Analysis of the C2_2 (d3Πg^3\Pi_g-a3Πu^3\Pi_u) Swan bands as a thermometric probe in CO2_2 microwave plasmas

The optical emission spectra of high pressure CO$_2$ microwave plasmas are usually dominated by the C$_2$ Swan bands. In this paper, the use of the C$_2$ Swan bands for estimating the gas temperature in CO$_2$ microwave plasmas is assessed. State by state fitting is employed to check the correctness of assuming a Boltzmann distribution for the rotational and vibrational distribution functions and, within statistical and systematic uncertainties, the C$_2$ Swan band can be fitted accurately with a single temperature for rotational and vibrational levels. The processes leading to the production of the C$_2$ molecule and particularly its d$^3\Pi_g$ state are briefly reviewed as well as collisional relaxation times of the latter. It is concluded that its rotational temperature can be associated to the gas temperature of the CO$_2$ microwave plasma and the results are moreover cross-checked by adding a small amount of N$_2$ in the discharge and measuring the CN violet band system. The 2.45~GHz plasma source is analyzed in the pressure range 180-925~mbar, for input microwave powers ranging from 0.9 - 3 kW and with gas flow rates of 5-100~L/min. An intense C$_2$ Swan bands emission spectrum can be measured only when the plasma is operated in contracted regime. A unique temperature of about 6000 $\pm$ 500 K is obtained for all investigated conditions. A spectroscopic database is constructed using the recent compilation and calculations by Brooke et al. \cite{BROOKE201311} of the line strengths and molecular constants for the C$_2$ (d$^3\Pi_g$-a$^3\Pi_u$) Swan bands system and made available as Supplementary Material in a format compatible with the open source MassiveOES software

Modeling strategies for origami-based drag sail

LAUREA MAGISTRALEPer un ambiente spaziale sostenibile sono necessarie strategie innovative di mitigazione dei detriti spaziali per ridurne l’impatto sulle missioni di esplorazione. Un approccio efficace in orbita terrestre bassa è il deorbiting dei satelliti. Tra le varie tecnologie disponibili, di grande interesse sono le drag sails. Esse sono membrane di grande superficie in grado di accelerare il rientro del satellite, portandolo alla disintegrazione nell’atmosfera terrestre. La progettazione di un sistema di dispiegamento appropriato implica che, una volta raggiunta la fase di fine vita, la drag sail, stivata all’interno del satellite, venga dispiegata con successo attraverso un sistema di attuazione. La tecnica di piegatura può essere ottimizzata adottando un modello origami. Le applicazioni degli origami nell’ingegneria spaziale utilizzano modelli specifici, tra cui il Miura-Ori. Il modello di piega della struttura diventa un aspetto fondamentale nella progettazione di drag sail compatte e dispiegabili per il de-orbiting controllato. Attraverso ABAQUS®, sono state implementate diverse simulazioni numeriche per studiare il comportamento strutturale di una singola piega e di una cella unitaria di Miura-Ori. Le deformazioni, le concentrazioni di stress e la distribuzione della rigidità rotazionale lungo le pieghe hanno permesso di ottenere un modello più realistico attraverso prove ed errori iterativi del processo di simulazione. Una possibilità significativa nel realizzare l’auto-dispiegamento è data dall’integrazione di strutture basate su origami con attuatori torsionali basati su leghe a memoria di forma. Questa specifica classe di materiali può recuperare una predeterminata forma quando viene sottoposta a uno specifico stimolo esterno, come una variazione di temperatura. Analisi computazionali hanno permesso di studiare il comportamento di un filo di NiTi e la sua interazione con le sfaccettature dell’origami e verificare l’integrità strutturale dell’intero sistema. L’obiettivo non è quello di fornire un meccanismo finito, ma piuttosto di gettare le basi per un’analisi futura più accurata dell’intero pattern. Potenziali sviluppi futuri potrebbero essere le convalide sperimentali e ulteriori indagini sul comportamento fuori piano sotto l’azione di grandi spostamenti, per comprendere con maggiore precisione il sistema.Innovative space debris mitigation strategies are required for a sustainable space environ ment to reduce the space debris impact on exploration missions. An effective approach to space debris mitigation in low Earth orbit (LEO) is satellite de-orbiting. Among the various technologies available for de-orbit, one of great interest is the deployment of drag sails. Drag sails are large-area membranes that are able to accelerate the satellite’s reen try, leading to its subsequent disintegration within the Earth’s atmosphere. The design of an appropriate deployment system implies that once the satellite has reached the end of-life phase, the drag sail, stored within the host structure, is then successfully deployed through an actuation system. The folding technique can be optimized by adopting an origami pattern. Applications of origami in space engineering make use of some specific patterns, including Miura-Ori. The crease model of origami-based structure becomes a fundamental aspect in the design of compact and deployable drag sails for controlled de orbiting. ABAQUS® numerical simulations are implemented under different conditions to investigate the structural behavior of a single crease model and unit cell of Miura-Ori. The resulting deformations, stress concentrations, and rotational stiffness distribution along crease configurations allowed progress toward a more realistic model through iter ative trial and error of the simulation process. A significant possibility to accomplish the self-deployment requirement is through the integration of origami-based structures with shape memory alloy (SMA)-based torsional actuators. This specific class of materials can recover a predetermined shape when subjected to a specific external stimulus, such as temperature change. Computational analyses were performed to study the behavior of NiTi wire and its interaction with origami facets and to verify the structural integrity of the overall system. The objective was not to deliver a flight-ready mechanism, but rather to lay the basis for a more accurate future analysis of the entire origami pattern deployment. Potential future developments could be experimental validations and further investigations of out-of-plane behavior under the action of large displacements that would contribute to precisely understanding the behavior of the system

