Experimental and numerical investigations of flow fields behind a small wind turbine with a flanged diffuser

Experimental and numerical investigations were carried out for flow fields of a small wind turbine with a flanged diffuser. The present wind-turbine system gave a power coefficient higher than the Betz limit (=16/27) owing to the effect of the flanged diffuser. To elucidate the flow mechanism, mean velocity profiles behind a wind turbine were measured using a hot-wire technique. By processing the obtained data, characteristic values of the flow fields were estimated and compared with those for a bare wind turbine. In addition, computations corresponding to the experimental conditions were made to assess the predictive performance of the simulation model presently used and also to investigate the flow field in more detail. The present experimental and numerical results gave useful information about the flow mechanism behind a wind turbine with a flanged diffuser. In particular, a considerable difference was seen in the destruction process of the tip vortex between the bare wind turbine and the wind turbine with a flanged diffuser.     

Simulated microgravity triggers characteristic morphology and stress response in Saccharomyces cerevisiae

Reduction of gravity results in changes in gene expression and morphology in the budding yeast Saccharomyces cerevisiae. We studied the genes responsible for the morphological changes induced by simulated microgravity (SMG) using the yeast morphology data. We comprehensively captured the features of the morphological changes in yeast cells cultured in SMG with CalMorph, a high-throughput image-processing system. Statistical analysis revealed that 95 of 501 morphological traits were significantly affected, which included changes in bud direction, the ratio of daughter to mother cell size, the random daughter cell shape, the large mother cell size, bright nuclei in the M phase, and the decrease in angle between two nuclei. We identified downregulated genes that impacted the morphological changes in conditions of SMG by focusing on each of the morphological features individually. Gene Ontology (GO)-enrichment analysis indicated that morphological changes under conditions of SMG were caused by cooperative downregulation of 103 genes annotated to six GO terms, which included cytoplasmic ribonucleoprotein granule, RNA elongation, mitotic cell cycle phase transition, nucleocytoplasmic transport, protein–DNA complex subunit organization, and RNA localization. P-body formation was also promoted under conditions of SMG. These results suggest that cooperative downregulation of multiple genes occurs in conditions of SMG.     

Yeast Lrg1p acts as a specialized RhoGAP regulating 1,3-beta-glucan synthesis.

Selection of an extragenic suppressor of fks1-1154 Deltafks2, mutations in the catalytic subunits of yeast 1,3-beta-glucan synthase (GS) conferring temperature-sensitivity, led to the LRG1 gene, which was originally identified as a LIM-RhoGAP homologous gene. Mutations in the LRG1 gene restore impaired 1,3-beta-glucan synthesis in the fks1-1154 Deltafks2 mutant as well as that in rho1-2, a temperature-sensitive mutant of Rho-type GTPase that functions as a regulatory subunit of GS. Two-hybrid analyses of Lrg1p, which contains a sequence conserved among Rho GTPase-activating proteins (GAPs), revealed its specific interactions with the active form of Rho1p. Among eight potential yeast RhoGAPs, Lrg1p is the only member that negatively regulates GS activity: mutations in the rest of GAPs, including bem2, Deltabem3, Deltasac7, Deltabag7, Deltarga1, Deltarga2 and Deltargd1, do not suppress impairment of 1,3-beta-glucan synthesis. Analyses of Mpk1p phosphorylation revealed the inability of Lrg1p to regulate the Pkc1p-MAP kinase cascade, a distinct Rho1p-regulating signalling pathway known to be affected by the GAPs, Bem2p and Sac7p. Thus, different groups of Rho1p GAPs control the activity of different Rho1p-effector proteins.     

Monolayer assemblies of a sandwich-type double-decker porphyrin complex of cerium with an additional pendant porphyrin unit

