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Paola Imbrici Elena Conte Rikard Blunck Fabrizia Stregapede Antonella Liantonio Michele Tosi Maria Cristina DAdamo Annamaria De Luca Vesna Brankovic Ginevra Zanni 《International journal of molecular sciences》2021,22(18)
Kv1.2 channels, encoded by the KCNA2 gene, are localized in the central and peripheral nervous system, where they regulate neuronal excitability. Recently, heterozygous mutations in KCNA2 have been associated with a spectrum of symptoms extending from epileptic encephalopathy, intellectual disability, and cerebellar ataxia. Patients are treated with a combination of antiepileptic drugs and 4-aminopyridine (4-AP) has been recently trialed in specific cases. We identified a novel variant in KCNA2, E236K, in a Serbian proband with non-progressive congenital ataxia and early onset epilepsy, treated with sodium valproate. To ascertain the pathogenicity of E236K mutation and to verify its sensitivity to 4-AP, we transfected HEK 293 cells with Kv1.2 WT or E236K cDNAs and recorded potassium currents through the whole-cell patch-clamp. In silico analysis supported the electrophysiological data. E236K channels showed voltage-dependent activation shifted towards negative potentials and slower kinetics of deactivation and activation compared with Kv1.2 WT. Heteromeric Kv1.2 WT+E236K channels, resembling the condition of the heterozygous patient, confirmed a mixed gain- and loss-of-function (GoF/LoF) biophysical phenotype. 4-AP inhibited both Kv1.2 and E236K channels with similar potency. Homology modeling studies of mutant channels suggested a reduced interaction between the residue K236 in the S2 segment and the gating charges at S4. Overall, the biophysical phenotype of E236K channels correlates with the mild end of the clinical spectrum reported in patients with GoF/LoF defects. The response to 4-AP corroborates existing evidence that KCNA2-disorders could benefit from variant-tailored therapeutic approaches, based on functional studies. 相似文献
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Mattia Bramini Martina Chiacchiaretta Andrea Armirotti Anna Rocchi Deepali D. Kale Cristina Martin Ester Vzquez Tiziano Bandiera Stefano Ferroni Fabrizia Cesca Fabio Benfenati 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(15)
The use of graphene nanomaterials (GNMs) for biomedical applications targeted to the central nervous system is exponentially increasing, although precise information on their effects on brain cells is lacking. In this work, the molecular changes induced in cortical astrocytes by few‐layer graphene (FLG) and graphene oxide (GO) flakes are addressed. The results show that exposure to FLG/GO does not affect cell viability or proliferation. However, proteomic and lipidomic analyses unveil alterations in several cellular processes, including intracellular Ca2+ ([Ca2+]i) homeostasis and cholesterol metabolism, which are particularly intense in cells exposed to GO. Indeed, GO exposure impairs spontaneous and evoked astrocyte [Ca2+]i signals and induces a marked increase in membrane cholesterol levels. Importantly, cholesterol depletion fully rescues [Ca2+]i dynamics in GO‐treated cells, indicating a causal relationship between these GO‐mediated effects. The results indicate that exposure to GNMs alters intracellular signaling in astrocytes and may impact astrocyte–neuron interactions. 相似文献
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Aldo D'Alessio Fabrizia Turchi Piero Narducci Piergiorgio Vergamini Francesco Ciardelli Stefano Catanorchi 《Polymer International》2004,53(10):1567-1571
Attempts have been performed to obtain spectroscopic evidence of intermolecular interactions between fluorinated polymers to be used as protective materials and various stones. In this paper we report an investigation by means of FTIR spectroscopy on poly(vinyl fluoride)(PVF) which contains acid hydrogens that can give rise to intermolecular interactions with calcium carbonate. Spectral changes have been found in the C? H and C? F stretching regions at 3000–2840 and 1200–950 cm?1, respectively. These last are attributed to intermolecular interactions of the polymer with CO32? and with conformational changes of the macromolecular chain. Scanning electron microscopy investigations were also performed on marble slabs coated with a PVF film in order to gain information about the morphology of the polymer film. Copyright © 2004 Society of Chemical Industry 相似文献
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Fabrizia Caiazzo Vittorio Alfieri Francesco Cardaropoli Vincenzo Sergi 《The International Journal of Advanced Manufacturing Technology》2013,67(9-12):2157-2169
