scholarly journals Carbenoxolone as a Multifunctional Vehicle for Electrodeposition of Materials

2021 ◽  
Vol 11 (19) ◽  
pp. 9110
Author(s):  
Xinqian Liu ◽  
Stephen Veldhuis ◽  
Ritch Mathews ◽  
Igor Zhitomirsky
Keyword(s):  
Carbon Materials ◽  
Electrochemical Techniques ◽  
Composite Films ◽  
Deposition Process ◽  
Electrode Reactions ◽  
Deposition Yield ◽  
Film Forming ◽  
Film Microstructure ◽  
First Time

This investigation describes for the first time the application of carbenoxolone for electrophoretic deposition (EPD) of different carbon materials, polytetrafluoroethylene (PTFE) and their composite films. Carbenoxolone is a versatile biosurfactant, which adsorbs on materials due to its amphiphilic structure and allows their charging and dispersion. Moreover, carbenoxolone exhibits film-forming properties, which are investigated in experiments on EPD of films using water and ethanol-water solvents. The new deposition process is monitored in situ and the deposition yield and film microstructure are analyzed at different conditions. The EPD mechanism of materials involves electrode reactions of the carbenoxolone surfactant. The data of potentiodynamic studies coupled with the results of impedance spectroscopy show that PTFE films can be applied to protect metals from corrosion. Electron microscopy, electrochemical techniques and modeling are used for analysis of the microstructure and porosity of films prepared at different conditions. Carbenoxolone is applied as a co-surfactant for the EPD of composites.

Structural and Electrochemical Investigation of Na+ Insertion Into λ-Mn1-xNixO2

2015 ◽  
Vol 1810 ◽  
Author(s):  
J. R. Kim ◽  
G. G. Amatucci
Keyword(s):  
High Voltage ◽  
Low Cost ◽  
Electrochemical Techniques ◽  
Positive Electrode ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
Positive Electrodes ◽  
Insertion Mechanism ◽  
First Time

AbstractIncreased demand for low cost energy storage options has expanded the scope of Na+ batteries considerably; and with the growing interest in Na-based chemistries, the importance of high voltage positive electrodes is quickly realized as the Na/Na+ redox introduces lower operating voltages as compared to Li/Li+ based electrochemical cells. The 4.7V LiMn1.5Ni0.5O4 spinel has exhibited considerable properties as a high voltage Li+ positive electrode, with a host structure (λ-Mn0.75Ni0.25O2) that may provide an analogous high voltage Na+ positive electrode. Structural and electrochemical properties of NaxMn1.56Ni0.44O4 and NaxMn2O4 are investigated for the first time[1] utilizing ex-situ, in-situ X-ray diffraction, and high-resolution electrochemical techniques to provide an insightful study of the Na+ insertion mechanism.

In Situ Ellipsometry Study of the Diamond Film Evolution Process

1999 ◽  
Vol 580 ◽  
Author(s):  
L.M. Cancel ◽  
O.L. Figueroa ◽  
B.R. Weiner ◽  
G. Morell
Keyword(s):  
Chemical Vapor Deposition ◽  
Diamond Film ◽  
Vapor Deposition ◽  
Film Growth ◽  
Growth Parameters ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Ex Situ ◽  
Film Microstructure

AbstractWe employed in situ ellipsometry to monitor and study the nucleation and growth processes of diamond thin films fabricated by chemical vapor deposition. The films were grown on Si substrates in a hot filament chemical vapor deposition (HFCVD) system. We monitored the effective extinction coefficient (k) at 1.96 eV of the diamond films during growth through ellipsometry. The behavior of this parameter was found to be reproducible, making it suitable as a basis for dividing the deposition process into intervals. The film growth was aborted at various k values yielding diamond film samples that represent snapshots of the growth process at different stages. These films were removed for ex situ characterization using Raman spectroscopy and scanning electron microscopy (SEM). These characterizations were used to correlate the ellipsometric data with film microstructure, enabling us from now on to monitor the diamond film growth in real time and to design experiments targeted at modifying the film microstructure by changing growth parameters in the middle of film fabrication.

Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

2018 ◽  
Author(s):  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Rachel Evans
Keyword(s):  
Real Time ◽  
Absorption Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Wormlike Micelles ◽  
Tetraethylene Glycol ◽  
Light Illumination ◽  
First Time ◽  
Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such as<i></i>drug delivery and micellar catalysis. Currently, their behaviour in the equilibrium <i>cis-</i>and <i>trans</i>-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>) using small-angle neutron scattering (SANS). We show that the incorporation of <i>in-situ</i>UV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>could switch between wormlike micelles (<i>trans</i>native state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked <i>in</i><i>-situ</i>through combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

The Total Synthesis of Rhabdastrellic Acid A

2018 ◽  
Author(s):  
Yaroslav Boyko ◽  
Christopher Huck ◽  
David Sarlah
Keyword(s):  
Total Synthesis ◽  
Late Stage ◽  
Cross Coupling ◽  
Side Chains ◽  
General Strategy ◽  
Modular Approach ◽  
Linear Sequence ◽  
Generating Sequence ◽  
First Time

<div>The first total synthesis of rhabdastrellic acid A, a highly cytotoxic isomalabaricane triterpenoid, has been accomplished in a linear sequence of 14 steps from commercial geranylacetone. The prominently strained <i>trans-syn-trans</i>-perhydrobenz[<i>e</i>]indene core characteristic of the isomalabaricanes is efficiently accessed in a selective manner for the first time through a rapid, complexity-generating sequence incorporating a reductive radical polyene cyclization, an unprecedented oxidative Rautenstrauch cycloisomerization, and umpolung 𝛼-substitution of a <i>p</i>-toluenesulfonylhydrazone with in situ reductive transposition. A late-stage cross-coupling in concert with a modular approach to polyunsaturated side chains renders this a general strategy for the synthesis of numerous family members of these synthetically challenging and hitherto inaccessible marine triterpenoids.</div>

Isopotential points in square-wave voltammetry of reversible electrode reactions

2009 ◽  
Vol 74 (10) ◽  
pp. 1489-1501 ◽  
Author(s):  
Marina Zelić ◽  
Milivoj Lovrić
Keyword(s):  
Square Wave Voltammetry ◽  
Electrode Reaction ◽  
Time Model ◽  
Model Calculations ◽  
Square Wave ◽  
Electrode Reactions ◽  
Wave Voltammetry ◽  
Electron Transfer Processes ◽  
Diagnostic Criterion ◽  
First Time

Isopotential points in square-wave voltammetry are described for the first time. Model calculations and real measurements (performed with UO22+ and Eu3+ in perchlorate and bromide solutions, respectively) indicate that such an intersection could be observed when backward components of the net response, resulting from an increase in frequency or reactant concentration, are presented together. The electrode reaction should be fully reversible because quasireversible or slower electron transfer processes give the isopoints only at increasing reactant concentrations but not at increasing square-wave frequencies. The effect could be used as an additional diagnostic criterion for recognition of reversible electrode reactions where products remain dissolved in the electrolyte solution.

The use of in-situ Raman spectroscopy in investigating carbon materials as the anodes of alkali metal-ion batteries

Carbon ◽  
2021 ◽  
Vol 177 ◽  
pp. 428
Author(s):  
Xiaoqin Cheng ◽  
Huijun Li ◽  
Zhenxin Zhao ◽  
Yong-zhen Wang ◽  
Xiaomin Wang
Keyword(s):  
Raman Spectroscopy ◽  
Alkali Metal ◽  
Metal Ion ◽  
Carbon Materials ◽  
In Situ Raman Spectroscopy ◽  
Alkali Metal Ion ◽  
In Situ Raman

scholarly journals Engineered Phage Endolysin Eliminates Gardnerella Biofilm without Damaging Beneficial Bacteria in Bacterial Vaginosis Ex Vivo

