scholarly journals Method for the Direct Observation and Quantification of Survival of Bacteria Attached to Negatively or Positively Charged Surfaces in an Aqueous Medium

2011 ◽  
Vol 45 (19) ◽  
pp. 8345-8351 ◽  
Author(s):  
Bahareh Asadishad ◽  
Subhasis Ghoshal ◽  
Nathalie Tufenkji
Keyword(s):  
Aqueous Medium ◽  
Direct Observation ◽  
Charged Surfaces ◽  
Positively Charged

scholarly journals Constructing Positively Charged Thin-Film Nanocomposite Nanofiltration Membranes with Enhanced Performance

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2526
Author(s):  
Wenyao Shao ◽  
Chenran Liu ◽  
Tong Yu ◽  
Ying Xiong ◽  
Zhuan Hong ◽  
...  
Keyword(s):  
Thin Film ◽  
Heavy Metal ◽  
Water Flux ◽  
Water Contact ◽  
Salt Rejection ◽  
Thin Film Composite ◽  
Charged Surfaces ◽  
Active Layers ◽  
Positively Charged ◽  
Thin Film Nanocomposite

Using polyethylenimine (PEI) as the aqueous reactive monomers, a positively charged thin-film nanocomposite (TFN) nanofiltration (NF) membrane with enhanced performance was developed by successfully incorporating graphene oxide (GO) into the active layer. The effects of GO concentrations on the surface roughness, water contact angle, water flux, salt rejection, heavy metal removals, antifouling property, and chlorine resistance of the TFN membranes were evaluated in depth. The addition of 20 ppm GO facilitated the formation of thin, smooth, and hydrophilic nanocomposite active layers. Thus, the TFN-PEI-GO-20 membrane showed the optimal water flux of 70.3 L·m−2·h−1 without a loss of salt rejection, which was 36.8% higher than the thin-film composite (TFC) blank membrane. More importantly, owing to the positively charged surfaces, both the TFC-PEI-blank and TFN-PEI-GO membranes exhibited excellent rejections toward various heavy metal ions including Zn2+, Cd2+, Cu2+, Ni2+, and Pb2+. Additionally, compared with the negatively charged polypiperazine amide NF membrane, both the TFC-PEI-blank and TFN-PEI-GO-20 membranes demonstrated superior antifouling performance toward the cationic surfactants and basic protein due to their hydrophilic, smooth, and positively charged surface. Moreover, the TFN-PEI-GO membranes presented the improved chlorine resistances with the increasing GO concentration.

scholarly journals Photodegradation of Rhodamine B in Presence of CaO and NiO-CaO Catalysts

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Tobias Kornprobst ◽  
Johann Plank
Keyword(s):  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Rhodamine B ◽  
Uv Light ◽  
Mechanistic Study ◽  
Light Conditions ◽  
No Adsorption ◽  
Charged Surfaces ◽  
Positively Charged

A CaO catalyst was prepared by mild calcination (650°C) of facilely precipitated Ca(OH)2and compared to an NiO-CaO catalyst obtained from an Ni(OH)2/Ca(OH)2coprecipitate as a precursor. Both catalysts degraded rhodamine B (RB) effectively when exposed to ultraviolet light but exhibited slower degradation under visible light conditions. Under UV light, CaO was more effective than NiO-CaO, while in visible light, the opposite was observed. A mechanistic study revealed no influence of the specific surface area of the catalysts on RB degradation, no adsorption of RB on the positively charged surfaces of the catalysts, and only incomplete degradation of RB. Consequently, both materials represent nonconventional photocatalysts.

