Tube-rolling and formation of mechanically robust micro-tubes in graphene oxide aqueous dispersions during shear flow

Soft Matter ◽  
2019 ◽  
Vol 15 (21) ◽  
pp. 4238-4243
Author(s):  
Chang Min Ok ◽  
Seo Gyun Kim ◽  
Seung Yol Jeong ◽  
Heon Sang Lee
Keyword(s):  
Graphene Oxide ◽  
Shear Flow ◽  
Low Ph ◽  
Tube Rolling ◽  
Confined Geometry ◽  
Aqueous Dispersions ◽  
Ph Values

Mechanically robust GO micro-tubes are formed spontaneously when GO aqueous dispersions flow slowly in a confined geometry at low pH values.

scholarly journals Adaptation of Lactobacillus plantarum IMDO 130201, a Wheat Sourdough Isolate, to Growth in Wheat Sourdough Simulation Medium at Different pH Values through Differential Gene Expression

2011 ◽  
Vol 77 (10) ◽  
pp. 3406-3412 ◽  
Author(s):  
Gino Vrancken ◽  
Luc De Vuyst ◽  
Tom Rimaux ◽  
Joke Allemeersch ◽  
Stefan Weckx
Keyword(s):  
Gene Expression ◽  
Lactobacillus Plantarum ◽  
Differential Gene Expression ◽  
Lipoteichoic Acid ◽  
Low Ph ◽  
Exponential Growth Phase ◽  
Cellular Mechanisms ◽  
Content Type ◽  
Ph Values ◽  
Differential Gene

ABSTRACTSourdough is a very competitive and challenging environment for microorganisms. Usually, a stable microbiota composed of lactic acid bacteria (LAB) and yeasts dominates this ecosystem. Although sourdough is rich in carbohydrates, thus providing an ideal environment for microorganisms to grow, its low pH presents a particular challenge. The nature of the adaptation to this low pH was investigated forLactobacillus plantarumIMDO 130201, an isolate from a laboratory wheat sourdough fermentation. Batch fermentations were carried out in wheat sourdough simulation medium, and total RNA was isolated from mid-exponential-growth-phase cultures, followed by differential gene expression analysis using a LAB functional gene microarray. At low pH values, an increased expression of genes involved in peptide and amino acid metabolism was found as well as that of genes involved in plantaricin production and lipoteichoic acid biosynthesis. The results highlight cellular mechanisms that allowL. plantarumto function at a low environmental pH.

scholarly journals Mechanism of Coagulation of Humic Acid in Presence of Metal Ion Coagulants at Low pH Values

1970 ◽  
Vol 73 (5) ◽  
pp. 874-878 ◽  
Author(s):  
Takao YOTSUYANAGI ◽  
Katsumi GOTO ◽  
Masaichi NAGAYAMA
Keyword(s):  
Humic Acid ◽  
Metal Ion ◽  
Low Ph ◽  
Ph Values

scholarly journals Histidine-Rich Glycoprotein Inhibits HIV-1 Infection in a pH-Dependent Manner

2018 ◽  
Vol 93 (4) ◽  
Author(s):  
Ezequiel Dantas ◽  
Fernando Erra Díaz ◽  
Pehuén Pereyra Gerber ◽  
Augusto Varese ◽  
Diana Alicia Jerusalinsky ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Respiratory Syncytial Virus ◽  
Herpes Simplex ◽  
Low Ph ◽  
Vaginal Mucosa ◽  
Ph Values ◽  
Syncytial Virus ◽  
Simplex Virus ◽  
Herpes Simplex Virus 2 ◽  
Hiv 1

ABSTRACTHistidine-rich glycoprotein (HRG) is an abundant plasma protein with a multidomain structure, allowing its interaction with many ligands, including phospholipids, plasminogen, fibrinogen, IgG antibodies, and heparan sulfate. HRG has been shown to regulate different biological responses, such as angiogenesis, coagulation, and fibrinolysis. Here, we found that HRG almost completely abrogated the infection of Ghost cells, Jurkat cells, CD4+T cells, and macrophages by HIV-1 at a low pH (range, 6.5 to 5.5) but not at a neutral pH. HRG was shown to interact with the heparan sulfate expressed by target cells, inhibiting an early postbinding step associated with HIV-1 infection. More importantly, by acting on the viral particle itself, HRG induced a deleterious effect, which reduces viral infectivity. Because cervicovaginal secretions in healthy women show low pH values, even after semen deposition, our observations suggest that HRG might represent a constitutive defense mechanism in the vaginal mucosa. Of note, low pH also enabled HRG to inhibit the infection of HEp-2 cells and Vero cells by respiratory syncytial virus (RSV) and herpes simplex virus 2 (HSV-2), respectively, suggesting that HRG might display broad antiviral activity under acidic conditions.IMPORTANCEVaginal intercourse represents a high-risk route for HIV-1 transmission. The efficiency of male-to-female HIV-1 transmission has been estimated to be 1 in every 1,000 episodes of sexual intercourse, reflecting the high degree of protection conferred by the genital mucosa. However, the contribution of different host factors to the protection against HIV-1 at mucosal surfaces remains poorly defined. Here, we report for the first time that acidic values of pH enable the plasma protein histidine-rich glycoprotein (HRG) to strongly inhibit HIV-1 infection. Because cervicovaginal secretions usually show low pH values, our observations suggest that HRG might represent a constitutive antiviral mechanism in the vaginal mucosa. Interestingly, infection by other viruses, such as respiratory syncytial virus and herpes simplex virus 2, was also markedly inhibited by HRG at low pH values, suggesting that extracellular acidosis enables HRG to display broad antiviral activity.

