Surgeons' Volume-Outcome Relationship for Lobectomies and Wedge Resections for Cancer Using Video-Assisted Thoracoscopic Techniques

This study examined the effect of surgeons' volume on outcomes in lung surgery: lobectomies and wedge resections. Additionally, the effect of video-assisted thoracoscopic surgery (VATS) on cost, utilization, and adverse events was analyzed. The Premier Hospital Database was the data source for this analysis. Eligible patients were those of any age undergoing lobectomy or wedge resection using VATS for cancer treatment. Volume was represented by the aggregate experience level of the surgeon in a six-month window before each surgery. A positive volume-outcome relationship was found with some notable features. The relationship is stronger for cost and utilization outcomes than for adverse events; for thoracic surgeons as opposed to other surgeons; for VATS lobectomies rather than VATS wedge resections. While there was a reduction in cost and resource utilization with greater experience in VATS, these outcomes were not associated with greater experience in open procedures

Surface processes recorded by rocks and soils on Meridiani Planum, Mars: Microscopic Imager observations during Opportunity's first three extended missions

The Microscopic Imager (MI) on the Mars Exploration Rover Opportunity has returned images of Mars with higher resolution than any previous camera system, allowing detailed petrographic and sedimentological studies of the rocks and soils at the Meridiani Planum landing site. Designed to simulate a geologist's hand lens, the MI is mounted on Opportunity's instrument arm and can resolve objects 0.1 mm across or larger. This paper provides an overview of MI operations, data calibration, and analysis of MI data returned during the first 900 sols (Mars days) of the Opportunity landed mission. Analyses of Opportunity MI data have helped to resolve major questions about the origin of observed textures and features. These studies support eolian sediment transport, rather than impact surge processes, as the dominant depositional mechanism for Burns formation strata. MI stereo observations of a rock outcrop near the rim of Erebus Crater support the previous interpretation of similar sedimentary structures in Eagle Crater as being formed by surficial flow of liquid water. Well-sorted spherules dominate ripple surfaces on the Meridiani plains, and the size of spherules between ripples decreases by about 1 mm from north to south along Opportunity's traverse between Endurance and Erebus craters

Genetic Population Structure in the Antarctic Benthos: Insights from the Widespread Amphipod, Orchomenella franklini

Currently there is very limited understanding of genetic population structure in the Antarctic benthos. We conducted one of the first studies of microsatellite variation in an Antarctic benthic invertebrate, using the ubiquitous amphipod Orchomenella franklini (Walker, 1903). Seven microsatellite loci were used to assess genetic structure on three spatial scales: sites (100 s of metres), locations (1–10 kilometres) and regions (1000 s of kilometres) sampled in East Antarctica at Casey and Davis stations. Considerable genetic diversity was revealed, which varied between the two regions and also between polluted and unpolluted sites. Genetic differentiation among all populations was highly significant (FST = 0.086, RST = 0.139, p<0.001) consistent with the brooding mode of development in O. franklini. Hierarchical AMOVA revealed that the majority of the genetic subdivision occurred across the largest geographical scale, with Nem≈1 suggesting insufficient gene flow to prevent independent evolution of the two regions, i.e., Casey and Davis are effectively isolated. Isolation by distance was detected at smaller scales and indicates that gene flow in O. franklini occurs primarily through stepping-stone dispersal. Three of the microsatellite loci showed signs of selection, providing evidence that localised adaptation may occur within the Antarctic benthos. These results provide insights into processes of speciation in Antarctic brooders, and will help inform the design of spatial management initiatives recently endorsed for the Antarctic benthos

Inhibition of Retinoblastoma Tumor Suppressor Activity by RNA Interference in Lung Cancer Lines

Background: Inactivation of retinoblastoma (RB) tumor suppressor function occurs frequently in lung cancer. Short-hairpin RNA can be constructed to target specific sequences and efficiently knock down protein expression. We developed a short-hairpin RNA approach to specifically target Rb in lung cancer cells to determine the influence of RB knockdown on proliferation. Methods: NCI-H520 human lung cancer cells (wild-type Rb) were transfected with pMSCVpuro-Rb3C, a plasmid containing a short-hairpin sequence targeted to human Rb. Transfectants harboring the construct were selected with puromycin. Loss of RB expression in selected cell populations was determined by immunoblotting. Proliferating cells were counted to establish growth rates. Retinoblastoma-proficient and RB-deficient tumor growth was monitored in nude mice. Results: Transfection with pMSCVpuro-Rb3C dramatically diminished RB expression and led to aberrant expression of RB-regulated genes. Cells harboring pMSCVpuro-Rb3C grew at an increased rate compared with control cells: 480.6 ± 37.7 versus 159.4 ± 36.2 (relative cell count at 12 days). Tumor growth in nude mice also increased with RB knockdown compared with control mice: 135.2 ± 73.6 mm3 versus 40.0 ± 17.0 mm3 (tumor volume at 10 days). Conclusions: Inhibition of RB expression is efficiently achieved in lung cancer cells with short-hairpin RNA. Genetic targets of RB are deregulated with RB knockdown. Retinoblastoma depletion increases growth in vitro and in murine xenografts. These studies indicate that even in the context of an established tumor cell line, RB limits tumorigenic proliferation. Additionally, this model will serve as an ideal system to evaluate the role of RB activity on therapeutic response. © 2006 The Society of Thoracic Surgeons

A Multidimensional Modeling System For Simulating Coupled Canal, Overland, And Groundwater Flow In South Florida

Given the complex nature of hydrologic process in South Florida and the flood protection works that affect the hydrologic cycle, it is essential to have hydroinformatic systems to assist decision makers. The hydroinformatic systems must contain hydrologic models that can accurately simulate physical processes at the proper time and space scales without the crude schematization that has been common in previous modeling systems. The developed hydroinformatic system includes the FEMWATER123 model supported in the Department of Defense Groundwater Modeling System (GMS). The developed model (FEMWATER123) uses the Galerkin finite element method to simulate 1-D canal flow, 2-D overland flow, and 3-D groundwater flow in a coupled manner. The canals are simulated using the 1-D diffusive wave assumption including hydraulic structures with individual operation rules that are updated at one-minute intervals. The overland areas are simulated using the 2-D diffusive wave assumption while variably saturated groundwater flows are calculated using Richards equation. Results from the South Florida application are presented. Copyright ASCE 2004

A Model to Simulate the Interaction between Groundwater and Surface Water

A numerical model is being constructed to simulate the movement of water and constituents within a coupled groundwater and surface water system. The model is designed to run on all DoD HPC platforms. Local mesh refinement and coarsening and domain-decomposition preconditioners have been integrated into the model. The model has been exercised successfully on several test problems. Presently, the model is being applied to an instrumented watershed. Scientific ProblemScientific Problem The Department of Defense (DoD) is required to assess the environmental impact of its activities at both present and formerly used facilities. When warranted, the DoD must enact remedial measures to address environmental problems. The potential costs associated with environmental remediation at DoD sites is staggering. In addition to the cost of remediation, the DoD risks reduced or prohibited access to its training facilities unless environmental concerns are addressed adequately. For these reasons, accura..