1,711 research outputs found

    PHOTOGRAMMETRY AND MEDIEVAL ARCHITECTURE. USING BLACK AND WHITE ANALOGIC PHOTOGRAPHS FOR RECONSTRUCTING THE FOUNDATIONS OF THE LOST ROOD SCREEN AT SANTA CROCE, FLORENCE

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    In this research paper photogrammetric techniques have been successfully applied to historic black and white analogic photographs to convey previously inaccessible architectural and archaeological information. The chosen case study for this paper is the Franciscan Basilica of Santa Croce in Florence, Italy. A photogrammetric algorithm has been implemented over a series of b/w negatives portraying the archaeological excavations carried out in the years 1967–1969, after the traumatic flood of the river Arno in 1966 that severely damaged the city centre of Florence and, particularly, the Santa Croce monumental site. The final aim of this operation is to provide solid evidence for the virtual reconstruction of the lost rood screen of the basilica of Santa Croce, the current subject of the PhD research of one of the Authors (Giovanni Pescarmona) at the University of Florence. The foundations that were uncovered during the archaeological excavation in the ‘60s are one of the most important hints towards a convincing retro-planning of the structure. Using advanced photogrammetric techniques, and combining them with LIDAR scanning, it is possible to uncover new datasets that were previously inaccessible for scholars, opening new paths of research. This interdisciplinary approach, combining traditional art-historical research methods and state-of-the-art computational tools, tries to bridge the gap between areas of research that still do not communicate enough with each other, defining new frameworks in the field of Digital Art History

    Spectroscopic and Theoretical Study of the Grafting Modes of Phosphonic Acids on ZnO Nanorods

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    Metal oxides are versatile substrates for the design of a wide range of SAM-based organic-inorganic materials among which ZnO nanostructures modified with phosphonic SAM are promising semiconducting systems for applications in technological fields such as biosensing, photonics, and field-effect transistors (FET). Despite previous studies reported on various successful grafting approaches, issues regarding preferred anchoring modes of phosphonic acids and the role of a second reactive group (i.e., a carboxylic group) are still a matter of controversial interpretations. This paper reports on an experimental and theoretical study on the functionalization of ZnO nanorods with monofunctional alkylphosphonic and bifunctional carboxyalkylphosphonic acids. X-ray photoelectron and infrared spectroscopies have been combined with DFT modeling to explain and understand the interactions that drive the surface anchoring of phosphonic acids on ZnO surface. It was found that both monofunctional and bifunctional acids anchor on ZnO through a multidentate bonding which involves both P=O and P-O moieties of the phosphonic group. Moreover, anchored bifunctional acids bend to the surface, promoting a further interaction between surface hydroxyl groups and carboxylic terminations. This secondary interaction can be limited by increasing the surface density of the anchored molecules

    Insulin and insulin-like growth factor I (IGF I) stimulate phosphorylation of a Mr 175,000 cytoskeleton-associated protein in intact FRTL5 cells.

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    Abstract FRTL5 rat thyroid cells possess separate high affinity receptors for insulin and insulin-like growth factor I (IGF I) that undergo beta-subunit phosphorylation upon interaction with the specific ligand. Phosphorylation is rapid and dose-dependent and occurs primarily on tyrosine residues. Within 2 min, both insulin and IGF I also give rise to a Mr 175,000 phosphoprotein (pp175) that can be immunoprecipitated by anti-phosphotyrosine antibody (alpha-Tyr(P]. Phosphorylation of pp175 occurs on serine and threonine as well as tyrosine residues. When FRTL5 cells are solubilized with 1% Triton X-100, alpha-Tyr(P) immunoprecipitates phosphorylated insulin and IGF I receptors but little pp175 from the Triton-soluble fraction. After treatment of the Triton-insoluble portion with 1% sodium dodecyl sulfate at 100 degrees C, pp175 can be identified by immunoprecipitation with alpha-Tyr(P). The fraction of FRTL5 cells that remains after extraction of an attached monolayer with 1% Triton for 5 min at 22 degrees C contains most of the cytoskeleton and also nuclei. Extraction of this 32P-labeled cytoskeleton preparation with sodium dodecyl sulfate followed by alpha-Tyr(P) immunoprecipitation results in almost complete recovery of the pp175 content of the cells. When a nuclear fraction was prepared from FRTL5 cells by differential centrifugation, pp175 was not found in the nuclear pellet from labeled cells, but greater than 80% of pp175 was recovered in the supernatant. We conclude that pp175 is a common substrate for insulin and IGF I receptor kinases which, in FRTL5 cells, is associated with the cytoskeleton. It is suggested that phosphorylation of proteins associated with cytoskeletal elements could be involved in insulin and IGF I action in cells

    Ultralow loading electroless deposition of IrOx on nickel foam for efficient and stable water oxidation catalysis

