Rise Of pH Value Research Articles

A recyclable electrochemical sensing platform for breast cancer diagnosis based on homogeneous DNA hybridization and host-guest interaction between cucurbit [7]uril and ferrocene-nanosphere with signal amplification

Recently, many strategies have been developed to trace the breast cancer susceptibility gene (BRCA), which is closely related to the occurrence of breast cancer. In this work, a novel recyclable electrochemical sensing platform was constructed to detect BRCA DNA based on the homogeneous hybridization of this target sequence with ferrocene-labeled DNA/Au nanospheres (FcNS) and horseradish peroxidase-labeled DNA/Au nanospheres (HRPNS) concatamers, and the host-guest interaction between cucurbit [7]uril (CB [7]) adsorbed on the electrode and Fc on the hybridization complex. With the optimization of experimental conditions, the fabricated sensing platform showed improved sensitivity with a low detection limit of 25pM (S/N=3), contributed by the dual amplification of signal using FcNS and HRPNS concatamers, and high specificity for BRCA DNA. The captured complex was dissociated from CB [7]-modified electrode with the rise of pH value to recycle the sensing platform. Furthermore, this detection strategy displayed the reliability and applicability in the analysis of human serum samples, indicating great potential for applications in early diagnosis of breast cancer.

Stability of cantharidin and cantharidic acid in Mylabris aqueous solution

To investigate the stability and the conversion rules of cantharidin and cantharidic acid contained in the Mylabris aqueous solution under different conditions. The contents of cantharidin and cantharidic acid under different conditions (pH, temperature and light) were determined by HPLC-TQ-MS. The results showed that the content of cantharidin was gradually decreased with the rising of pH value, while on the contrary, the content of cantharidic acid was increased gradually; after Mylabris aqueous solution with different pH values were placed at 25, 40 ℃ and 25 ℃ respectively for lighting for 90 days, the samples were collected for analysis. The results showed the contents of cantharidin and cantharidic acid were changed greatly in the first 10 days, mainly including the decrease of cantharidic acid and increase of cantharidin when the solution was acidic, and the increase of cantharidic acid and decrease of cantharidin when the solution was alkaline. After that, the contents of the above two components basically remained stable. This study revealed that pH was the main factor to affect the contents of cantharidin and cantharidic acid, and they could be converted into each other with the changes of pH value. High temperature and light can accelerate the speed of achieving such balance. The study can provide certain reference for the quality control of the medicines using the Mylabris as raw material.

On the Factors Influencing the Liquidity of Slip Casting Al2O3 Slurry

Abstract: This paper use zeta potential test and dynamic viscosity test to research the influence of different factors such as pH value, mass fraction of solid phase and dispersant content on the liquidity of Al2O3 slurry. The test results show that, when the solid-phase mass fraction and particle size are given, the absolute value of zeta potential increases with the rise of pH value, raise at first then descrease with the adding of (NaPO3)6. This article analyzes the phenomena from a legal point of electric double layer effect. The results of liquidity test are consistent with zeta potential test. The optimum value of pH value, mass fraction of solid-phase and dispersant content are determined by formulation design. The study develop a Al2O3 slurry with high fluidity which has an important significant in slip casting process of Al2O3 ceramics.

Removal of cadmium(II) from wastewater with gas-assisted magnetic separation

In this study, a method combined low-field magnetic separation (MS) with flotation, named as gas-assisted magnetic separation (GAMS), was applied for the removal of cadmium from wastewater. With bubbles’ assistance, the speed of magnetic separation can be greatly improved and the limitation of magnetic force on the capture distance can be overcome. Thus, GAMS is much more efficient and easily scalable than MS. In this work, ethanediamine-modified magnetic poly-(glycidyl methacrylate) microspheres (EMPs) were synthesized as the adsorbent for cadmium. And GAMS was used to separate the EMPs and Cd-loaded EMPs. The effects of pH, gas flow rate, concentration of Cd-loaded EMPs, loading volume, and ionic strength on GAMS were investigated. The results indicated that the EMPs and Cd-loaded EMPs could be rapidly and remotely removed from the solution with GAMS. And the separation time decreased with the increase of gas flow rate and NaCl concentration, but grew with the rise of pH value, loading volume, and concentration of the EMPs. This work showed the great potential of GAMS in the area of water treatment.

