scholarly journals Fluorous-Phase Ion-Selective pH Electrodes: Electrode Body and Ionophore Optimization for Measurements in the Physiological pH Range

ACS Omega ◽  
2020 ◽  
Vol 5 (23) ◽  
pp. 13621-13629
Author(s):  
Xin V. Chen ◽  
Maral P.S. Mousavi ◽  
Philippe Bühlmann
Keyword(s):  
Ph Range ◽  
Ph Electrodes

scholarly journals A Minimally Invasive Microsensor Specially Designed for Simultaneous Dissolved Oxygen and pH Biofilm Profiling

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4747 ◽  
Author(s):  
Xavier Guimerà ◽  
Ana Moya ◽  
Antonio David Dorado ◽  
Xavi Illa ◽  
Rosa Villa ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Dissolved Oxygen ◽  
Ph Monitoring ◽  
Ph Sensing ◽  
Wide Ph Range ◽  
Ph Range ◽  
Biofilm Structure ◽  
Parallel Arrays ◽  
Ph Electrodes

A novel sensing device for simultaneous dissolved oxygen (DO) and pH monitoring specially designed for biofilm profiling is presented in this work. This device enabled the recording of instantaneous DO and pH dynamic profiles within biofilms, improving the tools available for the study and the characterization of biological systems. The microsensor consisted of two parallel arrays of microelectrodes. Microelectrodes used for DO sensing were bare gold electrodes, while microelectrodes used for pH sensing were platinum-based electrodes modified using electrodeposited iridium oxide. The device was fabricated with a polyimide (Kapton®) film of 127 µm as a substrate for minimizing the damage caused on the biofilm structure during its insertion. The electrodes were covered with a Nafion® layer to increase sensor stability and repeatability and to avoid electrode surface fouling. DO microelectrodes showed a linear response in the range 0–8 mg L−1, a detection limit of 0.05 mg L−1, and a sensitivity of 2.06 nA L mg−1. pH electrodes showed a linear super-Nernstian response (74.2 ± 0.7 mV/pH unit) in a wide pH range (pH 4−9). The multi-analyte sensor array was validated in a flat plate bioreactor where simultaneous and instantaneous pH and DO profiles within a sulfide oxidizing biofilm were recorded. The electrodes spatial resolution, the monitoring sensitivity, and the minimally invasive features exhibited by the proposed microsensor improved biofilm monitoring performance, enabling the quantification of mass transfer resistances and the assessment of biological activity.

Isolation and Characterization of Plasminogen Activator from Pig Leucocytes

1974 ◽  
Vol 31 (01) ◽  
pp. 072-085 ◽  
Author(s):  
M Kopitar ◽  
M Stegnar ◽  
B Accetto ◽  
D Lebez
Keyword(s):  
Molecular Weight ◽  
Plasminogen Activator ◽  
Gel Electrophoresis ◽  
Gel Filtration ◽  
Ph Optimum ◽  
Isolation And Characterization ◽  
Ph Range ◽  
Inhibition Studies ◽  
Final Purification

SummaryPlasminogen activator was isolated from disrupted pig leucocytes by the aid of DEAE chromatography, gel filtration on Sephadex G-100 and final purification on CM cellulose, or by preparative gel electrophoresis.Isolated plasminogen activator corresponds No. 3 band of the starting sample of leucocyte cells (that is composed from 10 gel electrophoretic bands).pH optimum was found to be in pH range 8.0–8.5 and the highest pH stability is between pH range 5.0–8.0.Inhibition studies of isolated plasminogen activator were performed with EACA, AMCHA, PAMBA and Trasylol, using Anson and Astrup method. By Astrup method 100% inhibition was found with EACA and Trasylol and 30% with AMCHA. PAMBA gave 60% inhibition already at concentration 10–3 M/ml. Molecular weight of plasminogen activator was determined by gel filtration on Sephadex G-100. The value obtained from 4 different samples was found to be 28000–30500.

HETEROGENEITY OF LONG ACTING THYROID STIMULATING (LATS) – ACTIVITY, THYROGLOBULIN ANTIBODIES AND THYROID MICROSOMAL ANTIBODIES

1973 ◽  
Vol 73 (3) ◽  
pp. 483-488 ◽  
Author(s):  
F. Adlkofer ◽  
H. Schleusener ◽  
L. Uher ◽  
A. Ananos ◽  
C. Brammeier
Keyword(s):  
Isoelectric Focusing ◽  
Graves Disease ◽  
Thyroid Antibodies ◽  
Thyroglobulin Antibodies ◽  
Ph Range ◽  
Long Acting ◽  
Thyroid Microsomal Antibodies

ABSTRACT Crude IgG of sera from 3 patients with Graves' disease, which contained LATS-activity and/or thyroid antibodies, was fractionated by isoelectric focusing in a pH-range between 6.0 to 10.0. LATS-activity was found in IgG-subfractions from pH 7.5 to 9.5, thyroglobulin antibodies and thyroid microsomal antibodies from pH 6.0 to 10.0. It was not possible to separate LATS-activity from the thyroid antibodies by this technique. The results indicate that LATS and the thyroid antibodies are heterogeneous and of polyclonal origin.

