511 research outputs found

    Interplay of the electronic and lattice degrees of freedom in A_{1-x}Fe_{2-y}Se_{2} superconductors under pressure

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    The local structure and electronic properties of Rb1x_{1-x}Fe2y_{2-y}Se2_2 are investigated by means of site selective polarized x-ray absorption spectroscopy at the iron and selenium K-edges as a function of pressure. A combination of dispersive geometry and novel nanodiamond anvil pressure-cell has permitted to reveal a step-like decrease in the Fe-Se bond distance at p11p\simeq11 GPa. The position of the Fe K-edge pre-peak, which is directly related to the position of the chemical potential, remains nearly constant until 6\sim6 GPa, followed by an increase until p11p\simeq 11 GPa. Here, as in the local structure, a step-like decrease of the chemical potential is seen. Thus, the present results provide compelling evidence that the origin of the reemerging superconductivity in A1xA_{1-x}Fe2y_{2-y}Se2_2 in vicinity of a quantum critical transition is caused mainly by the changes in the electronic structure

    Psychiatric profile of motor subtypes of de novo drug-naïve Parkinson's disease patients

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    Background: Parkinson's disease (PD) is a heterogeneous neurodegenerative disorder. It is well established that different motor subtypes of PD evolve with different clinical courses and prognoses. The complete psychiatric profile underlying these different phenotypes since the very early stage of the disease is debated. Aims of the study: We aimed at investigating the psychiatric profile of the three motor subtypes of PD (akinetic-rigid, tremor-dominant, and mixed) in de novo drug-naïve patients with PD. Methods: Sixty-eight patients with PD, divided into 39 akinetic-rigid (AR), seven mixed (MIX), and 22 tremor-dominant (TD) patients underwent a complete assessment of psychiatric, cognitive, and motor symptoms. Results: No significant differences were found among groups. Conclusions: Our results suggest that a differentiation of the psychiatric symptoms associated with specific motor subtypes of PD is not detectable in de novo drug-naïve patients. Previous evidence that emerges later along the disease progression may be a consequence of the dopaminergic and nondopaminergic damage increase

    Involvement of subcortical brain structures during olfactory stimulation in multiple chemical sensitivity

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    Multiple chemical sensitivity (MCS) patients usually react to odour compounds and the majority of neuroimaging studies assessed, especially at the cortical level, many olfactory-related correlates. The purpose of the present study was to depict sub-cortical metabolic changes during a neutral (NC) and pure (OC) olfactory stimulation by using a recently validated 18F-2-fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography/computer tomography procedure in 26 MCS and 11 healthy (HC) resting subjects undergoing a battery of clinical tests. Twelve subcortical volumes of interest were identified by the automated anatomical labeling library and normalized to thalamus FDG uptake. In both groups, when comparing OC to NC, the within-subjects ANOVA demonstrated a relative decreased metabolism in bilateral putamen and hippocampus and a relative increased metabolism in bilateral amygdala, olfactory cortex (OLF), caudate and pallidum. The between-groups ANOVA demonstrated in MCS a significant higher metabolism in bilateral OLF during NC. As in HC subjects negative correlations were found in OC between FDG uptake in bilateral amygdala and hippocampus and odor pleasantness scale, the latter positively correlated with MCS subjects\u27 bilateral putamen FDG uptake in OC. Besides FDG uptake resemblances in both groups were found, for the first time a relative higher metabolism increase in OLF in MCS subjects at rest with respect to HC was found. When merging this aspect to the different subcortical FDG uptake correlations patterns in the two groups, the present study demonstrated to describe a peculiar metabolic index of behavioral and neurological aspects of MCS complaints

    Homovanillic acid in CSF of mild stage Parkinson's disease patients correlates with motor impairment.

