784 research outputs found
C 1s core-level photoemission spectra of stilbene on Si(100)2x1 surface from first-principles calculations
Adsorption of the cis and trans stilbene on the Si(100)2 x 1 surface was studied using plane waves density functional theory (DFT). Configurations across a silicon dimer, along the dimers and along the channels between dimers were probed for the two isomers. Trans and cis stilbene both bind preferentially across the dimers. In the former case only the ethylenic carbon atoms are involved and the aromatic character is preserved. In the latter case the adsorption interaction involves also the two phenyl rings with the conversion to two 1,3-cyclohexadiene, yielding a more stable local minimum. The corresponding calculated C 1s core level shifts are distributed in an energy range of about 2.5 eV. The overall shape of the spectra of the two adsorbed isomers shows differences consistent with chemical changes observed upon adsorption. There is a good agreement between the simulated and the experimentally observed spectrum of trans stilbene on the Si surface
NICU Infants & SNHL: Experience of a western Sicily tertiary care centre
Introduction: The variability of symptoms and signs caused by central nervous system (CNS) lesions make multiple sclerosis difficult to recognize,Introduction: This study adds the evaluation of the independent etiologic factors that may play a role in the development of SNHL in a NICU population. We compared neonatal intensive care unit NICU infants with sensorineural hearing loss SNHL to age and gender matched normal hearing NICU controls. Materials and methods: 284 consecutive NICU infants positive to the presence of risk indicators associated with permanent congenital, delayed-onset, or progressive hearing loss underwent to global audiological assessment. The following risk factors were researched, making a distinction between prenatal and perinatal risk factors: in the first group, family history of permanent childhood hearing impairment, consanguinity, pregnant maternal infection and drugs exposition during pregnancy; in the second group, premature birth, respiratory distress, hyperbilirubinemia requiring exchange tranfusion, very low birth weight, cranio-facial abnormality, perinatal infections, ototoxic drugs administration, acidosis, hyponatremia, head trauma. Results: The analysis of the auditory deficit for infants according to numbers of risk factors showed mean values of: 78 + 28.08 dB nHL for infants positive to two risk factors; 75.71 + 30.30 dB nHL in cases positive to three risk factors; 96.66 + 34.46 dB nHL for four risk factors and 85 + 35 dB nHL in case of >5 risk factors. Conclusion: NICU infants have greater chances of developing SNHL, because of the presence of multiple risk factors; in fact, as the number of coexisting risk factors increases, the prevalence rate of SNHL also increases (r=0.81)
The Diameter of Cortical Axons Depends Both on the Area of Origin and Target.
In primates, different cortical areas send axons of different diameters into comparable tracts, notably the corpus callosum (Tomasi S, Caminiti R, Innocenti GM. 2012. Areal differences in diameter and length of corticofugal projections. Cereb Cortex. 22:1463-1472). We now explored if an area also sends axons of different diameters to different targets. We find that the parietal area PEc sends thicker axons to area 4 and 6, and thinner ones to the cingulate region (area 24). Areas 4 and 9, each sends axons of different diameters to the nucleus caudatus, to different levels of the internal capsule, and to the thalamus. The internal capsule receives the thickest axon, followed by thalamus and nucleus caudatus. The 2 areas (4 and 9) differ in the diameter and length of axons to corresponding targets. We calculated how diameter determines conduction velocity of the axons and together with pathway length determines transmission delays between different brain sites. We propose that projections from and within the cerebral cortex consist of a complex system of lines of communication with different geometrical and time computing properties. © The Author 2013
Myrtucommulone from Myrtus communis exhibits potent anti-inflammatory effectiveness in vivo.
