Dual Cell System Research Articles

Preparation of High-<tex>$B_rm s$</tex>Co–Fe Soft Magnetic Thin Films by Electrodeposition

Co-Fe soft magnetic thin films with high-saturation magnetic flux density B/sub s/ were prepared by electrodeposition. The B/sub s/ value of the Co-Fe alloy films deposited from the conventional cell system is lower than that of bulk alloys. With the use of a separated compartment dual cell system, the B/sub s/ value of the Co-Fe alloy films was reached the same as that of bulk alloy. The coercivity H/sub c/ values were higher than 12 Oe; however, the H/sub c/ value could be lowered to 8 Oe by annealing in vacuum with an applied magnetic field. It is suggested that decreasing H/sub c/ of the films by annealing is caused by relaxation of lattice distortion. In addition, the high-B/sub s/ Co-Fe films show good corrosion resistance.

Development of biochemical specialization and organelle partitioning in the single‐cell C4 system in leaves of Borszczowia aralocaspica (Chenopodiaceae)

The terrestrial plant Borszczowia aralocaspica (Chenopodiaceae) has recently been shown to contain the entire C(4) photosynthesis mechanism within individual, structurally and biochemically polarized chlorenchyma cells rather than in a dual cell system, as has been the paradigm for this type of carbon fixation (Nature 414: 543-546, 2001). Analysis of carbon isotope composition and (14)CO(2) fixation shows that photosynthesis and growth of B. aralocaspica occurs through carbon acquired by C(4) photosynthesis. The development of this unique single-cell C(4) system in chlorenchyma cells was studied by analysis of young (0.2-0.3 cm length), intermediate (ca. 0.5-0.6 cm length), and mature leaves (ca. 3 cm length). The length of chlorenchyma cells approximately doubles from young to intermediate and again from intermediate to the mature leaf stage. In young chlorenchyma cells, there is a single type of chloroplast; the chloroplasts are evenly distributed throughout the cytosol, and all contain starch and rubisco. During leaf development, the activities of phosphoenolpyruvate carboxylase (PEPC; which is cytosolic), rubisco, and pyruvate,Pi dikinase (PPDK) increase on a chlorophyll basis. As leaves mature, chloroplasts differentiate into two distinct structural and biochemical types that are spatially separated into the proximal and distal parts of the cell (the proximal end being closest to the center of the leaf). The early stages of this polarization are observed in intermediate leaves, and the polarization is fully developed in mature leaves. The chloroplasts in the distal ends of the cell have reduced grana and little starch, while those at the proximal ends have well-developed grana and abundant starch. In mature leaves, PPDK is expressed in chloroplasts at the distal end of the cells, while rubisco and adenosine diphosphate glucose (ADPG) pyrophosphorylase are selectively expressed in chloroplasts at the proximal end of the cell. Mitochondrial polarization also occurs during development as nicotinamide-adenine dinucleotide phosphate-malic enzyme (NAD-ME) and the photorespiratory enzyme glycine decarboxylase are expressed in mature but not young leaves and are localized in mitochondria at the proximal end of the cells. The data show that single-cell C(4) develops from a single pool of identical organelles that develop differential biochemical functions and spatial partitioning in the cell during maturation.

Electrogenerative leaching of galena with ferric chloride

A generative principle was applied to FeCl 3 leaching of galena for the first time in this study. It has been confirmed that a certain quantity of electrical energy, as well as the leached products, could be obtained during the leaching process. The factors affecting the power output, such as electrode structure, temperature, agitation, solution compositions and concentration, and the connections between catholyte and anolyde compartments were investigated by a dual cell system. The experiments indicated that the interior resistance of the leaching system and the activation of the electrode are of key importance. Agitation speeds have little influence over a certain value. The effects of ferric chloride concentration in the leaching are similar to the traditional leaching. The activation energy was determined to be 14.96 kJ mol −1 for FeCl 3 leaching of galena under the present conditions.

A High Moment CoFe Soft Magnetic Thin Film Prepared by Electrodeposition

A CoFe binary alloy film with 24 kG of saturation magnetic flux density, B s , was prepared by electrodeposition. The B s value of the CoFe alloy film prepared by electrodeposition from the conventional bath is usually equal to 21 kG. With the addition of trimethylamineborane, a well-known reducing agent, the B s value was found to increase to 23 kG. Furthermore, with the use of a separated compartment dual cell system, a B s value as high as 24 kG was reached. For obtaining the highest B s , it was found to be essential to avoid the oxidation of ferrous ion to ferric ion in the plating bath. The coercivity, H c , values were 15, 14, and 15 Oe for the films with 20, 23, and 24 kG of B s , respectively. The key for obtaining high B s materials is to avoid the oxidation of ferrous ions in the bath. In addition, it was found that the H c value of 15 Oe for CoFe film with the highest B s value of 24 kG could be lowered to 8 Oe by annealing in an applied magnetic field of 500 Oe.

Discussion on “On-line determination of bromide ion in spent brine”

Some errors in the mathematical treatment of a dual-cell system in the paper “On-line determination of bromide ion in spent brine” [Anal. Chim. Acta, 256 (1992) 97] were found and some necessary corrections to the mathematical treatment have been made.

Use of a Dual Coulometric-Amperometric Detection Cell Approach in Thyroid Hormone Assay

Abstract The development and application of a dual (in series) coulometric-amperometric thin-layer electrochemical detection cell system to the assay of thyroid hormones following reversed-phase chromatography is described. Using this approach the system was characterized by empirically determined electrolysis efficiencies, demonstrating adherence to the diffusion-layer approximation theory. When academic mixtures of the thyroid hormones were studied, the precision of both response and relative retention data was to within 4%. With the dual-cell approach, improvements by a factor of two in the limit of detection were noted over the same system using only amperometric detection. The electrochemical behavior of these analytes in the dual-cell system was also studied. These latter experiments demonstrated that, in principle, it is possible to assay the thyroid hormones with both cells set at a potential where mass transport control obtains, analyzing the oxidation products of the first cell at the amperometr...

Pulmonary clearance and phagocytic cell response to normal pharyngeal flora.

Because human lungs are repetitively inoculated with the normal bacterial flora of the pharynx, we determined the pulmonary clearance of representative species after aerosol inoculation of a murine model, and characterized the phagocytic cell response by bronchoalveolar lavage. Viable bacteria remaining in the lungs at 1, 2, and 4 h were: Streptococcus sanguis, 24%, 8%, and 1%; Streptococcus salivarius, 49%, 24%, and 5%; Neisseria catarrhalis, 69%, 49%, and 22%. Clearance of Streptococcus sanguis was associated with a twofold increase in alveolar macrophages (p less than 0.05); Streptococcus salivarius evoked a doubling of alveolar macrophages and a 20-fold rise in granulocytes (p less than 0.05); the response to Neisseria catarrhalis was a 400-fold increase in granulocytes (p less than 0.05). Thus, normal pharyngeal organisms are cleared rapidly from the lung by a dual phagocytic cell system. It is speculated that bacteria-phagocyte interaction allows the possibility of lung injury from proteolytic enzymes released from either set of phagocytes.