97/03378 Sulfo group-containing aromatic polymer dispersants with excellent surface activity and dispersive power

1997 ◽  
Vol 38 (4) ◽  
pp. 273
2020 ◽  
Author(s):  
Kenneth Lucas ◽  
George Barnes

We present the results of direct dynamics simulations and DFT calculations aimed at elucidating the effect of \textit{O}-sulfonation on the collision induced dissociation for serine. Towards this end, direct dynamics simulations of both serine and sulfoserine were performed at multiple collision energies and theoretical mass spectra obtained. Comparisons to experimental results are favorable for both systems. Peaks related to the sulfo group are identified and the reaction dynamics explored. In particular, three significant peaks (m\z 106, 88, and 81) seen in the theoretical mass spectrum directly related to the sulfo group are analyzed as well as major peaks shared by both systems. Our analysis shows that the m\z 106 peaks result from intramolecular rearrangements, intermolecular proton transfer among complexes composed of initial fragmentation products, and at high energy side-chain fragmentation. The \mz 88 peak was found to contain multiple constitutional isomers, including a previously unconsidered, low energy structure. It was also seen that the RM1 semi empirical method was not able to obtain all of the major peaks seen in experiment for sulfoserine. In contrast, PM6 did obtain all major experimental peaks.


2020 ◽  
Vol 16 ◽  
Author(s):  
Dian Riana Ningsih ◽  
Zusfahair Zusfahair ◽  
Dadan Hermawan ◽  
Wulan Anggraeni ◽  
Hassan Y. Aboul-Enein

Background: Acne is caused by several factors including the active secretion of sebaceous sweat glands, hyperkeratosis in the hair infundibulum and the effects of bacteria. One of the plants that has the potential as an antibacterial is the extract of arumanis mango leaves. Method: Determine the Minimum Inhibitory Concentration (MIC) of methanol extract of mango leaves which can inhibit Propionibacterium acnes activity. The antibacterial activity tests were performed using agar diffusion. The ointment formulation, the characteristics of ointment preparations and the ointment activity against P. Acnes are discussed. Result: MIC of methanol extract of mango leaves value is 5 ppm with an inhibition zone of 1 mm. The ointment obtained is white, has distinctive smell, semisolid form, possesses a pH of 4.92 - 5.87, dispersive power of 5.05 - 6.30 cm, adhesive power of 1 - 3.67 seconds, homogeneous and protective. Ointment preparations of methanol extract of mango leaves has activity on P. acnes on the 0 and 15th day of storage. The activities of ointment preparation on day 0 with concentrations of 0, 5, 10 and 15 ppm are 0.00 mm; 10.20 mm; 19.97 mm and 23.60 mm respectively, while the inhibition zones produced by the preparation of ointment on day 15 with concentrations of 0, 5, 10 and 15 ppm are 0.00 mm; 5.71 mm; 9.58 mm and 21.88 mm respectively. Conclusion: Methanol extract of mango leaves (Mangifera indica L.) and oinment preparation are able to inhibit the growth of Propionibacterium acnes.


1993 ◽  
Vol 58 (3) ◽  
pp. 496-505
Author(s):  
Ondřej Wein

Partial blocking of the transport surface under the stagnant (nerst) layer is simulated by periodically alternating bands of perfectly insulating zones and active zones with a constant potential of driving force. The numeric solution of the corresponding two-dimensional elliptic problem is represented by a simple empirical correlation for the transfer coefficients. The result is interpreted in terms of a simple electrochemical problem about limiting diffusion currents at electrodes with non-uniform surface activity.


2021 ◽  
Vol 334 ◽  
pp. 115988
Author(s):  
Angelica Mero ◽  
Andrea Mezzetta ◽  
Janusz Nowicki ◽  
Justyna Łuczak ◽  
Lorenzo Guazzelli

2021 ◽  
Vol 489 ◽  
pp. 229406
Author(s):  
Nana Sun ◽  
Dayu Zhou ◽  
Wenwen Liu ◽  
Aikui Li ◽  
Yunpeng Su ◽  
...  

2021 ◽  
Vol 13 (15) ◽  
pp. 8122
Author(s):  
Shijie Tian ◽  
Weiqiang Tan ◽  
Xinyuan Wang ◽  
Tingting Li ◽  
Fanhao Song ◽  
...  

Surface activity of humic acid (HA) and its six sub-fractions isolated from forest soil were characterized by surface tension measurements, dynamic light scattering, and laser doppler electrophoresis. The surface tension of HA and its sub-fractions reduced from 72.4 mN·m−1 to 36.8 mN·m−1 in exponential model with the increasing concentration from 0 to 2000 mg·L−1. The critical micelle concentration (CMC) and Z-average particle size ranged from 216–1024 mg·L−1 and 108.2–186.9 nm for HA and its sub-fractions, respectively. The CMC have related with alkyl C, O-alkyl C, aromatic C, and carbonyl C (p < 0.05), respectively, and could be predicted with the multiple linear regression equation of CMC, CMC = 18896 − 6.9 × C-296 × alkyl C-331 × aromatic C-17019 × H/C + 4054 × HB/HI (p < 0.05). The maximum particle size was 5000 nm after filtered by a membrane with pore size of 450 nm, indicating HA and its sub-fractions could progressed self-assembly at pH 6.86. The aggregate sizes of number-base particle size distributions were mainly in six clusters including 2 ± 1 nm, 5 ± 2 nm, 10 ± 3 nm, 21 ± 8 nm, 40 ± 10 nm, and >50 nm analyzed by Gaussian model that maybe due to the inconsistency of the components and structures of the HA sub-fractions, requiring further study. It is significance to explore the surface activity of HA and its sub-fractions, which is helpful to clarify the environmental behavior of HA.


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