Nuovi fasti dei magistri fontani in un frustulo epigrafico opistografo dal piccolo Aventino

Edizione di un nuovo frammento epigrafico, opistografo, rinvenuto a Roma sul piccolo Aventino e contenente liste di personaggi identificati, in base a vari indizi, con magistri Fontani

Clathrin-dependent endocytosis of membrane-bound RANKL in differentiated osteoclasts

Bone is continuously repaired and remodelled through well-coordinated activity of osteoblasts that form new bone and osteoclasts, which resorb it. Osteoblasts synthesize and secrete two key molecules that are important for osteoclast differentiation, namely the ligand for the receptor of activator of nuclear factor κB (RANKL) and its decoy receptor osteoprotegerin (OPG). Active membrane transport is a typical feature of the resorbing osteoclast during bone resorption. Normally, one resorption cycle takes several hours as observed by monitoring actin ring formation and consequent disappearance in vitro. During these cyclic changes, the cytoskeleton undergoes remarkable dynamic rearrangement. Active cells show a continuous process of exocytosis that plays an essential role in transport of membrane components, soluble molecules and receptor-mediated ligands thus allowing them to communicate with the environment. The processes that govern intracellular transport and trafficking in mature osteoclasts are poorly known. The principal methodological problem that have made these studies difficult is a physiological culture of osteoclasts that permit observing the vesicle apparatus in conditions similar to the in vivo conditions. In the present study we have used a number of morphological approaches to characterize the composition, formation and the endocytic and biosynthetic pathways that play roles in dynamics of differentiation of mature bone resorbing cells using a tri-dimensional system of physiologic coculture

Ice Shapes on a Tail Rotor

Testing of a thermally-protected helicopter rotor in the Icing Research Tunnel (IRT) was completed. Data included inter-cycle and cold blade ice shapes. Accreted ice shapes were thoroughly documented, including tracing, scanning and photographing. This was the first time this scanning capability was used outside of NASA. This type of data has never been obtained for a rotorcraft before. This data will now be used to validate the latest generation of icing analysis tools

Zn–al layered double hydroxides synthesized on aluminum foams for fluoride removal from water

Fluoride excess in water represents an environmental issue and a risk for human health since it can cause several diseases, such as fluorosis, osteoporosis, and damage of the nervous system. Layered double hydroxides (LDHs) can be exploited to remove this contaminant from water by taking advantage of their high ion-exchange capability. LDHs are generally mixed with polluted water in the form of powders, which then cause the problem of uneasy separation of the contaminated LDH sludge from the purified liquid. In this work, Zn–Al LDH films were directly grown in situ on aluminum foams that acted both as the reactant and substrate. This method enabled the removal of fluoride ions by simple immersion, with ensuing withdrawal of the foam from the de-contaminated water. Different LDH synthesis methods and aluminum foam types were investigated to improve the adsorption process. The contact time, initial fluoride concentration, adsorbent dosage, and pH were studied as the parameters that affect the fluoride adsorption capacity and efficiency. The highest absorption efficiency of approximately 70% was obtained by using two separate growth methods after four hours, and it effectively reduced the fluoride concentration from 3 mg/L to 1.1 mg/L, which is below the threshold value set by WHO for drinking water

Silica containing composite anion exchange membranes by sol–gel synthesis: a short review

This short review summarizes the literature on composite anion exchange membranes (AEM) containing an organo-silica network formed by sol-gel chemistry. The article covers AEM for diffusion dialysis (DD), for electrochemical energy technologies including fuel cells and redox flow batteries, and for electrodialysis. By applying a vast variety of organically modified silica compounds (ORMOSIL), many composite AEM reported in the last 15 years are based on poly (vinylalcohol) (PVA) or poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) used as polymer matrix. The most stringent requirements are high permselectivity and water flux for DD membranes, while high ionic conductivity is essential for electrochemical applications. Furthermore, the alkaline stability of AEM for fuel cell applications remains a challenging problem that is not yet solved. Possible future topics of investigation on composite AEM containing an organo-silica network are also discussed

Optical bistability: a self-consistent analysis of fluctuations and the spectrum of scattered light

The main purpose of this paper is to study the behavior of the atomic fluctuations and the spectrum of the light transmitted by an absorptive bistable device. To this end we develop an approximation scheme based on the so-called system-size expansion and apply it to the quantum-mechanical Langevin equations for the atomic fluctuation operators. The Bonifacio-Lugiato mean-field equations for bistability are derived from the lowest-order approximation to the system-size expansion, while the atomic correlation functions result from the next-higher-order expansion. The calculated spectrum of the transmitted light exhibits line narrowing near the bistable thresholds, discontinuous formation of sidebands along the high-transmission branch of the device, and hysteresis effects

Absorption spectrum of optically bistable systems

The quantum-mechanical theory of optical bistability developed in an earlier paper is generalized to calculate the absorption spectrum (gain coefficient) of an optically bistable system in the presence of a weak probe field. The behavior of the gain coefficient on the cooperative branch and the single-atom branch is analyzed in detail

Quantum analysis of optical bistability and spectrum of fluctuations

We discuss the approach to equilibrium and the fluctuations of a bistable system under dynamical conditions such that the field variables can be eliminated adiabatically. The atomic system evolves under the action of the coherent pumping of an external field and of collective and incoherent relaxation processes. The competition between pumping and relaxation effects causes the atomic steady-state configurations to depend discontinuously on the strength of the driving field. We derive an explicit expression for the spectrum of the forward-scattered light, which exhibits hysteresis and a discontinuous dependence on the driving-field amplitude

Lamellar and «club-shaped» corpuscular nerve endings in human gingival mucosa. A light and electron microscopic study

A study on the presence of corpuscular nerve endings in human gingival mucosa was performed using both light and transmission electron microscopic (TEM) techniques. Both round and oval lamellar corpuscles were detected by light microscopy. They were located either subepithelially, close to the basement membrane, or within the papillae, deeply invaginated into the overlying epithelium. TEM techniques showed convoluted structures with unmyelinated fibre arborizations leading to an afferent fibre supported by the so called lamellar cells. The presence of blood vessels, collagenous fibrils, desmosome-like junctions, cytoplasmic organelles, as well as the similarity with some previously described mechanoreceptors, suggested the role of such corpuscular nerve endings in transmitting a nervous impulse induced by mechanical stimulation. Other simpler structures were also observed and named «club-shaped» corpuscles: they could support the more complex ones in responding to the strengths and the movements directly influencing the gingival mucosa.La présence de terminaisons nerveuses corpusculaires dans la muqueuse gingivale humaine a été observée tant en microscopie optique qu’en microscopie électronique à transmission. En microscopie optique on a remarqué des corpuscules lamellaires ronds et ovalaires, qui étaient localisés tant au dessous de l’épithélium, tout près de la membrane basale, qu’au dedans des papilles, profondément insérés dans l’épithélium.En microscopie électronique on a observé des structures convolutées pourvues d’arborisations de fibres nerveuses sans myéline qui vont se réunir dans une fibre afférente supportée par des cellules dites lamellaires. La présence de vaisseaux, de fibrilles collagènes, de jonctions telles que desmoses, d’inclusions cytoplasmiques autant que la ressemblance avec quelques mécanorécepteurs décrits en littérature, suggérait un rôle de ces terminaisons nerveuses corpusculaires en envoyant un impulse nerveux induit par une stimulation mécanique. On a aussi observé des corpuscules plus simples appelés «club-shaped» qui pourraient supporter les plus complexes dans la réponse aux forces et aux mouvements qui influencent directement la muqueuse gingivale