Biomedical subjects

Teruya Maki

Publications and source records attributed to Teruya Maki.

4 recordsLinked to original sources

PubMed2006

Adsorption of platinum (IV), palladium (II) and gold (III) from aqueous solutions onto L-lysine modified crosslinked chitosan resin.

Crosslinked chitosan resin chemically modified with L-lysine has been used to investigate the adsorption of Pt(IV), Pd(II) and Au(III) from aqueous solutions. Batch adsorption studies were carried out with various parameters, such as initial metal ion concentration, contact time, pH and temperature. The maximum adsorption capacity was found at pH 1.0 for Pt(IV), at pH 2.0 for Au(III) and Pd(II). Langmuir and Freundlich isotherm models were applied to analyze the experimental data. The best interpretation for the experimental data was given by the Langmuir isotherm and the maximum adsorption capacity was found to be 129.26 mg/g for Pt(IV), 109.47 mg/g for Pd(II) and 70.34 mg/g for Au(III). The kinetic data was tested using pseudo-first-order and pseudo-second-order kinetic models. Kinetic data correlated well with the pseudo-second-order kinetic model, indicating that the chemical sorption was the rate-limiting step. Thermodynamic parameters like Gibbs free energy (DeltaG degrees), enthalpy (DeltaH degrees) and entropy (DeltaS degrees) were evaluated by applying the Van't Hoff equation. The thermodynamic study indicated that the adsorption process is spontaneous and exothermic in nature. The desorption studies were carried out using various reagents. The maximum percent desorption of precious metal ions were obtained when the reagent 0.7 M thiourea-2 M HCl was used.

Adsorption↗

PubMed2005

Determination of Cu, Pb, Fe, and Zn in plant component polymers of a hyperaccumulating plant.

Phytoremediation is an innovative technology that utilizes the natural properties of plants to remediate hazardous waste sites. For more cost-effective phytoremediation, it is important to utilize a hyperaccumulating plant after phytoremediation, i.e. the recovery of valuable metals and the production of useful materials. In this work, the determination of metals in plant component polymers in a fern, Athyrium yokoscense, as a hyper-accumulating plant was established using steam explosion, Wayman's extraction method, and ICP emission spectrometry. After A. yokoscense plants were treated by steam explosion, the steam-exploded A. yokoscense were separated into four plant component polymers, ie. water-soluble material fraction, holocellulose fraction, methanol-soluble lignin fraction, and residual lignin fraction. The concentrations of Cu, Pb, Fe, and Zn in these plant component polymers and the dry weights of plant component polymers were measured. These analytical process determining metals in the plants will contribute to not only the evaluation and the efforts of phytoremediation using a hyperaccumulating plant, but also to the development of more effective phytoremediation.

Biopolymers↗

PubMed2004

Classification for dimethylarsenate-decomposing bacteria using a restrict fragment length polymorphism analysis of 16S rRNA genes.

A new monitoring system for bacterial communities involving dimethylarsinic acid (DMAA) decomposition was provided by combining the MPN (Most Probable Number) method and RFLP (restriction-fragment-length polymorphism analysis). The abundance of DMAA decomposing bacteria was estimated by the MPN method using a bacterial culture medium, which included DMAA as the sole carbon source, indicating bacterial cell densities of 1700 cells/ml in Lake Kahokugata and 330 cells/ml in Lake Kibagata. After isolating the dominant bacteria using agar plates, the isolates were classified into some genotype groups by RFLP analysis using 16S rDNA sequences. Classification of the RFLP analysis indicated that 14 isolates of Lake Kahokugata were classified into 6 types, which included 2 dominant types related to genus Pseudomonas, while 8 isolates of Lake Kibagata displayed 6 types including one or two isolates. Moreover, the RFLP types were unique for each lake, suggesting that DMAA decomposing bacteria were specific for the aquatic environment related to the arsenic cycle. The activities of DMAA decomposition mostly matched with the RFLP type category of the isolates. Accordingly, combining the MPN method with the RFLP analysis will play an important role in elucidating the distributions and dynamics of the DMAA-decomposing bacterial community.

Bacteria↗

PubMed2004

Detection of iron(III)-binding ligands originating from marine phytoplankton using cathodic stripping voltammetry.

The sample preparation and analytical methodology are described for detecting biologically produced iron(III)-binding ligands in laboratory cultures of coastal marine phytoplankton. The iron(III)-binding ligands from the culture media were purified by passage through a column packing with a hydrophobic absorbent. The concentrations and stability constants of the ligands were determined by adsorptive cathodic stripping voltammetry with competitive ligand equilibration. The analytical results of the cultivated cultures suggest that eukaryotic phytoplankton would produce iron(III)-binding ligands in analogy with other microorganisms.

Electrochemistry↗