Grand-Reaction Method for Simulations of Ionization Equilibria and Ion Partitioning in a Broad Range of pH and Ionic Strength

2019 ◽  
Author(s):  
Jonas Landsgesell ◽  
Oleg Rud ◽  
Pascal Hebbeker ◽  
Raju Lunkad ◽  
Peter Košovan ◽  
...  
Keyword(s):  
Mean Field ◽  
Coarse Grained ◽  
Reactive System ◽  
Acid Base ◽  
Buffer Solution ◽  
Reaction Method ◽  
Ionization Equilibria ◽  
Coarse Grained Simulations ◽  
Ph Range ◽  
Weak Polyelectrolytes

We introduce the grand-reaction method for coarse-grained simulations of acid-base equilibria in a system coupled to a reservoir at a given pH and concentration of added salt. It can be viewed as an extension of the constant-pH method and the reaction ensemble, combining explicit simulations of reactions within the system, and grand-canonical exchange of particles with the reservoir. Unlike the previously introduced methods, the grand-reaction method is applicable to acid-base equilibria in the whole pH range because it avoids known artifacts. However, the method is more general, and can be used for simulations of any reactive system coupled to a reservoir of a known composition. To demonstrate the advantages of the grand-reaction method, we simulated a model system: A solution of weak polyelectrolytes in equilibrium with a buffer solution. By carefully accounting for the exchange of all constituents, the method ensures that all chemical potentials are equal in the system and in the multi-component reservoir. Thus, the grand-reaction method is able to predict non-monotonic swelling of weak polyelectrolytes as a function of pH, that has been known from mean-field predictions and from experiments but has never been observed in coarse-grained simulations. Finally, we outline possible extensions and further generalizations of the method, and provide a set of guidelines to enable safe usage of the method by a broad community of users.<br><br>

Kinetic of oxidation of methyl orange by vanadium(V) under conditions VO2+ and decavanadates coexist: Catalysis by Triton X-100 micellar medium

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Methyl Orange ◽  
Solution Ph ◽  
Vanadium Concentration ◽  
Limiting Behavior ◽  
First Order ◽  
First Order Kinetics ◽  
Ph Range ◽  
Kinetic Pattern ◽  
Triton X ◽  
Kinetics Of

The kinetics of oxidation of methyl orange by vanadium(V) {V(V)} has been investigated in the pH range 2.3-3.79. In this pH range V(V) exists both in the form of decavanadates and VO2+. The kinetic results are distinctly different from the results obtained for the same reaction in highly acidic solution (pH &lt; 1) where V(V) exists only in the form of VO2+. The reaction obeys first order kinetics with respect to methyl orange but the rate has very little dependence on total vanadium concentration. The reaction is accelerated by H+ ion but the dependence of rate on [H+] is less than that corresponding to first order dependence. The equilibrium between decavanadates and VO2+ explains the different kinetic pattern observed in this pH range. The reaction is markedly accelerated by Triton X-100 micelles. The rate-[surfactant] profile shows a limiting behavior indicative of a unimolecular pathway in the micellar pseudophase.

Evaluation of Metal Contents in Correlation with Phytosanitary Treatments at Vineyard

2017 ◽  
Vol 68 (6) ◽  
pp. 1289-1293
Author(s):  
Oana Mihai ◽  
Octav Pantea ◽  
Daniela Roxana Popovici ◽  
Catalina Gabriela Gheorghe
Keyword(s):  
Soil Samples ◽  
Flame Atomic Absorption ◽  
Mobile Forms ◽  
Before And After ◽  
Phytosanitary Treatment ◽  
Zinc Concentrations ◽  
Zinc Levels ◽  
Ph Range ◽  
In The Beginning ◽  
Short Time

The present work aims with the evaluation of copper, manganese and zinc concentrations (mobile forms) from vineyard soil before and after phytosanitary treatment with Curzate Manox and Dithane M-45 compounds, during and after remanence period. Different vineyard soils types were collected at 0-20 cm and 20-40 cm depths. Flame Atomic Absorption Spectroscopy (FAAS) method was used for measurements of the micronutrients. The soil samples were analyzed after 5 and 21 days after treatment application. Since copper is mainly accumulates in the upper layer following fungicidal sprays application, high levels of copper concentrations are obtained. The soil samples exhibits different behavior in terms of manganese and zinc contents. Manganese and zinc levels are classified as medium in the beginning of the experiment (Mn-M0 and Zn-M0), whereas these levels increased in the soil samples (at moments M1- 5 days and M2- 21 days after treatment). This behavior can be due to the Mancozeb decomposition, knowing that Mancozeb decomposes in the pH range 5-9 and it remains short time into the soil.

