Areas Of High Flow Research Articles

Theory of Mind and Schizophrenia: A Positron Emission Tomography Study of Medication-Free Patients

"Theory of mind" (TOM) refers to the ability to attribute mental states (ie, beliefs and goals) to one's self and others and to recognize that behaviors are guided by these mental states. This capacity, critical for social competence, is impaired in schizophrenia. We undertook a study of TOM in a group of patients with schizophrenia and healthy controls. We used positron emission tomography to identify the neural circuits recruited during a verbal task that required participants to attribute mental states to a character in a story of their creation. The comparison task consisted of reading aloud a neutral story, controlling for the speech component of the task. Patients and controls generated the same percentage of TOM utterances. However, the two groups had markedly different patterns of brain activation. Compared with controls, patients had a lower blood flow in multiple regions in the left hemisphere including the frontal and visual association cortices, posterior hippocampus, and insula. The flow was also lower in contralateral areas in the lateral cerebellum and vermis, thalamus, and posterior insula. On the other hand, the flow was higher in the patients predominantly in the right hemisphere, including multiple frontal and parietal regions, insula, visual association cortex, and pulvinar. The areas of lower flow are consistent with previous studies indicating impairment in recruiting cortical-cerebellar circuitry in schizophrenia. The areas of higher flow may reflect a need to draw on the right hemisphere to compensate for deficits in left hemisphere networks that include frontal cortex, anterior cingulate, cerebellum, and thalamus.

Annular Fast Reactor Cores with Low Sodium Void Worth for TRU Burning

Annular sodium-cooled fast reactor cores [600 MW(electric)] with low sodium void worth are developed for burning transuranic nuclides discharged from light water reactors. The several core design variants are developed by changing the core configuration, the core height, the fuel assembly design and type of nonfuel assemblies in the core, and their core performance parameters including safety-related reactivity coefficients are analyzed and inter-compared. The study focuses on the core neutronic parameters without going into the detailed safety and material compatibility studies. The study shows that the several cores of the annular type can be designed to have low sodium void worth, high transmutation capability, and all the negative temperature reactivity coefficients except for the positive one related to coolant expansion that can be compensated for by the reactivity coefficients by the fuel axial expansion and the fuel Doppler effects under the off-normal events, which increase temperatures. Of the cores considered, the use of a larger central control region and fuel assemblies with high coolant flow area in the core boundaries is found to be the most effective and simple way to achieve low sodium void worth and high transmutation capability.

Spatial heterogeneity of myocardial perfusion predicts local potassium channel expression and action potential duration

In the heart, there is not only a transmural gradient of left ventricular perfusion and action potential duration (APD), but also spatial heterogeneity within each myocardial layer, where local blood flow and energy turnover vary more than three-fold between individual regions. We analysed at high spatial resolution whether a corresponding heterogeneity also extends to ion channel gene expression and APD. In the open-chest beagle dog, left ventricular 300 microL samples of very low or high flow were identified by radioactive microspheres and expression levels determined by quantitative PCR. The distribution of epicardial APD was assessed by mapping local activation repolarization intervals (ARIs) and QT interval (QT). ERG, the potassium channel mediating IKr, and KChIP2, the interacting protein modulating Ito, were increased in Low flow (3.3- and 2.5-fold, P < 0.001 and <0.05, respectively; n = 6 hearts, 30-31 samples each) as compared with High flow areas. This suggested enhanced repolarizing currents in Low flow areas, and in consequence, mathematical model analysis predicted a shorter local APD upon enhanced ERG and IKr. Epicardial mapping revealed a patchy, temporally stable APD pattern (n = 11), a small apico-basal gradient and an APD prolongation induced by the ERG blocker dofetilide predominantly in areas of short basal ARI or QT, respectively (n = 9). In addition, in Short QT areas, ERG expression was three-fold increased (P < 0.05, n = 4). The spatial pattern of perfusion is matched by the novel patterns of K+ channel expression and APD. Whenever this newly recognized intramural dispersion of APD increases, it may contribute to arrhythmogenesis.

