Aerodynamic drag of modern soccer balls

Soccer balls such as the Adidas Roteiro that have been used in soccer tournaments thus far had 32 pentagonal and hexagonal panels. Recently, the Adidas Teamgeist II and Adidas Jabulani, respectively having 14 and 8 panels, have been used at tournaments; the aerodynamic characteristics of these balls have not yet been verified. Now, the Adidas Tango 12, having 32 panels, has been developed for use at tournaments; therefore, it is necessary to understand its aerodynamic characteristics. Through a wind tunnel test and ball trajectory simulations, this study shows that the aerodynamic resistance of the new 32-panel soccer ball is larger in the high-speed region and lower in the middle-speed region than that of the previous 14- and 8-panel balls. The critical Reynolds number of the Roteiro, Teamgeist II, Jabulani, and Tango 12 was ~2.2 × 105 (drag coefficient, Cd ≈ 0.12), ~2.8 × 105 (Cd ≈ 0.13), ~3.3 × 105 (Cd ≈ 0.13), and ~2.4 × 105 (Cd ≈ 0.15), respectively. The flight trajectory simulation suggested that the Tango 12, one of the newest soccer balls, has less air resistance in the medium-speed region than the Jabulani and can thus easily acquire large initial velocity in this region. It is considered that the critical Reynolds number of a soccer ball, as considered within the scope of this experiment, depends on the extended total distance of the panel bonds rather than the small designs on the panel surfaces

Factors of unpredictable shots concerning new soccer balls

AbstractThe configuration of new soccer balls has closely approached a perfect round shape by not only reducing the number of panels but also by eliminating roughness of the panel joints by utilizing thermal bonding process recently. Therefore, in a non-rotating or low-rotating moving shot, a soccer ball drops and curves, i.e. motion by the change of wake flow, which is called a knuckle ball effect. Factors of the knuckle ball effect on the new soccer balls were investigated in case of a non-rotating shot and a low-rotating one. A correlation between fluctuation of the wake and fluid forces was identified in a symmetric panel configuration of the ball. The asymmetric configuration of the ball panel was also investigated as a factor to bring unpredictable change of the ball flight path. The low-rotating ball changes its frontal area against the moving direction and it produces irregular lateral forces. Consequently, the factors which produced the knuckle ball effect were found to be different from the case of non-rotating shots and low rotating shots

AERODYNAMIC EFFECTS OF A PANEL ORIENTATION IN VOLLEYBALL FLOAT SERVE

The purpose of this study was to clarify the aerodynamic and trajectory characteristics on four type volleyballs using the wind tunnel experiments and a hitting robot. We confirmed, in particular, that the critical Reynolds number (Recr) changed depending on the ball types and panel orientations. Recr for Mizuno ball (conventional) was determined to be ~2.8 × 105 (Drag coefficient; Cd = 0.16) on panel orientation A and ∼2.0 × 105 (Cd = 0.20) on panel orientation B. On the other hand, Recr for Mikasa ball (Olympic Official) was ∼2.9 × 105 (Cd = 0.16) in the panel orientation A and ∼3.3 × 105 (Cd = 0.15) in panel orientation B. Moreover, we found that the landing position of all volleyballs varied depending on the ball type and the orientation of the panel. In particular, Molten ball has a longer flight distance than other balls and its landing point was biased toward the left side. On the other hand, Mikasa ball had a relatively short flight trajectory and its landing point was biased to the right. Therefore, it can be hypothesized that during a float serve, the flight trajectory will change depending on the type of volleyball and their orientation

Replacement of Tyr50 stacked on the si-face of the isoalloxazine ring of the flavin adenine dinucleotide prosthetic group modulates Bacillus subtilis ferredoxin-NADP+ oxidoreductase activity toward NADPH

