posture stability in archery players

Objectives : The effects of full-field dynamic visual disturbance on body sway were examined in archery players (n = 24), ball game players (n = 35), and untrained subjects (n = 34). Methods : Participants were asked to stand on a platform surrounded a box, the inside of which was randomly dotted. After the box suddenly began to swing and continued to swing back and forth at a frequency of 0.42 Hz for 60 seconds in a damped sinusoidal waveform, the body center sway was recorded using a stabilometer. Results : Standard deviation (SD) of body center sway in the anterior-posterior direction suddenly increased just after the box began to swing, and gradually decreased as the box swung in a damped sinusoidal waveform. After a sudden initial increase in SD of body center sway, it significantly decreased in archery players, compared with that of ball game players 20 seconds or untrained subjects 15 and 20 seconds after the onset of the box motion. Conclusion : Archery players showed higher stability against visual disturbance, compared with ball game players and untrained subjects, suggesting that they rely on proprioceptive inputs to maintain balance, and that their training re-weights sensorimotor dominance from vision to proprioception for posture regulation to increase shooting accuracy

The Witten index for one-dimensional split-step quantum walks under the non-Fredholm condition

Split-step quantum walks possess chiral symmetry. From a supercharge, that is the imaginary part of the time evolution operator, the Witten index can be naturally defined and it gives the lower bound of the dimension of eigenspaces of $1$ or $-1$. The first three authors studied the Witten index as a Fredholm index under the condition that the supercharge satisfies the Fredholm condition. In this paper, we establish the Witten index formula under the non-Fredholm condition. To derive it, we employ the spectral shift function induced by the fourth-order difference operator with a rank one perturbation on the half-line. Under two-phase limit conditions and trace conditions, the Witten index only depends on parameters of two-side limits. Especially, half-integer indices appear.Comment: 26 pages, 1 figure

Identifying vertebral fractures in the Japanese population using the trabecular bone score : a cross-sectional study

Background: The trabecular bone score (TBS) is reported to be an independent predictor of fracture risk in patients with primary or secondary osteoporosis. However, there have been few reports on its use in the Japanese population. This study aimed to investigate the risk factors for vertebral fracture in the Japanese population and to evaluate the usefulness of TBS. Methods: This cross-sectional study involved 279 patients aged 60–90 years in whom bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry (DXA). TBS was calculated based on the DXA scans. The presence or absence of vertebral fractures was assessed from T11 to L5. The patients were divided into those with vertebral fractures (VF group, n = 104) and those without vertebral fractures (non-VF group, n = 175). Results: Of the 104 patients in the VF group, 75 had 1 vertebral fracture and 29 had 2 or more fractures. The mean TBS was 1.28 in the VF group and 1.35 in the non-VF group (p  1.23). Conclusion: TBS was a significant indicator of vertebral fractures in the Japanese population and might contribute to identifying patients with vertebral fractures, particularly those with osteopenia who need pharmacologic therapy

Right adrenal vein identification using unenhanced magnetic resonance imaging

Purpose: Unenhanced magnetic resonance imaging (MRI) is known to be useful in characterizing adrenal adenomas through the implementation of in-phase (IPI) and opposed-phase imaging (OPI) based on chemical shift artifacts. However, whether unenhanced MRI can contribute to the identification of right adrenal vein (RAV) remains unclear. The aim of this study was to evaluate the feasibility of unenhanced MRI for the identification of RAV. Material and methods: This retrospective study reviewed 30 patients (16 men; median age 60 years; range 34-76 years) who underwent MRI and subsequent adrenal venous sampling (AVS). Chemical shift MRI was acquired using echo times of 2.3 ms (OPI) and 4.6 ms (IPI) with a slice thickness of 3 mm and a gap of 1 mm. T2-weighted imaging (T2WI) was also performed. Identification of RAVs was performed by 2 independent radiologists. Inter-observer agreement on a 3-point rating scale was evaluated using κ statistics. The identification rate of RAVs was compared between OPI, IPI, and T2WI using McNemar’s test. Results: Good inter-observer agreement was found for the OPI (κ = 0.744), whereas fair agreement was obtained for both other sequences (IPI: κ = 0.375; T2WI: 0.348). For both raters, the identification rate of RAVs was higher with OPI (36/60; 60.0%) than with other sequences (IPI: 16/60, 26.7%; T2WI: 9/60, 15.0%; p < 0.05, each). Conclusions: OPI may play a screening role in the identification of RAVs preceding AVS, which could reduce the required radiation exposure and doses of contrast agent

