Ph Values
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Author(s):  
J.N. Nwite ◽  
A.J. Ajana ◽  
I. Alinchi

Background: Low soil productivity in Nigeria and Africa sub sahara is considered as one of the major causes of food insecurity and under nutrition. This area is considered among the most regions affected by acidity on soil nutrients optimization. Despite of its severity, there is limited knowledge about limiting effect of pH on nutrients availability and maize yield in the state. Evolving a technology that does not depend on traditional system of amendment for pH assessment for increased soil productivity must first of all go through a good knowledge of the nature and distribution of soil studied. The present study aimed to evaluate three pH (4, 7 and 9) values on soil chemical properties in the state and assess maize performance under these conditions in order to control and manage pH related problems. Methods: In the field-laboratory investigation during 2018-2019 at different localities of Ebonyi State were surveyed. Three sampling localities were selected based on geographical situation, climate and local condition. In the laboratory, the soil samples of natural stock collected were processed for mean pH values and confirmed with pH meter using standard laboratory method. Maize was used as test crop to assess effect of pH on its performance. Result: Our investigations in Ebonyi State have allowed us to inventory three pH values. Among the inventoried pH values, some are regarded adverse for soil productivity. The implication of soil pH on nutrients availability and maize performance was discussed. The current work will be a complementary contribution of detailed study of effect of pH on soil productivity.


Author(s):  
Yoko Takyu ◽  
Taro Asamura ◽  
Ayako Okamoto ◽  
Hiroshi Maeda ◽  
Michio Takeuchi ◽  
...  

Abstract Aspergillus oryzae RIB40 has 11 aspartic endopeptidase genes. We searched for milk-clotting enzymes based on the homology of the deduced amino acid sequence with chymosins. As a result, we identified a milk-clotting enzyme in A. oryzae. We expected other Aspergillus species to have a homologous enzyme with milk-clotting activity, and we found the most homologous aspartic endopeptidase from A. luchuensis had milk-clotting activity. Surprisingly, two enzymes were considered as vacuole enzymes according to a study on A. niger proteases. The two enzymes from A. oryzae and A. luchuensis cleaved a peptide between the 105Phe-106Met bond in κ-casein, similar to chymosin. Although both enzymes showed proteolytic activity using casein as a substrate, the optimum pH values for milk-clotting and proteolytic activities were different. Furthermore, the substrate specificities were highly restricted. Therefore, we expected that the Japanese traditional fermentation agent, koji, could be used as an enzyme source for cheese production.


Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 542
Author(s):  
Benjamin Udo Emmel ◽  
Kamila Maria Gawel ◽  
Mohammad Hossain Bhuiyan ◽  
Malin Torsæter ◽  
Laura Edvardsen

Reservoir formation waters typically contain scaling ions which can precipitate and form mineral deposits. Such mineral deposition can be accelerated electrochemically, whereby the application of potential between two electrodes results in oxygen reduction and water electrolysis. Both processes change the local pH near the electrodes and affect the surface deposition of pH-sensitive minerals. In the context of the plugging and abandonment of wells, electrochemically enhanced deposition could offer a cost-effective alternative to the established methods that rely on setting cement plugs. In this paper, we tested the scale electro-deposition ability of six different formation waters from selected reservoirs along the Norwegian continental shelf using two experimental setups, one containing CO2 and one without CO2. As the electrochemical deposition of scaling minerals relies on local pH changes near the cathode, geochemical modelling was performed to predict oversaturation with respect to the different mineral phases at different pH values. In a CO2-free environment, the formation waters are mainly oversaturated with portlandite at pH > 12. When CO2 was introduced to the system, the formation waters were oversaturated with calcite. The presence of mineral phases was confirmed by powder X-ray diffraction (XRD) analyses of the mineral deposits obtained in the laboratory experiments. The geochemical-modelling results indicate several oversaturated Mg-bearing minerals (e.g., brucite, dolomite, aragonite) in the formation waters but these, according to XRD results, were absent in the deposits, which is likely due to the significant domination of calcium-scaling ions in the solution. The amount of deposit was found to be proportional to the concentration of calcium present in the formation waters. Formation waters with a high concentration of Ca ions and a high conductivity yielded more precipitate.


2022 ◽  
Author(s):  
Ernesto Alva Sevilla ◽  
Annitta George ◽  
Lorenzo Brancaleon ◽  
Marcelo Marucho

Actin filament′s polyelectrolyte and hydrodynamic properties, their interactions with the biological environment, and external force fields play an essential role in their biological activities in eukaryotic cellular processes. In this article, we introduce a unique approach that combines dynamics and electrophoresis light scattering experiments, an extended semiflexible worm-like chain model, and an asymmetric polymer length distribution theory to characterize the polyelectrolyte and hydrodynamic properties of actin filaments in aqueous electrolyte solutions. We used the same sample and experimental conditions and considered several g-actin and polymerization buffers to elucidate the impact of their chemical composition, reducing agents, pH values, and ionic strengths on the filament translational diffusion coefficient, electrophoretic mobility, structure factor, asymmetric length distribution, effective filament diameter, electric charge, zeta potential, and semiflexibility. Compared to those values obtained from molecular structure models, our results revealed a lower value of the effective G-actin charge and a more significant value of the effective filament diameter due to the formation of the double layer of the electrolyte surrounding the filaments. Additionally, compared to the values usually reported from electron micrographs, the lower values of our results for the persistence length and average contour filament length agrees with the significant difference in the association rates at the filament ends that shift to submicro lengths, the maximum of the length distribution.