We have prepared a novel sandwich-type double-decker porphyrin complex with cerium, in which one of the porphyrins has long alkyl chains and the other has a pendant free-base porphyrin unit. The preparation of the complex was achieved with a Sonogashira coupling reaction between a preformed double-decker complex bearing an ethynyl moiety and an iodophenyl porphyrin. This complex forms moderately ordered self-assembled monolayers at the interface of 1-phenyloctane and highly oriented pyrolytic graphite. STM images with submolecular resolution revealed that the double-decker complexes form monolayers through adsorption of the alkyl-substituted porphyrin unit, presenting the other porphyrin having the additional porphyrin unit to the solution. All molecules are oriented in the same direction within single ordered domains. The double-decker complex and the corresponding free-base porphyrin form mixed monolayers due to their common adsorbing group and the matching unit cell parameters. The high spots for the double-decker cores are accompanied by lower spots, which can be assigned as the pendant free-base porphyrin units, revealing that the double-decker complexes predominantly take perpendicular orientation, in which the additional porphyrin unit orients perpendicular to the molecular row. Both the double-decker complex and the free-base porphyrin adsorb on the surface initially after the mixture was deposited, but the double-decker complex is gradually replaced by free-base porphyrin toward the thermodynamically stable assembly, in which the free-base porphyrin predominates. This behavior is unique to this particular complex among some analogous complexes with the same adsorbing group, which implies that groups not directly involved in adsorption may have profound effects on the adsorption and assembling properties of the molecule.     

Ultrastructure of immotile spermatozoa obtained from infertile male patients

We sometimes experienced infertile patients whose sperms had no motility but were not stained by Eosin Y. In this paper we report five cases of so-called "immotile spermatozoa". The ultrastructure of sperm tails was examined by transmission electrone microscope (TEM). These cases were selected from the out-patient population who attended infertility clinic of our department. The semen analyses showed that all the cases had sperm motility below 1% and more than 90% of the spermatozoa were proven alive. Family history revealed that one case had an infertile sibling. None of them had situs inversus, bronchiectasis and chronic sinusitis which are classic trias of Kartagener's syndrome. They had no symptoms of upper respiratory tract infection which was caused by the abnormality in the flagella of the respiratory tract. The TEM pictures of sperm tails showed partial deletion of inner dynein arms in two cases, lack of central microtubular doublets (so-called 9 + 0) in two cases and disarrangement of microtubular doublets in one case. For the treatment of these cases there is no effective means but AID. However, the rapid progress of IVF-ET techniques and a report that the spermatozoa from Kartagener's syndrome had showed penetration into eggs encouraged us to think the micromanipulation of spermatozoa with IVF-ET as a hopeful option of the treatment in the near future.     

Current concept of the treatment of biliary atresia

Hepatic portoenterostomy (Kasai operation) for the patient with biliary atresia (BA) can restore the bile flow in approximately 80% of children operated on before 60 days of life [1]. However, in terms of long-term survival, according to a recent nationwide survey among the major pediatric centers in Japan, only 325 of 2013 patients had more than 10 years' survival, and only 157 patients (7.8%) remained jaundice-free with normal liver function [2]. About 20% of BA cases without jaundice are generally able to survive for long periods; and most of those patients have portal hypertension or abnormal liver function [3-5]. As the results of liver transplantation have improved, controversy has arisen over the optimal care of these children [4, 6, 7]. Some investigators have claimed that transplantation is the favored primary therapy for most patients with BA [8]. We are thus at a turning point concerning the primary therapy of BA, which makes it necessary to determine the exact indications for the Kasai portoenterostomy and the timing of liver transplantation. This paper describes our strategy for the optimal treatment of BA patients based on our 117 patients who have had various form of portoenterostomy.     

An analysis of reverse osmotic characteristics of American-standard type tubular module

Reverse osmosis experiments were carried out with a TM-5-14 tubular module to obtain its reverse osmotic characteristics. Analysis of the data based on the general equations proposed by Ohya and Sourirajan (5) gives membrane characteristic constants, A = 0.845 x 10^?6 g·mole H₂O/cm²·atm·s, and (D_AM/ kδ) = 1.38 x 10^-5cm/sec. The experimental data of mass transfer coefficients agree well with the equation proposed by Linton and Sherwood (7).     

An analysis of reverse osmotic characteristics of ROGA-4000 spiral-wound module

Reverse osmosis experiments were carried out with a ROGA-4000 Spiral-Wound module to obtain its reverse osmotic characteristics. Analysis of the data based on the general equations proposed by Ohya and Sourirajan (10) gives membrane characteristic constants, A = 1.24 × 10^-6 g mole H·₂O/cm²·atmsec, and (D_AM /kδ) = 2.3 × 10^-5 cm/sec, which show the membrane belongs to the CA-NRC-18 type family. The experimental data of mass-transfer coefficients always show about 35% lower values than the theoretical value of laminar flow between flat parallel membranes proposed by Kimura and Sourirajan (12).