Portal vein thrombosis and outcomes for pediatric liver transplant candidates and recipients in the United States

The effect of occlusive portal vein thrombosis (PVT) on the mortality of pediatric liver transplant candidates and recipients is poorly defined. Using standard multivariate techniques, we studied the relationship between PVT and waiting‐list and posttransplant survival rates with data from the Scientific Registry of Transplant Recipients (September 2001 to December 2007). In all, 5087 liver transplant candidates and 3630 liver transplant recipients were evaluated during the period. PVT was found in 1.4% of the liver transplant candidates (n = 70) and in 3.7% of the liver transplant recipients (n = 136). PVT was not associated with increased wait‐list mortality [hazard ratio (HR) = 1.1, 95% confidence interval (CI) = 0.5‐2.4, P = 0.77]. Conversely, PVT patients had a significantly lower unadjusted survival rate in the posttransplant period ( P = 0.01). PVT was independently associated with increased posttransplant mortality in multivariate models (30‐day survival: HR = 2.9, 95% CI = 1.6‐5.3, P = 0.001; overall survival: HR = 1.7, 95% CI = 1.1‐2.4, P = 0.01). The presence of PVT in pediatric liver candidates was not associated with increased wait‐list mortality but was clearly associated with posttransplant mortality, especially in the immediate postoperative period. Liver Transpl 17:1066–1072, 2011. © 2011 AASLD.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87010/1/22371_ftp.pd

Morphological evidence for geologically young thaw of ice on Mars: a review of recent studies using high-resolution imaging data

Liquid water is generally only meta-stable on Mars today; it quickly freezes, evaporates or boils in the cold, dry, thin atmosphere (surface pressure is about 200 times lower than on Earth). Nevertheless, there is morphological evidence that surface water was extensive in more ancient times, including the Noachian Epoch (~4.1 Ga to ~3.7 Ga bp), when large lakes existed and river-like channel networks were incised, and early in the Hesperian Epoch (~3.7 Ga to ~2.9 Ga bp), when megafloods carved enormous channels and smaller fluvial networks developed in association with crater-lakes. However, by the Amazonian Epoch (~3.0 Ga to present), most surface morphogenesis associated with liquid water had ceased, with long periods of water sequestration as ice in the near-surface and polar regions. However, inferences from observations using imaging data with sub-metre pixel sizes indicate that periglacial landscapes, involving morphogenesis associated with ground-ice and/or surface-ice thaw and liquid flows, has been active within the last few million years. In this paper, three such landform assemblages are described: a high-latitude assemblage comprising features interpreted to be sorted clastic stripes, circles and polygons, non-sorted polygonally patterned ground, fluvial gullies, and solifluction lobes; a mid-latitude assemblage comprising gullies, patterned ground, debris-covered glaciers and hillslope stripes; and an equatorial assemblage of linked basins, patterned ground, possible pingos, and channel-and-scarp features interpreted to be retrogressive thaw-slumps. Hypotheses to explain these observations are explored, including recent climate change, and hydrated minerals in the regolith ‘thawing’ to form liquid brines at very low temperatures. The use of terrestrial analogue field sites is also discussed

Power output and columbic efficiencies from biofilms of Geobacter sulfurreducens comparable to mixed community microbial fuel cells

It has been previously noted that mixed communities typically produce more power in microbial fuel cells than pure cultures. If true, this has important implications for the design of microbial fuel cells and for studying the process of electron transfer on anode biofilms. To further evaluate this, Geobacter sulfurreducens was grown with acetate as fuel in a continuous flow ‘ministack’ system in which the carbon cloth anode and cathode were positioned in close proximity, and the cation-selective membrane surface area was maximized in order to overcome some of the electrochemical limitations that were inherent in fuel cells previously employed for the study of pure cultures. Reducing the size of the anode in order to eliminate cathode limitation resulted in maximum current and power densities per m2 of anode surface of 4.56 A m−2 and 1.88 W m−2 respectively. Electron recovery as current from acetate oxidation was c. 100% when oxygen diffusion into the system was minimized. This performance is comparable to the highest levels previously reported for mixed communities in similar microbial fuel cells and slightly higher than the power output of an anaerobic sludge inoculum in the same ministack system. Minimizing the volume of the anode chamber yielded a volumetric power density of 2.15 kW m−3, which is the highest power density per volume yet reported for a microbial fuel cell. Geobacter sulfurreducens formed relatively uniform biofilms 3–18 μm thick on the carbon cloth anodes. When graphite sticks served as the anode, the current density (3.10 A m−2) was somewhat less than with the carbon cloth anodes, but the biofilms were thicker (c. 50 μm) with a more complex pillar and channel structure. These results suggest that the previously observed disparity in power production in pure and mixed culture microbial fuel cell systems can be attributed more to differences in the fuel cell designs than to any inherent superior capability of mixed cultures to produce more power than pure cultures

MAINTAINING LONG-TERM MANAGEMENT: Herbicide-resistant weeds challenge some signature cropping systems

Invasive and endemic weeds pose recurring challenges for California land managers. The evolution of herbicide resistance in several species has imposed new challenges in some cropping systems, and these issues are being addressed by UC Cooperative Extension farm advisors, specialists and faculty. There are currently 24 unique herbicide-resistant weed biotypes in the state, dominated by grasses and sedges in flooded rice systems and, more recently, glyphosate-resistant broadleaf and grass weeds in tree and vine systems, roadsides and glyphosate-tolerant field crops. Weed scientists address these complex issues using approaches ranging from basic physiology and genetics research to applied research and extension efforts in grower fields throughout the state. Although solutions to herbicide resistance are not simple and are affected by many biological, economic, regulatory and social factors, California stakeholders need information, training and solutions to address new weed management problems as they arise. Coordinated efforts conducted under the Endemic and Invasive Pests and Disease Strategic Initiative directly address weed management challenges in California's agricultural industries

Herbicide-resistant weeds challenge some signature cropping systems

Invasive and endemic weeds pose recurring challenges for California land managers. The evolution of herbicide resistance in several species has imposed new challenges in some cropping systems, and these issues are being addressed by UC Cooperative Extension farm advisors, specialists and faculty. There are currently 24 unique herbicide-resistant weed biotypes in the state, dominated by grasses and sedges in flooded rice systems and, more recently, glyphosate-resistant broadleaf and grass weeds in tree and vine systems, roadsides and glyphosate-tolerant field crops. Weed scientists address these complex issues using approaches ranging from basic physiology and genetics research to applied research and extension efforts in grower fields throughout the state. Although solutions to herbicide resistance are not simple and are affected by many biological, economic, regulatory and social factors, California stakeholders need information, training and solutions to address new weed management problems as they arise. Coordinated efforts conducted under the Endemic and Invasive Pests and Disease Strategic Initiative directly address weed management challenges in California's agricultural industries