Effect of Chloride Ions on the Adsorption of 3-Mercapto-1-propanesulfonic acid and Bis(3-sulfopropyl)-disulfide on a Au(111) Surface

Langmuir ◽  
2010 ◽  
Vol 26 (16) ◽  
pp. 13263-13271 ◽  
Author(s):  
Yung-Fang Liu ◽  
Yuh-Lang Lee ◽  
Yaw-Chia Yang ◽  
Zheng-Yan Jian ◽  
Wei-Ping Dow ◽  
...  
2018 ◽  
Author(s):  
◽  
Shendu Yang

Metamaterials typically consist of metallic and dielectric repeating structures. Electrodeposition of copper is the preferred approach to fabricating the metallic part of the metamaterials of interest in this study. The highly-variant topography requires chemical additives, like chloride ions, 3-mercapto-1-propanesulfonic acid (MPSA), polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) to enhance bottom-up superfilling while maintaining terrace flatness. This study focuses on both experimental and computational investigations of the degradation potential of the additives and their adsorption mechanism in a highly-acidic copper electrolyte in order to optimally parameterize the copper electrodeposition process. Results show Cl-MPSAPEG-PVP additives perform well, but substitution of PVP with Janus Green B provides better terrace leveling. Additionally, NMR data show a quick and complete conversion of MPSA to bis(3-sulfopropyl) disulfide (SPS) in the acidic copper bath. Finally, FEM simulations further show that the accelerator species may initially accumulate and be transported vertically until overplating, whereby they are transported laterally. Our study also show that the electromagnetic performance of metamaterial is dependent on SU-8 related parameters, including pillar height, bottom side length and spacing between pillars. The metamaterial geometry is successfully optimized and it can localize the surface plasmon with the peak frequency of 1.2 THz to the nano-antenna and the highest terahertz absorption is 30%.


2017 ◽  
Vol 164 (7) ◽  
pp. D419-D424 ◽  
Author(s):  
Fuliang Wang ◽  
Yijie Li ◽  
Hu He ◽  
Yan Wang ◽  
Wenhui Zhu ◽  
...  

Author(s):  
Al W. Stinson

The stratified squamous epithelium which lines the ruminal compartment of the bovine stomach performs at least three important functions. (1) The upper keratinized layer forms a protective shield against the rough, fibrous, constantly moving ingesta. (2) It is an organ of absorption since a number of substances are absorbed directly through the epithelium. These include short chain fatty acids, potassium, sodium and chloride ions, water, and many others. (3) The cells of the deeper layers metabolize butyric acid and to a lesser extent propionic and acetic acids which are the fermentation products of rumen digestion. Because of the functional characteristics, this epithelium is important in the digestive process of ruminant species which convert large quantities of rough, fibrous feed into energy.Tissue used in this study was obtained by biopsy through a rumen fistula from clinically healthy, yearling holstein steers. The animals had been fed a typical diet of hay and grain and the ruminal papillae were fully developed. The tissue was immediately immersed in 1% osmium tetroxide buffered to a pH of 7.4 and fixed for 2 hrs. The tissue blocks were embedded in Vestapol-W, sectioned with a Porter-Blum microtome with glass knives and stained with lead hydroxide. The sections were studied with an RCA EMU 3F electron microscope.


1984 ◽  
Vol 52 (03) ◽  
pp. 347-349 ◽  
Author(s):  
Daan W Traas ◽  
Bep Hoegee-de Nobel ◽  
Willem Nieuwenhuizen

SummaryNative human plasminogen, the proenzyme of plasmin (E. C. 3.4.21.7) occurs in blood in two well defined forms, affinity forms I and II. In this paper, the feasibility of separating these forms of human native plasminogen by affinity chromatography, is shown to be dependent on two factors: 1) the ionic composition of the buffer containing the displacing agent: buffers of varying contents of sodium, Tris, phosphate and chloride ions were compared, and 2) the type of adsorbent. Two adsorbents were compared: Sepharose-lysine and Sepharose-bisoxirane-lysine. Only in the phosphate containing buffers, irrespective of the type of adsorbent, the affinity forms can be separated. The influence of the adsorbent can be accounted for by a large difference in dissociation constants of the complex between plasminogen and the immobilized lysine.


2020 ◽  
Vol 61 (9) ◽  
pp. 1775-1781
Author(s):  
Li-Bin Niu ◽  
Shoichi Kosaka ◽  
Masaki Yoshida ◽  
Yusuke Suetake ◽  
Kazuo Marugame

2020 ◽  
Author(s):  
Victor Kwan ◽  
Styliani Consta

<div>Charged droplets play a central role in native mass spectrometry, atmospheric aerosols and in serving as micro-reactors for accelerating chemical reactions. The surface excess charge layer in droplets has often been associated with distinct chemistry. Using molecular simulations for droplets with Na+ and Cl- ions we have found that this layer is ≈ 1.5−1.7 nm thick and depending on the droplet size it includes 33%-55% of the total number of ions. Here, we examine the effect of droplet size and nature of ions in the structure of the surface excess charge layer by using molecular dynamics. We find that in the presence of simple ions the thickness of the surface excess charge layer is invariant not only with respect to droplet size but also with respect to the nature of the simple ions and it is not sensitive to fine details of different force fields used in our simulations.</div><div> In the presence of macroions the excess surface charge layer may extend to 2.0. nm. For the same droplet size, iodide and model hydronium ions show considerably higher concentration than the sodium and chloride ions. <br></div><div>We also find that differences in the average water dipole orientation in the presence of cations and anions in this layer are reflected in the charge distributions. Within the surface charge layer, the number of hydrogen bonds reduces gradually relative to the droplet interior where the number of hydrogen bonds is on the average 2.9 for droplets of diameter < 4 nm and 3.5 for larger droplets. The decrease in the number of hydrogen bonds from the interior to the surface is less pronounced in larger droplets. In droplets with diameter < 4 nm and high concentration of ions the charge of the ions is not compensated only by the solvent polarization charge but by the total charge that also includes the other free charge. This finding shows exceptions to the commonly made assumption that the solvent compensates the charge of the ions in solvents with very high dielectric constant. The study provides molecular insight into the bi-layer droplet structure assumed in the equilibrium partitioning model of C. Enke and assesses critical assumptions of the Iribarne-Thomson model for the ion-evaporation mechanism. <br></div>


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