A methodology to construct training images for vein-type deposits

Fracture models of vein formation can produce realistic training images (TIs) for use in multiple-point geostatistics. Vein formation is modeled by applying flow simulation to a fracture model to mimic the flow of an ore-bearing fluid through fractured rock. TIs are generated by assuming that veins form in areas of high flow where there would be preferential deposition of the mineral of interest. We propose a methodology to simulate mineralized veins by constructing a fracture model within the deposit, modeling the permeability and simulating the flow of ore-bearing fluids. The veins are defined by considering the areas of high flow. The methodology is implemented with a fracture model of the Whiteshell area in Manitoba. To assess the reasonableness of the TIs, comparisons are made to geological models of gold deposits in Quebec and Nova Scotia that display similar geometric characteristics such as braiding, thickening and thinning. A FORTRAN program TIGEN, based on GSLIB program formats is included and can be used to generate TIs from fracture models.

Flow‐dependent regulation of angiopoietin‐2

Endothelial cells are constantly exposed to high or low shear stress in arteries and veins by the flowing blood. Angiopoietin-2 (Ang-2) is acting as a critical regulator of vessel maturation and endothelial cell quiescence. In this study, flow-dependent regulation of Ang-2 was analyzed in vitro and in vivo. Ang-2 mRNA, protein expression and release was upregulated by 24 h of low (1 dyne/cm(2)), but downregulated by high flow (30 dyne/cm(2)) in human endothelial cells. Increased endothelial NO synthase expression and NO formation was not affecting regulation of Ang-2 by low or high flow. Low and high flow increased VEGF-A expression. Inhibition of VEGFR-2 prevented upregulation of Ang-2 by low flow, but not downregulation of Ang-2 by high flow. Furthermore, upregulation of Ang-2 by VEGF was reduced by application of high flow. Forkhead box O (FOXO) transcription factor FOXO1 has been shown to regulate Ang-2 expression in endothelial cells. FOXO1 binding activity was reduced by high flow. Nuclear localization of transcription factor FOXO1 was not changed by low flow, but reduced by high flow. In vivo, Ang-2 was higher expressed in veins compared to arteries. Arterial ligation augmented Ang-2 expression in distal arterial low flow areas. Our results support a VEGF-dependent induction of Ang-2 in low flow areas, and FOXO1-dependent downregulation of Ang-2 in high flow areas. These data suggest a new mechanism of flow-dependent regulation of vessel stability and differentiation.

Abstract 442: Flow-Dependent Regulation of Angiopoietin-2

Background: Endothelial cells are constantly exposed to high or low shear stress in arteries and veins by the flowing blood. Angiopoietin-2 (Ang-2) is acting as a critical regulator of vessel maturation and endothelial cell quiescence. In this study, we determined the effect of low and high laminar shear stress on the expression and release of angiopoietin (Ang-)2 in human endothelial cells, studied the role of nitric oxide and protein kinases in this context, determined the impact of VEGF on Ang-2, studied the expression, activity and translocation of the forkhead box O transcription factor FOXO1 by low and high shear stress, and analyzed the vessel- and flow-dependent expression of Ang-2 in vivo . Methods and Results: Primary cultures of human umbilical vein endothelial cells (HUVEC) were subjected to laminar shear stress at different physiological levels of laminar shear stress of 1, 5, 10, 15, and 30 dyne/cm 2 in a cone-and-plate viscometer. Ang-2 mRNA, protein expression and release was upregulated by 24 h of low (1 dyne/cm 2 ), but downregulated by high flow (30 dyne/cm 2 ) in human endothelial cells. Increased endothelial NO synthase expression and NO formation was not affecting regulation of Ang-2 by low or high flow. Tie2 protein expression, but not Tie2 phosphorylation was induced by high flow. Furthermore, low and high flow increased VEGF-A expression. Inhibition of VEGFR-2 prevented upregulation of Ang-2 by low flow, but not downregulation of Ang-2 by high flow. Upregulation of Ang-2 by VEGF was reduced by application of high flow. Forkhead box O (FOXO) transcription factor FOXO1 has been shown to regulate Ang-2 expression in endothelial cells. FOXO1 binding activity was reduced by high flow. Nuclear localization of transcription factor FOXO1 was not changed by low flow, but reduced by high flow. In vivo , Ang-2 was higher expressed in veins compared to arteries. Arterial ligation augmented Ang-2 expression in distal arterial low flow areas. Conclusion: Our results support a VEGF-dependent induction of Ang-2 in low flow areas, and FOXO1-dependent downregulation of Ang-2 in high flow areas. These data suggest a new mechanism of flow-dependent regulation of vessel stability and differentiation.