Synthesis, structural studies and biological properties of new TBA analogues containing an acyclic nucleotide

A new modified acyclic nucleoside, namely N(1)-(3-hydroxy-2-hydroxymethyl-2-methylpropyl)-thymidine, was synthesized and transformed into a building block useful for oligonucleotide (ON) automated synthesis. A series of modified thrombin binding aptamers (TBAs) in which the new acyclic nucleoside replaces, one at the time, the thymidine residues were then synthesized and characterized by UV, CD, MS, and (1)H NMR. The biological activity of the resulting TBAs was tested by Prothrombin Time assay (PT assay) and by purified fibrinogen clotting assay. From a structural point of view, nearly all the new TBA analogues show a similar behavior as the unmodified counterpart, being able to fold into a bimolecular or monomolecular quadruplex structure depending on the nature of monovalent cations (sodium or potassium) coordinated in the quadruplex core. From the comparison of structural and biological data, some important structure-activity relationships emerged, particularly when the modification involved the TT loops. In agreement with previous studies we found that the folding ability of TBA analogues is more affected by modifications involving positions 4 and 13, rather than positions 3 and 12. On the other hand, the highest anti-thrombin activities were detected for aptamers containing the modification at T13 or T12 positions, thus indicating that the effects produced by the introduction of the acyclic nucleoside on the biological activity are not tightly connected with structure stabilities. It is noteworthy that the modification at T7 produces an ON being more stable and active than the natural TBA

AVNP2 protects against cognitive impairments induced by C6 glioma by suppressing tumour associated inflammation in rats

© 2020 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/).Glioblastoma is a kind of malignant tumour and originates from the central nervous system. In the last century, some researchers and clinician have noticed that the psychosocial and neurocognitive functioning of patients with malignant gliomas can be impaired. Many clinical studies have demonstrated that part of patients, adults or children, diagnosed with glioblastoma will suffer from cognitive deficiency during their clinical course, especially in long-term survivors. Many nanoparticles (NPs) can inhibit the biological functions of tumours by modulating tumour-associated inflammation, which provokes angiogenesis and tumour growth. As one of the best antiviral nanoparticles (AVNPs), AVNP2 is the 2nd generation of AVNP2 that have been conjugated to graphite-graphene for improving physiochemical performance and reducing toxicity. AVNP2 inactivates viruses, such as the H1N1 and H5N1influenza viruses and even the SARS coronavirus, while it inhibits bacteria, such as MRSA and E. coli. As antimicrobials, nanoparticles are considered to be one of the vectors for the administration of therapeutic compounds. Yet, little is known about their potential functionalities and toxicities to the neurotoxic effects of cancer. Herein, we explored the functionality of AVNP2 on inhibiting C6 in glioma-bearing rats. The novel object-recognition test and open-field test showed that AVNP2 significantly improved the neuro-behaviour affected by C6 glioma. AVNP2 also alleviated the decline of long-term potentiation (LTP) and the decreased density of dendritic spines in the CA1 region induced by C6. Western blot assay and immunofluorescence staining showed that the expressions of synaptic-related proteins (PSD-95 and SYP) were increased, and these findings were in accordance with the results mentioned above. It revealed that the sizes of tumours in C6 glioma-bearing rats were smaller after treatment with AVNP2. The decreased expression of inflammatory factors (IL-1β, IL-6 and TNF-α) by Western blotting assay and ELISA, angiogenesis protein (VEGF) by Western blotting assay and other related proteins (BDNF, NF-ĸB, iNOS and COX-2) by Western blotting assay in peri-tumour tissue indicated that AVNP2 could control tumour-associated inflammation, thus efficiently ameliorating the local inflammatory condition and, to some extent, inhibiting angiogenesis in C6-bearing rats. In conclusion, our results suggested that AVNP2 could have an effect on the peri-tumor environment, obviously restraining the growth progress of gliomas, and eventually improving cognitive levels in C6-bearing rats.Peer reviewedProo