Myrtucommulone a nonprenylated acylphloroglucinol contained in the leaves of myrtle (Myrtus communis), has been reported to suppress the biosynthesis of eicosanoids by inhibition of 5-lipoxygenase and cyclooxygenase-1 in vitro and to inhibit the release of elastase and the formation of reactive oxygen species in activated polymorphonuclear leukocytes. Here, in view of the ability of MC to suppress typical proinflammatory cellular responses in vitro, we have investigated the effects of MC in in vivo models of inflammation. MC was administered to mice intraperitoneally, and paw edema and pleurisy were induced by the subplantar and intrapleural injection of carrageenan, respectively. MC (0.5, 1.5, and 4.5 mg/kg i.p.) reduced the development of mouse carrageenan-induced paw edema in a dose-dependent manner. Moreover, MC (4.5 mg/kg i.p. 30 min before and after carrageenan) exerted anti-inflammatory effects in the pleurisy model. In particular, 4 h after carrageenan injection in the pleurisy model, MC reduced: 1) the exudate volume and leukocyte numbers; 2) lung injury (histological analysis) and neutrophil infiltration (myeloperoxidase activity); 3) the lung intercellular adhesion molecule-1 and P-selectin immunohistochemical localization; 4) the cytokine levels (tumor necrosis factor-α and interleukin-1 ÎČ in the pleural exudate and their immunohistochemical localization in the lung; 5) the leukotriene B 4, but not prostaglandin E2, levels in the pleural exudates; and 6) lung peroxidation (thiobarbituric acid-reactant substance) and nitrotyrosine and poly (ADP-ribose) immunostaining. In conclusion, our results demonstrate that MC exerts potent anti-inflammatory effects in vivo and offer a novel therapeutic approach for the management of acute inflammation. Copyright © 2009 by The American Society for Pharmacology and Experimental Therapeutics
Cooperative Collision Avoidance at Intersections: Algorithms and Experiments
In this paper, we leverage vehicle-to-vehicle (V2V) communication technology to implement computationally efficient decentralized algorithms for two-vehicle cooperative collision avoidance at intersections. Our algorithms employ formal control theoretic methods to guarantee a collision-free (safe) system, whereas overrides are only applied when necessary to prevent a crash. Model uncertainty and communication delays are explicitly accounted for by the model and by the state estimation algorithm. The main contribution of this work is to provide an experimental validation of our method on two instrumented vehicles engaged in an intersection collision avoidance scenario in a test track
Cortico-spinal modularity in the parieto-frontal system: a new perspective on action control
: Classical neurophysiology suggests that the motor cortex (MI) has a unique role in action control. In contrast, this review presents evidence for multiple parieto-frontal spinal command modules that can bypass MI. Five observations support this modular perspective: (i) the statistics of cortical connectivity demonstrate functionally-related clusters of cortical areas, defining functional modules in the premotor, cingulate, and parietal cortices; (ii) different corticospinal pathways originate from the above areas, each with a distinct range of conduction velocities; (iii) the activation time of each module varies depending on task, and different modules can be activated simultaneously; (iv) a modular architecture with direct motor output is faster and less metabolically expensive than an architecture that relies on MI, given the slow connections between MI and other cortical areas; (v) lesions of the areas composing parieto-frontal modules have different effects from lesions of MI. Here we provide examples of six cortico-spinal modules and functions they subserve: module 1) arm reaching, tool use and object construction; module 2) spatial navigation and locomotion; module 3) grasping and observation of hand and mouth actions; module 4) action initiation, motor sequences, time encoding; module 5) conditional motor association and learning, action plan switching and action inhibition; module 6) planning defensive actions. These modules can serve as a library of tools to be recombined when faced with novel tasks, and MI might serve as a recombinatory hub. In conclusion, the availability of locally-stored information and multiple outflow paths supports the physiological plausibility of the proposed modular perspective
Nickel(II) 3,4;9,10-Perylenediimide bis-Phosphonate Pentahydrate: A MetalâOrganic Ferromagnetic Dye
The new metalâorganic compound nickel(II) 3,4;9,10-
perylenediimide bis-phosphonate pentahydrate, i.e. Ni2[(PDI-BP)-
(H2O)2]·3H2O (1), has been synthesized and its structural and magnetic
properties have been studied. Reaction of 3,4;9,10-perylenediimide bisphosphonate
(PDI-BP, hereafter) ligand and nickel chloride in water resulted
in the precipitation of a red and poorly crystalline solid (1). As the solid shows
a poor crystalline organization of aggregates, the energy dispersive X-ray
diffraction analysis (EDXD) technique has been used to obtain short-range
order structural information of the single nanoaggregates by radial distribution
function analysis. The overall structure of the compound is characterized by
layers containing perylene planes shifted in the direction perpendicular to the
stacking axes in such a way that only the outer rings overlap. The edges of the
perylene planes are connected to the phosphonate groups through an imido
group. The oxygen atoms of the [âPO3]2â group and those of the water
molecules are bonded to the nickel ions resulting in a [NiO6] octahedral coordination sphere. The NiâO bond lengths are 0.21
± 0.08 nm and the NiâOâNi angles of aligned moieties are 95 ± 2°. The oxygen atoms of the water molecules and the nickel
atoms are nearly planar and almost perpendicular to the perylene planes forming chains of edge-sharing octahedra. The magnetic
properties of (1) show the presence of intrachain ferromagnetic NiâNi interactions and a long-range ferromagnetic order below
21 K with a canting angle and with a spin glasslike behavior due to disorder in the inorganic layer. Hysteresis cycles show a
coercive field of ca. 272 mT at 2 K that decreases as the temperature is increased and vanishes at ca. 20 K
Surface area of lipid membranes regulates the DNA-binding capacity of cationic liposomes.
We have applied electrophoresis on agarose gels to investigate the DNA-binding capacity of cationic liposomes made of cationic DC-cholesterol and neutral dioleoylphosphatidylethanolamine as a function of membrane charge density and cationic lipid/DNA charge ratio. While each cationic liposome formulation exhibits a distinctive DNA-protection ability, here we show that such a capacity is universally regulated by surface area of lipid membranes available for binding in an aspecific manner. The relevance of DNA protection for gene transfection is also discussed
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