Assimilation-type and Contrast-type Bias of Motion Induced by the Surround in a Random-dot Display: Evidence for Center-Surround Antagonism

AbstractAs a mechanism to detect differential motion, we have proposed a model of “a motion contrast detector” that has a center-surround antagonistic receptive field with respect to the direction of motion. Supporting evidence has been obtained in the studies of induced motion, motion capture, and motion aftereffect. In order to obtain further evidence in a more strictly controlled situation, we examined the perceptual bias of motion in a center stimulus induced by another, surrounding motion. By using a stochastic random-dot display configured in a center-surround concentric fashion, we measured the % signal in the center stimulus that made the stimulus perceptually stationary in the presence of a moving surround. Measurements were done for various stimulus sizes and eccentricities. The amount of bias changed as a function of stimulus size and eccentricity. At several eccentricities. smaller stimulus sizes tended to yield assimilation-type biases, whereas larger sizes tended to yield contrast-type biases. However, a spatial scaling procedure revealed that the amount of bias was a simpler function of “scaled” stimulus size that was obtained by dividing the physical size by a scaling factor at each eccentricity. In the scaled profile, assimilation-type bias changed to contrast-type bias with increasing size, reached the peak of contrast-type bias at a certain size, and decreased slightly with further increasing size. Furthermore, a model of a difference of Gaussians, DOG, function well approximated the behavior of the profile. From these results, we concluded that the process specific to perceiving relative motion is mediated by a motion contrast detector, which is possibly located in area MT. Copyright © 1996 Elsevier Science Ltd

Evaluation of novel CEX resin for continous processing of MAb purification

We have evaluated novel cation exchange resin and membrane which is potentially suited for continuous process in biologics manufacturing. Typically cation exchange chromatography (CEX) is used in a bind/elute (B/E) mode for the MAb process since MAb act as cation at the buffer condition used for CEX due to the pI from neutral to weak basic. Generally, purpose of CEX chromatography is to remove aggregates and other impurities like HCP and DNA. Especially, aggregate removal is of interest to the industries. A continuous process in MAb downstream process can solve several bottlenecks in typical batch process. However its capability cannot be fully utilized if some step of chromatography is used in a B/E mode since it will take a longer process time due to the posing of product stream for binding and washing and it will take a more cost due to the requirement of large amount of resins as we use at the batch process. In such a case, chromatography in flowthrough mode has a potential to overcome those issues for both cost and time and enables us to develop more streamlined continuous process. We will present the result of our study to evaluate novel CEX resin developed by Merck Millipore by comparing with the existing process of Mab A and we obtained a conclusion that this resin is fitted to the continuous processing very much. The novel resin showed a better impurity clearance than our existing process. For example, over 65% removal of aggregate by the novel resin was obtained in contrast to no removal by the existing process. A 20-fold better clearance for DNA was confirmed for the novel resin than the existing process. This indicates an additional polishing step can be omitted and this new chromatography can be a strong option if we need to reduce such impurities further. Also the resin cost is expected to be reduced down to 1/10 in maximum since those impurity clearance results were obtained about 10-times larger load than the typical B/E mode operation of CEX. Considering those aspects, we conclude that this resin showed a better fit for a continuous process. We will also discuss an expected effect of the novel CEX resin on cost and process time savings by a continuous proces

Relationship between Tourniquet Pressure and a Cross-Section Area of Superficial Vein of Forearm