Author(s):  
Ping Guo ◽  
Weiwei Xu ◽  
Shi Tang ◽  
Binxia Cao ◽  
Danna Wei ◽  
...  

One cold-adapted strain, named Planococcus sp. XW-1, was isolated from the Yellow Sea. The strain can produce biosurfactant with petroleum as sole source of carbon at low temperature (4 °C). The biosurfactant was identified as glycolipid-type biosurfactant species by thin-layer chromatography (TLC) and Fourier transform infrared spectroscopy (FTIR). It reduced the surface tension of water to 26.8 mN/m with a critical micelle concentration measurement of 60 mg/L. The produced biosurfactant possesses high surface activity at wide ranges of temperature (−18–105 °C), pH values (2–12), and salt concentrations (1–18%). The biosurfactant exhibited higher surface activity and higher growth rate of cells with hexadecane and diesel as carbon source. The strain Planococcus sp. XW-1 was also effective in degrading crude oil, after 21 days of growth at 4 °C in medium with 1% crude oil and 1% (v/v) bacteria broth, 54% of crude oil was degraded. The results suggest that Planococcus sp. XW-1 is a promising candidate for use in the bioremediation of petroleum-contaminated seawater in the Yellow Sea during winter. This study reported for the first time that Planococcus isolated from the Yellow Sea can produce biosurfactant using petroleum as the sole carbon source at low temperature (4 °C), showing its ecological role in the remediation of marine petroleum pollution.


2022 ◽  
Author(s):  
Abdullah Al-Enezi ◽  
Mohammed Al-Othman ◽  
Mishari Al-Shtail ◽  
Yousef Al-Sadeeqi ◽  
Kutbuddin Bhatia ◽  
...  

Abstract The unconventional Bahrah field is a high potential field which poses several challenges in terms of hydrocarbon flow assurance through highly heterogeneous tight carbonate intervals with poor reservoir quality and curtailed mobility. Due to this, the field development strategies have prioritized well completion using horizontal acid fracturing technology over vertical wells. During fracturing, the acid system tends to form highly conductive channels in the formation. Most of the fluid will flow into the path of least resistance leaving large portions of the formation untreated. As a result, the fracturing treatment options dwindle significantly, thus reservoir stimulation results are not optimum in each stage. Achieving complete wellbore coverage is a challenge for any acid frac treatment performed in long lateral with variations in reservoir characteristics. The multistage acid fracturing using Integrated Far-field Diversion (IFD) is performed using selective openhole completion, enabling mechanical annular segmentation of the wellbore using swellable packers and sliding sleeves. The mechanical as well as chemical diversion in IFD methodology is highly important to the overall stimulation success. The technique includes pumping multiple self-degrading particle sizes, considering the openhole annular space and wide presence of natural fractures, followed by in-situ HCL based crosslinked system employed for improving individual stage targets. A biomodal strategy is employed wherein larger particles are supplemented with smaller that can bridge pore throats of the larger particles and have the desired property of rigidity and develop a level of suppleness once exposed to reservoir conditions. The IFD diversion shifts the fracture to unstimulated areas to create complex fractures that increase reservoir contact volume and improving overall conductivity. This paper examines IFD in acid fracturing and describes the crucial diversion strategy. Unlike available diverters used in other fields, the particulates are unaffected at low pH values and in live acids. Proper agent selection and combination with in-situ crosslink acid effectively plug the fracture generated previously and generate pressure high enough to initiate another fracture for further ramification. The optimization and designing of the IFD diversion in each stage plays a key role and has helped to effectively plug fractures and realize segmentation. Concentration of diversion agents, volume of fluid system and open-hole stage length sensitivity plays vital role for the success of this treatment. The application of IFD methodology is tuned as fit-for-purpose to address the unique challenges of well operations, formation technical difficulties, high-stakes economics, and untapped high potential from this unconventional reservoir. A direct result of this acid fracturing treatment is that the post-operation data showed high contribution of all fractured zones along the section in sustained manner. Furthermore, this methodology can be considered as best practice for application in unconventional challenges in other fields.


2022 ◽  
Author(s):  
Emin Zümrütdal

Abstract Yogurt is a known food item all over the world. Consuming yogurt can be quite difficult for people with lactose intolerance at times. In addition to its active carbon adsorbent feature, it is a lactose chelate. It is aimed to use yoghurt prepared by using activated carbon for nutritional purposes. For this purpose, aroma and pH changes in yogurt made with activated carbon compared to classical yogurt production were studied. It was determined that the active carbon usage method used in the study did not cause any aroma change in yoghurt, however, it increased the pH. This result makes us think that lactose cannot be used by yogurt microorganisms and that yogurt with activated carbon may be an alternative for lactose intolerant people who want to consume yogurt.