Microgel reinforced composite hydrogels with pH-responsive, self-healing properties

Composite hydrogels have attracted great interest because of their superior performances and potential applications. In this work, microgel reinforced composite hydrogels (MC gels) with self-healing and pH-responsive properties were prepared via microgels as macro-cross-linkers. Compared to the general hydrogels cross-linked by borax (B gels), the MC gels demonstrate superior properties on the aspects of viscosity, viscoelastic and temperature resistance. The viscosities of MC gels increase with the rising of pH value and the MC gels can dynamically reconstruct after being destructed by external force. Furthermore, the microstructure of MC gels was characterized by SEM, which confirmed that the microgels indeed as cross-linkers and each macro-cross-linker can cross-link several chains. These features indicate that the microgels can enhance the strength of composite hydrogels significantly.

PH, geoelectrical and membrane flux parameters for the monitoring of water-saturated silicate and carbonate porous media contaminated by CO2

Characteristics of potable water aquifer contaminated by CO2 are investigated using well-defined laboratory experiments. The porous media domain was prepared with silica sand and limestone in separate experiments. The investigations used combinations of techniques to measure various parameters in the water-saturated porous media domain on which pressure of CO2 was imposed, under various conditions, which correspond to different geological depths. Measured parameters included the pH, geoelectrical parameters, and the diffusion of the CO2 gas through the water-saturated porous media domain using non-porous silicone rubber sheet. Experimental results revealed the existence of three stages in the profile of pH change with time as CO2 dissolved and diffused in the water-saturated porous media domain, which was composed of silica sand. The first stage was characterised by rapid decline in the pH. This is associated with quick dissolution of CO2 and the formation of carbonic acid together with bicarbonate. The second stage showed short rise in pH value, which was attributed to the reverse reaction, i.e., the formation of aqueous and gaseous CO2 and water from the carbonic acid. The third stage was that of the equilibrium in the forward and the reverse reactions, marked by steady state in pH value, which remained unchanged till the end of the experiment. The bulk electrical conductivity (σb) of the water-saturated porous domain increased in the presence of CO2. This is attributed to the formation of ionic species, especially bicarbonate, as CO2 dissolved in the domain. The rise in σb coincided with the first stage of the change in the pH of the system. In addition, the σb was higher in limestone than silica sand, and it increased with pressure of the domain. But, the bulk dielectric constant (εb) showed no change with the dissolution of the CO2 under different conditions. Furthermore, permeation of CO2 through the silicone rubber indicated the diffusion of the CO2 gas through the water-saturated domain. CO2 flux through the membrane was shown to increase with depth or pressure of the domain. A mathematical expression derived in this work shows the dependence of σb on the pH and the initial value of σb. Predictions of the changes in the σb for different porous domains show the reliability of the mathematical expression developed in this work.

Comparison of Storage Characteristics and Quality of Semi-Dry Fermented Sausage Using Microwave Vacuum Drying and Hot Air Drying

The aim of this work was to find out an alternative drying process for semi-dry fermented sausages. Fermented sausages were subjected to hot air drying (HA) and microwave vacuum drying (MWV), respectively. The HA was carried out at 70 °C for 60 min. For MWV, three temperatures i.e. 30 °C, 40 °C and 50 °C were applied with pressure controlled at 80 kPa and microwave intensity at 6 kW for 2 min. After drying, the dehydration rates were determined immediately. The products were stored at room temperature until the end of experiment. The pH value, 2-thiobarbituric acid (TBA) and total volatile basic nitrogen (TVB-N) contents were measured at 0, 7, 14 and 28 days, respectively. In addition, the sensory properties were evaluated at 28 d. The results showed that compared to the HA, MWV could postpone the rise of pH value, TBA and TVB-N contents during the storage. Moreover, the sensory properties of MWV were better than that of HA, indicating that MWV would be a greatly promising drying process for semi-fry fermented sausages.