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    In Parkinson's disease (PD), several efforts have been spent in order to find biochemical parameters able to identify the progression of the pathological processes at the basis of the disease. It is already known that advanced PD patients manifesting dyskinesia are featured by the high homovanillic acid (HVA)/dopamine (DA) ratio, suggesting the increased turnover of DA in these patients. Less clear is whether similar changes affect mild and moderate stages of the disease (between 1 and 2.5 of Hoehn & Yahr -H&Y- stage). Hence, here we tested whether cerebrospinal fluid (CSF) concentrations of DA and its major metabolites, either 3,4-dihydroxyphenylacetic acid (DOPAC) or HVA, correlate with motor performance in mild and moderate PD patients. CSF samples were collected after 2 days of anti-PD drugs washout, via lumbar puncture (LP) performed 130 min following administration of oral levodopa (LD) dose (200 mg). LP timing was determined in light of our previous tests clarifying that 2 h after oral LD administration CSF DA concentration reaches a plateau, which was un-respective of PD stage or duration. DA, DOPAC and HVA were assayed by high performance liquid chromatography in a group of 19 patients, distributed in two groups on the basis of the H&Y stage with a cut-off of 1.5. In these PD patients, HVA was correlated with DOPAC (R = 0,56, p < 0,01) and both HVA and DOPAC CSF levels increased in parallel with the motor impairment. More importantly, HVA correlated with motor impairment measured by the Unified Parkinson's Disease Score -III (UPDRS) (R = 0.61; p < 0.0001). The present findings showed the early alteration of the DA pre-synaptic machinery, as documented by the progressive increase of CSF HVA concentrations, which also correlated with PD motor impairment. Therefore, we suggest the potential use of measuring the CSF HVA level as a possible biomarker of PD stage changes in order to monitor the effectiveness of PD-modifying pharmacological therapies

    Mutations in proteins involved in E-C coupling and SOCE and congenital myopathies

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    In skeletal muscle, Ca2+ necessary for muscle contraction is stored and released from the sarcoplasmic reticulum (SR), a specialized form of endoplasmic reticulum through the mechanism known as excitation-contraction (E-C) coupling. Following activation of skeletal muscle contraction by the E-C coupling mechanism, replenishment of intracellular stores requires reuptake of cytosolic Ca2+ into the SR by the activity of SR Ca2+-ATPases, but also Ca2+ entry from the extracellular space, through a mechanism called store-operated calcium entry (SOCE). The fine orchestration of these processes requires several proteins, including Ca2+ channels, Ca2+ sensors, and Ca2+ buffers, as well as the active involvement of mitochondria. Mutations in genes coding for proteins participating in E-C coupling and SOCE are causative of several myopathies characterized by a wide spectrum of clinical phenotypes, a variety of histological features, and alterations in intracellular Ca2+ balance. This review summarizes current knowledge on these myopathies and discusses available knowledge on the pathogenic mechanisms of disease

    Successful transition to groundwork combat during Junior and Senior Judo World Championships

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    The main goal of the present study was to describe the successful transition phases from standing combat to groundwork combat in a high-level judo competition (2017 World Championship) to determine the type of transition (turtle, supine, prone, half-guard, besides, guard, standing and seated) and their rhythms (i.e. time spent by the scoring athletes) mostly used by these athletes. Our sample was based on the junior and senior, male and females, 2017 Judo World Championships. Transition phases (n&nbsp;=&nbsp;373) that resulted in a score during the junior (n&nbsp;=&nbsp;179) and senior (n&nbsp;=&nbsp;194) were analysed. The main findings of this study indicated an immediate link between standing and groundwork actions observed in almost half of the occurrences. Most of the scoring actions (~75%) were achieved through an osae-komi-waza (immobilisation techniques), and these actions were performed mainly when the match was tied (~71%). No significant differences (p&nbsp;&gt;&nbsp;0.05) were observed between sex and age groups concerning the type of techniques and body position. The different types of transitions were used similarly along the competition phases, indicating that athletes need to be able to cope with different situations in the transition phase to be successful

    Towards 3d multi-layer scaffolds for periodontal tissue engineering applications: Addressing manufacturing and architectural challenges

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    Reduced periodontal support, deriving from chronic inflammatory conditions, such as periodontitis, is one of the main causes of tooth loss. The use of dental implants for the replacement of missing teeth has attracted growing interest as a standard procedure in clinical practice. However, adequate bone volume and soft tissue augmentation at the site of the implant are important prerequisites for successful implant positioning as well as proper functional and aesthetic reconstruction of patients. Three-dimensional (3D) scaffolds have greatly contributed to solve most of the challenges that traditional solutions (i.e., autografts, allografts and xenografts) posed. Nevertheless, mimicking the complex architecture and functionality of the periodontal tissue represents still a great challenge. In this study, a porous poly(ε-caprolactone) (PCL) and Sr-doped nano hydroxyapatite (Sr-nHA) with a multi-layer structure was produced via a single-step additive manufacturing (AM) process, as a potential strategy for hard periodontal tissue regeneration. Physicochemical characterization was conducted in order to evaluate the overall scaffold architecture, topography, as well as porosity with respect to the original CAD model. Furthermore, compressive tests were performed to assess the mechanical properties of the resulting multi-layer structure. Finally, in vitro biological performance, in terms of biocompatibility and osteogenic potential, was evaluated by using human osteosarcoma cells. The manufacturing route used in this work revealed a highly versatile method to fabricate 3D multi-layer scaffolds with porosity levels as well as mechanical properties within the range of dentoalveolar bone tissue. Moreover, the single step process allowed the achievement of an excellent integrity among the different layers of the scaffold. In vitro tests suggested the promising role of the ceramic phase within the polymeric matrix towards bone mineralization processes. Overall, the results of this study demonstrate that the approach undertaken may serve as a platform for future advances in 3D multi-layer and patient-specific strategies that may better address complex periodontal tissue defects

