Comparative between Ammonia Ion Selective Electrode and Dye Binding Method to study effect of Processing Methods on Protein Content of Plain Yogurt

In this study, two analytical methods were used to determinate the protein, the ammonia ion selective electrode method and dye binding method using orange G and the spectrophotometer at λmax 478 nm by determining the linearity, accuracy, precision, limit of detection and limit of quantitation of each. In comparison, the dye binding method was chosen for its accuracy, repeatability, sensitivity (LOD, LOQ) and speed of performance. After that, it was applied to samples of prepared plain yogurt to study effect of different properties (source, heat treatment and type) of used milk on protein content of plain yogurt.

Electrocatalytic Properties of Ni(II) Schiff Base Complex Polymer Films

Platinum electrodes were modified with polymers of the (±)-trans-N,N′-bis(salicylidene)-1,2-cyclohexanediaminenickel(II) ([Ni(salcn)]) and (±)-trans-N,N′-bis(3,3′-tert-Bu-salicylidene)-1,2-cyclohexanediaminenickel(II) ([Ni(salcn(Bu))]) complexes to study their electrocatalytic and electroanalytical properties. Poly[Ni(salcn)] and poly[Ni(salcn(Bu))]) modified electrodes catalyze the oxidation of catechol, aspartic acid and NO2−. In the case of poly[Ni(salcn)] modified electrodes, the electrocatalysis process depends on the electroactive surface coverage. The films with low electroactive surface coverage are only a barrier in the path of the reducer to the electrode surface. The films with more electroactive surface coverage ensure both electrocatalysis inside the film and oxidation of the reducer directly on the electrode surface. In the films with the most electroactive surface coverage, electrocatalysis occurs only at the polymer–solution interface. The analysis was based on cyclic voltammetry, EQCM (electrochemical quartz crystal microbalance) and rotating disc electrode method.

Culturing and Scaling up Stem Cells of Dental Pulp Origin Using Microcarriers

Ectomesenchymal stem cells derived from the dental pulp are of neural crest origin, and as such are promising sources for cell therapy and tissue engineering. For safe upscaling of these cells, microcarrier-based culturing under dynamic conditions is a promising technology. We tested the suitability of two microcarriers, non-porous Cytodex 1 and porous Cytopore 2, for culturing well characterized dental pulp stem cells (DPSCs) using a shake flask system. Human DPSCs were cultured on these microcarriers in 96-well plates, and further expanded in shake flasks for upscaling experiments. Cell viability was measured using the alamarBlue assay, while cell morphology was observed by conventional and two-photon microscopies. Glucose consumption of cells was detected by the glucose oxidase/Clark-electrode method. DPSCs adhered to and grew well on both microcarrier surfaces and were also found in the pores of the Cytopore 2. Cells grown in tissue culture plates (static, non-shaking conditions) yielded 7 × 105 cells/well. In shake flasks, static preincubation promoted cell adhesion to the microcarriers. Under dynamic culture conditions (shaking) 3 × 107 cells were obtained in shake flasks. The DPSCs exhausted their glucose supply from the medium by day seven even with partial batch-feeding. In conclusion, both non-porous and porous microcarriers are suitable for upscaling ectomesenchymal DPSCs under dynamic culture conditions.

Preference of Proteomonas sulcata anion channelrhodopsin for NO3− revealed using a pH electrode method

Ion channel proteins are physiologically important molecules in living organisms. Their molecular functions have been investigated using electrophysiological methods, which enable quantitative, precise and advanced measurements and thus require complex instruments and experienced operators. For simpler and easier measurements, we measured the anion transport activity of light-gated anion channelrhodopsins (ACRs) using a pH electrode method, which has already been established for ion pump rhodopsins. Using that method, we successfully measured the anion transport activity and its dependence on the wavelength of light, i.e. its action spectra, and on the anion species, i.e. its selectivity or preference, of several ACRs expressed in yeast cells. In addition, we identified the strong anion transport activity and the preference for NO3− of an ACR from a marine cryptophyte algae Proteomonas sulcata, named PsuACR_353. Such a preference was discovered for the first time in microbial pump- or channel-type rhodopsins. Nitrate is one of the most stable forms of nitrogen and is used as a nitrogen source by most organisms including plants. Therefore, PsuACR_353 may play a role in NO3− transport and might take part in NO3−-related cellular functions in nature. Measurements of a mutant protein revealed that a Thr residue in the 3rd transmembrane helix, which corresponds to Cys102 in GtACR1, contributed to the preference for NO3−. These findings will be helpful to understand the mechanisms of anion transport, selectivity and preference of PsuACR_353.