This study investigated the appropriate tourniquet pressure (TP) and duration of tourniquet application for venipuncture by calculating the venous cross-section (VCS) area on ultrasonography. Twenty healthy volunteers without cardiovascular risk factors were enrolled in this study. A target vein (either a cephalic or median cubital vein) was selected on ultrasonography. The pneumatic tourniquet was inflated using a rapid cuff inflator system at setting pressure for 120sec. TP strength was varied from 20mmHg to 100mmHg, in 20mmHg increments. The order of TP was randomized. Compari-sons among more than 3 groups were performed by one-way repeated-measures ANOVA and the Bonferroni method. The VCS area increased rapidly until 10sec after tourniquet inflation. The VCS area then increased gradually until 30sec after tourniquet inflation. After that, the VCS area did not increase remarkably. The VCS area increased with TP strength up to 80mmHg, but the VCS area at TP 100mmHg decreased to less than that at TP 40mmHg. Based on these results, we recommend a tourniquet pressure of 60mmHg, and duration of tourniquet application is 30 to 60sec for venipuncture

ROLE OF MUSCLE SPINDLE DURING DYNAMIC HUMAN MOVEMENTS: EXPERIMENTAL AND SIMULATION STUDIES

INTRODUCTION: Muscle spindle does important roles balancing muscle tone during human movement such as exercise and stretching. The primary objective of this study is to explore the contribution of muscle spindles on the modulation of voluntary movement

Ossified Metaplastic Spinal Meningioma Without Psammomatous Calcification : A Case Report

Meningiomas constitute approximately 25% of primary spinal cord tumors, and 1% to 5% are calcified. Ossification is a rare event and the etiology of ossification in meningiomas is not well known. We present the case of a 29-year-old female with a rare case of ossified thoracic spinal metaplastic meningioma. The tumor was successfully resected, and pathology confirmed ossified metaplastic meningioma. On histopathological examination, only mature bone tissue and tumor cells were present in the region containing no psammoma bodies, suggesting that the tumor cells had transitioned to mature osteocytes

Successful Treatment of Staphylococcus schleiferi Infection after Aortic Arch Repair: In Situ Aortic Arch Replacement and Domino Reconstruction of the Debranching Graft using Autologous Iliac Artery

A 62-year-old Japanese male presented with graft infection by Staphylococcus schleiferi 50 days after debranching of the left subclavian artery and frozen elephant trunk repair for the entry closure of a Stanford type B aortic dissection. The graft was removed, and the patient was successfully treated using in situ reconstruction of the arch with omental flap coverage, removal of the debranching graft, autologous iliac artery grafting, and longterm antibiotics. Domino reconstruction of the infected debranching graft using autologous external iliac artery and a Dacron graft can thus be a good option in similar cases

Measurements of radial profile of hydrogen and deuterium density in isotope mixture plasmas using bulk charge exchange spectroscopy

A bulk charge exchange spectroscopy system has been applied to measure the radial profiles of the hydrogen (H) and deuterium (D) density ratio in the isotope mixture plasma in a large helical device. Charge exchange lines of Hα and Dα are fitted by 4 Gaussian of H and D cold components and H and D hot components with 5 parameters by combining the measurement of plasma toroidal rotation velocity with carbon charge exchange spectroscopy. The radial profiles of the relative density of hydrogen and deuterium ions are derived from H and D hot components measured and the beam density calculated from beam attenuation calculation. A proof-of-principle experiment is performed by the H pellet and the D pellet injections into the H-D mixture plasma

Logical design of oral glucose ingestion pattern minimizing blood glucose in humans

Excessive increase in blood glucose level after eating increases the risk of macroangiopathy, and a method for not increasing the postprandial blood glucose level is desired. However, a logical design method of the dietary ingestion pattern controlling the postprandial blood glucose level has not yet been established. We constructed a mathematical model of blood glucose control by oral glucose ingestion in three healthy human subjects, and predicted that intermittent ingestion 30 min apart was the optimal glucose ingestion patterns that minimized the peak value of blood glucose level. We confirmed with subjects that this intermittent pattern consistently decreased the peak value of blood glucose level. We also predicted insulin minimization pattern, and found that the intermittent ingestion 30 min apart was optimal, which is similar to that of glucose minimization pattern. Taken together, these results suggest that the glucose minimization is achieved by suppressing the peak value of insulin concentration, rather than by enhancing insulin concentration. This approach could be applied to design optimal dietary ingestion patterns