1,722,058 research outputs found
A novel mechanism of action of corticotropin releasing factor in rat Leydig cells.
No full textWe have recently demonstrated the presence in the rat Leydig cells of a corticotropin releasing factor (CRF) receptor and an inhibitory action of the peptide on human chorionic gonadotropin (hCG)-induced cAMP generation and steroidogenesis. The inhibitory action of CRF was unaffected by pertussis toxin and was completely reversed by 8-bromo-cAMP (Ulisse, S., Fabbri, A., and Dufau, M. L. (1989) J. Biol. Chem. 264, 2156-2163). In this study, we have evaluated the participation of protein kinase C in CRF action in the Leydig cells and the level of the gonadotropin signal pathway affected by CRF. Binding of 125I-labeled ovine CRF to Leydig cell membranes was reduced by GTP and guanyl-5'-yl imidodiphosphate (Gpp(NH)p), in a dose-dependent manner. Phorbol 12-myristate 13-acetate, like CRF, caused time-dependent inhibition of hCG-induced cAMP generation and steroidogenesis. This inhibitory action was reversed by 8-bromo-cAMP. Both CRF and 12-O-tetradecanoylphorbol-13-acetate did not affect 125I-hCG binding. No additive effects of CRF and the phorbol ester were observed in these studies. CRF caused a rapid translocation of protein kinase C in Leydig cells. Preincubation of cells with protein kinase C inhibitors or TPA-induced depletion of protein kinase C prevented the inhibitory actions of CRF and TPA. CRF and TPA were able to inhibit the stimulation of cAMP and testosterone production by cholera toxin and forskolin. Adenylate cyclase stimulation by Gpp(NH)p, luteinizing hormone + Gpp(NH)p, and NaF in crude membranes or by forskolin and manganese in solubilized membranes, prepared from CRF- and TPA-treated cells, was also markedly inhibited. We conclude that CRF receptors interact with a pertussis toxin-insensitive G protein (possibly Gp) in the Leydig cell and that the inhibitory action of CRF on Leydig cell function is exerted mainly on the catalytic subunit of adenylate cyclase through a direct or indirect action of protein kinase C
Vis/NIR hyperspectral imaging technology in predicting the quality properties of three fruit cultivars during production and storage
No full textHyperspectral imaging technology has its origins in the mid-1980s: from hyperspectral cameras developed for remote sensing by aerial vehicles or satellites, the technology has moved to proximal sensing applications on a lab-scale under controlled conditions. In the agri-food sector, hyperspectral imaging technology emerged in the non-destructive measurement of food quality parameters. In recent years, due to the miniaturization of hyperspectral cameras and the increase in computational and data storage capabilities, there is growing interest towards the in-field application of proximal remote sensing hyperspectral cameras mounted on airborne or unmanned aerial vehicles or ground vehicles. As example of the application of the hyperspectral imaging in the agri-food sector, quality attributes (soluble solids content, flesh firmness) of apricots, kiwifruits and grape were monitored by means of a hyperspectral camera, in order to observe their evolution during storage and directly in field
Quantum energy momentum tensor and equal time correlations in a Reissner-Nordström black hole
Full text linkWe consider a Reissner-Nordström black hole formed by the collapse of a charged null shell. The renormalized expectation values of the energy-momentum tensor operator for a massless scalar field propagating in the two-dimensional section of this spacetime are given. We then analyze the across-the- horizon correlations of the related energy density operator for free-falling observers to reveal the correlations between the Hawking particles and their interior partners
Re-dosing of prostaglandin-E-1 versus prostaglandin-E-1 plus phentolamine in male erectile dysfunction: a dynamic color power Doppler study - Reply to HC Porst
No full textValidation of a finite element program for the design of roll-over protective framed structures (ROPS) for agricultural tractors
No full textThe design and testing of roll-over protective structures (ROPS) present considerable challenges for small- to medium-sized agricultural tractor manufacturers. Moreover, these manufacturers experience difficulties in using commercial finite element packages. As a consequence, a finite element program, previously described (Fabbri, 1996, 1999, 2000), has been developed to simulate the behaviour of the most common roll-over protective structures (ROPS), when tested according to OECD/EEC (Organisation for Economical Co-operation and Development/Economic European Community) codes.
The program developed in this study was validated against analytical models and other commercial finite element packages, as well as data directly measured in ROPS testing. The model predicts the force–displacement characteristics of tractor cabs to within 20% of the actual test value. The accuracy is directly related to the reliability of the description of the geometry, the material properties and the boundary conditions. The program requires relatively little operator training, and is particularly suitable for use by small-to medium-sized agricultural tractor manufacturers
Microniological remarks on use of cefuroxime (Considerazioni microbiologiche sull'uso del cefuroxime)
No full textTesticular and thyroid function as survival predictors in the elderly patient candidate to surgery
No full textThe relationship between testosterone deficiency (TD) syndrome and surgical resilience has a great impact in the modern approach to male elderly patients. There is good evidence that low levels of T are a strong marker for cardiovascular risk; also, TD is frequently associated with increased cardiovascular and all-cause mortality especially in cardiac older frail men. Screening for low T should be mandatory in high risk groups candidate to surgery including those with diabetes, metabolic syndrome and obesity, even though benefits from T-treatment on survival rates are unclear.The low-T3 syndrome, named non-thyroidal illness (NTI) that occurs during critical illness refers to a syndrome with different faces in both sexes. The acute stress or critical illness-induced alterations within the thyroid axis occur in the first days of critical illness i.e. post-surgery and are brought about at least in part by the concomitant macronutrient deficit. The NTI that occurs in prolonged critically ill patients or in post-surgical resilience patients who continue to be dependent on intensive medical care for weeks or months, may have an impact on surgical outcomes because of frequent occurrence of cardiac arrhythmias. Future directions should better routinely investigate circulating thyroid hormones in population at risk before surgery after excluding iatrogenic drug interferences, and investigate the effect of possible treatments on survival rates after surgery
Workers Buyout: Why Employee-owned Enterprises are more resilient than corporate business in time of Economic and Financial Crisis? The case of Emilia-Romagna Region
No full textThe Workers BuyOut (WBO) is an economic and social phenomenon that has
developed since the beginning of the 2008 financial and economic crisis and is still
growing. In Italy, its roots can be traced back to the 1970s and today journalists and
politicians are publishing reportages and books on this phenomenon. Inside the
Italian scientific community, also some economists have dedicated accurate but rare
studies to the topic. Nevertheless, the WBO has not yet become the focus of a
precise and in-depth research by sociologists, despite its evident social relevance.
The present paper is the result of a sociological investigation carried out by the
authors and aims at illustrating this phenomenon through the lens of organizational
analysis. It is structured in five sections: a general introduction; a description of the
phenomenon at the national level, through the analysis of its normative grounds and
its quantitative dimensions; a more detailed description of the WBO in EmiliaRomagna Region; a focus on the case study of one firm that turned into a successful
WBO; a critical conclusion, highlighting the main incentives and obstacles for the full
development of WBO experiences
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