Poly(l-lactic acid)/hydroxyapatite/collagen composite coatings on AZ31 magnesium alloy for biomedical application

Surface modification of biomedical magnesium alloy using composite coating shows an attemptable approach for the development of Mg-based biomaterials with excellent cytocompatibility. Hydroxyapatite/collagen composite was preliminarily fabricated by biomineralization, the bioactive poly(l-lactic acid)/hydroxyapatite/collagen composite coatings were spin coated on AZ31 magnesium alloy using poly(l-lactic acid) solution mixed with hydroxyapatite/collagen particles, and the resultant materials and coatings were characterized in structure and related properties; furthermore, the in vitro degradation behavior of modified magnesium alloy in 1.5-fold Hank's solution was investigated. The results show that hydroxyapatite/collagen composite achieved chemical bonding between hydroxyapatite and collagen similar to natural bone; composite coatings on AZ31 magnesium alloy retained the bioactive functional groups of the componential materials and improved the corrosion resistance of Mg alloy; the mass fraction of hydroxyapatite/collagen particles incorporated into the composite affected the porous structure, interfacial adhesion and thus the corrosion resistance of the composite coating due to phase separation as well as volume concentration effects of polymer solution. Composite coatings suppressed the sharp rising of pH value and the released Mg(2+) from substrate to extensive degree, and the degradation behavior of the modified magnesium alloy was supposed to be correlated to microstructure of the coating as well as the synergistic reactions among alkaline- and acidic-degraded products.

Research on the Relational Model of Corrosion Factors of Air Cooler on Atmospheric Tower

Corrosion perforation of air cooler on atmospheric tower in refinery is mainly caused by the outer wall pitting, and the leading factors which results in the air cooler failure are Cl-, PH , temperature and Na+. With orthogonal model design test program to the main factors, and through polarization curves experiments obtain the corresponding corrosion potential, corrosion rate, pitting potential. Analysis the change of Cl-, PH value, Temperature and Na+ to the air condenser corrosion influence. The results show that, Cl- concentration, Na+ concentration rise make air cooler on atmospheric tower happening corrosion easily; PH value rise make air cooler on atmospheric tower happening corrsion not easily, which has a protective effect to the passive film; Temperature rise make air cooler on atmospheric tower passivation membrane formation rate increase, and at the same time pitting corrosion is more easily to happen.

Influence of Influent pH on Ceramic Printing Wastewater Treatment

Investigated the influence of absorbency, turbidity and suspended substance in printing wastewater treatment by regulating the pH value of water treatment. Firstly, was acidified the wastewater samples to 5, 4, 3, 2, then alkalize them to 8、9、10、11、12. Calculated decolorization removal, turbidity removal and the suspended substance removal. The results show that, the decolorization removal and the turbidity removal were low after acidification. While after alkalized treatment the decolorization removal and the turbidity removal were all rise. The decolorization removal and turbidity removal increased following with the increase of pH of samples that first acidified and then alkalized. And it was the most obvious when the pH was 12. When the wastewater samples first acidized the pH to 4 and then alkalized the pH to 12, the dispose effects was the best. In these conditions, the decolorization removal and turbidity removal could reach 57.7 % and 72.8 %. After acidification, the suspended solids removal came down followed with the rise of pH value. As the water samples in same acidification value and then alkalized, with the increase of pH, the suspended solids removal first rose and then came down. It could get the best dispose effects at the pH 11, the suspended solids removal could reach 41.4 %.