Continental magmatism, volatile recycling, and a heterogeneous mantle caused by lithospheric gravitational instabilities

Removal of the lower lithosphere (mantle lithosphere with or without portions of the crust) through ductile gravitational instabilities can produce magma under continents. Using numerical experiments approximating the rheology of continental crust and lithosphere and underlying asthenosphere and using phase equilibria from the literature, I investigate the topographic and magmatic results of lithospheric gravitational instabilities, along with the fate of the sinking material. Lithospheric removal, commonly referred to as delamination regardless of the mechanism, may allow asthenospheric material to rise and to melt adiabatically, and this asthenosphere can conductively heat portions of the lithosphere previously at lower temperatures. The size and rheology of the sinking material greatly influence the resulting surface topography as well as whether or not melting occurs. The sinking material may devolatilize as it reaches higher temperatures and pressures, just as a subducting slab does, triggering further melting. Gravitational instabilities are possible causes of nonmagmatic basins, continental magmatism of varying volume and composition in the absence of subduction, areas of high heat flow and uplift, and creation of an upper mantle heterogeneous in major and trace elements and volatiles. Magmatism can be simultaneous with topographic subsidence and possibly with subsequent uplift. In those cases that produce magma, melting can occur over a depth range from ∼30 to 200 km, though anomalously hot mantle is required to reach the volume of flood basalts.

Comparison and validation of Airborne Thematic Mapper thermal imagery using ground-based temperature data for Grímsvötn caldera, Vatnajökull, Iceland

Abstract Grímsvötn, Iceland's most active volcano, is also one of the most powerful geothermal areas in Iceland. This subglacial volcano is located in the centre of Vatnajökull, Europe's largest temperate ice cap, and it erupted most recently in 1998 and 2004. As part of continuing research on heat flux, morphological changes and volcanic processes at Grímsvötn, thermal anomalies were mapped using remote sensing Natural Environmental Research Council (NERC) Airborne Research and Survey Facility (ARSF) data. The 2001 Airborne Thematic Mapper (ATM) thermal images of the Grímsvötn subglacial caldera reveal distinct areas of geothermal activity and provide an overview of the thermal anomalies associated with water and rock exposures. A crater lake located on the 1998 eruption site is shown to have a surface temperature of 30–35 °C. There is a good correlation between the ARSF data and ground-based temperature measurements. The thermal images also revealed previously undetected areas of high heat flow. Factors that complicate the interpretation and comparison of different datasets from an ice-covered area include recent cornice collapses and variations in atmospheric humidity. To reduce uncertainty in future missions, temperature measurements should be made at points whose position is well constrained using differential global positioning system. In addition, humidity and temperature measurements should be made at the time of flight.

The Cornubian Batholith: an Example of Magmatic Fractionation on a Crustal Scale

Abstract. The Cornubian Batholith comprises six major and several smaller bodies of S-type granite in southwestern England. These late-Variscan granites comprise two-mica granites, and much less abundant Li-mica granites that are restricted to one of the major bodies (St Austell) and smaller bodies. Some of these intrusive rocks are associated with major Sn mineralization. This paper is concerned with the geochemistry of the two-mica granites, which are felsic, strongly peraluminous, and have a high total alkali content and low Na:K. Rocks with very similar compositions to these granites occur elsewhere, including the Variscan granites of continental Europe, and in southeastern Australia. In detail all of the major plutons of this batholith have distinctive compositions, except for Bodmin Moor and Carnmenellis which cannot be discriminated from each other compositionally. A comparison with experimental data shows that the granites attained their major element composition under conditions of crystal-liquid equilibrium, with the final melt being saturated in H2O, at temperatures close to 770d̀C and pressures about 50 MPa. That temperature estimate is in good agreement with values obtained from zircon saturation thermometry. The specific minimum-temperature composition excludes the possibility of widespread transfer of elements during hydrothermal alteration. Minor elements that are relatively very abundant are Li, B, Cs and U, while F, Ga, Ge, Rb, Sn, Ta, W and Tl are quite abundant and P is high for felsic rocks. Sr, Ba, and the trace transition metals Sc to Zn, are low, but not as low as they commonly are in very felsic granites. These trace element abundances, and the EL2O-saturation, resulted from the fractional crystallization of a melt derived by the partial melting of feldspathic greywackes in the crust. The Cornubian granites have compositions very similar to the more felsic rocks of the Koetong Suite of southeastern Australia, where a full range of granites formed at the various stages of magmatic fractionation postulated for the Cornubian granites, can be observed. The operation of fractional crystallization in the Cornubian granites is confirmed by the high P abundances in the feldspars, with P contents of the plagioclase crystals correlating with Ab-con-tent Most of the granites represent solidified melt compositions but within the Dartmoor pluton there is a significant component of granites that are cumulative, shown by their higher Ca contents. The Cornubian plutons define areas of high heat flow, of a magnitude which requires that fractionated magmas were transported laterally from their sources and concentrated in the exposed plutons. The generation of these granite plutons therefore involved magmatic fractionation during the stages of partial melting, removal of unmelted material from that melt, and fractional crystallization. During the later stages of those processes, movement of those magmas occurred on a crustal scale.

