7,395 research outputs found

    Differential effect of denervation on free radical scavenging enzymes in slow and fast muscle of rat

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    To determine the effect of denervation on the free radical scavenging systems in relation to the mitochondrial oxidative metabolism in the slow twitch soleus and fast twitch extensor digitorum longus (EDL) muscles, the sciatic nerve of the rat was crushed in the mid-thigh region and the muscle tissue levels of 5 enzymes were studied 2 and 5 weeks following crush. Radioimmunoassays were utilized for the selective measurement of cuprozinc (cytosolic) and mangano (mitochondrial) superoxide dismutases. These data represent the first systematic report of free radical scavening systems in slow and fast muscles in response to denervation. Selective modification of cuprozinc and manganosuperoxide dismutases and differential regulation of GSH-peroxidase was demonstrated in slow and fast muscle

    Paleomagnetism and Tectonic Significance of the Goble Volcanics of Southern Washington

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    The upper Eocene to lower Oligocene Goble Volcanic series of southwest Washington is a thick sequence of areal to submarine basaltic to andesitic flows, pyroclastics, and minor sediments. Major element geochemical analyses suggest that these rocks may represent early magmatism of the Cascade arc. Paleomagnetic results from 37 sites indicate that the direction of remanent magnetization in the Goble Volcanics has a declination of 18.5°, an inclination of 57.5°, and a circle of 95% confidence (∝ 95)of 4.33°. The expected upper Eocene direction in the sampling area is D = 353.5°; Ī = 61.5°. Thus the Goble Volcanics block appears to have rotated approximately 25° in a clockwise direction relative to the North American interior since the late Eocene. Comparison of this result with those of Cox, Simpson, and Plumley for the Oregon Coast Range, which show an apparently greater degree of rotation, suggests that the Goble Volcanics are not part of the Coast Range block. This also is supported by geochemical and geophysical differences between the provinces. Simpson (1977) has proposed two models to explain the Coast Range rotation. Model I assumes that the block extends to the Olympic Mountains and rotated seaward around its northern end in response to extension from behind. Model II assumes the block did not extend as far as the Olympic Mountains, and that it rotated around a pivot point at its southern end. Both models have major problems, which are compounded by results from the Goble Volcanics. Two possible models for rotation of the Goble Volcanics as part of an independent block have been examined. These are: (1) the ball-bearing model , in which an equant block rotates between right-lateral faults in a large continental shear zone; and (2) the Fitch model , wherein an equant block rotates between a subduction zone and a transcurrent fault pair formed in response to oblique subduction. A preferred but very tentative model proposed in this thesis to explain rotation in both the Goble and Coast Range blocks is a revised model I. It assumes a break in the Coast Range block near the Columbia River. The Coast Range would then rotate around a pivot point in the Tillamook highland area. The Goble Volcanics, which would lie northeast of the rotating block, might then rotate independently in a ball-bearing fashion between right-lateral strike-slip faults trending northwest-southeast. These faults, including the Brothers, Eugene - Denio, Vale and Portland fault may have formed in response to basin and range extension. In particular, the Portland fault which may extend through the Coast Range block, and possible faults to the north parallel to the Olympic - Wallowa lineament may have been responsible for the rotation of the Goble Volcanics

    Determination of the Limits and Accuracy of Potassium Ferricyanide as an Outside Indicator in the Determination of Iron and a Comparison of this Outside Indicator with Diphenylamine as an Inside Indicator

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    In the volumetric course as offered by the Department of Chemistry of South Dakota State College for the spring term of 1931, we experienced difficulties in the methods which we were using for the determination of iron. The general method used was that of Penny\u27s, using an outside indicator of potassium ferricyanide, and titrating with potassium dichromate

