340 research outputs found
Perceived duration of chromatic and achromatic light
Luminance and color information are considered to be processed in parallel systems. The integration of information from these two separate systems is crucial for the visual system to produce a coherent percept. To investigate how luminance and color lights are perceived in time, we measured the perceived duration of light stimuli with and without colors in a paradigm involving simultaneous perception with presentation of two successive stimulus frames. Luminance contrast and color contrast of the stimuli were set with a chromatic substitution technique. In Experiment 1, the perceived duration of both chromatic stimuli and achromatic stimuli increased as the luminance contrast decreased. Experiment 2 tested if the duration of the percept was influenced by color contrast which was defined by colorimetric purity of the stimuli, when luminance contrast was set as low as practically possible. The result showed that the duration of the percept decreased with increasing color contrast of the stimuli. Moreover, Experiment 3 demonstrated that the trend of perceived duration was consistent with the four primary colors, provided that the effective color contrast of stimulus was corrected based on the contrast sensitivity to the color. These experiments indicate that, with a high luminance contrast level, perceived duration of a stimulus is predominantly defined by luminance contrast, whereas in low luminance contrast conditions, the duration depends on the color contrast. The perceived duration of color stimuli showed an "inverse color contrast effect", similar to the well-known "inverse intensity effect" for luminance stimuli. The similarities and the differences between the two systems, as well as their priorities in processing temporal information of visual stimuli are further discussed. © 2011 Elsevier Ltd. All rights reserved
Recurrence of angina pectoris after percutaneous coronary intervention is reduced by statins in Japanese patients
SummaryBackgroundStatins have been reported to reduce cardiovascular events in patients with coronary artery disease (CAD). Percutaneous coronary intervention (PCI) is commonly used to relieve ischemic symptoms in patients with CAD. However, there is little information on the effect of statins on cardiovascular events after PCI, even in the era of coronary stent implantation.MethodsA total of 1019 patients with acute or chronic CAD and modest total cholesterol levels (180–240mg/dl) were enrolled and randomly assigned to treatment with or without statins. We evaluated the effect of any available statin on the incidence of cardiovascular events after PCI. The primary endpoint was a composite of cardiovascular death, nonfatal acute myocardial infarction (MI), recurrent angina pectoris requiring emergency rehospitalization (rAP), heart failure, and stroke.ResultsIndications for PCI were stable angina in 54%, ST-elevation MI in 41% and non-ST-elevation MI/unstable angina pectoris in 5%. After 2 years of statin treatment, low-density lipoprotein cholesterol (LDL-C) decreased from 133 to 96mg/dl. Stents were implanted in 84% of all cases. The primary endpoint event rate was 9.5% in the statin group and 14.7% in the non-statin group (p=0.0292). Of all primary endpoint events, only rAP was significantly suppressed by statins (p=0.0027). In rAP patients, coronary angiography revealed that statins suppressed restenosis but not new lesions.ConclusionsFor Japanese CAD patients treated with PCI and stent implantation, statin therapy reduced the incidence of recurrent cardiovascular events, particularly rAP. Discretionary statin treatment to achieve LDL-C levels <100mg/dl effectively reduced restenosis causing rAP
Role of KIT-Positive Interstitial Cells of Cajal in the Urinary Bladder and Possible Therapeutic Target for Overactive Bladder
In the gastrointestinal tract, interstitial cells of Cajal (ICCs) act as pacemaker cells to generate slow wave activity. Interstitial cells that resemble ICCs in the gastrointestinal tract have been identified by their morphological characteristics in the bladder. KIT is used as an identification marker of ICCs. ICCs in the bladder may be involved in signal transmission between smooth muscle bundles, from efferent nerves to smooth muscles, and from the urothelium to afferent nerves. Recent research has suggested that not only the disturbance of spontaneous contractility caused by altered detrusor ICC signal transduction between nerves and smooth muscle cells but also the disturbance of signal transduction between urothelial cells and sensory nerves via suburothelial ICC may induce overactive bladder (OAB). Recent reports have suggested that KIT is not only a detection marker of these cells, but also may play a crucial role in the control of bladder function. Research into the effect of a c-kit receptor inhibitor, imatinib mesylate, on bladder function implies that KIT-positive ICCs may be therapeutic target cells to reduce bladder overactivity and that the blockage of c-kit receptor may offer a new therapeutic strategy for OAB treatment, although further study will be needed
Development of Safety Measures of Bicycle Trafflc by Observation wffh Deep-Leamlng, Drive Recorder Data, Probe Blcycle wlth LIDAR, and Connected Simulators
This research outlines the development of evaluating safety measures for bicycle traffic using state-of-the-art technology, which was started since 2020 as a four-year project. The project is funded by the Commission on Advanced Road Technology in the Ministry of Land, Infrastructure, Transport and Tourism(MLIT).
While Japan has a high bicycle modal share of 12% (2010), bicycle-related fatalities are relatively high among other countries in the IRTAD database (2019). Under these circumstances, since 2007, various measures for bicycle traffic measures have been implemented to improve the safe bicycle traffic environment, including the revision of the Road Traffic Act and the formulation of a national plan to promote bicycle use.
