145 research outputs found

    The Steady Two-dimensional Flow of Viscous Incompressible Fluid Past an Elliptic Valve of Zero Angle of Attack Placed in a Rectilinear Channel : As a Model of a Flow Past a Fully Open Butterfly Valve

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    We studied the steady two-dimensional flow of a viscous incompressibe fluid past an elliptic valve of zero angle of attack placed in a rectilinear channel. We apply generalized curvilinear coordinates, by which the channel walls and the valve surface are mapped onto corresponding coordinate lines, to the solution of the stream function-vorticity formulation of the Navier-Stokes equations. The ADI and the Euler explicit method of solution are applied to solve the transformed basic equations. Flow patterns, pressure distributions and drag coefficients are obtained for several values of Reynolds number between 0 and 40

    STANDARD MOTION OF SPRINT RUNNING FOR MALE ELITE AND STUDENT SPRINTERS

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    The purpose of this study was to show standard motion models of male elite and student sprinters and investigate the characteristics of the elite sprinters’ motion. Fourteen male international level sprinters and twenty-one male student sprinters were videotaped at the maximum running velocity phase, standard motion models were prepared and kinematic variables were then calculated. Running velocity, stride length, release distance and flight distance of the elite sprinters were significantly greater than in the student sprinters. The elite sprinters did not fully extend the knee and ankle joints of the support leg at the toeoff while the student sprinters tended to show the converse motion. Student sprinters should use hip joint extension rather than flexion-extension of the knee and ankle joints, and should keep the shank leaning forward during the support phase

    Specific inhibition of p38 mitogen-activated protein kinase with FR167653 attenuates vascular proliferation in monocrotaline-induced pulmonary hypertension in rats

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    AbstractObjectivesp38 mitogen-activated protein kinase is associated with many clinical entities characterized by inflammation. We postulated that inhibition of p38 mitogen-activated protein kinase with FR167653 attenuates inflammation and the development of pulmonary hypertension in monocrotaline-treated rats.MethodsRats were divided into 4 groups: (1) the control group (daily 0.9% saline), (2) the FR group (daily FR167653, 2 mg · kg−1 · d−1), (3) the MCT group (daily 0.9% saline the day after a single monocrotaline dose, 60 mg/kg), and (4) the MCT+FR group (daily FR167653, 2 mg · kg−1 · d−1, the day after a single MCT dose). Body weight, pulmonary artery pressure, and morphometric changes of the pulmonary artery with the histopathologic method were observed weekly for 4 weeks. Also, p38 mitogen-activated protein kinase activity and inflammatory cytokine expression in the lung were measured.ResultsFour weeks after monocrotaline administration, mean pulmonary artery pressure in the MCT+FR group was lower than in the MCT group (MCT+FR vs MCT: 24.7 ± 1.9 vs 36.5 ± 2.1 mm Hg; P < .05). In morphometric analysis the percentage of medial wall thickness and the percentage of muscularization in the MCT+FR group were reduced compared with those in the MCT group after 4 weeks (P < .05); however, the number of macrophages was not significantly different. p38 mitogen-activated protein kinase activity was significantly attenuated in the MCT+FR group compared with in the MCT group (7.2 ± 0.52 vs 2.1 ± 0.23 fold-increase, P < .05, at 1 week). Although mRNA levels of tumor necrosis factor α and interleukin 1β were reduced in the MCT+FR group compared with in the MCT group (tumor necrosis factor α: 1.18 ± 0.36 vs 3.05 ± 1.12 fold-increase, P < .05, at 2 weeks; interleukin 1β: 2.2 ± 0.34 vs 4.4 ± 1.09 fold-increase, P < .05, at 1 week), FR167653 did not suppress increased monocyte chemotactic protein 1 mRNA expression induced by monocrotaline (3.2 ± 0.62 vs 3.1 ± 0.42 fold-increase, at 1 week).ConclusionFR167653 significantly attenuates the expression of inflammatory cytokines, ultimately preventing the progression of pulmonary hypertension. These results suggest that p38 mitogen-activated protein kinase might play a central role in the molecular events that underlie the development and progression of pulmonary hypertension

    Indigo Carmine Dye-Assisted Lymphatic-Sparing Laparoscopic Palomo Varicocelectomy In Children