Author(s):  
Fangting Wang ◽  
Ke Bao ◽  
Changsheng Huang ◽  
Xinwen Zhao ◽  
Wenjing Han ◽  
...  

Cadmium is a toxic element with a half-life of several decades, which can accumulate in the human body by entering the food chain and seriously harm health. The cadmium adsorption and desorption processes in the soil directly affect the migration, transformation, bioavailability, and ecotoxicity of this element in soil-plant systems. Coastal zones are located in the transitional zone between land and sea, and large amounts of terrigenous material input have important environmental effects on this ecosystem. The pH, hydrodynamic conditions, soil organic matter (SOM), and other factors defining the sea-land interaction within the sedimentary environment are significantly different from those defining land facies. In order to study the key factors affecting cadmium adsorption in soils at the sea-land interface in the Nansha area of the Pearl River Delta, a test was conducted on a column of undisturbed soil. The results showed that the adsorption constant KF and the Cd2+ adsorption capacity of marine soils were higher than those of terrestrial soils. However, the saturation adsorption of cadmium in terrestrial sediments was higher than in marine sediments. Soil pH was an important factor affecting cadmium adsorption capacity in both terrestrial and ma-rine sediments. Neutral and alkaline topsoil conditions inhibited the vertical migration of cadmium, while the acidic environment favored it. The higher the clay and SOM were, the stronger the Cd2+ adsorption capacity of the soil was. These findings suggest that the distribution of cadmium in marine and continental sedimentary soils is not only related to adsorption, but also to the physical and chemical processes occurring in different sedimentary environments.


Author(s):  
Wei-Zhuo Gai ◽  
Shi-Hu Zhang ◽  
Yang Yang ◽  
Kexi Sun ◽  
Hong Jia ◽  
...  

Abstract Aluminum hydroxide is an eye catching and extensively researched adsorbent for fluoride removal and its defluoridation performance is closely related to the preparation method and crystalline phase. In this research, the defluoridation performances of aluminum hydroxides with different crystalline phases are compared and evaluated in terms of fluoride removal capacity, sensitivity to pH values and residual Al contents after defluoridation. It is found that the defluoridation performance of different aluminum hydroxides follows the order of boehmite > bayerite > gibbsite. The fluoride adsorption on aluminum hydroxides follows pseudo-second-order kinetic model and Langmuir isotherm model, and the maximum defluoridation capacities of boehmite, bayerite and gibbsite are 42.08, 2.97 and 2.74 mg m−2, respectively. The pH values and FTIR analyses reveal that the ligand exchange between fluoride and surface hydroxyl groups is the fluoride removal mechanism. Different aluminum hydroxides have different surface hydroxyl group densities, which results in the different defluoridation capacities. This work provides a new idea to prepare aluminum hydroxide with outstanding defluoridation performance.


Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 466
Author(s):  
Kaixin Chang ◽  
Qianjin Zhu ◽  
Liyan Qi ◽  
Mingwei Guo ◽  
Woming Gao ◽  
...  

Nitrogen-doped carbon quantum dots (N-CQDs) were synthesized in a one-step hydrothermal technique utilizing L-lactic acid as that of the source of carbon and ethylenediamine as that of the source of nitrogen, and were characterized using dynamic light scattering, X-ray photoelectron spectroscopy ultraviolet-visible spectrum, Fourier-transformed infrared spectrum, high-resolution transmission electron microscopy, and fluorescence spectrum. The generated N-CQDs have a spherical structure and overall diameters ranging from 1–4 nm, and their surface comprises specific functional groups such as amino, carboxyl, and hydroxyl, resulting in greater water solubility and fluorescence. The quantum yield of N-CQDs (being 46%) is significantly higher than that of the CQDs synthesized from other biomass in literatures. Its fluorescence intensity is dependent on the excitation wavelength, and N-CQDs release blue light at 365 nm under ultraviolet light. The pH values may impact the protonation of N-CQDs surface functional groups and lead to significant fluorescence quenching of N-CQDs. Therefore, the fluorescence intensity of N-CQDs is the highest at pH 7.0, but it decreases with pH as pH values being either more than or less than pH 7.0. The N-CQDs exhibit high sensitivity to Fe3+ ions, for Fe3+ ions would decrease the fluorescence intensity of N-CQDs by 99.6%, and the influence of Fe3+ ions on N-CQDs fluorescence quenching is slightly affected by other metal ions. Moreover, the fluorescence quenching efficiency of Fe3+ ions displays an obvious linear relationship to Fe3+ concentrations in a wide range of concentrations (up to 200 µM) and with a detection limit of 1.89 µM. Therefore, the generated N-CQDs may be utilized as a robust fluorescence sensor for detecting pH and Fe3+ ions.


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