99mTc-ECD brain perfusion SPECT in hyperalgesic fibromyalgia

Neuro-imaging studies with (99m)Tc-HMPAO SPECT in fibromyalgia (FM) patients have reported only limited subcortical hypoperfusion. (99m)Tc-ECD SPECT is known to provide better evaluation of areas of high cerebral blood flow and regional metabolic rate. We evaluated a homogeneous group of hyperalgesic patients with FM using (99m)Tc-ECD SPECT. The aim of this study was to investigate brain processing associated with spontaneous pain in FM patients. Eighteen hyperalgesic FM women (mean age 49 years, range 25-63 years; American College of Rheumatology criteria) and ten healthy women matched for age were enrolled in the study. A voxel-by-voxel group analysis was performed using SPM2 (p<0.05, corrected for multiple comparisons). Visual Analogue Scale score for pain was 82+/-4 at the time of the SPECT study. Compared with control subjects, we observed individual brain SPECT abnormalities in FM patients, confirmed by SPM2 analysis, with hyperperfusion of the somatosensory cortex and hypoperfusion of the frontal, cingulate, medial temporal and cerebellar cortices. In the present study, performed without noxious stimuli in hyperalgesic FM patients, we found significant hyperperfusion in regions of the brain known to be involved in the sensory dimension of pain processing and significant hypoperfusion in areas assumed to be associated with the affective-attentional dimension. As current pharmacological and non-pharmacological therapies act differently on the two components of pain, we hypothesise that SPECT could be a valuable and readily available tool to guide individual therapeutic strategy and provide objective follow-up of pain processing recovery under treatment.

Tracking quasi‐stationary flow of weak fluorescent signals by adaptive multi‐frame correlation

We have developed a novel cross-correlation technique to probe quasi-stationary flow of fluorescent signals in live cells at a spatial resolution that is close to single particle tracking. By correlating image blocks between pairs of consecutive frames and integrating their correlation scores over multiple frame pairs, uncertainty in identifying a globally significant maximum in the correlation score function has been greatly reduced as compared with conventional correlation-based tracking using the signal of only two consecutive frames. This approach proves robust and very effective in analysing images with a weak, noise-perturbed signal contrast where texture characteristics cannot be matched between only a pair of frames. It can also be applied to images that lack prominent features that could be utilized for particle tracking or feature-based template matching. Furthermore, owing to the integration of correlation scores over multiple frames, the method can handle signals with substantial frame-to-frame intensity variation where conventional correlation-based tracking fails. We tested the performance of the method by tracking polymer flow in actin and microtubule cytoskeleton structures labelled at various fluorophore densities providing imagery with a broad range of signal modulation and noise. In applications to fluorescent speckle microscopy (FSM), where the fluorophore density is sufficiently low to reveal patterns of discrete fluorescent marks referred to as speckles, we combined the multi-frame correlation approach proposed above with particle tracking. This hybrid approach allowed us to follow single speckles robustly in areas of high speckle density and fast flow, where previously published FSM analysis methods were unsuccessful. Thus, we can now probe cytoskeleton polymer dynamics in living cells at an entirely new level of complexity and with unprecedented detail.

