scholarly journals Photo-induced changes in the Langmuir adsorption constants of metal oxide layers in self-cleaning cation sensors.

2012 ◽  
Vol 1406 ◽  
Author(s):  
Philip S. Foran ◽  
Colin Boxall
Keyword(s):  
Metal Oxide ◽  
Quartz Crystal ◽  
Photoinduced Change ◽  
Langmuir Adsorption ◽  
Adsorption Sites ◽  
Adsorption Processes ◽  
Two Parameters ◽  
Induced Changes ◽  
First Time

ABSTRACTFor the first time, we have used a metal oxide-coated quartz crystal microbalance (QCM) to measure Cs+ adsorption onto illuminated and un-illuminated mesoporous TiO2 (m-TiO2) films by microgravimetric means in-situ. In the simplest case, such experiments yield two parameters of interest: K, the Langmuir adsorption coefficient and mmax the maximum mass of adsorbate to form a complete monolayer at the m-TiO2-coated quartz crystal piezoelectric surface. Importantly, we have found that illumination of the m-TiO2 film with ultra bandgap light results in an increase in mmax i.e. illumination allows for greater adsorption of substrate to occur than in the dark. Our studies also show that under illumination, K also increases indicating a higher affinity for surface adsorption. The photoinduced change in mmax and K are thought to be due to an increase in surface bound titanol groups, thus increasing the number of available adsorption sites – and so providing evidence to support the notion of photoinduced adsorption processes in photocatalytic systems. These findings have implications for the development of a reversible adsorption based microgravimetric sensor for Cs+.

Corrosion Behaviors Studied in Self-Assembled Processes of Alkanethiol Monolayers on Polycrystalline Gold Substrates

2007 ◽  
Vol 121-123 ◽  
pp. 385-388
Author(s):  
Z. Cao ◽  
Zhong Liang Xiao ◽  
Ning Gu ◽  
S. Shimada ◽  
T. Fukuda ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Quartz Crystal ◽  
Force Microscopy ◽  
Atomic Force ◽  
Gold Substrates ◽  
Corrosion Behaviors ◽  
Polycrystalline Gold ◽  
First Time ◽  
Fast Stage

In this paper, the corrosion phenomenon occurred on the polycrystalline gold substrates has been for the first time observed by in situ quartz crystal microbalance (QCM) method for adsorption of alkanethiol monolayers, which may be attributed to thiol-induced dissolution of gold during the adsorption process in the presence of oxygen. It is evident from the image of many corrosive defects or holes produced on the surface of gold grains by using atomic force microscopy (AFM). The kinetic equation on corrosion rate of gold dissolved in the organothiol solution has been obtained. The gold corrosion rate at fast stage can be estimated to be 9.2 × 1011 Au atoms cm-2 s-1.

Microgravimetric Corrosion Studies on UO2

2003 ◽  
Vol 807 ◽  
Author(s):  
Detlef H. Wegen ◽  
T. Gouder ◽  
M. Eckle ◽  
T. Wiss ◽  
J.-P. Glatz
Keyword(s):  
Thin Film ◽  
Cyclic Voltammetry ◽  
Weight Change ◽  
Quartz Crystal ◽  
Spent Fuel ◽  
Corrosion Studies ◽  
Fuel Storage ◽  
First Time ◽  
Micro Balance

ABSTRACTFor the first time at ITU electrochemical quartz crystal micro-balance has been used for the investigation of UO2 thin film oxidation. The combination of cyclic voltammetry with nano-gram weight change measurements in-situ has shown at least two steps in the initial stages of UO2 dissolution under oxidising conditions relevant to spent fuel storage.

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>

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.

New-onset systemic sclerosis and scleroderma renal crisis under docetaxel

2021 ◽  
pp. 239719832110076
Author(s):  
Véronique Debien ◽  
Arthur Petitdemange ◽  
Dorothée Bazin ◽  
Carole Ederle ◽  
Benoit Nespola ◽  
...  
Keyword(s):  
Systemic Sclerosis ◽  
Rna Polymerase Iii ◽  
Systemic Autoimmune Disease ◽  
Scleroderma Renal Crisis ◽  
Prostate Cancers ◽  
Poor Outcomes ◽  
Induced Changes ◽  
First Time ◽  
Lung And Kidney ◽  
New Onset

Systemic sclerosis is a rare systemic autoimmune disease characterized by microvascular impairment and fibrosis of the skin and other organs with poor outcomes. Toxic causes may be involved. We reported the case of a 59-year-old woman who developed an acute systemic sclerosis after two doses of adjuvant chemotherapy by docetaxel and cyclophosphamide for a localized hormone receptor + human epithelial receptor 2—breast cancer. Docetaxel is a major chemotherapy drug used in the treatment of breast, lung, and prostate cancers, among others. Scleroderma-like skin-induced changes (morphea) have been already described for taxanes. Here, we report for the first time a case of severe lung and kidney flare with thrombotic microangiopathy after steroids for acute interstitial lung disease probably induced by anti-RNA polymerase III + systemic sclerosis after docetaxel.

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