Ferredoxin-NAD(P)+ oxidoreductases ([EC 1.18.1.2], [EC 1.18.1.3], FNRs) from green sulfur bacteria, purple non-sulfur bacteria and most of Firmicutes, such as Bacillus subtilis (BsFNR) are homo-dimeric flavoproteins homologous to bacterial NADPH-thioredoxin reductase. These FNRs contain two unique aromatic residues stacked on the si- and re-face of the isoalloxazine ring moiety of the FAD prosthetic group whose configurations are often found among other types of flavoproteins including plant-type FNR and flavodoxin, but not in bacterial NADPH-thioredoxin reductase. To investigate the role of the si-face Tyr50 residue in BsFNR, we replaced Tyr50 with Gly, Ser, and Trp and examined its spectroscopic properties and enzymatic activities in the presence of NADPH and ferredoxin (Fd) from B. subtilis (BsFd). The replacement of Tyr50 to Gly (Y50G), Ser (Y50S), and Trp (Y50W) in BsFNR resulted in a blue shift of the FAD transition bands. The Y50G and Y50S mutations enhanced the FAD fluorescence emission, whereas those of the wild type and Y50W mutant were quenched. All three mutants decreased thermal stabilities compared to wild type. Using a diaphorase assay, the kcat values for the Y50G and Y50S mutants in the presence of NADPH and ferricyanide were decreased to less than 5 % of the wild type activity. The Y50W mutant retained approximately 20 % reactivity in the diaphorase assay and BsFd-dependent cytochrome c reduction assay relative to wild type. The present results suggest that Tyr50 modulates the electronic properties and positioning of the prosthetic group

Crystallization and preliminary X-ray studies of ferredoxin-NADP + oxidoreductase encoded by Bacillus subtilis yumC

金沢大学理工研究域物質化学系Ferredoxin-NADP+ oxidoreductase encoded by Bacillus subtilis yumC has been purified and successfully crystallized in complex with NADP + in two forms. Diffraction data from crystals of these two forms were collected at resolutions of 1.8 and 1.9 Å. The former belonged to space group P21212, with unit-cell parameters a = 63.90, b = 135.72, c = 39.19 Å, and the latter to space group C2, with unit-cell parameters a = 207.47, b = 64.85, c = 61.12 Å, Β = 105.82°. The initial structure was determined by the molecular-replacement method using a thioredoxin reductase-like protein as a search model. © 2010 International Union of Crystallography All rights reserved

Kinetics of NADP+/NADPH reduction–oxidation catalyzed by the ferredoxin-NAD(P)+ reductase from the green sulfur bacterium Chlorobaculum tepidum

Ferredoxin-NAD(P)+ oxidoreductase (FNR, [EC 1.18.1.2], [EC 1.18.1.3]) from the green sulfur bacterium Chlorobaculum tepidum (CtFNR) is a homodimeric flavoprotein with significant structural homology to bacterial NADPH-thioredoxin reductases. CtFNR homologs have been found in many bacteria, but only in green sulfur bacteria among photoautotrophs. In this work, we examined the reactions of CtFNR with NADP+, NADPH, and (4S-2H)-NADPD by stopped-flow spectrophotometry. Mixing CtFNRox with NADPH yielded a rapid decrease of the absorbance in flavin band I centered at 460 nm within 1 ms, and then the absorbance further decreased gradually. The magnitude of the decrease increased with increasing NADPH concentration, but even with ~50-fold molar excess NADPH, the absorbance change was only ~45 % of that expected for fully reduced protein. The absorbance in the charge transfer (CT) band centered around 600 nm increased rapidly within 1 ms, then slowly decreased to about 70 % of the maximum. When CtFNRred was mixed with excess NADP+, the absorbance in the flavin band I increased to about 70 % of that of CtFNRox with an apparent rate of ~4 s−1, whereas almost no absorption changes were observed in the CT band. Obtained data suggest that the reaction between CtFNR and NADP+/NADPH is reversible, in accordance with its physiological function. © 2016 Springer Science+Business Media DordrechtEmbargo period 12 month

Role of the C-terminal extension stacked on the re-face of the isoalloxazine ring moiety of the flavin adenine dinucleotide prosthetic group in ferredoxin-NADP+ oxidoreductase from Bacillus subtilis