    The ''motion silencing'' illusion results from global motion and crowding

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    Suchow and Alvarez (2011) recently devised a striking illusion, where objects changing in color, luminance, size, or shape appear to stop changing when they move. They refer to the illusion as ''motion silencing of awareness to visual change.'' Here we present evidence that the illusion results from two perceptual processes: global motion and crowding. We adapted Suchow and Alvarez's stimulus to three concentric rings of dots, a central ring of ''target dots'' flanked on either side by similarly moving flanker dots. Subjects had to identify in which of two presentations the target dots were continuously changing (sinusoidally) in size, as distinct from the other interval in which size was constant. The results show: (a) Motion silencing depends on target speed, with a threshold around 0.2 rotations per second (corresponding to about 108/s linear motion). (b) Silencing depends on both target-flanker spacing and eccentricity, with critical spacing about half eccentricity, consistent with Bouma's law. (c) The critical spacing was independent of stimulus size, again consistent with Bouma's law. (d) Critical spacing depended strongly on contrast polarity. All results imply that the ''motion silencing'' illusion may result from crowding

    A visual sense of number

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    The ventriloquist effect results from near-optimal bimodal integration

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    Results for the various unimodal location discriminations for naive observer L.M. are shown in Figure 1A. The curves plot the proportion of trials in which the second stimulus was seen to the left of the first, as a function of actual physical displacement. Following standard practice, the data were fitted with cumulative Gaussian functions free to vary in position and width: the position of the median (50 % leftward) is termed the point of subjective equality (PSE), and the width � 3Department of Psychology represents the estimate of localization accuracy (pre-University of Florence sumed to depend on internal noise). For all unimodal 50125 Florence conditions, the PSE was near 0�, but � varied consider-Italy ably. For visual stimuli, � was smallest (approximatel

    Meaningful auditory information enhances perception of visual biological motion

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    Robust perception requires efficient integration of information from our various senses. Much recent electrophysiology points to neural areas responsive to multisensory stimulation, particularly audiovisual stimulation. However, psychophysical evidence for functional integration of audiovisual motion has been ambiguous. In this study we measure perception of an audiovisual form of biological motion, tap dancing. The results show that the audio tap information interacts with visual motion information, but only when in synchrony, demonstrating a functional combination of audiovisual information in a natural task. The advantage of multimodal combination was better than the optimal maximum likelihood prediction

    Russian approaches to energy security and climate change: Russian gas exports to the EU

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    The proposition that EU climate policy represents a threat to Russia’s gas exports to the EU, and therefore to Russia’s energy security, is critically examined. It is concluded that whilst the greater significance of climate-change action for Russian energy security currently lies not in Russia’s own emissions reduction commitments but in those of the EU, an even greater threat to Russia’s energy security is posed by the development of the EU internal gas market and challenges to Russia’s participation in that market. However, the coming decades could see Russia’s energy security increasingly influenced by climate-change action policies undertaken by current importers of Russian gas such as the EU, and potential importers such as China and India. The challenge for Russia will be to adapt to developments in energy security and climate-change action at the European and global levels

    Extracellular matrix components isolated from diabetic mice alter cardiac fibroblast function through the AGE/RAGE signaling cascade

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    © 2020 The Authors Individuals suffering from diabetes have an increased risk of developing cardiovascular complications such as heart failure. Heart failure can be a result of the stiffening of the left ventricle, which occurs when cardiac fibroblasts become “active” and begin to remodel the extracellular matrix (ECM). Fibroblast “activation” can be triggered by the AGE/RAGE signaling cascade. Advanced Glycation End products (AGEs) are produced and accumulate in the ECM over time in a healthy individual, but under hyperglycemic conditions, this process is accelerated. In this study, we investigated how the presence of AGEs in either non-diabetic or diabetic ECM affected fibroblast-mediated matrix remodeling. In order to address this question, diabetic and non-diabetic fibroblasts were embedded in 3D matrices composed of collagen isolated from either non-diabetic or diabetic mice. Fibroblast function was assessed using gel contraction, migration, and protein expression. Non-diabetic fibroblasts displayed similar gel contraction to diabetic cells when embedded in diabetic collagen. Thus, suggesting the diabetic ECM can alter fibroblast function from an “inactive” to “active” state. Addition of AGEs increase the AGE/RAGE cascade leading to increased gel contraction, whereas inhibiting the cascade resulted in little or no gel contraction. These results indicated 1) the ECM from diabetic and non-diabetic mice differ from one another, 2) diabetic ECM can impact fibroblast function and shift them toward an “active” state, and 3) that fibroblasts can modify the ECM through activation of the AGE/RAGE signaling cascade. These results suggested the importance of understanding the impact diabetes has on the ECM and fibroblast function
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