Effect of intermolecular and intramolecular forces on hydrodynamic diameters of poly(N‐isopropylacrylamide) copolymers in aqueous solutions

AbstractA novel copolymer, poly(N‐isopropylacrylamide‐co‐hydroxypropyl methacrylate‐co‐3‐trimethoxysilypropyl methacrylate) has been synthesized and the hydrodynamic diameters in various aqueous solutions under different temperatures are determined by dynamic light scattering. The results show that the hydrodynamic diameters of copolymers have no obvious change in each working solution below lower critical solution temperature (LCST); across LCST, the diameters increased suddenly at different initial temperature in various aqueous solutions; above LCST, they decreased slightly as the temperature increased in UHQ water, and increased continuously with increasing temperature or salt concentration in saline solutions, and reduced with the rising of pH value in pH buffer. These are attributed to different intermolecular and intramolecular forces leading to disparity in dimension, conformation, and LCST of copolymers. The hydrogen bonding between water molecules and copolymer chains could maintain size and conformation of copolymer single chain; the hydrogen bonding between amide linkages and hydrophobic interactions between isopropyl groups result in intramolecular collapse and intermolecular aggregation; the electrostatic repulsion weakens aggregation extent of copolymers. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Study on preparation of Co–Pt–W alloy films by electrodeposition

Co–Pt–W alloy films were prepared by the electroplating method to replace costly sputtering on a copper substrate. Effects of different pH values and current densities on composition, microstructure and magnetic properties of films were investigated. With the rise in pH values, the amounts of tungsten and cobalt decrease simultaneously as a result of less tungstate oxides in higher OH– concentration solution. Almost all the deposited films were crystalline and formed fcc CoPt(111) and hcp CoPt(002). Co–Pt–W alloy films intend to change from fcc to hcp structure when the current density was >20 mA cm−2. It was found that hcp structures of Co–Pt–W alloy films possess high coercivity performance. Moreover, higher pH values induced lower saturation magnetisation while higher current densities could result in larger saturation magnetisation. Dissimilar surface morphology could be detected under different current densities. With increasing the current density, grains of films tend to agglomerate and grow perpendicularly to substrate. Bigger agglomerated particles and ‘hill-like’ structure could be observed when the current density was up to 30 mA cm−2.

Study on Thiourea Dioxide’s Reducing Capacity and its Reactivity with Reactive Dyes

In this paper, potential analysis method was applied to study the effects of pH value and temperature on potential and reducing capacity of thiourea dioxide, and the reactivity between thiourea dioxide and reactive dyes as ground shade dyes under simulated printing steaming conditions in aqueous solution was also investigated. The results showed that thiourea dioxide’s reduction potential increased with the rise of pH value and temperature. when temperature was lower than 60 °C, thiourea dioxide had low reactivity with reactive dyes as ground shade dyes, and when temperature was up to 80 °C, thiourea dioxide began to break reactive dyes, which was in accordance with the reduction potential change rule of thiourea dioxide along with temperature.

Catalytic upgrading of bio-oil using 1-octene and 1-butanol over sulfonic acid resin catalysts

Raw bio-oil from fast pyrolysis of biomass must be refined before it can be used as a transportation fuel, a petroleum refinery feed or for many other fuel uses. Raw bio-oil was upgraded with the neat model olefin, 1-octene, and with 1-octene/1-butanol mixtures over sulfonic acid resin catalysts from 80 to 150 °C in order to simultaneously lower water content and acidity and to increase hydrophobicity and heating value. Phase separation and coke formation were key factors limiting the reaction rate during upgrading with neat 1-octene, although octanols were formed by 1-octene hydration along with small amounts of octyl acetates and ethers. GC-MS analysis confirmed that olefin hydration, carboxylic acid esterification, acetal formation from aldehydes and ketones and O- and C-alkylations of phenolic compounds occurred simultaneously during upgrading with 1-octene/1-butanol mixtures. Addition of 1-butanol increased olefin conversion dramatically by reducing mass transfer restraints and serving as a cosolvent or emulsifying agent. It also reacted with carboxylic acids and aldehydes/ketones to form esters and acetals, respectively, while also serving to stabilize bio-oil during heating. 1-Butanol addition also protected the catalysts, increasing catalyst lifetime and reducing or eliminating coking. Upgrading sharply increased ester content and decreased the amounts of levoglucosan, polyhydric alcohols and organic acids. Upgrading lowered acidity (pH value rise from 2.5 to >3.0), removed the unpleasant odor and increased hydrocarbon solubility. Water content decreased from 37.2% to <7.5% dramatically and calorific value increased from 12.6 MJ kg−1 to about 30.0 MJ kg−1.

