Search

David Lam,1,* Doris Pierson,1,* Osman Salaria,1 Richa Wardhan,2 Jinlei Li1 1Department of Anesthesiology, Yale University School of Medicine, New Haven, CT, USA; 2Department of Anesthesiology, Florida University College of Medicine, Gainesville, FL, USA*These authors contributed equally to this workCorrespondence: Jinlei Li, Department of Anesthesiology, Yale University School of Medicine, 20 York Street, New Haven, CT, 06510, USA, Tel +1-203-785-2802, Fax +1-203-785-6664, Email jinlei.li@yale.eduAbstract: Acute compartment syndrome (ACS) is a devastating complication that can happen in almost every part of the human body, most noticeably after long bone fractures. The cardinal symptom of ACS is pain in excess of what would otherwise be expected from the underlying injury and unresponsive to routine analgesia treatment. There is paucity of literature on major analgesic management strategies including opioid analgesia, epidural anesthesia, and peripheral nerve blocks with regard to their differential efficacy and safety of pain management in patients at risk of developing ACS. The lack of quality data has led to recommendations that are perhaps more conservative than they should be, particularly when it comes to peripheral nerve blocks. In this review article, we attempt to make recommendations in favor of regional anesthesia in this vulnerable group of patients and strategies that will optimize adequate pain control and improve surgical outcome without jeopardizing patient safety.Keywords: regional anesthesiology, trauma, nerve blocks, acute compartment syndrome

Byline: M. T. Gladwin (1), D. J. Pierson (2) Author Affiliation: (1) Department of Critical Care Medicine, NIH, Building 10, Room 7D43, 10 Center Drive, 20892, Bethesda, MD, USA (2) Division of Pulmonary and Critical Care Medicine, Harborview Medical Center, 325 Ninth Avenue, Box 359762, 98104, Seattle, WA, USA Article History: Registration Date: 23/03/2009 Received Date: 01/01/1998 Accepted Date: 20/05/1998

For aquatic scientists mesocosm experiments are important tools for hypothesis testing as they offer a compromise between experimental control and realism. Here we present a new mesocosm infrastructure—SITES AquaNET—located in five lakes connected to field stations in Sweden that cover a ~760 km latitudinal gradient. SITES AquaNet overcomes major hindrances in aquatic experimental research through: (i) openness to the scientific community, (ii) the potential to implement coordinated experiments across sites and time, and (iii) high‐frequency measurements (temperature, photosynthetic photon flux density, turbidity and dissolved oxygen, chlorophyll a and phycocyanin concentrations) with an autonomous sensor system. Moreover, the infrastructure provides operational guidance and sensor expertise from technical staff, and connections to a multi‐layered monitoring programme ("SITES Water") for each lake. This enables ecological observations from whole lake ecosystems to be compared with experimental studies aiming at disentangling major drivers and mechanisms underlying observed changes. Here we describe the technical properties of the infrastructure along with possibilities for experimental manipulations to tackle pressing issues in aquatic ecology and global change science. As a proof of concept, we also present a first mesocosm experiment across all five field sites with a cross‐factorial design to evaluate responses of the sensor measurements to press/bottom‐up (constant light reduction) and pulse/top‐down (temporary fish predation) disturbances. This demonstrates the suitability of the infrastructure and autonomous sensor system to host modularized experiments and exemplifies the power and advantages of the approach to integrate a network of mecsocosm facilities with manageable costs across large geographic areas. [ABSTRACT FROM AUTHOR]

