A navigation system for open liver surgery: design, workflow and first clinical applications

The surgical treatment of liver tumours relies on precise localization of the lesions and detailed knowledge of the patient-specific vascular and biliary anatomy. Detailed three-dimensional (3D) anatomical information facilitates complete tumour removal while preserving a sufficient amount of functional liver tissue.

Phylogenetic analysis of the gag region encoding the matrix protein of small ruminant lentiviruses: comparative analysis and molecular epidemiological applications

Little sequence information exists on the matrix-protein (MA) encoding region of small ruminant lentiviruses (SRLV). Fifty-two novel sequences were established and permitted a first phylogenetic analysis of this region of the SRLV genome. The variability of the MA encoding region is higher compared to the gag region encoding the capsid protein and surprisingly close to that reported for the env gene. In contrast to primate lentiviruses, the deduced amino acid sequences of the N- and C-terminal domains of MA are variable. This permitted to pinpoint a basic domain in the N-terminal domain that is conserved in all lentiviruses and likely to play an important functional role. Additionally, a seven amino acid insertion was detected in all MVV strains, which may be used to differentiate CAEV and MVV isolates. A molecular epidemiology analysis based on these sequences indicates that the Italian lentivirus strains are closely related to each other and to the CAEV-CO strain, a prototypic strain isolated three decades ago in the US. This suggests a common origin of the SRLV circulating in the monitored flocks, possibly related to the introduction of infected goats in a negative population. Finally, this study shows that the MA region is suitable for phylogenetic studies and may be applied to monitor SRLV eradication programs.

Simulating dioxane transport in a heterogeneous glacial aquifer system (Washtenaw County, Michigan) using publicly available models and data

The primary challenge in groundwater and contaminant transport modeling is obtaining the data needed for constructing, calibrating and testing the models. Large amounts of data are necessary for describing the hydrostratigraphy in areas with complex geology. Increasingly states are making spatial data available that can be used for input to groundwater flow models. The appropriateness of this data for large-scale flow systems has not been tested. This study focuses on modeling a plume of 1,4-dioxane in a heterogeneous aquifer system in Scio Township, Washtenaw County, Michigan. The analysis consisted of: (1) characterization of hydrogeology of the area and construction of a conceptual model based on publicly available spatial data, (2) development and calibration of a regional flow model for the site, (3) conversion of the regional model to a more highly resolved local model, (4) simulation of the dioxane plume, and (5) evaluation of the model's ability to simulate field data and estimation of the possible dioxane sources and subsequent migration until maximum concentrations are at or below the Michigan Department of Environmental Quality's residential cleanup standard for groundwater (85 ppb). MODFLOW-2000 and MT3D programs were utilized to simulate the groundwater flow and the development and movement of the 1, 4-dioxane plume, respectively. MODFLOW simulates transient groundwater flow in a quasi-3-dimensional sense, subject to a variety of boundary conditions that can simulate recharge, pumping, and surface-/groundwater interactions. MT3D simulates solute advection with groundwater flow (using the flow solution from MODFLOW), dispersion, source/sink mixing, and chemical reaction of contaminants. This modeling approach was successful at simulating the groundwater flows by calibrating recharge and hydraulic conductivities. The plume transport was adequately simulated using literature dispersivity and sorption coefficients, although the plume geometries were not well constrained.

Digital processing and data compilation approach for using remotely sensed imagery to identify geological lineaments in hard-rock terrains : an application for groundwater explorations in Nicaragua

