EFFECTS OF ROPE LENGTHS ON JUMP CYCLE DURING SKIPPING

This study determined the effects of different jump-rope lengths on jump cycles while skipping rope. Twelve college students performed the basic jump using three ropes of differing lengths (1.30, 1.39, and 1.48 times their height; short, middle, and long rope, respectively). Cycle time, contact time, and take off time were measured using a switch mat, and coefficient variations (CVs) during 50 consecutive skips were calculated. Cycle time rapidly increased along with take off time when exceeding the middle length of rope (P < 0.05). Also, significant correlations were observed between take off time and its CV for short and middle rope conditions (both P c 0.05). Thus, results suggested that the long rope could lead to longer take off time (higher jump), and stable jumping would be achieved by higher jumping when using the middle or short rope

Effects of different types of ropes on jump cycle while skipping

This study aimed to determine the effects of different types of jump ropes on jump cycles while skipping. Thirteen youth volunteers performed the basic jump and the alternate-foot jump using two ropes differing in diameter and weight. Two-way ANOVA revealed that the main effects of skipping patterns and type of rope were significant in cycle time, contact time, and takeoff time, respectively (P < 0.05 for all variables). In the coefficient of variations (CVs) for each measured variable, the main effect was significant in skipping patterns (P < 0.05 for all variables) but not in the type of rope (P > 0.05 for all variables). However, a clear difference was found between the two ropes for correlation coefficient of CV in cycle times between skipping patterns. These results suggested that different types of ropes affect jump cycles while skipping

IS ACTN3 R577X GENOTYPE ASSOCIATED WITH WEIGHT-BEARING INDEX IN MALE COLLEGE STUDENTS?

The purpose of this study was to determine the association between weight-bearing index (WBI) and ACTN3 genotype in male college students. Subjects were healthy male college students aged 18 to 21 years old. The maximal static forces of knee extension (leg strength) of the subjects were measured, and WBI was calculated by dividing the leg strength by the subjects’ body weight. Genomic DNA was extracted from each subject using hair strands, and its base sequence determined genotypes in RR, RX, and XX. Welch-type ANOVA revealed that WBI in the XX type was greater than in the RR and RX types despite no significant difference in leg strength and lean body mass among genotypes. Although it is difficult to find apparent or direct evidence to explain this result, some inferences can be proposed, such as compensatory force exertion based on its muscle fibers, regulation in calcineurin via the α-actine-2 gene, or functional enhancement of myoglobin-based endurance slow muscles in XX type may increase muscular activities against gravity, making WBI greater

Security of quantum key distribution with iterative sifting

Several quantum key distribution (QKD) protocols employ iterative sifting. After each quantum transmission round, Alice and Bob disclose part of their setting information (including their basis choices) for the detected signals. The quantum phase of the protocol then ends when the numbers of detected signals per basis exceed certain pre-agreed threshold values. Recently, however, Pfister et al. [New J. Phys. 18 053001 (2016)] showed that iterative sifting makes QKD insecure, especially in the finite key regime, if the parameter estimation for privacy amplification uses the random sampling theory. This implies that a number of existing finite key security proofs could be flawed and cannot guarantee security. Here, we solve this serious problem by showing that the use of Azuma's inequality for parameter estimation makes QKD with iterative sifting secure again. This means that the existing protocols whose security proof employs this inequality remain secure even if they employ iterative sifting. Also, our results highlight a fundamental difference between the random sampling theorem and Azuma's inequality in proving security.Comment: 9 pages. We have found a flaw in the first version, which we have corrected in the revised versio

Tree-Like Features Formed on Photoelectrochemically etched n-GaN surfaces ―Revelation of threading dislocations in GaN―

Electrochemical etching behavior of n-type GaN films grown on sapphire has been studied under UV (λ=325 nm) light illumination. As the cases for photoelectrochemical etching of n-type GaAs and InP, three different features appear on etched n-GaN surfaces depending on current density for etching; a high density (10^10 cm^<-2>) of tree-like protrusions at a lower c-urrent density, a relatively flat surface at an intermediate current density, and peeling of the film from the substrate at a higher current density. From the shape and the density of tree-like protrusions, in addition to the analogy of these results with those for n-type GaAs and InP, it is reasonable to conclude that tree-like protrusions formed at a low current density are due to threading dislocations involved in n-GaN films. Thus, the photoelectrochemical etching is found to become a convenient method to detect dislocations in n-type III nitride materials

活動的歩行の機械的仕事およびトレッドミル水平負荷牽引歩行の換気性作業閾値に関する研究

13301甲第4140号博士（理学）金沢大学博士論文本文Full 以下に掲載：1.Health 5(12) pp.1993-1996 2013. Scientific Research Publishing. 共著者：Akihiro Azuma　2.Perceptual and Motor Skills 119(1) pp.6-19 2014. AMMONS SCIENTIFIC. 共著者：Akihiro Azum

