 for the CG-L and CG-H groups, respectively. There were no significant differences in final mean body weight or length between the CG-L group (206 ± 23 g, 24.6 ± 2 cm) and the CG-H group (215.5 ± 32 g, 24.8 ± 2 cm). The condition index was similar between the two groups (1.38 and 1.42 for CG-L and CG-H, respectively). The feed conversion ratio was high in both the CG-H (2.39) and CG-L (2.32) cages. These results demonstrate that viable growth rates of tub gurnard may be obtained by feeding recycled fishery discards and rearing in cages placed on the seabed, which allows for the natural benthic behavior of this species

Reprogramming Human Female Adipose Mesenchymal Stem Cells into Primordial Germ Cell-Like Cells

In the last two decades, considerable progress has been made in the derivation of mammalian germ cells from pluripotent stem cells such as Embryonic Stem Cells (ESCs) and induced Pluripotent Stem Cells (iPSCs). The pluripotent stem cells are generally first induced into pre-gastrulating endoderm/mesoderm-like status and then specified into putative primordial germ cells (PGCs) termed PGC-like cells (PGCLCs) which possess the potential to generate oocytes and sperms. Adipose-derived mesenchymal stromal cells (ASCs) are multipotent cells, having the capacity to differentiate into cell types such as adipocytes, osteocytes and chondrocytes. Since no information is available about the capability of female human ASCs (hASCs) to generate PGCLCs, we compared protocols to produce such cells from hASCs themselves or from hASC-derived iPSCs. The results showed that, providing pre-induction into a peri-gastrulating endoderm/mesoderm-like status, hASCs can generate PGCLCs. This process, however, shows a lower efficiency than when hASC-derived iPSCs are used as starting cells. Although hASCs possess multipotency and express mesodermal genes, direct induction into PGCLCs resulted less efficient

Obesity and Breast Cancer: Molecular Interconnections and Potential Clinical Applications

Obesity is an important risk factor for breast cancer (BC) in postmenopausal women; interlinked molecular mechanisms might be involved in the pathogenesis. Increased levels of estrogens due to aromatization of the adipose tissue, inflammatory cytokines such as tumor necrosis factor-α, interleukin-6, and prostaglandin E2, insulin resistance and hyperactivation of insulin-like growth factors pathways, adipokines, and oxidative stress are all abnormally regulated in obese women and contribute to cancerogenesis. These molecular factors interfere with intracellular signaling in the mitogen-activated protein kinase and phosphatydilinositol-3-phosphate/mammalian target of rapamycin (mTOR) pathways, which regulate the progression of the cell cycle, apoptosis, and protein synthesis. In this context, structural defects of typical genes related to both BC and obesity, such as leptin, leptin receptor, serum paraoxonase/arylesterase 1, the fat mass and obesity-associated gene and melanocortin receptor 4, have been associated with a high or low risk of BC development. The early detection of these gene alterations might be useful as risk predictors in obese women, and targeting these pathways involved in the BC pathogenesis in obese women is a potential therapeutic tool. In particular, mTOR pathway deregulation concurs in both obesity and BC, and inhibition of this might disrupt the molecular interlinks in a similar manner to that of metformin, which exerts definite anticancer activity and is currently used as an antidiabetic drug with a weight-reducing property. The identification of both genetic and pharmacological implications on the prevention and management of BC is the ultimate aim of these studies

Depuration Capacity of Mussels (Mytilus galloprovincialis) in Presence of Marteilia Spp. Parasites

Bivalve molluscs are filter-feeding organisms present in the water column: during their activity, they could retain micro-organisms that are potentially dangerous to human health. For this reason, EU Regulations may require that a purification treatment be performed prior to bivalve trade. The length of the purification process could be affected by stress factors, such as parasitic infections. The purpose of this study was to determine if the presence of Marteilia spp. parasite in shellfish could modify time and efficacy of their microbiological purification treatment, in order to set up specific protocols. Lysosomal membrane stability, phagocytosis capacity, granulocyte/hyalinocyte rate and neutral lipid accumulation are biomarkers used to evaluate shellfish physiological state. These biomarkers were used to exclude any differences caused by stressor factors that could affect the purification results. Mussels were sampled from two different production areas. The presence or absence of parasites was confirmed by cytological test. Both groups of parasitized and non-parasitized mussels were contaminated with E.coli: they were then sampled for microbiological analyses and tested for biomarkers for up to 70 hours of purification. Parasitized and non-parasitized molluscs did not show any differences in levels of E. coli after 12, 24, 36, 48 and 70 hours of depuration. In relation to biomarkers, mussels seem to react to Lysosomal membrane stability in presence of Marteilia. The present study shows that the presence of Marteilia spp. does not affect the purification rate of mussels

Surface X-ray Diffraction Study of a Bi-Layer Junction Based on Cu and Cd Sulfides for Photovoltaic Applications

none9noThis study investigates the crystal structure of thin films of chalcogenides, particularly a junction with a p-type (Cu2S) and an n-type (CdS) layer deposited one on top of the other on a Ag(111) substrate, starting from an aqueous solution and by means of electrochemical atomic layer deposition (E-ALD) (the system is denoted by (Cu2S)60/(CdS)60/Ag(111)).mixedTommaso Baroni; Francesco Di Benedetto; Andrea Giaccherini; Enrico Berretti; Francesca Russo; Annalisa Guerri; Massimo Innocenti; Francesco Carlà; Roberto FeliciBaroni, Tommaso; DI BENEDETTO, Francesco; Giaccherini, Andrea; Berretti, Enrico; Russo, Francesca; Guerri, Annalisa; Innocenti, Massimo; Carlà, Francesco; Felici, Robert

Analysis of Secreted Proteins from Prepubertal Ovarian Tissues Exposed In Vitro to Cisplatin and LH

It is well known that secreted and exosomal proteins are associated with a broad range of physiological processes involving tissue homeostasis and differentiation. In the present paper, our purpose was to characterize the proteome of the culture medium in which the oocytes within the primordial/primary follicles underwent apoptosis induced by cisplatin (CIS) or were, for the most part, protected by LH against the drug. To this aim, prepubertal ovarian tissues were cultured under control and in the presence of CIS, LH, and CIS + LH. The culture media were harvested after 2, 12, and 24 h from chemotherapeutic drug treatment and analyzed by liquid chromatography-mass spectrometry (LC-MS). We found that apoptotic conditions generated by CIS in the cultured ovarian tissues and/or oocytes are reflected in distinct changes in the extracellular microenvironment in which they were cultured. These changes became evident mainly from 12 h onwards and were characterized by the inhibition or decreased release of a variety of compounds, such as the proteases Htra1 and Prss23, the antioxidants Prdx2 and Hbat1, the metabolic regulators Ldha and Pkm, and regulators of apoptotic pathways such as Tmsb4x. Altogether, these results confirm the biological relevance of the LH action on prepuberal ovaries and provide novel information about the proteins released by the ovarian tissues exposed to CIS and LH in the surrounding microenvironment. These data might represent a valuable resource for future studies aimed to clarify the effects and identify biomarkers of these compounds' action on the developing ovary