Dispersion of red blood cells in microchannels : a confocal micro-PTV assessment

Blood in large arteries may be treated as a homogenous fluid from a macroscopic prospective. However, in reality blood is a suspension of deformable cells in viscous fluid plasma. In microcirculation, which comprises the smallest arteries and veins, the flow behavior of individual blood cells and their interactions provide the microrheological basis of flow properties of blood at a macroscopic level. Hence, in microcirculation it is fundamental to study the flow behavior of blood at cellular level. Several studies on both individual and concentrated RBCs have already been performed in the past. However, all studies used conventional microscopes and also ghost cells to obtain visible trace RBCs through the microchannel. The present study is concerned in providing further insights into the microscale blood flow behavior through microchannels by applying an emerging optical technique known as confocal micro-PIV/PTV. The technique consists of a spinning disk confocal microscope, high speed camera and a diode-pumped solid state (DPSS) laser combined with a single particle tracking (SPT) software (MtrackJ). Detailed measurements on the motions of RBCs were measured at different haematocrits (Hct) and the correspondent radial dispersion coefficient was determined

Measurement of multi-red blood cells interactions in blood flow by confocal micro-PTV

In microcirculation the flow behavior of red blood cells (RBCs) plays a crucial role in many physiological and pathological phenomena. For instance, the interaction of RBCs in shear flow is believed to play an important role to the thrombogenesis process. Despite the relevance of this phenomenon on the blood mass transport, very little studies have been performed during the years, partly due to the absence of adequate visualization techniques able to obtain both direct and quantitative measurements on multi-RBCs motions in concentrated suspensions. Past studies on both individual and concentrated RBCs used conventional microscopes and/or ghost cells to obtain visible trace RBCs at high concentration suspension of blood cells [1, 2]. Recently, advances of confocal microscopy and consequent advantages over conventional microscopes have led to an emerging technique known as confocal micro-PIV [3, 4]. This paper presents the application of a confocal micro- PTV system to measure RBC-RBC hydrodynamic interactions in flowing blood

Immunoglobulin Production by Peripheral Blood Mononuclear Cells in IgA Nephropathy Patients and their Relatives

Immunoglobulin production by peripheral blood mononuclear cells of 27 patients of IgA nephropathy and 11 relatives was determined. In comparison with 15 healthy controls, no significant difference could be observed in both IgA nephropathy patients and relatives of the group not stimulated with PWM, but in the group stimulated with PWM a significant elevation in the production of IgA, IgG and IgM was seen in IgA nephropathy patients, while in the relatives a significant elevation in production of IgA and IgG was observed. It is speculated that immune complexes mainly IgA are the chief cause of development and progression of IgA nephropathy and that IgG and IgM are also involved. In also relatives, the presence of immunological abnormalities similar to those of IgA nephropathy patients is suggested

Experimental IgA Nephropathy Induced by Oral Administration of Dextran

Attempts were made to produce experimental IgA nephropathy by oral administration for 18 weeks of dextran having a molecular weight of 10,000, 70,000, and 500,000 to 6-week old female BALB/c mice. It was observed that in three out of eight cases belonging to the group given dextran having a molecular weight of 70,000 and in three out of seven cases belonging to the group given dextran having a molecular weight of 500,000, deposition of IgA on the mesangium was demonstrated by immunofluorescence direct method. Furthermore, deposition of IgG and IgM was observed in not only the groups given dextran but also in the control group, but no significant difference in deposition pattern could be demonstrated between the groups. C3 was observed only in one case belonging to the group given dextran having a molecular weight of 10,000. The serum IgA value showed a higher value in the cases with IgA deposition than in the control group. Serum C3 value was higher in the IgA deposition cases in the group given dextran having a molecular weight of 500,000 than in the control group. These results suggest that it is possible to produce experimental IgA nephropathy by continual oral administration of carbohydrate antigen of bacterial origin and that bacterial infection is involved in the development of IgA nephropathy