Biochemical characteristics of iodperoxidase activity of human saliva

Peroxidase-catalyzed oxidation of iodide in human saliva leads to the formation of a brown product with lambda max 287 nm and 353 nm (I3-) identified by the method of UV-spectrophotometry. I3- directly reacts with starch producing the characteristic blue complex. Salivary iodide peroxidase activity was found to be from 1.2 to 2.3 times higher then the activity of salivary peroxidases with natural substrates (SCN- and Cl-). Optimum for the iodide peroxidase activity in human saliva was found to be near pH 5.8. Salivary iodide peroxidase activity progressively lowers with the rise of pH value of the reaction mixture until total loss at the pH>7.4 was observed. Iodide peroxidase activity in human saliva at pH>7.4 is masked due to decomposition of I3- with the increase of pH along with the inhibition of peroxidases and I3- reduction by low molecular weight dialyzable salivary components possibly by Cl- and NCS-. Salivary iodide peroxidase activity was completely inhibited by peroxidase inhibitors (NaN3, 2-mercaptoethanol, thiourea), while addition of the peroxidase alternative substrates (ascorbate, quercetin, thiocyanate) resulted in partial inhibition of iodide peroxidase activity. The results of the study confirm the idea, that high activity of human saliva peroxidase with iodide as a substrate may play a crucial role in the bioavailability and metabolism of biologically active iodide.

Experimental Study on Formation Conditions of Ammoniojarosite and Its Environmental Significance

Abstract Formation conditions of ammoniojarosite in system Fe2(SO4)3-(NH4)2SO4-H2O are investigated in this paper. The results show that ammoniojarosite can be formed rapidly under normal temperature and pressure by controlling suitable pH value and Fe2(SO4)3 and (NH4)2SO4 concentrations. The pH value, temperature and concentration of Fe2(SO4)3 medium are key factors influencing the formation of ammoniojarosite. Under normal temperature, precipitation of ammoniojarosite can be seen within 24 hours at pH values between 2.6-3.1, and a great quantity of ammoniojarosite is formed within 48 hours. At about 90°C, the pH value range forming ammoniojarosite extends to 1.2–3.1, and within this range the rise of pH value is advantageous to the formation of ammoniojarosite and high Fe2(SO4)3 concentration is also advantageous. Relative pure ammoniojarosite is synthesized under high Fe2(SO4)3 concentration (≥0.05 M) and ammoniojarosite containing melanterite and colloid amorphous hydroxide vitriol iron is formed at low Fe2(SO4)3 concentration. The deposition process of ammoniojarosite can be used to harness wastewater from mines and other industries and remove S, Fe and other toxic and harmful elements, such as As, Cr, Hg, Pb in water. Rapid formation of ammoniojarosite and other jarosite analogs under normal temperature and pressure has a good potential prospect for harnessing acid wastewater by means of precipitation of jarosite and its analogs.

Speciation of water-soluble titanium citrate: Synthesis, structural, spectroscopic properties and biological relevance

Titanium(IV) citrate complexes with different anions Na 3[Ti(H 2cit) 2(Hcit)] · 9H 2O ( 1), K 4[Ti(H 2cit)(Hcit) 2] · 4H 2O ( 2), K 5[Ti(Hcit) 3] · 4H 2O ( 3) and Na 7[TiH(cit) 3] · 18H 2O ( 4) (H 4cit = citric acid) were isolated in pure forms from the solutions of titanate and citrate at various pH values. X-ray structural analyses revealed the presence of a monomeric tricitrato titanium unit in the four complexes. Each Ti(IV) ion is coordinated octahedrally by the three citrate ligands in different protonated forms. The citrate ligand chelates bidentately to the titanium ion through its negatively charged α-alkoxy and α-carboxy groups. This is consistent with the large downfield 13C NMR shifts for the carbon atoms bearing the α-alkoxy and α-carboxy groups. The very strong hydrogen-bonds existing in the protonated and deprotonated β-carboxy groups may be the key factor for the stabilization of the titanium citrate complexes. When the pH value is lower than 7.0, 13C NMR spectra of 1:3 Ti:citrate solutions are similar to those of the titanium citrate complexes isolated at the corresponding pH values. The dissociation of free citrate increases with the rise of pH value. However, 13C NMR spectra of 1:3 Ti:citrate solutions indicate that there may exist different citrate titanium species when the pH value is higher than 7.0.

