704 research outputs found

    Electrochemical Characterization of Charge Storage at Anodes for Sodium-Ion Batteries Based on Corncob Waste-Derived Hard Carbon and Binder

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    Sodium-ion batteries (SIBs) represent a potential alternative to lithium-ion batteries in large-scale energy storage applications. To improve the sustainability of SIBs, the utilization of anode carbonaceous materials produced from biomass and the selection of a bio-based binder allowing an aqueous electrode processing are fundamental. Herein, corncobs are used as raw material for the preparation of hard carbon and it is also used as cellulose sources for the synthesis of carboxymethyl cellulose (CMC) binder. The corncob-derived electrodes deliver a high discharge capacity of around 264 mAhg(-1) at 1 C (300 mAg(-1)), with promising capacity retention (84 % after 100 cycles) and good rate capability. Additionally, this work expands the fundamental insight of the sodium storage behavior of Hard Carbons through an electrochemical approach, suggesting that the reaction mechanism is controlled by capacitive process in the sloping voltage region, while the diffusion-controlled intercalation is the predominant process in the low-voltage plateau

    Enhanced 10 Gb/s operations of directly modulated reflective semiconductor optical amplifiers without electronic equalization

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    We report enhanced 10 Gb/s operation of directly modulated bandwidth-limited reflective semiconductor optical amplifiers. By using a single suitable arrayed waveguide grating we achieve simultaneously WDM demultiplexing and optical equalization. Compared to previous approaches, the proposed system results significantly more tolerant to seeding wavelength drifts. This removes the need for wavelength lockers, additional electronic equalization or complex digital signal processing. Uniform C-band operations are obtained experimentally with < 2 dB power penalty within a wavelength drift of 10 GHz (which doubles the ITU-T standard recommendations)

    Sub-tissue localization of phytochemicals in Cinnamomum camphora (L.) J. Presl. growing in Northern Italy

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    In the present paper, we focused our attention on Cinnamomum camphora (L.) J. Presl. (Lauraceae), studied at three levels: (i) micromorphological, with the analysis of the secretory structures and a novel in-depth histochemical characterization of the secreted compounds; (ii) phytochemical, with the characterization of the essential oils from young stems, fruits, and leaves, subjected to different conservation procedures (fresh, dried, stored at −20 °C, stored at −80 °C) and collected in two different years; (iii) bioactive, consisting of a study of the potential antibacterial activity of the essential oils. The micromorphological investigation proved the presence of secretory cells characterized by a multi-layered wall in the young stems and leaves. They resulted in two different types: mucilage cells producing muco-polysaccharides and oil cells with an exclusive terpene production. The phytochemical investigations showed a predominance of monoterpenes over sesquiterpene derivatives; among them, the main components retrieved in all samples were 1,8-cineole followed by α-terpineol and sabinene. Conservation procedures seem to only influence the amounts of specific components, i.e., 1,8-cineole and α-terpineol, while analyses on each plant part revealed the presence of some peculiar secondary constituents for each of them. Finally, the evaluation of the antibacterial activity of the essential oil showed a promising activity against various microorganisms, as Listeria monocytogenes, Staphylococcus aureus, Enterococcus faecalis and Pseudomonas aeruginosa. In conclusion, we combined a micromorphological and phytochemical approach of the study on different plant parts of C. camphora, linking the occurrence of secretory cells to the production of essential oils. We compared, for the first time, the composition of essential oils derived from different plant matrices conserved with different procedures, allowing us to highlight a relation between the conservation technique and the main components of the profiles. Moreover, the preliminary antibacterial studies evidenced the potential activity of the essential oils against various microorganisms potentially dangerous for plants and humans

    Prognostic significance of tyrosinase expression in sentinel lymph node biopsy for ultra-thin, thin, and thick melanomas

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    Abstract. – BACKGROUND: Investigate if the tyrosinase mRNA expression may be predictive of the outcome on ultra-thin, thin, and thick melanoma patients. AIM: In our study, we sought to correlate tyrosinase mRNA expression to the outcome in a group of 71 patients with thick, thin and ultra-thin melanomas. MATERIALS AND METHODS: 71 patients with melanomas underwent a SLNB (sentinel lymph node biopsy) at the “Sapienza” University of Rome. Among these, 38 patients had thin melanomas, while the other 33 patients had thick melanomas. In every patient’s sample histology, immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) was completed. We then correlated tyrosinase mRNA expression to the statistical analysis of the outcome of patients. RESULTS: Positivity of histology was found in one patient (1.4%), immunohistochemistry in five patients (7%), and tyrosinase in 52/71 (73.2%). Thickness and tyrosinase positivity were predictive for disease progression (p < 0.05). The median follow-up was 58.24 months. There were recurrences and/or deaths in both groups of patients. CONCLUSIONS: Nodal metastasis in melanoma is uncommon, especially in patients with thin melanomas. In this study, histology and immunohistochemistry were found to be non predictive for the risk of nodal metastases, while instead, tyrosinase m-RNA expression appeared to play a role in highlighting those patients with a risk of disease progression. Moreover, no differences among the thin melanoma groups of patients (0.30-0.75 mm and 0.76-1.00 mm) were observed

    Probing the single-particle character of rotational states in 19^{19}F using a short-lived isomeric beam

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    A beam containing a substantial component of both the Jπ=5+J^{\pi}=5^+, T1/2=162T_{1/2}=162 ns isomeric state of 18^{18}F and its 1+1^+, 109.77-min ground state has been utilized to study members of the ground-state rotational band in 19^{19}F through the neutron transfer reaction (d(d,p)p) in inverse kinematics. The resulting spectroscopic strengths confirm the single-particle nature of the 13/2+^+ band-terminating state. The agreement between shell-model calculations, using an interaction constructed within the sdsd shell, and our experimental results reinforces the idea of a single-particle/collective duality in the descriptions of the structure of atomic nuclei

    Searching for the γ decay from the near-neutron threshold 2+ state in 14C: A probe of collectivization phenomena in light nuclei

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    The γ decay from the 2+2 near-threshold resonance in 14C, located 142 keV above the neutron emission threshold, was searched for in a fusionevaporation experiment at Argonne National Laboratory with the GODDESS setup, comprising the GRETINA γ-ray spectrometer coupled to the ORRUBA charged particle detector. The Shell Model Embedded in the Continuum predicts a significant enhancement of the 2+2 → 0 transition probability, owing to a collectivization of the near-threshold state. The corresponding γ branch is expected to be of the order of 5 × 10−5, which is comparable with the sensitivity of this experiment
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