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    Abstract Photocatalysis and electrolysis are crucial processes for the development of a sustainable, clean energy system, since they enable solar fuel production, such as hydrogen by water splitting, as well as CO2 reduction. In these processes efficient and robust catalysts for water oxidation are required and the reduction of employed amount of noble metals is crucial to reduce costs and increase the sustainability of the technology. To obtain extremely low iridium loading on nickel foam electrodes we have employed electroless deposition by spontaneous galvanic displacement as a simple, low cost, highly scalable technique. After deposition the Ir oxidation has been achieved by annealing in air at 250 °C. By varying the deposition parameters, an optimal condition has been achieved, with an overpotential for water oxidation of 360 mV at 10 mA cm−2 in 1.0 M KOH solution. The Ni foam coverage with Ir oxide has also a positive impact on the electrode stability, strongly decreasing the degradation rate, compared to the case of bare Ni foam. The average amount of noble metal in the best performing electrode is only 35 μg cm−2 for a 1.6 mm thick Ni foam electrode. The proposed approach is highly promising for gas diffusion electrodes, and can be implemented in electrolytic cells, as well as in fuel cells

    Interval training normalizes cCardiomyocyte function, diastolic Ca<sup>2+</sup> control, and SR Ca<sup>2+</sup> release synchronicity in a mouse model of diabetic cardiomyopathy

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    In the present study we explored the mechanisms behind excitation-contraction (EC)-coupling defects in cardiomyocytes from mice with type-2 diabetes (db/db), and determined whether 13-weeks of aerobic interval training could restore cardiomyocyte Ca2+ cycling and EC-coupling. Reduced contractility in cardiomyocytes isolated from sedentary db/db was associated with increased diastolic sarcoplasmic reticulum (SR)-Ca2+ leak, reduced synchrony of Ca2+ release, reduced transverse (T)-tubule density, and lower peak systolic and diastolic Ca2+ and caffeine-induced Ca2+ release. Additionally, the rate of SR Ca2+ ATPase (SERCA2a)-mediated Ca2+ uptake during diastole was reduced, whereas a faster recovery from caffeine-induced Ca2+ release indicated increased Na+/Ca2+- exchanger (NCX) activity. The increased SR-Ca2+ leak was attributed to increased Ca2+-calmodulindependent protein kinase (CaMKII&#948;) phosphorylation, supported by the normalization of SR-Ca2+ leak upon inhibition of CaMKII&#948; (AIP). Exercise training restored contractile function associated with restored SR Ca2+ release synchronicity, T-tubule density, twitch Ca2+ amplitude, SERCA2a and NCX activities, and SR-Ca2+ leak. The latter was associated with reduced phosphorylation of cytosolic CaMKII&#948;. Despite normal contractile function and Ca2+ handling after the training period, phospholamban was hyperphosphorylated at Serine-16. Protein kinase A (PKA) inhibition (H-89) in cardiomyocytes from the exercised db/db group abolished the differences in SR-Ca2+ load when compared with the sedentary db/db mice. EC-coupling changes were observed without changes in serum insulin or glucose levels, suggesting that the exercise training-induced effects are not via normalization of the diabetic condition. These data demonstrate that aerobic interval training almost completely restored the contractile function of the diabetic cardiomyocyte to levels close to sedentary wild type (WT)

    Antiabsence effects of carbenoxolone in two genetic animal models of absence epilepsy (WAG/Rij rats and lh/lh mice)

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    Carbenoxolone (CBX), the succinyl ester of glycyrrhetinic acid, is an inhibitor of gap junctional intercellular communication. We have tested its possible effects upon two genetic animal models of epilepsy (WAG/Rij rats and lethargic (lh/lh) mice). Systemic administration of CBX was unable to significantly affect the occurrence of absence seizures in WAG/Rij rats. In particular, intravenous (5-40 mg/kg) or intraperitoneal (i.p.; 10-80 mg/kg) administration of CBX was unable to significantly modify the number and duration of spike-wave discharges (SWDs) in WAG/Rij rats, whereas the bilateral microinjection (0.05, 0.1, 0.5 and 1 microg/0.5 microl) of CBX into nucleus reticularis thalami (NRT) and nucleus ventralis posterolateralis (VPL) thalami produced a decrease in the duration and the number of SWDs. Bilateral microinjection of CBX into nucleus ventroposteromedial (VPM) thalami did not produce any significant decrease in the number and duration of SWDs. On the contrary, i.p. (5-40 mg/kg) or intracerebroventricular (0.5, 1, 2 and 4 microg/2 microl) administration of CBX in lh/lh mice induced a marked decrease in the number and duration of SWDs in a dose-dependent manner. At the doses used no movement disorders, or other behavioural changes, were recorded in both WAG/Rij rats and lh/lh mice. No effects were observed in both animal models following systemic or focal administration of glycyrrhizin into the same brain areas where CBX was shown to be effective
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