Time variations of the concentration profile of CuSO4 and of the velocity profile of laminar natural convective flow were measured near the electrode surface during the transient electrolysis after reversing the current. A symmetrical transient variation of natural convection was observed after anodic and cathodic current reversions. It was found that the concentration profile possesses an extreme value, and the inverted flow appears near the electrode surface. The effects of current density and vertical location on the natural convection were discussed. Based on the experimental results, the space-time structure of the transient natural convection was considered.Among numerous works (1-3) in the past on the natural convective flow along the surface of a plane vertical electrode installed in unstirred electrolyte, only a few works concerned the transient natural convection encountered in the unsteady electrolysis. This is in spite of its importance in the practical operation of unsteady electrolysis, such as periodic current reversal in copper refining, as well as in the study of the nature of transient natural convective flow itself.Tvarusko et al. (4, 5) studied the transient natural convection at the start of electrolysis by applying a technique of Mach-Zehnder interferometry and showed that both the concentration difference of CuSO4 between bulk electrolyte and cathode surface and the thickness of the cathodic diffusion layer increase in proportion to the square root of time elapsed from the start. However, they were not successful in photographing the concentration profile of CuSO4 in the diffusion layer which develops downstream. This is supposed to be due to the severe optical restriction in two-beam interferometry.Only after the application of a technique of holographic interferometry, it became possible to precisely measure the concentration profile in the diffusion layer near the electrode surface, and the transient cathodic diffusion layer (6, 7) was studied by applying this technique. In addition, the corresponding transient velocity profile was measured by recording the motion of colophonium particles suspended in the cathodic hydrodynamic boundary layer (7,8).Following these studies, it is intended in the present work to study the transient natural convection after the direction of eIectrolytic current is reversed. Time variations of the concentration profile of CuSO4 and of the velocity profile of natural convective flow are measured during the time period from reversing the current until the steady natural convection in reversed direction is established.
One atypical thiolane-type sulfide, garlicnin I (1), two 3,4-dimethylthiolane-type sulfides, garlicnins M (2) and N (3), and one thiabicyclic-type sulfide, garlicnin O (4), were isolated from the acetone extracts of Chinese garlic bulbs, Allium sativum and their structures were characterized. Hypothetical pathways for the production of the respective sulfides were discussed.
Familial hypocalciuric hypercalcemia (FHH) is characterized by lifelong asymptomatic hypercalcemia without PTH hypersecretion and is inherited as an autosomal dominant trait with near 100% penetrance. In contrast, neonatal severe hyperparathyroidism (NSHPT) is a life-threatening disorder characterized by marked hypercalcemia and PTH hypersecretion. FHH/NSHPT results from inactivating mutations of the human calcium-sensing receptor (Casr) gene on chromosome 3q13.3-24. Nearly 30 different mutations of the Casr gene associated with FHH/NSHPT have been reported previously. In this report, genetic analysis of 1 Japanese NSHPT family revealed 2 novel mutations at codon 185 (CGA-->TGA/Arg-->Ter) in exon 4 of the Casr gene and at codon 670 (GGG-->GAG/Gly-->Glu) in exon 7. The Arg185Ter change was shown to occur in the proband's unaffected father and paternal grandmother as well as in the proband. The other mutation in exon 7 was shown in the proband's unaffected mother of Philippine origin as well as in the proband. This family is the first case of manifestation of more than 1 mutation in a proband's chromosomes; 1 mutation was obtained from the unaffected father, and the other was from the unaffected mother. Our observations have given us important keys to help elucidate the structure-function relationships of the Casr.
Two atypical cyclic-type sulfides, garlicnin P (1) and garlicnin J (2), and one thiabicyclic-type sulfide, garlicnin Q (3), were isolated from the acetone extracts of garlic, Allium sativum, bulbs cultivated in the Kumamoto city area, and their structures characterized. Their production pathways are also discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.