A FLOW VISUALEATION OF UNDULATORY UNDERWATER SWIMMING -A PILOT STUDY OF THREE DEIMENTIONAL AMALYSIS

The purpose of this study was to visualize the flow characteristic behind a swimmer during undulatory underwater swimming (UUS). A male college swimmer performed dolphin kicks in a water flume channel (flow velocity was set at 0.8 m+sl). By using the stereo PIV system, we captured the flow vector field in cross-sectional areas behind the swimmer and the swimmer's motions with a synchronized motion capture system. The vector fields were averaged for each kicking phase, and for spatial cross-sectional plane. This enabled visualization oft he three dimensional flow field in UUS. The results showed that the swimmer created a counter vortex pair around the feet before the downward kid, and this appeared to assist the generation of thrust during the down kick motion

THREE-DIMENSIONAL FLOW FIELD AND LEG MOTION DURING UNDULATORY UNDERWATER SWIMMING

This study described swimmers’ leg motions and the three-dimensional flow field around their legs during undulatory underwater swimming (UUS). We used the particle image velocimetry (PIV) method and a three-dimensional motion capture system. Seven male swimmers participated and we acquired EMG data of one male swimmer during UUS after the previous experiment. After the downward kick motion that includes the legs’ lateral rotation and the ankles’ dorsal flexion, water’s backward momentum was observed. During the upward kick motion, backward flow velocity decreased, but flow occurred in a vertical, upward direction. This suggested that UUS could demonstrate great propulsion power by generating jet flow through the downward kick motion that might be assisted by upstream flow from the upward kick motion

Food processing and allergenicity

Food processing can have many beneficial effects. However, processing may also alter the allergenic properties of food proteins. A wide variety of processing methods is available and their use depends largely on the food to be processed. In this review the impact of processing (heat and non-heat treatment) on the allergenic potential of proteins, and on the antigenic (IgG-binding) and allergenic (IgE-binding) properties of proteins has been considered. A variety of allergenic foods (peanuts, tree nuts, cows’ milk, hens’ eggs, soy, wheat and mustard) have been reviewed. The overall conclusion drawn is that processing does not completely abolish the allergenic potential of allergens. Currently, only fermentation and hydrolysis may have potential to reduce allergenicity to such an extent that symptoms will not be elicited, while other methods might be promising but need more data. Literature on the effect of processing on allergenic potential and the ability to induce sensitisation is scarce. This is an important issue since processing may impact on the ability of proteins to cause the acquisition of allergic sensitisation, and the subject should be a focus of future research. Also, there remains a need to develop robust and integrated methods for the risk assessment of food allergenicity

Ab initio Molecular-Dynamics Study of Structural and Electronic Properties of Liquid MgSiO3 under Pressure

The structural and electronic properties of liquid MgSiO3 under pressure are investigated by ab initio molecular-dynamics simulations. At ambient pressure, most Si atoms have the same coordination even in the liquid state as in the crystallie phase, i.e., each Si atoms is bonded to two bridging oxygens twofold-coordinated to Si, and two nonbridging oxygens onefold-coodinated to Si. It is found that the structural defects, such as fivefold-or threefold-coordinated Si atoms, are always formed with the rearrangement of Si-O covalent bonds in the atomic diffusion processes. The population analysis clarifies that maximum of the diffusivity in the pressure dependence is originated from the increasing of the number of defects under compression

A Double-Blind, Randomized, Placebo-Controlled Trial of Heat-Killed Pediococcus acidilactici K15 for Prevention of Respiratory Tract Infections among Preschool Children

Although some probiotic bacteria have been reported to prevent infections in children, there are few well-designed double-blind studies. Here we evaluated the effects of a probiotic strain of lactic acid bacteria (LAB), Pediococcus acidilactici K15, on viral respiratory tract infections in preschool children. A four-month, randomized, double-blind, placebo-controlled study was performed in 172 healthy children aged 3 to 6 years. Subjects were administered dextrin alone or dextrin including heat-killed K15 (5 × 1010 bacteria). The number of febrile days was the primary outcome. The number of absent days from preschools and the influenza incidence were secondary outcomes. Secretory IgA (sIgA) concentrations in saliva were measured as an exploratory outcome. The primary and secondary outcomes were not significantly different between both groups. Analyses in children with little intake of fermented foods including LAB showed that the duration of a fever significantly decreased by K15 intake. The salivary sIgA level in the K15 group was maintained significantly higher than it was in the placebo group. The effects of K15 on preventing viral respiratory tract infections were not observed without the restriction of fermented foods intake. However, K15 supported anti-infectious immune systems in children who took less fermented foods and the maintenance of salivary sIgA levels in all subjects

An Acquired Form of Dandy-Walker Malformation with Enveloping Hemosiderin Deposits

Dandy-Walker malformation (DWM) is a posterior fossa anomaly characterized by hypoplasia and upward rotation of the cerebellar vermis and cystic dilation of the fourth ventricle. The cyst of DWM rarely extends posteriorly to almost completely fill the entire posterior fossa, which mimics primary cerebellar agenesis, a cerebellar porencephalic cyst, and an arachnoid cyst due to the lack of clarity of the thin cystic wall. A 10-month-old female born at 23 weeks’ gestation with cerebellar hemorrhage in the neonatal period was admitted to our hospital with dysphagia and side-to-side head bobbing. The detection of hemosiderin deposits enveloping the cyst wall by T2 star-weighted angiography (SWAN) was useful for the differential diagnosis of an acquired form of DWM from primary cerebellar agenesis. Cyst fenestration successfully improved dysphagia and head bobbing. A pathological specimen of the perforated cyst consisted of collagen fibers with hemosiderin deposits but lacked congenital cyst components. In infants with posterior fossa cysts, SWAN will be useful for a differential diagnosis between DWM and primary cerebellar agenesis

Direct Hydroxylation and Amination of Arenes via Deprotonative Cupration

Deprotonative directed ortho cupration of aromatic/heteroaromatic C–H bond and subsequent oxidation with <i>t</i>-BuOOH furnished functionalized phenols in high yields with high regio- and chemoselectivity. DFT calculations revealed that this hydroxylation reaction proceeds via a copper (I → III → I) redox mechanism. Application of this reaction to aromatic C–H amination using BnONH₂ efficiently afforded the corresponding primary anilines. These reactions show broad scope and good functional group compatibility. Catalytic versions of these transformations are also demonstrated