The Malachite Green Biodegradation in Bioreactors on Various pH Domains

2019 ◽  
Vol 70 (8) ◽  
pp. 2996-2999
Author(s):  
Viorel Gheorghe ◽  
Catalina Gabriela Gheorghe ◽  
Andreea Bondarev ◽  
Vasile Matei ◽  
Mihaela Bombos
Keyword(s):  
Malachite Green ◽  
Contact Time ◽  
Dominant Species ◽  
Wastewater Treatment Plants ◽  
Organic Substances ◽  
Biological Degradation ◽  
Growth Promoters ◽  
Ph Values ◽  
Biological Sludge ◽  
Ph Range

In the experimental study was studied the malachite green colorant biodegradation in biological sludge with biological activity. The biodegradability tests were carried out in laboratory bioreactors, on aqueous solutions of green malachite contacted with microorganisms in which the dominant species is Paramecium caudatum, in a pH range between 8 and 12, temperatures in the ranges 25-350C, using pH neutralizing substances and biomass growth promoters. The colorant initial concentrations and those obtained after biological degradation depending on the contact time, at certain pH values, were established through UV-Vis spectrometry. The studies have shown the measure of possible biological degradation of some organic substances with extended uses, with largely aromatic structure, resistance to biodegradation of microorganisms, commonly used in wastewater treatment plants.

Removal of Trace Metals From Wastewater by Activated Carbon

1973 ◽  
Vol 8 (1) ◽  
pp. 110-121
Author(s):  
A. Netzer ◽  
J.D. Norman
Keyword(s):  
Activated Carbon ◽  
Trace Metals ◽  
Organic Compounds ◽  
The Other ◽  
Published Data ◽  
Ph Adjustment ◽  
Nickel Silver ◽  
Ph Range ◽  
Carbon Treatment ◽  
Cobalt Copper

Abstract The merits of activated carbon for removal of organic compounds from wastewater have been well documented in the literature. On the other hand there is a lack of published data on the use of activated carbon for the removal of trace metals from wastewater. Experiments were designed to assess the possibility that activated carbon treatment would remove aluminum, cadmium, chromium, cobalt, copper, iron, lead, manganese, mercury, nickel, silver and zinc from wastewater. All metals studied were tested over the pH range 3-11. Greater than 99.5% removal was achieved by pH adjustment and activated carbon treatment for most of the metals tested.

Comparative Two-Dimensional Gel Electrophoresis of Trypanosoma cruzi Mammalian-Stage Forms in an Alkaline pH Range

2015 ◽  
Vol 22 (12) ◽  
pp. 1066-1075 ◽  
Author(s):  
Adriana Magalhães ◽  
Rayner Queiroz ◽  
Izabela Bastos ◽  
Jaime Santana ◽  
Marcelo Sousa ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Gel Electrophoresis ◽  
Two Dimensional ◽  
Alkaline Ph ◽  
Two Dimensional Gel Electrophoresis ◽  
Ph Range

pH-Dependent Thermal Stability of Vibrio cholerae L-asparaginase

2019 ◽  
Vol 26 (10) ◽  
pp. 743-750 ◽  
Author(s):  
Remya Radha ◽  
Sathyanarayana N. Gummadi
Keyword(s):  
Vibrio Cholerae ◽  
Conformational Changes ◽  
Kinetic Studies ◽  
Structural Features ◽  
Structure Stability ◽  
Kcal Mole ◽  
Scanning Calorimetry ◽  
Wide Range ◽  
Ph Dependent ◽  
Ph Range

Background:pH is one of the decisive macromolecular properties of proteins that significantly affects enzyme structure, stability and reaction rate. Change in pH may protonate or deprotonate the side group of aminoacid residues in the protein, thereby resulting in changes in chemical and structural features. Hence studies on the kinetics of enzyme deactivation by pH are important for assessing the bio-functionality of industrial enzymes. L-asparaginase is one such important enzyme that has potent applications in cancer therapy and food industry.Objective:The objective of the study is to understand and analyze the influence of pH on deactivation and stability of Vibrio cholerae L-asparaginase.Methods:Kinetic studies were conducted to analyze the effect of pH on stability and deactivation of Vibrio cholerae L-asparaginase. Circular Dichroism (CD) and Differential Scanning Calorimetry (DSC) studies have been carried out to understand the pH-dependent conformational changes in the secondary structure of V. cholerae L-asparaginase.Results:The enzyme was found to be least stable at extreme acidic conditions (pH< 4.5) and exhibited a gradual increase in melting temperature from 40 to 81 °C within pH range of 4.0 to 7.0. Thermodynamic properties of protein were estimated and at pH 7.0 the protein exhibited ΔG37of 26.31 kcal mole-1, ΔH of 204.27 kcal mole-1 and ΔS of 574.06 cal mole-1 K-1.Conclusion:The stability and thermodynamic analysis revealed that V. cholerae L-asparaginase was highly stable over a wide range of pH, with the highest stability in the pH range of 5.0–7.0.

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