scholarly journals Effect of water temperature and pH on the concentration and time of ozone saturation

2018 ◽  
Vol 21 (0) ◽  
Author(s):  
Melicia Cintia Galdeano ◽  
Allan Eduardo Wilhelm ◽  
Isabella Borges Goulart ◽  
Renata Valeriano Tonon ◽  
Otniel Freitas-Silva ◽  
...  
Keyword(s):  
Water Temperature ◽  
Molecular Oxygen ◽  
Half Life ◽  
Low Ph ◽  
Ozone Content ◽  
Effect Of Temperature ◽  
Saturation Time ◽  
Gas Concentration ◽  
Ph Values ◽  
Effect Of Water

Abstract Ozone has been used for many years to disinfect water due to its oxidizing potential. Since it decomposes quickly into molecular oxygen, leaving no residue, it has important advantages for use. The decomposition of ozone is affected by the temperature and pH of the medium, low pH values and temperatures increasing its half-life, which can result in more efficient disinfection. With the objective of increasing the effectiveness of ozonation, this study investigated the effect of temperature (8 ºC and 25 °C) and pH (3.0 and 6.0) of the water on the saturation time and gas concentration, employing two initial gas concentrations (13.3 and 22.3 mg L-1). The concentration of ozone saturation increased as the temperature and pH of the medium decreased, as also with the higher initial gas concentration ( C0). The highest saturation concentrations were obtained at pH 3.0 and 8 °C (4.50 and 8.03 mg L-1 with C0 of 13.3 and 22.3 mg L-1, respectively). This higher ozone content could result in greater decontamination efficiency of the food products washed with this water.

Efficacy of Bisulfite Ions as an Oxygen Scavenger in Monoethylene Glycol (At Least 20 wt%)/Water Mixtures

SPE Journal ◽  
2017 ◽  
Vol 22 (05) ◽  
pp. 1467-1477 ◽  
Author(s):  
Mobin Salasi ◽  
Thunyaluk Pojtanabuntoeng ◽  
Sindee Wong ◽  
Marc Lehmann
Keyword(s):  
Transition Metal ◽  
Oxygen Removal ◽  
Low Ph ◽  
Experimental Results ◽  
Oxygen Scavenger ◽  
Ph Values ◽  
Oxygen Scavenging ◽  
Monoethylene Glycol

Summary This study investigates the oxygen-scavenging behavior of bisulfite ions in monoethylene glycol (MEG)/water mixtures at concentrations commonly found in gas-transportation pipelines. Temperatures and pH values were varied. The influence of transition-metal (TM) ions to catalyze the bisulfite oxygen scavenging was studied. Experimental results indicate that MEG significantly inhibits bisulfite oxygen removal, which is hindered at low pH values and, to some extent, temperature. TMs can accelerate the oxygen-scavenging reaction in pH-unadjusted solutions, although the rate was still lower than that of the pH-adjusted solutions. The possible mechanism for such behavior and industrial implications are discussed.

Effect of pH on Glycolate and Ammonia Excretion in L-MSO Treated Chlorella Cells

1987 ◽  
Vol 42 (5) ◽  
pp. 525-529
Author(s):  
Yoshihiro Shiraiwa ◽  
Georg H. Schmid
Keyword(s):  
Chlorella Vulgaris ◽  
Major Part ◽  
Ammonia Excretion ◽  
Low Ph ◽  
Final Concentration ◽  
The Other ◽  
Effect Of Ph ◽  
Photosynthetic Rates ◽  
Ph Values ◽  
Glycolate Metabolism

Abstract The effect of pH changes on the excretion of ammonia and glycolate from algal cells into the medium was investigated in L-MSO (final concentration, 0.5 mм) -treated High-and Low CO2-cells of Chlorella vulgaris 211-11 h. The excretion was analyzed in the condition in which the cells were continuously gassed with air at 25 °C. At the values tested, generally more ammonia was excreted in L-MSO-treated Low CO2-cells than in L-MSO treated High CO2-cells. In both kinds of algal cells more ammonia was excreted at low pH-values and absolutely no ammonia was excreted at pH 8. In the dark, no or only slight ammonia excretion was observed in both L-MSO-treated High and Low CO2-cells. Under all these conditions no or only very low glycolate excretion was observed in both L-MSO treated High and Low CO2-cells. In High CO2-cells rates of photosynthesis were high at pH 6 and lower at higher pH values. On the other hand Low CO2-cells showed practically little dependence of photosynthetic rates on the pH. This result might indicate that the major part of the ammonia excretion observed, was not due to the inhibition of photosynthesis at acid pH values. It is known that ammonia excretion in L-MSO treated algal cells is due to the inhibition of the refixation of ammonia which originates from the glycine-serine aminotransferase reaction in the glycolate pathway. Our results demonstrate that glycolate production and glycolate metabolism are more intense at low pH values when compared to high pH values. This is valid for both High and Low CO2-cells. Low CO2-cells in Chlorella vulgaris 211-11 h exhibit a more active glycolate metabolism than High CO2-cells.

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