Fungal Biodegradation and Detoxification of Cork Boiling Wastewaters

AbstractThe ability of several fungal strains to degrade and to detoxify cork boiling wastewaters was investigated. The fungal strains used in this work were Sporothrix sp., Trichoderma koningii, Chrysonilia sitophila and Penicillium glabrum isolated from cork bark as well as Fusarium flocciferum and Phanerochaete chrysosporium. The results obtained in the degradation experiments carried out with each fungus showed that all fungi display similar abilities, with a chemical oxygen demand reduction of 54.2 % (± 4.7 %) attained within five days of incubation. F. flocciferum presented the highest value for the reduction of chemical oxygen demand of 62 %. In addition, a rise in pH values of around 3 units was detected with all the strains, except for Penicillium glabrum. Toxicity tests performed on Vibrio fischeri revealed that fungal treatment of the wastewaters causes the complete loss of toxicity in the cases of Sporothrix sp., T. koningii, P. chrysosporium and F. flocciferum. The other two tested strains were also able to detoxify the raw wastewaters, causing a ten‐fold decrease in toxicity. The results obtained in sequential biodegradation experiments with different pairs of fungi showed that although the increment in the COD reduction did not exceed 10 %, an important reduction in toxicity and a pH rise were attained.

Methodological tests of a heterotrophy index for aquatic ecosystems.

Experiments in glucose mineralization were carried out to investigate the effects caused by natural forcing functions on both the decomposition rates and heterotrophy capacity of aquatic ecosystems. In addition, the methodology used could show connections between mineralization rates measured in both laboratory and field work with those measured in aquatic ecosystems. Water samples from Infernão lagoon (21 degrees 35'S and 47 degrees 51'W) were collected, filtered, enriched with glucose, and incubated under aerobic and anaerobic conditions. The glucose concentration variation, dissolved oxygen (DO) consumption, pH, electric conductivity, and total CO2 amount in the water were determined for sixteen days. In the period with intense oxygen consumption there was also an evident glucose demand and the dissolved oxygen consumption rate was approximately the same as that for glucose mineralization. The process in the aerobic chambers was 2.2 times faster than that in the anaerobic chambers. An initial acidification of the water samples, probably due to microbial carbonic acid liberation, was noted. A rise in pH values was also observed at the end of the process. The electric conductivity was low for both aerobic and anaerobic chambers, indicating a probable ion uptake by microbial organisms due to the presence of carbon sources. The glucose content variations corresponded to both CO2 formation and dissolved oxygen consumption. It was estimated that 19.4% of the initial glucose content turned into CO2 and the remaining 80.6% into humic compounds and microbial biomass. This experiment showed that glucose can be used as a substrate indicating the heterotrophy of a given aquatic ecosystem.

Degradation potential of musty odour in a drinking water source by a biofilm method

The purpose of this study was to evaluate the degradation potential of 2-methylisoborneol (MIB) and its producer by a biofilm process. The cyanobacteria Phormidium tenue was isolated from the biofilm in a biological treatment facility for water supply. MIB was efficiently removed by the facility and the removal ratio was about 70% during the investigation period of 2 years. There was a favourable correlation between the removal rate of P. tenue and the number of micro-organisms, especially ciliates on the biofilm. But a high rise of pH value due to sudden proliferation of cyanobacteria induced a reduction in removal of P. tenue and MIB. It was found that the ciliate protozoa and pH value were very important factors for the removal of MIB and P. tenue .