Water flow influences oxygen transport and photosynthetic efficiency in corals

Recent studies indicate that the incidence and persistence of damage from coral reef bleaching are often highest in areas of restricted water motion, and that resistance to and recovery from bleaching is increased by enhanced water motion. We examined the hypothesis that water motion increases the efflux of oxygen from coral tissue thereby reducing oxidative stress on the photosynthetic apparatus of endosymbiotic zooxanthellae. We experimentally exposed colonies of Montastrea annularis and Agaricia agaricites to manipulations of water flow, light intensity, and oxygen concentration in the field using a novel mini-flume. We measured photosynthetic efficiency using a pulse amplitude modulated fluorometer to test the short-term response of corals to our manipulations. Under normal oxygen concentrations, A. agaricites showed a significant 8% increase in photosynthetic efficiency from 0.238 (± 0.032) in still water to 0.256 (± 0.037) in 15 cm s−1 flow, while M. annularis exhibited no detectable change. Under high-ambient oxygen concentrations, the observed effect of flow on A. agaricites was reversed: photosynthetic efficiencies showed a significant 11% decrease from 0.236 (± 0.056) in still water to 0.211 (± 0.048) in 15 cm s−1 flow. These results support the hypothesis that water motion helps to remove oxygen from coral tissues during periods of maximal photosynthesis. Flow mitigation of oxidative stress may at least partially explain the increased incidence and severity of coral bleaching in low flow areas and observations of enhanced recovery in high-flow areas.

Migration pathways in the Central North Slope foreland basin, Alaska USA: solute and thermal constraints on fluid flow simulations

AbstractThe North Slope foreland basin, Alaska, USA is an east–west asymmetrical trough‐shaped basin adjacent to the Brooks Range fold‐thrust mountain belt. Lower Cretaceous age rocks make up much of the sediment fill, including flysch‐like marine turbidites and shales of the Torok and Fortress Mountain formations and marine and sandstones, shales and conglomerates of the overlying Nanushuk group. Lower Cretaceous age rocks were deposited on top of a Palaeozoic and Mesozoic age passive margin sequence. We have conducted numerical simulations of fluid flow driven by topographic recharge in the Central North Slope foreland basin. These simulations are constrained by salinity estimates from well logs, location of oil and gas fields, vitrinite reflectance and heat flow measurements. Our model results indicate that there are two south to north pathways for fluid migration. The primary pathway for fluid movement is downward through the Fortress Mountain formation, then upwards along the interface between the Fortress Mountain and Torok Formation and finally northward through the permeable Nanushuk group. A smaller mass of groundwater moves along sands below the Torok formation and into offshore sediments north of Alaska. Very little meteoric water enters the underlying Palaeozoic rocks in our simulations, which could explain the presence of deep saline pore waters. Our results also show that permafrost is a primary control on the pathway and rate of fluid flow by controlling the distribution of surface recharge and discharge. For example, areas of high heat flow and low saline waters along the arctic coast may represent upward groundwater discharge because of the absence of permafrost. As surface temperatures were warmer in the Miocene, the absence of permafrost would produce a more local fluid circulation pattern and less transfer of heat energy from south to north.

Acoustic radiation force enhances targeted delivery of ultrasound contrast microbubbles: in vitro verification

Recent research has shown that targeted ultrasound contrast microbubbles achieve specific adhesion to regions of intravascular pathology, but not in areas of high flow. It has been suggested that acoustic radiation can be used to force free-stream microbubbles toward the target, but this has not been verified for actual targeted contrast agents. We present evidence that acoustic radiation indeed increases the specific targeted accumulation of microbubbles. Lipid microbubbles bearing an antibody as a targeting ligand were infused through a microcapillary flow chamber coated with P-selectin as the target protein. A 2.0 MHz ultrasonic pulse was applied perpendicular to the flow direction. Microbubble accumulation was observed on the flow chamber surface opposite the transducer. An acoustic pressure of 122 kPa enhanced microbubble adhesion up to 60-fold in a microbubble concentration range of 0.25 x 10(6) to 75 x 106) ml(-1). Acoustic pressure mediated the greatest adhesion enhancement at concentrations within the clinical dosing range. Acoustic pressure enhanced targeting nearly 80-fold at a wall shear rate of 1244 s(-1), suggesting that this mechanism is appropriate for achieving targeted microbubble delivery in high-flow vessels. Microbubble adhesion increased with the square of acoustic pressure between 25 and 122 kPa, and decreased substantially at higher pressures.

