28 research outputs found
Practical feasibility, scalability and effectiveness of coordinated scheduling algorithms in cellular networks towards 5G
Coordinated Scheduling (CS) is used to mitigate inter-cell interference in present (4G) and future (5G) cellular networks. We show that coordination of a cluster of nodes can be formulated as an optimization problem, i.e., placing the Resource Blocks (RB) in each node’s subframe with the least possible over-lapping with neighboring nodes. We provide a clever formulation, which allows optimal solutions to be computed in clusters of ten nodes, and algorithms that compute good suboptimal solutions for clusters of tens of nodes, fast enough for a network to respond to traffic changes in real time. This allows us to assess the relationship between the scale at which CS is performed and its benefits in terms of network energy efficiency and cell-edge user rate. Our results, obtained using realistic power, radiation and Signal-to-Interference-and-Noise-Ratio (SINR) models, show that optimal CS allows a significant protection of cell-edge users. Moreover, this goes hand-in-hand with a reduction in the num-ber of allocated RBs, which in turn allows an operator to reduce its energy consumption. Both benefits actually increase with the size of the clusters. The evaluation is carried out in both a 4G and a foreseen 5G setting, using different power models, system bandwidths and SINR-to-datarate mappings
Novel Potent Muscarinic Receptor Antagonists: Investigation on the Nature of Lipophilic Substituents in the 5- and/or 6-Positions of the 1,4-Dioxane Nucleus
A series of novel 1,4-dioxane analogues of the muscarinic acetylcholine receptor (mAChR) antagonist 2 was synthesized and studied for their affinity at M1-M5 mAChRs. The 6-cyclohexyl-6-phenyl derivative 3b, with a cis configuration between the CH2N+(CH3)3 chain in the 2-position and the cyclohexyl moiety in the 6-position, showed pKi values for mAChRs higher than those of 2 and a selectivity profile analogous to that of the clinically approved drug oxybutynin. The study of the enantiomers of 3b and the corresponding tertiary amine 33b revealed that the eutomers are (2S,6S)-(-)-3b and (2S,6S)-(-)-33b, respectively. Docking simulations on the M3 mAChR-resolved structure rationalized the experimental observations. The quaternary ammonium function, which should prevent the crossing of the blood-brain barrier, and the high M3/M2 selectivity, which might limit cardiovascular side effects, make 3b a valuable starting point for the design of novel antagonists potentially useful in peripheral diseases in which M3 receptors are involved
Structural and synthetic insights into the chemistry of lithium tetraorganozincates
Main group bimetallic complexes have emerged as powerful reagents in organometallic synthesis, exhibiting unique reactivity profiles that cannot be replicated by their homo-metallic components. This chapter focusses on a particular family of bimetallic reagents, namely higher order lithium zincates. Exhibiting the empirical formulation R4ZnLi2 (R = alkyl, aryl, alkynyl, etc.), these compounds have found widespread applications in cornerstone organic reactions such as deprotonative metalation, metal halogen exchange or C[sbnd]C bond forming processes. By switching on bimetallic cooperativity these reagents exhibit excellent functional group tolerance and regioselectivities while being kinetically activated in comparison with parent organozinc reagents R2Zn. Showcasing key selected examples here we provide an overview on the synthesis, structure, solution constitution and stability of these mixed lithium/zinc complexes and discuss their most representative applications in modern organic synthesis. A main aim of this chapter is to shed light on the close interplay between structure and reactivity in this family of mixed lithium/zinc reagents and how bimetallic cooperation can be maximized to develop more effective and regioselective synthetic protocols
Correzione chirurgica di alluce valgo bilaterale e retropiede valgo: Descrizione di un caso clinico
The only surgical correction of hallux valgus in patients who have associated pronated hindfoot shows high incidence of relapse. Surgical operations suggested in medical literature to correct valgus hindfoot in adult people are calcaneous osteotomy and talus-calcaneous arthrodeses (Grice). Arthrorisis, used in evolutive age, has showed good results. This has suggested us to adopt this technique also in the correction of pronated hindfoot in young adults. A case report of bilateral hallux valgus surgical correction associated with talus-calcaneous arthrorisis is presented. At a middle follow-up of 6 months a good clinical and radiological correction of feet without any signs of mobilization was observed
Palladium iodide catalyzed carbonylative double cyclization to a new class of S,O-bicyclic heterocycles
A Pd-catalyzed carbonylative double cyclization approach to a novel class of S,O-bicyclic heterocycles is pre-sented. It is based on the reaction between readily available 5-(methylthio)pent-1-yn-3-ols with CO in the presence of the PdI2/KI catalytic system carried out under oxidative conditions with oxygen as external oxidant. The process takes place through an ordered sequence of steps involving an initial 5-exo-dig S-cyclization (by intramolecular nucleoplilic attack by the thiomethyl group to the triple bond activated by coordination to the palladium center), followed by S-demethylation (by attack by the iodide anion), carbon monoxide insertion, O- cyclization (by intramolecular nucleophilic displacement of the hydroxyl group to the ensuing acylpalladium intermediate), and Pd(0) reoxidation. The method allows the construction of previously unreported 6,6a-dihy-drothieno[3,2-b]furan-2(5H)-ones starting from simple substrates (5-(methylthio)pent-1-yn-3-ols and CO) with the formation of 3 new bonds and two cycles in one step, and has been successfully applied to the synthesis of variously substituted products (57-81 %, 17 examples)
Off-label and unlicensed drug use among neonatal intensive care units (NICUs) in Southern Italy.
Hemiballism. Unusual clinical manifestation in three patients with frontoparietal infarct
The term hemiballism-hemichorea refers to a movement disorder characterized by involuntary movements, often violent, described as uncontrollable jerking, flinging, flailing or kicking, involving proximal muscles of a limb and it is often associated with lesions in the subthalamic nucleus. In this report, we described three cases of hemiballism-hemichorea as the first manifestation of acute ischemic stroke with lesion in the frontoparietal region on brain MRI and no involvement of the subthalamic nucleus. One patient was treated with thrombolysis and recovered within one hour. The other patients recovered within 48 h from symptoms onset. The impairment of the recently described "hyperdirect way", in which the cortical signal reach directly the subthalamic nucleus, may underlie the symptoms. We support, with a clinical point of view, the role of the frontoparietal region in the genesis of the hemiballism-hemichorea. An acute onset of this symptom should lead to think to an acute stroke