However, serious accidents involving bicycles are remained in some specific cases. According to the government's traffic accident analysis results (2019), right-hook crash at signalized intersections are one of the most serious types of collision involving bicycles, along with accidents at unsignalized intersections involving vehicles turning left, rear-end collisions, and single vehicle accidents due to off-road deviation. In particular, proactive safety measures are required at signalized intersections along arterial roads, where electric personal mobility vehicles traveling at speeds of up to 20 km/h are expected to share with bicycles in the future.
In order to evaluate safety measures for bicycle-vehicle crashes, this project set the following goals.
1) Identify factors influencing near-miss incidents and collisions through analysis of drive recorder data and accident statistical data.
2) Detailed analysis of traffic conditions from the cyclist's perspective using a probe bicycle equipped with a LiDAR sensor.
3) Development of an experimental environment using a connected simulator for evaluation of cooperative driving behavior.
4) Clarification of experimental conditions to evaluate different scenarios and conditions with and without intervention.
5) Proposal of effective interventions to improve crash cases based on experiments
Pharmacokinetic study of pleural fluid penetration of carbapenem antibiotic agents in chemical pleurisy
SummaryStudy objectivesWe investigated pleural fluid penetration of carbapenem antibiotic agents [imipenem (IPM), panipenem (PAPM), meropenem (MEPM), and biapenem (BIPM)] using an experimental rabbit pleuritis model to clarify the usefulness of the carbapenem agents for the treatment of bacterial pleurisy or pyothorax.Measurements and resultsSerum and pleural fluid specimens were serially collected at 5, 10, 15, 30, 60, 90, 120, 180, 240, 300, and 360min after antibiotic administration for measurement of antibiotic levels. We investigated each agent alone as well as drug solutions containing each agent and a dehydropeptidase-I-specific inhibitor, cilastatin (CS), to remove the influence of dehydropeptidase-I-related hydrolysis. Groups of animals (n=3) received each carbapenem agent with or without CS. Serum and pleural fluid antibiotic levels were measured by high-performance liquid chromatography (HPLC). Because Cmax is not useful for evaluating the antimicrobial effects of carbapenem antibiotic agents due to their dose-dependent antimicrobial activity, we also investigated the AUC, which is correlated with the total drug levels in vivo.Among the drug solutions containing CS, MEPM/CS had the highest pleural fluid AUC0–360 (1594.8±510.3μgmin/ml), and the highest pleural fluid AUC0–360/plasma AUC0–360 ratio (0.79±0.04). BIPM/CS had the highest plasma AUC0–360 (3040.1±1525.9μgmin/ml). In pleural fluid AUC0–360/plasma AUC0–360 ratio MEPM/CS was significantly higher than those for the remaining agents. In pleural fluid AUC0–360 and plasma AUC0–360 there were no significant differences among these mixed solutions.ConclusionsMEPM had the most favorable pleural fluid penetration. Pleural fluid penetration should be examined in infection models and in clinical trials
Boson peak dynamics of natural polymer starch investigated by terahertz time-domain spectroscopy and low-frequency Raman scattering
Terahertz time-domain spectroscopy and low-frequency Raman scattering were performed on the natural polymer starch to investigate the boson peak (BP) dynamics. In the infrared spectrum, the BP was observed at 0.99 THz at the lowest temperature. Compared to the result from a previous study for vitreous glucose, both the frequency of the BP and absorption coefficient show lower values than those of the vitreous glucose. These behaviors originate from the longer correlation length of the medium-range order and lower concentration of hydroxyl groups in the starch. In the Raman spectrum, the BP was observed at 1.1 THz at room temperature, although the BP was not observed around room temperature due to the excess wing of the fast relaxation modes in the infrared spectrum. The temperature dependence of ε″(ν) during the heating process and cooling process shows a hysteresis below 230 K. During the heating process, kinks were observed at 140 K and 230 K. These kinks are attributed to the β-relaxation and the βwet-relaxation, respectively
Pathophysiology of unilateral asterixis due to thalamic lesion.
[Objective]:Unilateral asterixis has been reported in patients with thalamic lesion. This study aims at elucidating the pathophysiology of the thalamic asterixis. [Methods]:Two cases with unilateral asterixis caused by an infarction in the lateral thalamus were studied by analysing the asterixis-related cortical activities, transcranial magnetic stimulation (TMS) for motor cortex excitability and probabilistic diffusion tractography for the thalamo-cortical connectivity. [Results]:Averaging of electroencephalogram (EEG) time-locked to the asterixis revealed rhythmic oscillations of a beta band at the central area contralateral to the affected hand. TMS revealed a decrease in the motor evoked potential (MEP) amplitude and a prolongation of the silent period (SP). The anatomical mapping of connections between the thalamus and cortical areas using a diffusion-weighted image (DWI) showed that the lateral thalamus involved by the infarction was connected to the premotor cortex, the primary motor cortex (M1) and the primary somatosensory cortex (S1) of the corresponding hemisphere. [Conclusions]:The thalamic asterixis is mediated by the sensorimotor cortex, which is subjected to excessive inhibition as a result of the thalamic lesion involving the ventral lateral nucleus. [Significance]:This is the first demonstration of participation of the sensorimotor cortex in the generation of asterixis due to the lateral thalamic lesion
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