    Verifica degli impatti socioeconomici ed ambientali conseguenza dei mutamenti climatici in atto nel bacino del Mediterraneo, attraverso l’uso del telerilevamento satellitare

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    Oggi l’uomo è pericolosamente prossimo ad un punto di non ritorno, in cui può decidere di cambiare rotta od accettare di vedere avverarsi ciò che più temeva l'economista statunitense Premio Nobel Paul Robin Krugmani, il quale sosteneva che le future generazioni non avrebbero più potuto contare, come avevano sempre fatto le precedenti, su di un tenore di vita migliore rispetto a quello di padri e nonni. Questo potrebbe avvenire perché è stato ormai sollevato il problema dell’assoluta carenza di risorse naturali, questione che per lungo tempo è stata risolta dai paesi più industrializzati con l’esclusione della maggioranza della popolazione mondiale dai consumi di massa propri dell’Occidente. Ma la problematica riguardante questa scarsità segue, ogni giorno di più, quella altrettanto drammatica che investe il clima e per la comunità scientifica è ormai ovvio che entrambi sono due facce di una stessa medaglia. Sempre più spesso, dunque, siamo chiamati a confrontarci non solo con la miseria, in preoccupante aumento in ogni Paese dopo la crisi economica globale iniziata nel 2008 e non ancora conclusasi, ma, anche, con tematiche come calamità naturali, eventi estremi, squilibri ecologici, avvenimenti pure essi in apparente, decisa crescita. Privazioni e mutamenti climatici hanno un costo economico e sociale altissimo e l’unico metodo per risolvere queste difficoltà parrebbe quello di ricondurre la dottrina al significato primigenio della parola economia, “oikos nomos”, che circa 2700 anni fa significava gestione della casa comune, ovvero la Terra, pianeta in cui viviamo. In questo contesto è da inquadrare il programma di studio interministeriale che ha per titolo “Modello integrato per l’evoluzione degli ecosistemi naturali ed agricoli in relazione ai cambiamenti climatici nell’area mediterranea (FISR-MICENA)”; il lavoro che qui si presenta è parte integrante dell’attività di ricerca n.19 di questo progetto

    Platelet-Rich Plasma Promotes the Proliferation of Human Muscle Derived Progenitor Cells and Maintains Their Stemness

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    Human muscle-derived progenitor cells (hMDPCs) offer great promise for muscle cell-based regenerative medicine; however, prolonged ex-vivo expansion using animal sera is necessary to acquire sufficient cells for transplantation. Due to the risks associated with the use of animal sera, the development of a strategy for the ex vivo expansion of hMDPCs is required. The purpose of this study was to investigate the efficacy of using platelet-rich plasma (PRP) for the ex-vivo expansion of hMDPCs. Pre-plated MDPCs, myoendothelial cells, and pericytes are three populations of hMDPCs that we isolated by the modified pre-plate technique and Fluorescence Activated Cell Sorting (FACS), respectively. Pooled allogeneic human PRP was obtained from a local blood bank, and the effect that thrombin-activated PRP-releasate supplemented media had on the ex-vivo expansion of the hMDPCs was tested against FBS supplemented media, both in vitro and in vivo. PRP significantly enhanced short and long-term cell proliferation, with or without FBS supplementation. Antibody-neutralization of PDGF significantly blocked the mitogenic/proliferative effects that PRP had on the hMDPCs. A more stable and sustained expression of markers associated with stemness, and a decreased expression of lineage specific markers was observed in the PRP-expanded cells when compared with the FBS-expanded cells. The in vitro osteogenic, chondrogenic, and myogenic differentiation capacities of the hMDPCs were not altered when expanded in media supplemented with PRP. All populations of hMDPCs that were expanded in PRP supplemented media retained their ability to regenerate myofibers in vivo. Our data demonstrated that PRP promoted the proliferation and maintained the multi-differentiation capacities of the hMDPCs during ex-vivo expansion by maintaining the cells in an undifferentiated state. Moreover, PDGF appears to be a key contributing factor to the beneficial effect that PRP has on the proliferation of hMDPCs. © 2013 Li et al
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