Water Increases (water + increase)

Distribution by Scientific Domains

Selected Abstracts

Does Off-Pump Revascularization Reduce Coronary Endothelial Dysfunction?

Harold L. Lazar M.D.
This experimental study sought to determine whether OPCAB reduces endothelial dysfunction, compared to standard cardiopulmonary bypass (CPB) with and without the anticomplement agent soluble complement receptor-1 (sCR1). Methods: In 10 pigs, OPCAB was simulated by snaring the left anterior descending (LAD) artery for 15 minutes followed by 3 hours of reperfusion. On-pump revascularization was simulated in 20 pigs by 15 minutes of LAD occlusion on CPB with cold blood cardioplegic arrest followed by 3 hours of reperfusion. Ten of these animals received sCR1 (10 mg/kg) prior to CPB. Inflammatory response was monitored by percent (%) lung water increase, wall motion scores (WMS) with transthoracic echocardiography where 4 = normal to ,1 = dyskinesia, and endothelial function in the distal LAD with bradykinin-induced coronary artery relaxation using organ chamber methodology. Results: OPCAB had no effect on lung edema (% increase = 1.7 ± 1.4 OPCAB vs. 3.4 ± 0.5 CPB vs. 2.3 ± 0.9 CPB + sCR1) and failed to prevent wall motion changes (WMS = 2.65 ± 0.08 OPCAB vs. 2.70 ± 0.04 CPB vs. 3.10 ± 0.07* CPB + sCR1, *p < 0.01) and coronary endothelial dysfunction (% relaxation = 41 ± 9 OPCAB vs. 40 ± 9 CPB vs. 78 ± 8** CPB + sCR1, **p < 0.001), which was best preserved with sCR1. Conclusions: This study suggests that agents which directly inhibit complement activation such as sCR1 are more important in preventing endothelial dysfunction during coronary revascularization than merely avoiding CPB. [source]

Fish habitat requirements as the basis for rehabilitation of eutrophic lakes by oxygenation

R. Müller
Abstract Eutrophic lakes often suffer from hypolimnetic oxygen depletion during summer and autumn, and the accumulation of reduced substances in the hypolimnion. The space fish can occupy is therefore reduced, and the potential for fish kills caused by toxic algae and the upwelling of anoxic water increases. Fish, such as coregonids, require at least 4 mg O2 L,1 to survive in the long-term. This critical level has been postulated as one of the major goals for the rehabilitation of several eutrophic Swiss lakes. It was predicted that this oxygen criterion would reduce phosphorus release from the sediment and increase phosphorus retention, and re-establish natural reproduction of coregonids. Rehabilitation measures applied to three eutrophic Swiss lakes were hypolimnetic oxygenation during summer stratification, and artificial mixing using compressed air to enhance circulation in winter. These lake-internal measures carried out for more than 15 years showed the 4 mg O2 L,1 criterion can be achieved most of the time. The measures have led to an expansion of habitat for oxygen-dependent organisms to greater depths. However, other goals were not attained, such as increasing phosphorus retention by the sediment. In addition, natural reproduction of coregonids could not be re-established. Excessive oxygen consumption by the sediment, arising from the decomposition of deposited organic matter produced during summer, caused death by suffocation of coregonid eggs developing on the sediment. Thus rehabilitation of eutrophic lakes by oxygenating the hypolimnion and artificial mixing will not be successful, unless it is accompanied by lowering the nutrient loading and thus primary production and oxygen consumption by the sediment. Nevertheless, positive effects of lake aeration were the expansion of living space for fish and benthic invertebrates, and the prevention of fish kills by upwelling anoxic hypolimnetic water. [source]

Distribution of the Ordovician Fluid in the Tahe Oilfield and Dynamic Response of Cave System S48 to Exploitation