STUDY ON PERMEABILITY AND ELECTRICAL RESISTIVITY OF RED CLAY CONTAMINATED BY CU2+

In order to study the permeability characteristics of heavy metal ions contaminated red clay and explore the rapid detection of permeability of heavy metal contaminated red clay. Through variable-head permeability test and electrical resistivity test (different voltages and methods), the effects of Cu2+ concentration and initial water content on hydraulic conductivity characteristic and resistivity of contaminated red clay was systematically investigated. The relationship between permeability characteristic and electrical resistivity was further explored by taking Cu2+ concentration and moisture content as the intermediate variable. The obtained results indicate that the different voltage has no obvious effect on the resistivity of the samples. The four-phase electrode method is more accurate than the two-phase electrode method. With increasing Cu2+ concentrations the hydraulic conductivity of specimens increases, however the permeability coefficient of contaminated soil decreases with increasing initial water content. In the resistivity test, with increasing of Cu2+ concentrations and water content, the resistivity of samples presented a downward trend, which is decreased sharply at first and then tended to be gentle. The relationship between hydraulic conductivity and resistivity of contaminated soil showed a good fitting curve no matter in different Cu2+ concentration or in different water content, but the fitting curves of them presented opposite trend.

Preference of Proteomonas Sulcata Anion Channelrhodopsin for Nitrate Revealed Using a pH Electrode Method

Ion channel proteins are physiologically important molecules in living organisms. Their molecular functions have been investigated using electrophysiological methods, which enable quantitative, precise and advanced measurements and thus require complex instruments and experienced operators. For simpler and easier measurements, we measured the anion transport activity of light-gated anion channelrhodopsins (ACRs) using a pH electrode method, which has already been established for ion pump rhodopsins. Using that method, we successfully measured the anion transport activity and its dependence on the wavelength of light, i.e. its action spectra, and on the anion species, i.e. its selectivity or preference, of several ACRs expressed in yeast cells. In addition, we identified the strong anion transport activity and the preference for NO3- of an ACR from a marine cryptophyte algae Proteomonas sulcata, named PsuACR_353. Such a preference was discovered for the first time in microbial pump- or channel-type rhodopsins. Nitrate is one of the most stable forms of nitrogen and is used as a nitrogen source by most organisms including plants. Therefore, PsuACR_353 may play a role in NO3- transport and might take part in NO3--related cellular functions in nature. Measurements of a mutant protein revealed that a Thr residue in the 3rd transmembrane helix, which corresponds to Cys102 in GtACR1, contributed to the preference for NO3-. These findings will be helpful to understand the mechanisms of anion transport, selectivity and preference of PsuACR_353.

DEPOSITION Ti-Sn ON AISI 316L SUBSTRATE WITH SURFACE MECHANICAL ALLOYING TREATMENT (SMAT) FOR BIOMATERIAL APPLICATION IN SIMULATED BODY FLUID

The properties of biomaterials such as biocompatibility, which is non-allergic and non-toxic to be the main requirements that must be owned by the biomaterials because of the presence of direct contact between the biomaterial with body parts. Therefore the study of biomaterials is constantly carried to repair the biocompatibility. In this research, the improvement of the properties the compatibility of the metal alloy AISI 316L with superimposed ideal bio-inert Ti-Sn with the method of Surface Mechanical Alloying Treatment. Manufacture of the alloy with bio-inert Ti-Sn using a variation of the composition of Sn of 10% and Sn 20% done using Mechanosynthesis process. The results of the process are sintered with the variation of temperature of 800oC and 900oC for 2 hours and then were characterized by an optical microscope. Corrosion testing of the alloy was carried out with Polarization Tafel System Three Electrode method for 10 minutes. The results of characterization with an optical microscope shows there is a layer of bio-inert Ti-Sn the results of the process of SMAT of AISI 316L. The results of corrosion testing on alloy AISI 316L Ti-Sn in a solution of SBF showed that the content of Ti-10%Sn with a temperature of 800oC the obtained corrosion rate 4.785 MPY and at 900oC amounted to 4.155 MPY as well as on the content of Ti-20%Sn with a temperature of 800oC the obtained corrosion rate 3.525 MPY and at 900oC amounted to 3.234 MPY. Keywords: Biocompatible; Biomaterial; AISI 316L; Ti-Sn; Corrosion Rate; Allergic Reaction; Deposition.