Changes in acetyl-CoA mediate Sik3-induced maturation of chondrocytes in endochondral bone formation

The maturation of chondrocytes is strictly regulated for proper endochondral bone formation. Although recent studies have revealed that intracellular metabolic processes regulate the proliferation and differentiation of cells, little is known about how changes in metabolite levels regulate chondrocyte maturation. To identify the metabolites which regulate chondrocyte maturation, we performed a metabolome analysis on chondrocytes of Sik3 knockout mice, in which chondrocyte maturation is delayed. Among the metabolites, acetyl-CoA was decreased in this model. Immunohistochemical analysis of the Sik3 knockout chondrocytes indicated that the expression levels of phospho-pyruvate dehydrogenase (phospho-Pdh), an inactivated form of Pdh, which is an enzyme that converts pyruvate to acetyl-CoA, and of Pdh kinase 4 (Pdk4), which phosphorylates Pdh, were increased. Inhibition of Pdh by treatment with CPI613 delayed chondrocyte maturation in metatarsal primordial cartilage in organ culture. These results collectively suggest that decreasing the acetyl-CoA level is a cause and not result of the delayed chondrocyte maturation. Sik3 appears to increase the acetyl-CoA level by decreasing the expression level of Pdk4. Blocking ATP synthesis in the TCA cycle by treatment with rotenone also delayed chondrocyte maturation in metatarsal primordial cartilage in organ culture, suggesting the possibility that depriving acetyl-CoA as a substrate for the TCA cycle is responsible for the delayed maturation. Our finding of acetyl-CoA as a regulator of chondrocyte maturation could contribute to understanding the regulatory mechanisms controlling endochondral bone formation by metabolites

Integration Capacity of Human Induced Pluripotent Stem Cell-Derived Cartilage

Chen X., Yamashita A., Morioka M., et al. Integration Capacity of Human Induced Pluripotent Stem Cell-Derived Cartilage. Tissue Engineering - Part A 25, 437 (2019); https://doi.org/10.1089/ten.tea.2018.0133.New cell and tissue sources are needed for the regenerative treatment of articular cartilage damage. Human induced pluripotent stem cells (hiPSCs) are an abundant cell source due to their self-renewal capacity. Hyaline cartilage tissue particles derived from hiPSCs (hiPS-Carts), 1–3 mm in diameter, are one candidate source that can be used for transplantation. When transplanted to fill the defects of articular cartilage, hiPS-Carts form a repair tissue by integrating with each other and with adjacent host tissue. In this study, we analyzed the integration capacity using an in vitro model and found that hiPS-Carts spontaneously integrate with each other in vitro. hiPS-Carts consist of cartilage at the center and perichondrium-like membrane that wraps around the cartilage. The integration started at the perichondrium-like membrane at around 1 week. Then, the integration progressed to the cartilage within 4–8 weeks. RNA sequencing analysis identified a higher expression of FGF18 in the perichondrium-like membrane in hiPS-Carts compared with the central cartilage. The addition of FGF18 to the model accelerated the integration of hiPS-Carts, whereas the addition of a FGFR inhibitor inhibited it. These results suggest that FGF18 secreted from the perichondrium-like membrane plays a role in the integration of hiPS-Carts. Understanding the integration mechanism of hiPS-Carts is expected to contribute to the realization of regenerative treatment for patients with articular cartilage damage

Quantum key distribution with setting-choice-independently correlated light sources

Despite the enormous theoretical and experimental progress made so far in quantum key distribution (QKD), the security of most existing practical QKD systems is not rigorously established yet. A critical obstacle is that almost all existing security proofs make ideal assumptions on the QKD devices. Problematically, such assumptions are hard to satisfy in the experiments, and therefore it is not obvious how to apply such security proofs to practical QKD systems. Fortunately, any imperfections and security-loopholes in the measurement devices can be perfectly closed by measurement-device-independent QKD (MDI-QKD), and thus we only need to consider how to secure the source devices. Among imperfections in the source devices, correlations between the sending pulses and modulation fluctuations are one of the principal problems, which unfortunately most of the existing security proofs do not consider. In this paper, we take into account these imperfections and enhance the implementation security of QKD. Specifically, we consider a setting-choice-independent correlation (SCIC) framework in which the sending pulses can present arbitrary correlations but they are independent of the previous setting choices such as the bit, the basis and the intensity settings. Within the framework of SCIC, we consider the dominant fluctuations of the sending states, such as the relative phases and the intensities, and provide a self-contained information-theoretic security proof for the loss-tolerant QKD protocol in the finite-key regime. We demonstrate the feasibility of secure quantum communication, and thus our work constitutes a crucial step towards guaranteeing the security of practical QKD systems.Grant-in-Aid for JSPS Fellows | Ref. KAKENHI N. JP17J04177MEXT/JSPS | Ref. KAKENHI N. JP18H05237Ministerio de Economía y Competitividad | Ref. TEC2014-54898-RJST-CREST | Ref. JPMJCR167