Pathogens ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 54
Author(s):  
Christine Landlinger ◽  
Lenka Tisakova ◽  
Vera Oberbauer ◽  
Timo Schwebs ◽  
Abbas Muhammad ◽  
...  
Keyword(s):  
Bacterial Vaginosis ◽  
Bactericidal Activity ◽  
High Selectivity ◽  
Ex Vivo ◽  
Vaginal Microbiome ◽  
Wild Type ◽  
Wild Type Enzyme ◽  
Promising Alternative ◽  
First Time

Bacterial vaginosis is characterized by an imbalance of the vaginal microbiome and a characteristic biofilm formed on the vaginal epithelium, which is initiated and dominated by Gardnerella bacteria, and is frequently refractory to antibiotic treatment. We investigated endolysins of the type 1,4-beta-N-acetylmuramidase encoded on Gardnerella prophages as an alternative treatment. When recombinantly expressed, these proteins demonstrated strong bactericidal activity against four different Gardnerella species. By domain shuffling, we generated several engineered endolysins with 10-fold higher bactericidal activity than any wild-type enzyme. When tested against a panel of 20 Gardnerella strains, the most active endolysin, called PM-477, showed minimum inhibitory concentrations of 0.13–8 µg/mL. PM-477 had no effect on beneficial lactobacilli or other species of vaginal bacteria. Furthermore, the efficacy of PM-477 was tested by fluorescence in situ hybridization on vaginal samples of fifteen patients with either first time or recurring bacterial vaginosis. In thirteen cases, PM-477 killed the Gardnerella bacteria and physically dissolved the biofilms without affecting the remaining vaginal microbiome. The high selectivity and effectiveness in eliminating Gardnerella, both in cultures of isolated strains as well as in clinically derived samples of natural polymicrobial biofilms, makes PM-477 a promising alternative to antibiotics for the treatment of bacterial vaginosis, especially in patients with frequent recurrence.

scholarly journals Chromosomal painting of the sandpiper (Actitis macularius) detects several fissions for the Scolopacidae family (Charadriiformes)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Melquizedec Luiz Silva Pinheiro ◽  
Cleusa Yoshiko Nagamachi ◽  
Talita Fernanda Augusto Ribas ◽  
Cristovam Guerreiro Diniz ◽  
Patricia Caroline Mary O´Brien ◽  
...  
Keyword(s):  
Chromosome Painting ◽  
Diploid Number ◽  
Chromosomal Evolution ◽  
Long Distance ◽  
Chromosomal Painting ◽  
Cytogenetic Studies ◽  
Burhinus Oedicnemus ◽  
Clear Idea ◽  
First Time

Abstract Background The Scolopacidae family (Suborder Scolopaci, Charadriiformes) is composed of sandpipers and snipes; these birds are long-distance migrants that show great diversity in their behavior and habitat use. Cytogenetic studies in the Scolopacidae family show the highest diploid numbers for order Charadriiformes. This work analyzes for the first time the karyotype of Actitis macularius by classic cytogenetics and chromosome painting. Results The species has a diploid number of 92, composed mostly of telocentric pairs. This high 2n is greater than the proposed 80 for the avian ancestral putative karyotype (a common feature among Scolopaci), suggesting that fission rearrangements have formed smaller macrochromosomes and microchromosomes. Fluorescence in situ hybridization using Burhinus oedicnemus whole chromosome probes confirmed the fissions in pairs 1, 2, 3, 4 and 6 of macrochromosomes. Conclusion Comparative analysis with other species of Charadriiformes studied by chromosome painting together with the molecular phylogenies for the order allowed us to raise hypotheses about the chromosomal evolution in suborder Scolopaci. From this, we can establish a clear idea of how chromosomal evolution occurred in this suborder.

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