Physiological aspects of high-altitude pulmonary edema

High-altitude pulmonary edema (HAPE) develops in rapidly ascending nonacclimatized healthy individuals at altitudes above 3,000 m. An excessive rise in pulmonary artery pressure (PAP) preceding edema formation is the crucial pathophysiological factor because drugs that lower PAP prevent HAPE. Measurements of nitric oxide (NO) in exhaled air, of nitrites and nitrates in bronchoalveolar lavage (BAL) fluid, and forearm NO-dependent endothelial function all point to a reduced NO availability in hypoxia as a major cause of the excessive hypoxic PAP rise in HAPE-susceptible individuals. Studies using right heart catheterization or BAL in incipient HAPE have demonstrated that edema is caused by an increased microvascular hydrostatic pressure in the presence of normal left atrial pressure, resulting in leakage of large-molecular-weight proteins and erythrocytes across the alveolarcapillary barrier in the absence of any evidence of inflammation. These studies confirm in humans that high capillary pressure induces a high-permeability-type lung edema in the absence of inflammation, a concept first introduced under the term "stress failure." Recent studies using microspheres in swine and magnetic resonance imaging in humans strongly support the concept and primacy of nonuniform hypoxic arteriolar vasoconstriction to explain how hypoxic pulmonary vasoconstriction occurring predominantly at the arteriolar level can cause leakage. This compelling but as yet unproven mechanism predicts that edema occurs in areas of high blood flow due to lesser vasoconstriction. The combination of high flow at higher pressure results in pressures, which exceed the structural and dynamic capacity of the alveolar capillary barrier to maintain normal alveolar fluid balance.

A Study of Lg Coda Attenuation beneath North China: Seismic Imaging of Lg Coda Q0

AbstractBy using 560 Lg coda Q0 values measured on propagating paths, the Q0 image in the crust beneath the North China region is restructured with a stochastic modeling and the singular value decomposition. The result indicates that there is remarkable lateral heterogeneity on Lg coda Q0 distribution in the crust beneath the North China region, similar to the velocity image, and closely related with the known surface geological features: the high Q0 areas exist beneath the Taihang and Yanshan mountains and the Luxi uplift area, and low Q0 values appear below the Jizhong, Huanghua and Jiyang depressions and the plain areas. There is a clear division between the high and low Q0 values. Compared with the heat flow values in North China, most the low Q0 value areas are located in the high heat flow areas. It is possibly related with hot material activity in the crust below these areas. Although there is a clear difference between the high and low Q0 value areas in the crust of North China, as a whole North China belongs to low Q0 value abnormal regions. It means that the region is a high seismic wave attenuation area. Probably it is resulted from the interaction between the Eurasia and Pacific plates, which causes crust thinning and hot material upwelling.

The central role of angiotensin I-converting enzyme in vertebrate pathophysiology.

Genomic epidemiologic data, increasingly supported by clinical outcomes results, strongly suggest that overactivity of angiotensin I-converting enzyme (ACE) may underlie most age-related diseases. Angiotensin II, the main product of ACE, is a pleiotropic hormone, capable of serving as a neurotransmitter, growth factor, angiogenesis factor, vasoconstrictor, pro-thrombotic agent, and cytokine. So it is perhaps not surprising that the ACE D/D genotype is associated with several major psychiatric diseases, most cancers except prostate cancer (where the D/D genotype is actually protective), most cardiovascular diseases, most autoimmune diseases, and even infectious diseases like tuberculosis and HIV. In a preliminary study, angiotensin II blockade appeared to hasten recovery from West Nile virus encephalitis; it may be equally useful in SARS. The ACE gene underwent duplication at the origin of Chordata, just before the "Cambrian Explosion" in the number of species. The ancestral, unduplicated form of ACE is still expressed during the terminal differentiation of human spermatocytes, suggesting a critical role in reproduction. The crystal structure of testicular ACE (tACE) was recently published. Computer modeling suggests that tACE may be activated by both mechanical forces and reducing agents. The duplicated form of ACE (somatic ACE, sACE) is expressed in areas of high fluid flow. sACE may auto-dimerize via a novel protein motif, the "disulfide zipper." The sACE dimer is predicted to have higher catalytic efficiency and redox resistance than tACE.

