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[en] The history and state-of-the-art in the detection, quantitative determination and characterisation of the primary structure of alginic acids and their salts (alginates) are reviewed. A brief survey of the structure and properties of these polysaccharides is given. Numerous analytical methods including chemical, physicochemical and enzymic procedures for the structural analysis of alginates which can also be used for the investigation of other uronic acid-containing polysaccharides are discussed. The bibliography includes 211 references.
[en] The retention of 137Cs in algal polysaccharides has been studied. Alginic acid showed higher retention value than the tested alginate samples. The retention of 137Cs in carrageenan types and agar was first investigated. The binding capacities were found to be equal for carrageenan types and agar. (author) 9 refs.; 3 figs
[en] We report on fabricating functional three-dimensional (3D) tissue constructs using an inkjet based bio-prototyping method. With the use of modified inkjet printers, contractile cardiac hybrids that exhibit the forms of the 3D rectangular sheet and even the 'half heart' (with two connected ventricles) have been fabricated by arranging alternate layers of biocompatible alginate hydrogels and mammalian cardiac cells according to pre-designed 3D patterns. In this study, primary feline adult and H1 cardiomyocytes were used as model cardiac cells. Alginate hydrogels with controlled micro-shell structures were built by spraying cross-linkers in micro-drops onto un-gelled alginic acid. The cells remained viable in constructs as thick as 1 cm due to the programmed porosity. Microscopic and macroscopic contractile functions of these cardiomyocyte constructs were observed in vitro. These results suggest that the inkjet bio-prototyping method could be used for hierarchical design of functional cardiac pseudo tissues, balanced with porosity for mass transport and structural support.
[en] Selective uptake and recovery of platinum group metals are an important subject in the high level liquid waste treatment. An extractant having a strong affinity for palladium, bis(2,4,4-trimethylpentyl) monothiophosphinic acid (Cyanex 302, HA), was enclosed into microscapsules by utilizing highly immobilizing ability of biopolymer (alginate and alginate acid gel polymers). The uptake of Pd2+, Ru(NO)3+ and Rh3+ for granular microcapsules has been studied by batch and column methods. A relatively large distribution coefficient of Pd2+, Kd,Pd, of above 104 cm3/g was obtained in the presence of 0.2-0.5 M HNO3 and the separation factors of Pd/Ru and Pd/Rh were estimated to be above 102. The uptake of Pd2+ on microcapsules followed a Langmuir-type uptake isotherm and the maximum uptake capacity was estimated to be 0.72-0.96 mmol/g. These metal cations were chromatographically separated through the column packed with HA-alginate microcapsules. (author)
[en] The uptake behavior of Am3+ was investigated by using alginic acid and alginate polymer gels. The affinity of radioactive nuclides for carboxyl groups in gel matrices increased in the order of Na+ < Cs+ < Co2+ < Pd2+, Sr2+, Fe3+ < Eu3+, Am3+. Among alginate gels, calcium alginate exhibited relatively higher uptake rate and distribution coefficient of Am3+. The column packed with calcium alginate beads was effective for the removal of trace amounts of Am3+ from acidic nitrate solutions. (author)
[en] 60Co was used as indicator for studies on the separation of cobalt with sodium alginate. Effect of eight experimental parameters (digestion time, digestion temperature, mode of separation, concentration of reagents, pH, order of heating, ammonia, mixing of reagents) on the precipitation and separation of cobalt alginate have been investigated. (author). 2 refs., 2 figs
[en] The next step beyond conventional scaffold-based tissue engineering is cell-based direct biofabrication techniques. In industrial processes, various three-dimensional (3D) prototype models have been fabricated using several different rapid prototyping methods, such as stereo-lithography, 3D printing and laser sintering, as well as others, in which a variety of chemical materials are utilized. However, with direct cell-based biofabrication, only biocompatible materials can be used, and the manufacturing process must be performed under biocompatible and physiological conditions. We have developed a direct 3D cell printing system using inkjet and gelation techniques with inkjet droplets, and found that it had good potential to construct 3D structures with multiple types of cells. With this system, we have used alginate and fibrin hydrogel materials, each of which has advantages and disadvantages. Herein, we discuss the roles of hydrogel for biofabrication and show that further developments in biofabrication technology with biomatrices will play a major part, as will developments in manufacturing technology. It is important to explore suitable biomatrices as the next key step in biofabrication techniques.
[en] Microcapsules enclosing an extractant with strong affinity for Am were prepared by employing a biopolymer gel as an immobilization matrix. A relatively large separation factor between Am and Eu was exhibited by the microcapsule containing of bis(2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex 301, HA) and alginic acid (HALG). The chromatographic separation of these metal ions was accomplished by gradient elution through the column packed with HA-HALG. (author)