1,562 research outputs found
Dynamics of Flexible High-Molecular-Weight Polymers in Dilute Solution under Circular Couette Flow (FUNDAMENTAL MATERIAL PROPERTIES-Molecular motion analysis)
Chain dynamics of poly(a-methylstyrene) of high molecular weight in benzene, a good solvent, in dilute solution was investigated by dynamic light scattering under Couette flow. At the shear gradient above 2.8-4.5s-1, the internal modes of motions were exclusively suppressed and only the center-of-mass translational diffusion motion of the chain was detected. Whereas, in the intermediate shear region, the decay rate for the internal mode was constant, and that of the diffusion mode increased with increasing the shear rate. The obtained universal ratio W/D0q2 was located close to the theoretical curve predicted for the flexible chains with the microscopic description of chain dynamics in Q state. This quantitative agreement between theory and experiments means that the coupled kinetic equations for chain segments and solvent in the same dynamic level is indispensable for describing rigorously chain dynamics in dilute solution
On the Anionic Preparation of Poly (α-methyl styrene) (Special Issue on Polymer Chemistry, V)
Methemoglobinemia induced by chlorphenamidine
A 76-year old farmer ingested 100 g of chlorphenamidine (Galectron), a plant acaricle, for the purpose of suicide. Gastric lavage was performed and the patient survived. Methemoglobinemia was noted after emergency treatment and was still present at 20 hours after ingestion of the compound. The patient was lethargic for at least 50 hours. Moderate neutrophilic leukocytosis and kidney injury were observed.</p
A case of alcaptonuria with fatal cardiovascular disturbance
A case of alcaptonuria combined with aortic insufficiency was found in a 28-year-old male. The patient was palpitating at admission. The daily excretion of homogentisic acid was 2.0-6.0 g. Electrocardiography indicated atrial fibrillation and left ventricular hypertrophy with a ST-T change and right axis deviation. Cartilage tissues in the knee-joints showed no pigmentation. Vertebral X-ray revealed no calcification. The patient's history disclosed a family intermarriage in his grandparents. The patient's mother noticed the presence of black stains on diapers in his infancy and brown pigmentation on the skin and sclera in childhood. No kin had similar symptoms.</p
3D tumor localization through real-time volumetric x-ray imaging for lung cancer radiotherapy
Recently we have developed an algorithm for reconstructing volumetric images
and extracting 3D tumor motion information from a single x-ray projection. We
have demonstrated its feasibility using a digital respiratory phantom with
regular breathing patterns. In this work, we present a detailed description and
a comprehensive evaluation of the improved algorithm. The algorithm was
improved by incorporating respiratory motion prediction. The accuracy and
efficiency were then evaluated on 1) a digital respiratory phantom, 2) a
physical respiratory phantom, and 3) five lung cancer patients. These
evaluation cases include both regular and irregular breathing patterns that are
different from the training dataset. For the digital respiratory phantom with
regular and irregular breathing, the average 3D tumor localization error is
less than 1 mm. On an NVIDIA Tesla C1060 GPU card, the average computation time
for 3D tumor localization from each projection ranges between 0.19 and 0.26
seconds, for both regular and irregular breathing, which is about a 10%
improvement over previously reported results. For the physical respiratory
phantom, an average tumor localization error below 1 mm was achieved with an
average computation time of 0.13 and 0.16 seconds on the same GPU card, for
regular and irregular breathing, respectively. For the five lung cancer
patients, the average tumor localization error is below 2 mm in both the axial
and tangential directions. The average computation time on the same GPU card
ranges between 0.26 and 0.34 seconds
Measurement of Brain Function of Car Driver Using Functional Near-Infrared Spectroscopy (fNIRS)
The aim of this study is to propose a method for analyzing measured signal obtained
from functional Near-Infrared Spectroscopy (fNIRS), which is applicable for
neuroimaging studies for car drivers. We developed a signal processing method by
multiresolution analysis (MRA) based on discrete wavelet transform. Statistical group
analysis using Z-score is conducted after the extraction of task-related signal using
MRA. Brain activities of subjects with different level of mental calculation are
measured by fNIRS and fMRI. Results of mental calculation with nine subjects by using
fNIRS and fMRI showed that the proposed methods were effective for the evaluation of
brain activities due to the task. Finally, the proposed method is applied for evaluating
brain function of car driver with and without adaptive cruise control (ACC) system for
demonstrating the effectiveness of the proposed method. The results showed that frontal
lobe was less active when the subject drove with ACC
Measurement and Evaluation of Brain Activity for Train Drivers Using Wearable NIRS
Human errors of train drivers may cause serious damage. Therefore, research on human error prevention has been conducted by many researchers. In this context, brain activity measurement of train drivers using near-infrared spectroscopy (NIRS) has been conducted to monitor the condition of train drivers. In this study, we developed a compact wireless wearable NIRS that can be used in natural environments. The wearable NIRS has been used to measure train drivers’ brain function using a train driving simulator. Experimental results showed that brain activity of the dorsolateral prefrontal cortex (DLPFC) increased when the driver made braking operation. The experiment for train driving with an accidental event was carried out to evaluate the relation between drivers’ attention and the brain activity. As a result, there was a difference in brain activity between with and without prior notice. Results showed that the increased attention of the train driver can be shown in the NIRS signal from the outer part of the prefrontal cortex
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