226 research outputs found

    Photochemical Energy Conversion with Artificial Molecular Machines

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    The exploitation of sunlight as a clean, renewable, and distributed energy source is key to facing the energetic demand of modern society in a sustainable and affordable fashion. In the past few decades, chemists have learned to make molecular machines, that is, synthetic chemical systems in which energy inputs cause controlled movements of molecular components that could be used to perform a task. A variety of artificial molecular machines operated by light have been constructed by implementing photochemical processes within appropriately designed (supra)molecular assemblies. These studies could open up new routes for the realization of nanostructured devices and materials capable to harness, convert, and store light energy

    Clonal variability of several grapevine cultivars (V. vinifera L.) grown in the Emilia-Romagna

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    Clonal selection has been performed over the past 2 decades by the University of Bologna to maintain the traditional grapevine cultivars grown in the Emilia-Romagna. Around 1980 budwood canes from several biotypes of the cvs Lambrusco di Sorbara, Lambrusco Salamino, Lambrusco Grasparossa, Lambrusco Maestri and Fortana were collected from old vineyards and used to establish a preliminary trial. The vines were tested for their virus status and compared for yield, grape quality, leaf characters and phenological phases in order to evaluate the biotype variability and clonal repeatability within each cultivar. L. Salamino, L. Grasparossa and L. Maestri showed very low degrees of genetic determination for yield and quality, while Fortana and L Sorbara exhibited quite high degrees. The results in both cases were independent on the virus status of the vines. While for cvs L. Salamino, L. Maestri and L. Grasparossa selection can be made only on the basis of virus status, good selection potentials were found with cvs L. Sorbara and Fortana. Fortana also exhibited marked differences in leaf morphology and phenological phases. Further investigations are needed to better characterize the diversity among biotypes of this variety, since the delimitation between cultivars and clones remains questionable

    An Efficient Method for the Surface Functionalization of Luminescent Quantum Dots with Lipoic Acid Based Ligands

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    We describe herein an operationally advantageous general methodology for efficiently activating lipoic acid based compounds, a family of popular surface ligands for semiconductor nanocrystals, through the use of a borohydride exchange resin, and the use of the activated species to replace the native surface ligands of quantum dots. The procedure enabled phase transfer of the nanocrystals between polar and aqueous media and, if unsubstituted lipoic acid was used, a facile adjustment of their solubility in a wide range of solvents with varying polarity (from hexane to water). We show that the protocol is applicable to different types of nanocrystals and a variety of lipoic acid based ligands, and that the resulting quantum dots maintain their optical properties, in particular, an intense luminescence, and long-term colloidal stability

    An efficient method for the surface functionalization of luminescent quantum dots with lipoic acid-based ligands

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    We describe an operationally advantageous general methodology to efficiently activate lipoic acid-based compounds - a family of popular surface ligands for semiconductor nanocrystals - by the use of a borohydride exchange resin, and the use of the activated species to replace the native surface ligands of quantum dots. The procedure enables the phase transfer of the nanocrystals between polar and aqueous media and, if unsubstituted lipoic acid is used, a facile adjustment of their solubility in a wide range of solvents with varying polarity (from hexane to water). We show that the protocol is applicable to different types of nanocrystals and a variety of lipoic acid-based ligands, and that the resulting quantum dots maintain their optical properties - in particular, an intense luminescence - and long term colloidal stability

    Massively parallel computing on an organic molecular layer

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    Current computers operate at enormous speeds of ~10^13 bits/s, but their principle of sequential logic operation has remained unchanged since the 1950s. Though our brain is much slower on a per-neuron base (~10^3 firings/s), it is capable of remarkable decision-making based on the collective operations of millions of neurons at a time in ever-evolving neural circuitry. Here we use molecular switches to build an assembly where each molecule communicates-like neurons-with many neighbors simultaneously. The assembly's ability to reconfigure itself spontaneously for a new problem allows us to realize conventional computing constructs like logic gates and Voronoi decompositions, as well as to reproduce two natural phenomena: heat diffusion and the mutation of normal cells to cancer cells. This is a shift from the current static computing paradigm of serial bit-processing to a regime in which a large number of bits are processed in parallel in dynamically changing hardware.Comment: 25 pages, 6 figure

    Fast optical investigation of cardiac electrophysiology by parallel detection in multiwell plates