Enhanced Healing of Cutaneous Wounds in Rats Using Beads with Positively Charged Surfaces

1992 ◽  
Vol 89 (5) ◽  
pp. 898-899
Author(s):  
Thomas A. Mustoe ◽  
Dean A. Weber ◽  
Marilyn Krukowski
Keyword(s):  
Cutaneous Wounds ◽  
Charged Surfaces ◽  
Positively Charged

Molecular simulations of cytochrome c adsorption on positively charged surfaces: the influence of anion type and concentration

2016 ◽  
Vol 18 (15) ◽  
pp. 9979-9989 ◽  
Author(s):  
Chunwang Peng ◽  
Jie Liu ◽  
Yun Xie ◽  
Jian Zhou
Keyword(s):  
Cytochrome C ◽  
Molecular Simulations ◽  
Charged Surfaces ◽  
Anion Type ◽  
Positively Charged

The influence of anion type and concentration on the adsorption of cytochrome c onto the positively charged NH2-SAM surface.

scholarly journals Adsorption of Fibronectin Fragment on Surfaces Using Fully Atomistic Molecular Dynamics Simulations

2018 ◽  
Vol 19 (11) ◽  
pp. 3321 ◽  
Author(s):  
Evangelos Liamas ◽  
Karina Kubiak-Ossowska ◽  
Richard Black ◽  
Owen Thomas ◽  
Zhenyu Zhang ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Electrostatic Interactions ◽  
Charged Surface ◽  
Cell Binding ◽  
Binding Region ◽  
Charged Surfaces ◽  
Fibronectin Fragment ◽  
Dynamics Simulations ◽  
Positively Charged

The effect of surface chemistry on the adsorption characteristics of a fibronectin fragment (FNIII8–10) was investigated using fully atomistic molecular dynamics simulations. Model surfaces were constructed to replicate self-assembled monolayers terminated with methyl, hydroxyl, amine, and carboxyl moieties. It was found that adsorption of FNIII8–10 on charged surfaces is rapid, specific, and driven by electrostatic interactions, and that the anchoring residues are either polar uncharged or of opposing charge to that of the targeted surfaces. On charged surfaces the presence of a strongly bound layer of water molecules and ions hinders FNIII8–10 adsorption. In contrast, adsorption kinetics on uncharged surfaces are slow and non-specific, as they are driven by van der Waals interactions, and the anchoring residues are polar uncharged. Due to existence of a positively charged area around its cell-binding region, FNIII8–10 is available for subsequent cell binding when adsorbed on a positively charged surface, but not when adsorbed on a negatively charged surface. On uncharged surfaces, the availability of the fibronectin fragment’s cell-binding region is not clearly distinguished because adsorption is much less specific.

High-Efficiency Retroviral Transduction of Mammalian Cells on Positively Charged Surfaces

2000 ◽  
Vol 11 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Burkhard Hennemann ◽  
Jean Y. Chuo ◽  
Patricia D. Schley ◽  
Karen Lambie ◽  
R. Keith Humphries ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
High Efficiency ◽  
Retroviral Transduction ◽  
Charged Surfaces ◽  
Positively Charged

scholarly journals Utilization of Sodium Hexametaphosphate for Separating Scheelite from Calcite and Fluorite Using an Anionic–Nonionic Collector

Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 705 ◽  
Author(s):  
Jianhua Kang ◽  
Yuehua Hu ◽  
Wei Sun ◽  
Zhiyong Gao ◽  
Runqing Liu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Negative Charge ◽  
Electrostatic Force ◽  
Sodium Hexametaphosphate ◽  
Infrared Spectrometry ◽  
Low Grade ◽  
X Ray ◽  
Charged Surfaces ◽  
Selective Reagent ◽  
Positively Charged

This study presents a highly selective reagent system that utilizes sodium hexametaphosphate (SHMP) to improve the separation of scheelite from calcite and fluorite using an anionic–nonionic collector. The recoveries of calcite and fluorite decreased to 20% as the SHMP dose exceeded 6 × 10−6 mol/L, whereas that of scheelite remained at 85%. The interaction mechanisms of minerals with SHMP were investigated through equilibrium speciation, Zeta potential, Fourier transform infrared spectrometry, and X-ray photoelectron spectroscopy analyses. SHMP exists as hydrogen phosphate anion in the aqueous solution with a pH of 7–12. Moreover, it may be adsorbed intensively on the positively charged surfaces of calcite and fluorite via electrostatic force or chelation with calcium ion to impede further adsorption of the assembled collector. By comparison, the adsorption of SHMP is feeble on the scheelite surface because of its negative charge. The roughing grade of low-grade scheelite ore is substantially improved from 0.74% to 1.65% compared with that in the contrast test in the absence of SHMP.

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