Addendum: Quantitative Analysis of Honey Bee Blood-Ethanol Levels Following Exposure to Ethanol Vapors

This addendum reports an additional statistical analysis of the data of our earlier paper on the effect of exposing bees to ethanol vapor. The analysis indicated that inhaled ethanol is absorbed into the hemolymph, similar to the more traditional method of feeding bees ethanol. Therefore, both ingestion and inhalation can be used as effective methods of ethanol administration in honey bees.&nbsp

Impairment of cocaine-mediated behaviours in mice by clinically relevant Ras-ERK inhibitors

Ras-ERK signalling in the brain plays a central role in drug addiction. However, to date, no clinically relevant inhibitor of this cascade has been tested in experimental models of addiction, a necessary step toward clinical trials. We designed two new cell-penetrating peptides - RB1 and RB3 - that penetrate the brain and, in the micromolar range, inhibit phosphorylation of ERK, histone H3 and S6 ribosomal protein in striatal slices. Furthermore, a screening of small therapeutics currently in clinical trials for cancer therapy revealed PD325901 as a brain-penetrating drug that blocks ERK signalling in the nanomolar range. All three compounds have an inhibitory effect on cocaine-induced ERK activation and reward in mice. In particular, PD325901 persistently blocks cocaine-induced place preference and accelerates extinction following cocaine self-administration. Thus, clinically relevant, systemically administered drugs that attenuate Ras-ERK signalling in the brain may be valuable tools for the treatment of cocaine addictio

Spatial learning and long-term memory impairments in RasGrf1 KO, Pttg1 KO, and double KO mice

Background: RasGrf1 is a guanine-nucleotide releasing factor that enhances Ras activity. Human PTTG1 is an oncoprotein found in pituitary tumors and later identified as securin, a protein isolated from yeast with a reported role in chromosome separation. It has been suggested that RasGrf1 is an important upstream component of signal transduction pathways regulating Pttg1 expression and controlling beta cell development and their physiological response. At memory formation level, there are contradictory data regarding the role of RasGrf1, while Pttg1 has not been previously studied. Both proteins are expressed in the mammalian hippocampus, which is one of the key brain areas for spatial learning and memory. Objective: The aim of this work was to study a potential link between RasGrf1 and Pttg1 in memory formation. Method: Spatial learning and memory test in the Pttg1 KO, RasGrf1 KO, and Pttg1-RasGrf1 double KO and their correspondent WT mice using a Barnes maze. Results: In comparison with the WT control mice, Pttg1 KO mice learned how to solve the task in a less efficient way, suggesting problems in memory consolidation. RasGrf1 KO mice performance was similar to controls, and they learned to use the best searching strategy. Double KO mice reached a better spatial learning level than WT. Conclusion: A role for Pttg1 in memory consolidation/formation is suggested, while our RasGrf1 KO mice do not show hippocampus associated memory defects

Different loop arrangements of intramolecular human telomeric (3+1) G-quadruplexes in K(+) solution

Intramolecular G-quadruplexes formed by the human telomeric G-rich strand are promising anticancer targets. Here we show that four-repeat human telomeric DNA sequences can adopt two different intramolecular G-quadruplex folds in K(+) solution. The two structures contain the (3+1) G-tetrad core, in which three G-tracts are oriented in one direction and the fourth in the opposite direction, with one double-chain-reversal and two edgewise loops, but involve different loop arrangements. This result indicates the robustness of the (3+1) core G-quadruplex topology, thereby suggesting it as an important platform for structure-based drug design. Our data also support the view that multiple human telomeric G-quadruplex conformations coexist in K(+) solution. Furthermore, even small changes to flanking sequences can perturb the equilibrium between different coexisting G-quadruplex forms