LOU Zhanghua
Abstract: The Tahe Oilfield is a complex petroleum reservoir of Ordovician carbonate formation and made up of spatially overlapping fracture-cavity units. The oilfield is controlled by a cave system resulting from structure-karst cyclic sedimentation. Due to significant heterogeneity of the reservoir, the distribution of oil and water is complicated. Horizontally, a fresh water zone due to meteoric water can be found in the north part of the Akekule uplift. A marginal freshening zone caused by water released from mudstone compaction is found at the bottom of the southern slope. Located in a cross-formational flow discharge zone caused by centripetal and the centrifugal flows, the main part of the Tahe Oilfield, featuring high salinity and concentrations of Cl, and K++Na+, is favorable for accumulation of hydrocarbon. Three types of formation water in the Tahe Ordovician reservoir are identified: (1) residual water at the bottom of the cave after oil and gas displacement, (2) residual water in fractures/pores around the cave after oil and gas displacement, and (3) interlayer water below reservoirs. The cave system is the main reservoir space, which consists of the main cave, branch caves and depressions between caves. Taking Cave System S48 in the Ordovician reservoir as an example, the paper analyzes the fluid distribution and exploitation performance in the cave system. Owing to evaporation of groundwater during cross-formational flow, the central part of the main cave, where oil layers are thick and there is a high degree of displacement, is characterized by high salinity and Br, concentration. With high potential and a long stable production period, most wells in the central part of the main cave have a long water-free oil production period. Even after water breakthrough, the water content has a slow or stepwise increase and the hydrochemistral characteristics of the produced water in the central part of the main cave are uniform. From the center to the edge of the main cave, displacement and enrichment of oil/gas become weaker, residual water increases, and the salinity and concentration of Br, decrease. At the edge of the main cave, although the wells have a high deliverability at the beginning with a short stable production period and water-free production period. After water breakthrough, the pressure and deliverability drop quickly, and the water content rises quickly. The hydrochemistral characteristics of the produced water are relatively uniform. Wells in the branch caves have a relatively low deliverability at the beginning, with a short stable production period. Water breakthrough appears quickly and then the pressure and deliverability drop quickly. The salinity and concentrations of Cl, and K++Na+ are usually fluctuant or descend slowly in the produced water. Wells in low areas of ancient karst have a low deliverability and a short stable production period. The yield drops quickly and the water content is high, while the characteristics of the produced water may vary significantly well to well. The salinity and concentrations of Cl, and K++Na+ in the produced water are usually fluctuant with a precipitous decline. [source]

Water quality and hydrogeochemical characteristics of the River Buyukmelen, Duzce, Turkey

Rustem Pehlivan
Abstract The River Buyukmelen is located in the province of Duzce in northwest Turkey and its water basin is approximately 470 km2. The Aksu, Kucukmelen and Ugursuyu streams flow into the River Buyukmelen. It flows into the Black Sea with an output of 44 m3 s,1. The geological succession in the basin comprises limestone and dolomitic limestone of the Y,lanl, formation, sandstone, clayey limestone and marls of the Akveren formation, clastics and volcano-clastics of the Caycuma formation, and cover units comprised of river alluvium, lacutrine sediments and beach sands. The River Buyukmelen is expected to be a water source that can supply the drinking water needs of Istanbul until 2040; therefore, it is imperative that its water quality be preserved. The samples of rock, soil, stream water, suspended, bed and stream sediments and beach sand were collected from the Buyukmelen river basin. They were examined using mineralogical and geochemical methods. The chemical constituents most commonly found in the stream waters are Na+, Mg2+, SO2,4, Cl, and HCO3, in the Guz stream water, Ca2+ in the Abaza stream water, and K+ in the Kuplu stream water. The concentrations of Na+, K+, Ca2+, Mg2+, SO2,4, HCO,3, Cl,, As, Pb, Ni, Mn, Cr, Zn, Fe and U in the Kuplu and Guz stream waters were much higher than the world average values. The Dilaver, Gubi, Tepekoy, Maden, Celik and Abaza streams interact with sedimentary rocks, and the Kuplu and Guz streams interact with volcanic rocks. The amount of suspended sediment in the River Buyukmelen in December 2002 was 120 mg l,1. The suspended and bed sediments in the muddy stream waters are formed of quartz, calcite, plagioclase, clay (kaolinite, illite and smectite), muscovite and amphibole minerals. As, Co, Cd, Cr, Pb, Ni, Zn and U have all accumulated in the Buyukmelen river-bed sediments. The muddy feature of the waters is related to the petrographic features of the rocks in the basin and their mineralogical compositions, as most of the sandstones and volcanic rocks (basalt, tuffite and agglomerate) are decomposed to a clay-rich composition at the surface. Thus, the suspended sediment in stream waters increases by physical weathering of the rocks and water,rock interaction. Owing to the growing population and industrialization, water demand is increasing. The plan is to bring water from the River Buyukmelen to Istanbul's drinking-water reservoirs. According to the Water Pollution Regulations, the River Buyukmelen belongs to quality class 1 based on Hg, Cd, Pb, As, Cu, Cr, Zn, Mn, Se, Ba, Na+, Cl,, and SO2,4; and to quality class 3 based on Fe concentration. The concentration of Fe in the River Buyukmelen exceeds the limit values permitted by the World Health Organization and the Turkish Standard. Because water from the River Buyukmelen will be used as drinking water, it will have an adverse effect on water quality and humans if not treated in advance. In addition, the inclusion of Mn and Zn in the Elmali drinking-water reservoir of Istanbul and Fe in the River Buyukmelen water indicates natural inorganic contamination. Mn, Zn and Fe contents in the waters are related to geological origin. Moreover, the River Buyukmelen flow is very muddy in the rainy seasons and it is inevitable that this will pose problems during the purification process. Copyright © 2005 John Wiley & Sons, Ltd. [source]