Sustainable yields from water wells in hard-rock aquifers are achieved when the well bore intersects fracture networks. Fracture networks are often not readily discernable at the surface. Lineament analysis using remotely sensed satellite imagery has been employed to identify surface expressions of fracturing, and a variety of image-analysis techniques have been successfully applied in “ideal” settings. An ideal setting for lineament detection is where the influences of human development, vegetation, and climatic situations are minimal and hydrogeological conditions and geologic structure are known. There is not yet a well-accepted protocol for mapping lineaments nor have different approaches been compared in non-ideal settings. A new approach for image-processing/synthesis was developed to identify successful satellite imagery types for lineament analysis in non-ideal terrain. Four satellite sensors (ASTER, Landsat7 ETM+, QuickBird, RADARSAT-1) and a digital elevation model were evaluated for lineament analysis in Boaco, Nicaragua, where the landscape is subject to varied vegetative cover, a plethora of anthropogenic features, and frequent cloud cover that limit the availability of optical satellite data. A variety of digital image processing techniques were employed and lineament interpretations were performed to obtain 12 complementary image products that were evaluated subjectively to identify lineaments. The 12 lineament interpretations were synthesized to create a raster image of lineament zone coincidence that shows the level of agreement among the 12 interpretations. A composite lineament interpretation was made using the coincidence raster to restrict lineament observations to areas where multiple interpretations (at least 4) agree. Nine of the 11 previously mapped faults were identified from the coincidence raster. An additional 26 lineaments were identified from the coincidence raster, and the locations of 10 were confirmed by field observation. Four manual pumping tests suggest that well productivity is higher for wells proximal to lineament features. Interpretations from RADARSAT-1 products were superior to interpretations from other sensor products, suggesting that quality lineament interpretation in this region requires anthropogenic features to be minimized and topographic expressions to be maximized. The approach developed in this study has the potential to improve siting wells in non-ideal regions.

Once daily dosing of netilmicin in neonatal and pediatric intensive care

OBJECTIVE: To examine a once daily dosing regimen of netilmicin in critically ill neonates and children. DESIGN AND SETTING: Open, prospective study on 81 antibiotic courses in 77 critically ill neonates and children, hospitalized in a multidisciplinary pediatric/neonatal intensive care unit. For combined empiric therapy (aminoglycoside and beta-lactam), netilmicin was given intravenously over 5 min once every 24 h. The dose ranged from 3.5-6 mg/kg, mainly depending upon gestational and postnatal age. Peak levels were determined by immunoassay 30 min after the second dose and trough levels 1 h before the third and fifth dose or after adaptation of dosing. RESULTS: All peak levels (n = 28) were clearly above 12 mumol/l (mean 22, range 13-41 mumol/l). Eighty-nine trough levels were within desired limits (< 4 mumol/l) and 11 (11%) above 4 mumol/l, mostly in conjunction with impaired renal function. CONCLUSIONS: Optimal peak and trough levels of netilmicin can be achieved by once daily dosing, adapted to gestational/postnatal age and renal function.

Interview and translation strategies: coping with multilingual settings and data

Central Eastern Europe, the research area this paper is concerned with, is a region characterized by a high diversity of languages and cultures. It is, at the same time, an area where political, cultural and social conflicts have emerged over time, nowadays especially in border zones, where people of different ethnic, cultural or linguistic background live. In this context, it is important for us researchers to get balanced interview data, and consequently we very often have to conduct interviews in several different languages and within changing cultural contexts. In order to avoid "communication problems" or even conflictual (interview) situations, which might damage the outcome of the research, we are thus challenged to find appropriate communication strategies for any of these situations. This is especially difficult when we are confronted with language or culture-specific terminology or taboo expressions that carry political meaning(s). Once the interview data is collected and it comes to translating and analysing it, we face further challenges and new questions arise. First of all, we have to decide what a good translation strategy would be. Many words and phrases that exist in one language do not have an exact equivalent in another. Therefore we have to find a solution for translating these expressions and concepts in a way that their meanings do not get "lost by translation". In this paper I discuss and provide insights to these challenges by presenting and discussing numerous examples from the region in question. Specifically, I focus on the deconstruction of the meaning of geographical names and politically loaded expressions in order to show the sensitivities of language, the difficulties of research in multilingual settings and with multilingual data as well as the strategies or "ways out" of certain dilemmas.