Higher productivity, lower distortion and better penetration are the main advantages provided by laser welding in comparison with conventional processes. A Trumpf TruDisk 2002 Yb:YAG disk laser is used in this work to increases productivity and quality. Aluminium alloys lead to many technological issues in laser welding, resulting in shallow penetration and defects. In particular, AA 2024 aluminium alloy in a thin sheet is investigated in this paper, being it is used extensively in the automotive and aerospace industries. Bead-on-plate and butt autogenous laser welding tests with continuous wave emission on 1.25 mm thick AA 2024 aluminium alloy sheets were examined morphologically and micro-structurally. The geometric and mechanical features of the welding bead were evaluated via a three-level experimental plan. In addition to the power and speed which are traditionally referred to, beam defocusing was considered as an additional governing factor in a central composite design scheme because it massively affects keyhole conditions. Softening in the fused zone is discussed via Vickers micro-hardness testing and magnesium loss through energy dispersive spectrometry. After properly performing the modelling and optimisation of the fused zone and the cross-section shape factor as the response variables, the laser welding conditions for thin sheets of AA 2024 aluminium alloy are suggested. X-ray and tensile tests were conducted on the specimens obtained with the recommended processing parameters to characterise the AA 2024 disk laser welded beads. 相似文献
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Marta Balietti Patrizia Fattoretti Belinda Giorgetti Tiziana Casoli Giuseppina Di Stefano Daniela Platano Giorgio Aicardi Fabrizia Lattanzio Carlo Bertoni‐Freddari 《Microscopy research and technique》2009,72(12):933-938
Ketogenic diets (KDs) have shown beneficial effects in experimental models of neurodegeneration, designating aged individuals as possible recipients. However, few studies have investigated their consequences on aging brain. Here, late‐adult rats (19 months of age) were fed for 8 weeks with two medium chain triglycerides‐supplemented diets (MCT‐SDs) and the average area (S), numeric density (Nvs), and surface density (Sv) of synapses, as well as the average volume (V), numeric density (Nvm), and volume density (Vv) of synaptic mitochondria were evaluated in granule cell layer of the cerebellar cortex (GCL‐CCx) by computer‐assisted morphometric methods. MCT content was 10 or 20%. About 10%MCT‐SD induced the early appearance of senescent patterns (decreased Nvs and Nvm; increased V), whereas 20%MCT‐SD caused no changes. Recently, we have shown that both MCT‐SDs accelerate aging in the stratum moleculare of CA1 (SM CA1), but are “antiaging” in the outer molecular layer of dentate gyrus (OML DG). Since GCL‐CCx is more vulnerable to age than OML DG but less than SM CA1, present and previous results suggest that the effects of MCT‐SDs in the aging brain critically depend on neuronal vulnerability to age, besides MCT percentage. Microsc. Res. Tech. 2009. © 2009 Wiley‐Liss, Inc. 相似文献
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Decesari S Mircea M Cavalli F Fuzzi S Moretti F Tagliavini E Facchini MC 《Environmental science & technology》2007,41(7):2479-2484
The functional group compositions of atmospheric aerosol water-soluble organic compoundswere obtained employing proton nuclear magnetic resonance (1H NMR) spectroscopy in a series of recent experiments in several areas of the world characterized by different aerosol sources and pollution levels. Here, we discuss the possibility of using 1H NMR functional group distributions to identifythe sources of aerosol in the different areas. Despite the limited variability of functional group compositions of atmospheric aerosol samples, characteristic 1H NMR fingerprints were derived for three major aerosol sources: biomass burning, secondary formation from anthropogenic and biogenic VOCs, and emission from the ocean. The functional group patterns obtained in areas characterized by one of the above dominant source processes were then compared to identify the dominant sources for samples coming from mixed sources. This analysis shows that H NMR spectroscopy can profitably be used as a valuable tool for aerosol source identification. In addition, compared to other existing methodologies, it is able to relate the source fingerprints to integral chemical properties of the organic mixtures, which determine their reactivity and their physicochemical properties and ultimately the fate of the organic particles in the atmosphere. 相似文献
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Thermally reversible highly cross‐linked polymeric materials based on furan/maleimide Diels‐Alder adducts
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Placido Mineo Vincenzina Barbera Giovanni Romeo Fabrizia Ghezzo Emilio Scamporrino Fabiola Spitaleri Ugo Chiacchio 《应用聚合物科学杂志》2015,132(30)
A novel thermally reversible cross‐linked polymer has been synthesized by a Diels‐Alder (DA) reaction between bis(4‐maleimido‐phenyl)fluorene (cBMI) and tetrakis‐furan monomers (4F) under microwave (MW) irradiation. The ultimate aim of this work was the preparation of a thermosetting material recyclable by a simple thermal treatment. The use of the MW irradiation was necessary because under thermal conditions the DA polymerization could lead to materials only partially cross‐linked for a not desired equilibrium between DA and retro‐DA processes induced by the high temperature. The easy thermal degradation of this cross‐linked material was ascertained by appropriate experiments. Moreover, to better study the involved reactions of formation and decomposition, a more simple model‐compound was also synthesized. The reported data confirm the recyclability of the synthesized cross‐linked polymer by simply heating with the possibility of a regeneration of the polymer network by a further MW irradiation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42314. 相似文献