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    The ideal method for varicocelectomy in children remains controversial. We present our experience with dye-assisted lymphatic-sparing laparoscopic varicocelectomy (LSLV) in children, which overcomes the limitations of previously described techniques. Materials and methods : Five consecutive LSLVs were performed over a period of three years on children with a mean age of twelve years. The varicocele grade was three in one case and grade 2 in four cases, respectively. A left subdartos injection of 2 ml of Indigo carmine dye was done using a 25-gauge needle at ten minutes before an operation. A scrotal injection of lymphatic dye was utilized to spare at least one lymphatic and the remaining spermatic vessels were divided. Results : Lymphatic-sparing was accomplished in all cases. No peri-operative complication was noted.We spared one lymphatic channel in one patient (20%) and two channels in four patients (80%). There were no cases of hydrocele or residual varicocele. Conclusion : Dye-assisted LSLV is easily accomplished with an excellent surgical outcome and sparing one or two lymphatics appears to be sufficient to avoid secondary hydrocele

    Iliopsoas Abscess in an Infant

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    Iliopsoas abscess (IPA) is uncommon in childhood and very rare in the neonate and infant. We present a case of IPA after an umbilical granuloma in an infant. A baby girl with a birth weight of 2,970 g was born at thirty-seven weeks and two days gestation by Caesarean Section. On the fourteenth day after birth, her umbilicus was wet and developed the granulomatous formation. At two months of age, she presented with right leg and groin swelling with mild bluish discoloration and without fever. She had poor movement of her right leg and showed apparent discomfort. Her umbilicus was dry and there was no granulomatous material. Ultrasonography and computed tomography demonstrated an iliopsoas abscess in the right position. Therefore, an extraperitoneal surgical drainage was performed, aspirating yellowish pus. Culture of the purulent material revealed Staphylococcus aureus. Systemic antibiotic therapy was continued for ten days. After three days of drainage, full-range motion of the right leg was gained, and then after eleven days, CT findings comfirmed the disappearance of the iliopsoas abscess. IPA is extremely rare and it is difficult to diagnose. However, it should be included in the differential diagnosis of an infant with poor leg movement and swelling of the groin to the femur

    Induction of inverted morphology in brain organoids by vertical-mixing bioreactors

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    上下動撹拌培養装置を用いた流体制御により誘導した反転型脳オルガノイド 脳オルガノイド誘導の流体シミュレーションと流体力学的理解. 京都大学プレスリリース. 2021-10-27.How you mix cells changes the brain. 京都大学プレスリリース. 2021-10-28.Organoid technology provides an opportunity to generate brain-like structures by recapitulating developmental steps in the manner of self-organization. Here we examined the vertical-mixing effect on brain organoid structures using bioreactors and established inverted brain organoids. The organoids generated by vertical mixing showed neurons that migrated from the outer periphery to the inner core of organoids, in contrast to orbital mixing. Computational analysis of flow dynamics clarified that, by comparison with orbital mixing, vertical mixing maintained the high turbulent energy around organoids, and continuously kept inter-organoid distances by dispersing and adding uniform rheological force on organoids. To uncover the mechanisms of the inverted structure, we investigated the direction of primary cilia, a cellular mechanosensor. Primary cilia of neural progenitors by vertical mixing were aligned in a multidirectional manner, and those by orbital mixing in a bidirectional manner. Single-cell RNA sequencing revealed that neurons of inverted brain organoids presented a GABAergic character of the ventral forebrain. These results suggest that controlling fluid dynamics by biomechanical engineering can direct stem cell differentiation of brain organoids, and that inverted brain organoids will be applicable for studying human brain development and disorders in the future

    The Shock State of Itokawa Sample

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    One of the fundamental aspects of any astromaterial is its shock history, since this factor elucidates critical historical events, and also because shock metamorphism can alter primary mineralogical and petrographic features, and reset chronologies [1]. Failure to take shock history into proper account during characterization can result in seriously incorrect conclusions being drawn. Thus the Hayabusa Preliminary Examination Team (HASPET) made shock stage determination of the Itokawa samples a primary goal [2]. However, we faced several difficulties in this particular research. The shock state of ordinary chondrite materials is generally determined by simple optical petrographic observation of standard thin sections. The Itokawa samples available to the analysis team were mounted into plastic blocks, were polished on only one side, and were of non-standard and greatly varying thickness, all of which significantly complicated petrographic analysis but did not prevent it. We made an additional estimation of the sample shock state by a new technique for this analysis - electron back-scattered diffraction (EBSD) in addition to standard petrographic techniques. We are also investigating the crystallinity of Itokawa olivine by Synchrotron X-ray diffraction (SXRD)
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