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    Current techniques for fast characterization of cardiac electrophysiology employ optical technologies to control and monitor action potential features of single cells or cellular monolayers placed in multiwell plates. High-speed investigation capacities are commonly achieved by serially analyzing well after well employing fully automated fluorescence microscopes. Here, we describe an alternative cost-effective optical approach (MULTIPLE) that exploits high-power LED arrays to globally illuminate a culture plate and an sCMOS sensor for parallel detection of the fluorescence coming from multiple wells. MULTIPLE combines optical detection of action potentials using a red-shifted voltage-sensitive fluorescent dye (di-4-ANBDQPQ) with optical stimulation, employing optogenetic actuators, to ensure excitation of cardiomyocytes at constant rates. MULTIPLE was first characterized in terms of interwell uniformity of the illumination intensity and optical detection performance. Then, it was applied for probing action potential features in HL-1 cells (i.e., mouse atrial myocyte-like cells) stably expressing the blue light-activatable cation channel CheRiff. Under proper stimulation conditions, we were able to accurately measure action potential dynamics across a 24-well plate with variability across the whole plate of the order of 10%. The capability of MULTIPLE to detect action potential changes across a 24-well plate was demonstrated employing the selective K(v)11.1 channel blocker (E-4031), in a dose titration experiment. Finally, action potential recordings were performed in spontaneous beating human induced pluripotent stem cell derived cardiomyocytes following pharmacological manipulation of their beating frequency. We believe that the simplicity of the presented optical scheme represents a valid complement to sophisticated and expensive state-of-the-art optical systems for high-throughput cardiac electrophysiological investigations.Cardiolog

    Synthesis of Densely Packaged, Ultrasmall Pt02Clusters within a Thioether-Functionalized MOF: Catalytic Activity in Industrial Reactions at Low Temperature

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    The gram\u2010scale synthesis, stabilization, and characterization of well\u2010defined ultrasmall subnanometric catalytic clusters on solids is a challenge. The chemical synthesis and X\u2010ray snapshots of Pt02 clusters, homogenously distributed and densely packaged within the channels of a metal\u2013organic framework, is presented. This hybrid material catalyzes efficiently, and even more importantly from an economic and environmental viewpoint, at low temperature (25 to 140\u2009\ub0C), energetically costly industrial reactions in the gas phase such as HCN production, CO2 methanation, and alkene hydrogenations. These results open the way for the design of precisely defined catalytically active ultrasmall metal clusters in solids for technically easier, cheaper, and dramatically less\u2010dangerous industrial reactions

    DEVELOPMENT AND CHARACTERIZATION OF TIO2 COATINGS PREPARED BY ELECTRIC ARC-PHYSICAL VAPOUR DEPOSITION SYSTEM

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    TiO2 thin coatings were prepared, on various substrates, through evaporation of metallic titanium in an oxidizing atmosphere by modified electric arc physical vapor deposition (EA-PVD). The coatings were characterized chemically (by means of XPS and SIMS) and from the structural point of view (by means of XRD and Raman spectroscopy), in order to understand the factors which lead to homoge-neous coatings with high anatase content. The type of substrate is the main parameter that influence the crystal structure of the coatings: when stainless steel is used as substrate the coatings consist es-sentially of rutile, while on glass substrates coatings containing mainly anatase are obtained. The photocatalytic activity of the samples upon UVA irradiation was tested by using phenol as the target molecule. Phenol in the solution can be photocatalytically and rapidly degraded through the EA-PVD anatase TiO2 coatings

    Endovascular Abdominal Aortic Aneurysm Repair With Ovation Alto Stent Graft: Protocol for the ALTAIR (ALTo endogrAft Italian Registry) Study

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    Background: Since 2010, the Ovation Abdominal Stent Graft System has offered an innovative sealing option for abdominal aortic aneurysm (AAA) by including a sealing ring filled with polymer 13 mm from the renal arteries. In August 2020, the redesigned Ovation Alto, with a sealing ring 6 mm closer to the top of the fabric, received CE Mark approval. Objective: This registry study aims to evaluate intraoperative, perioperative, and postoperative results in patients treated by the Alto stent graft (Endologix Inc.) for elective AAA repair in a multicentric consecutive experience. Methods: All consecutive eligible patients submitted to endovascular aneurysm repair (EVAR) by Alto Endovascular AAA implantation will be included in this analysis. Patients will be submitted to EVAR procedures based on their own preferences, anatomical features, and operators experience. An estimated number of 300 patients submitted to EVAR with Alto stent graft should be enrolled. It is estimated that the inclusion period will be 24 months. The follow-up period is set to be 5 years. Full data sets and cross-sectional images of contrast-enhanced computed tomography scan performed before EVAR, at the first postoperative month, at 24 or 36 months, and at 5-year follow-up interval will be reported in the central database for a centralized core laboratory review of morphological changes. The primary endpoint of the study is to evaluate the technical and clinical success of EVAR with the Alto stent graft in short- (90-day), mid- (1-year), and long-term (5-year) follow-up periods. The following secondary endpoints will be also addressed: operative time; intraoperative radiation exposure; contrast medium usage; AAA sac shrinkage at 12-month and 5-year follow-up; any potential role of patients' baseline characteristics, valuated on preoperative computed tomography angiographic study, and of device configuration (number of component) in the primary endpoint. Results: The study is currently in the recruitment phase and the final patient is expected to be treated by the end of 2023 and then followed up for 5 years. A total of 300 patients will be recruited. Analyses will focus on primary and secondary endpoints. Updated results will be shared at 1- and 3-5-year follow-ups. Conclusions: The results from this registry study could validate the safety and effectiveness of the new design of the Ovation Alto Stent Graft. The technical modifications to the endograft could allow for accommodation of a more comprehensive range of anatomies on-label
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