Erosion and sedimentation as processes controlling the BSR-derived heat flow on the Eastern Nankai margin

In 2000, a 3D MCS survey was carried out on the Eastern Nankai Trough. A strong and widespread bottom-simulating reflector (BSR) was observed and mapped after a preserved amplitude 3D prestack migration of the seismic data. We use this BSR to calculate a heat flow map over the 3D survey area. This map presents some high and low heat flow areas, that cannot be correlated to known active wedge faults and previously observed fluid venting sites. Since the heat flow anomalies are not correlated to known major faults or fluid venting sites, large fluid circulation is not likely to explain the varying BSR-derived heat flow distribution. In order to explain this heat flow distribution quantitatively, we calculate the rates of erosion and sedimentation that are necessary to create these anomalies. These rates are in good agreement with observations on seismic profiles, and are locally consistent with a sedimentation rate calculated from slope basin depth, and reflect the distribution of erosion, landsliding and deposition on the margin slope. We therefore propose that the observed BSR-derived heat flow anomalies are mainly due to active erosion and sedimentation, and that heat flow distribution on the margin section of the 3D survey is controlled by surface processes. Fluid migration could occur where a BSR is absent, but is probably episodic or limited where a BSR is present, and does not affect the BSR-derived heat flow in this part of the margin. These surface processes are the consequence of the tectonic and seismic activity of the wedge and are influenced by the subduction of a wide oceanic ridge below the Eastern Nankai margin.

Myocardial ferritin content is closely related to the degree of ischaemia.

Ferritin acts as an iron scavenger and thereby may reduce iron catalysed oxygen radical production during reperfusion injury. We tested the hypothesis that the myocardial ferritin concentration is enhanced during ischaemia in proportion to the blood flow reduction. In 10 anaesthetized, open chest Beagle dogs (six controls and four with 60 min coronary occlusion) regional myocardial blood flow (RMBF) was measured with the tracer microsphere technique and ferritin was determined in samples with an average mass of 125 mg (124-256 samples per heart). Under physiological conditions heart rate was 88 +/- 12 bpm, mean aortic pressure 98 +/- 8 mmHg, and RMBF 0.99 +/- 0.33 mL min-1 g-1. Data did not differ between experimental groups, P > 0.05. In the control group regional myocardial ferritin concentration averaged 11.76 +/- 3.54 ng mg-1 protein and exhibited a significant blood flow independent heterogeneity (CV(biol) = 0.27). However, between low and high flow areas (relative flow <0.5 and >1.5 times the average RMBF, respectively) no significant difference in ferritin was found, P > 0.05. In four experiments, in which regional blood flow was reduced by 40% to 0.60 +/- 0.23 mL min-1 g-1, regional ferritin content was significantly higher as compared with the control group 27.95 +/- 6.16 vs. 11.76 +/- 3.54 ng mg-1 protein, respectively. An inverse relationship was observed between ferritin and RMBF, r = -0.61, P < 0.001. Thus, a reduction of RMBF of >80% was associated with a 2.75-fold increase of the average ferritin content. Between subepicardium and subendocardium no significant difference in ferritin content was observed, neither in the control group nor in the group with induced ischaemia. Regions with control low and high flow responded similarly to the coronary constriction with regard to the local ferritin concentration: 27.88 +/- 15.22 vs. 30.10 +/- 14.91 ng mg-1, P > 0.05, respectively. A data analysis using Baye's theorem indicated that sensitivities were 0.28 and 0.94 for average flow reductions of 5 and 93%. In additional in vitro measurements (ischaemic incubation at 37 degrees C) myocardial ferritin content increased almost linearly within the first 60 min of incubation and thereafter remained unchanged. (1). Local physiological ferritin content in myocardium is heterogeneous and unrelated to control myocardial blood flow. (2). Ischaemia results in an enhanced ferritin content in relation to the degree of ischaemia. (3). The increase of myocardial ferritin requires a severe degree of ischaemia.

横浜・野島海岸における積算平均流速の簡易計測と二枚貝類の分布

To measure spatial distribution of water flow in tidal flat, a simple method using gypsum body was developed. Gypsum body dissolution rate in steady water flow was proportional to the velocity. The investigation about water flow with gypsum body and bivalves distribution was carried out in Nojima beach, Yokohama. Relationship was confirmed between velocity with flowmetry and calculated velocity with gypsum body. As a result, the method is applicable to measurement of cumulative-averaged velocity. The bivalves distribution in Nojima beach showed lower distribution at the north off shore, where is corresponded to high water flow area. It was implied that high water flow is one of restricted habitat factors of the bivalves in Nojima beach.