Ferredoxin-NADP+ oxidoreductase [EC 1.18.1.2] from Bacillus subtilis (BsFNR) is homologous to the bacterial NADPH-thioredoxin reductase, but possesses a unique C-terminal extension that covers the re-face of the isoalloxazine ring moiety of the flavin adenine dinucleotide (FAD) prosthetic group. In this report, we utilize BsFNR mutants depleted of their C-terminal residues to examine the importance of the C-terminal extension in reactions with NADPH and ferredoxin (Fd) from B. subtilis by spectroscopic and steady-state reaction analyses. The depletions of residues Y313 to K332 (whole C-terminal extension region) and S325 to K332 (His324 intact) resulted in significant increases in the catalytic efficiency with NADPH in diaphorase assay with ferricyanide, whereas Km values for ferricyanide were increased. In the cytochrome c reduction assay in the presence of B. subtilis ferredoxin, the S325-K332 depleted mutant displayed a significant decrease in the turnover rate with an Fd concentration range of 1-10 μM. The Y313-K332 depleted mutant demonstrated an increase in the rate of the direct reduction of horse heart cytochrome c in the absence of Fd. These data indicated that depletion of the C-terminal extension plays an important role in the reaction of BsFNR with ferredoxin. © 2014 Elsevier Masson SAS. All rights reserved

Jasmonate-dependent plant defense restricts thrips performance and preference

<p>Abstract</p> <p>Background</p> <p>The western flower thrips (<it>Frankliniella occidentalis </it>[Pergande]) is one of the most important insect herbivores of cultivated plants. However, no pesticide provides complete control of this species, and insecticide resistance has emerged around the world. We previously reported the important role of jasmonate (JA) in the plant's immediate response to thrips feeding by using an <it>Arabidopsis </it>leaf disc system. In this study, as the first step toward practical use of JA in thrips control, we analyzed the effect of JA-regulated <it>Arabidopsis </it>defense at the whole plant level on thrips behavior and life cycle at the population level over an extended period. We also studied the effectiveness of JA-regulated plant defense on thrips damage in Chinese cabbage (<it>Brassica rapa </it>subsp. <it>pekinensis</it>).</p> <p>Results</p> <p>Thrips oviposited more on <it>Arabidopsis </it>JA-insensitive <it>coi1-1 </it>mutants than on WT plants, and the population density of the following thrips generation increased on <it>coi1-1 </it>mutants. Moreover, thrips preferred <it>coi1-1 </it>mutants more than WT plants. Application of JA to WT plants before thrips attack decreased the thrips population. To analyze these important functions of JA in a brassica crop plant, we analyzed the expression of marker genes for JA response in <it>B. rapa</it>. Thrips feeding induced expression of these marker genes and significantly increased the JA content in <it>B. rapa</it>. Application of JA to <it>B. rapa </it>enhanced plant resistance to thrips, restricted oviposition, and reduced the population density of the following generation.</p> <p>Conclusion</p> <p>Our results indicate that the JA-regulated plant defense restricts thrips performance and preference, and plays an important role in the resistance of <it>Arabidopsis </it>and <it>B. rapa </it>to thrips damage.</p

Studies of interaction of homo-dimeric ferredoxin-NAD(P)+ oxidoreductases of Bacillus subtilis and Rhodopseudomonas palustris, that are closely related to thioredoxin reductases in amino acid sequence, with ferredoxins and pyridine nucleotide coenzymes

金沢大学理工研究域物質化学系Ferredoxin-NADP+ oxidoreductases (FNRs) of Bacillus subtilis (YumC) and Rhodopseudomonas palustris CGA009 (RPA3954) belong to a novel homo-dimeric type of FNR with high amino acid sequence homology to NADPH-thioredoxin reductases. These FNRs were purified from expression constructs in Escherichia coli cells, and their steady-state reactions with [2Fe-2S] type ferredoxins (Fds) from spinach and R. palustris, [4Fe-4S] type Fd from B. subtilis, NAD(P)+/NAD(P)H and ferricyanide were studied. From the Km and kcat values for the diaphorase activity with ferricyanide, it is demonstrated that both FNRs are far more specific for NADPH than for NADH. The UV-visible spectral changes induced by NADP+ and B. subtilis Fd indicated that both FNRs form a ternary complex with NADP+ and Fd, and that each of the two ligands decreases the affinities of the others. The steady-state kinetics of NADPH-cytochrome c reduction activity of YumC is consistent with formation of a ternary complex of NADPH and Fd during catalysis. These results indicate that despite their low sequence homology to other FNRs, these enzymes possess high FNR activity but with measurable differences in affinity for different types of Fds as compared to other more conventional FNRs. © 2008 Elsevier B.V. All rights reserved