Heat uptake is a key variable for understanding the Earth system response to greenhouse gas forcing. Despite the importance of this heat budget, heat uptake by inland waters has so far not been quantified. Here we use a unique combination of global‐scale lake models, global hydrological models and Earth system models to quantify global heat uptake by natural lakes, reservoirs, and rivers. The total net heat uptake by inland waters amounts to 2.6 ± 3.2 ×1020 J over the period 1900–2020, corresponding to 3.6% of the energy stored on land. The overall uptake is dominated by natural lakes (111.7%), followed by reservoir warming (2.3%). Rivers contribute negatively (‐14%) due to a decreasing water volume. The thermal energy of water stored in artificial reservoirs exceeds inland water heat uptake by a factor ∼10.4. This first quantification underlines that the heat uptake by inland waters is relatively small, but non‐negligible. Plain Language Summary: Human‐induced emissions of CO2 and other greenhouse gases cause energy accumulation in the Earth system. Oceans trap most of this excess energy, thereby largely buffering the warming of the atmosphere. However, the fraction of excess energy stored in lakes, reservoirs, and rivers is currently unknown, despite the high heat capacity of water. Here we quantify this human‐induced heat storage, and show that it amounts up to 3.6% of the energy stored on land, while covering 2.58% of the land surface. The increase in heat storage from 1900 to 2020 is dominated by warming of lakes. The thermal heat contained in the water stored in man‐made reservoirs is about ten times larger. Our study overall highlights the importance of inland waters–next to oceans, ice and land–for buffering atmospheric warming, especially on regional scale. Key Points: We use a unique combination of lake models, hydrological models, and Earth System models to quantify global heat uptake by inland watersHeat uptake by inland waters over the industrial period amounts up to 2.6 × 1020 J, or 3.6% of the continental heat uptakeThe thermal energy of the water trapped on land due to dam construction (26.8 × 1020 J) is 10.4 times larger than inland water heat uptake [ABSTRACT FROM AUTHOR]

Phytoplankton biomass and production regulates key aspects of freshwater ecosystems yet its variability and subsequent predictability is poorly understood. We estimated within‐lake variation in biomass using high‐frequency chlorophyll fluorescence data from 18 globally distributed lakes. We tested how variation in fluorescence at monthly, daily, and hourly scales was related to high‐frequency variability of wind, water temperature, and radiation within lakes as well as productivity and physical attributes among lakes. Within lakes, monthly variation dominated, but combined daily and hourly variation were equivalent to that expressed monthly. Among lakes, biomass variability increased with trophic status while, within‐lake biomass variation increased with increasing variability in wind speed. Our results highlight the benefits of high‐frequency chlorophyll monitoring and suggest that predicted changes associated with climate, as well as ongoing cultural eutrophication, are likely to substantially increase the temporal variability of algal biomass and thus the predictability of the services it provides. [ABSTRACT FROM AUTHOR]

The physical dynamics of lake temperature and ice phenology are important in the modelling and management of temperate aquatic ecosystems. One-dimensional hydrothermal lake models have not been well evaluated in terms of how they simulate ice dynamics in particular. We chose four models (Hostetler, Minlake, Simple Ice Model or SIM and General Lake Model) to test and compare their performance modelling water temperature and ice dynamics using 16 years of field data from Harp Lake, an extensively studied inland lake in south-central Ontario. Each model produced satisfactory water temperature profiles over the simulated period, with small differences in the model performance. Model fits for ice phenology and ice thickness were, however, considerably lower than those for water temperature, with Minlake generating the best agreement with observed ice-on and ice-off dates as well as ice thickness, followed by SIM. The responses of lake ice dynamics to future climate scenarios were simulated by running each of the four models for 91 years, from 2010 to 2100. The predicted decrease in ice season length was significantly different among models, varying between 30 and 81 days, with an average of 48 days. Corresponding decreases in ice thickness varied between 0.11 and 0.20 m, averaging 0.17 m. This study demonstrates that uncertainty due to model performance and selection is considerable, and further testing and refinement of hydrothermal lake dynamic models are needed to improve predictive abilities for ice dynamics. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The cycling of carbon in terrestrial ecosystems is closely coupled with the cycling of water. An important mechanism connecting ecological and hydrological processes in terrestrial ecosystems is lateral flow of water along landscapes. Few studies, however, have examined explicitly how consideration of water routing affects simulated water and carbon dynamics in terrestrial ecosystems. The objective of this study is to explore how consideration of water routing in a process-based hydroecological model affects simulated water and carbon dynamics. To achieve that end, we rasterized the regional hydroecological simulation systems (RHESSys) and employed the rasterized RHESSys (R-RHESSys) in a forested watershed. We performed and compared two contrasting simulations, one with and another without water routing. We found that R-RHESSys is able to correctly simulate major hydrological and ecological variables regardless of whether water routing is considered. When water routing was neglected, however, soil water table depth and saturation deficit were simulated to be smaller and spatially more homogeneous. As a result, evaporation, forest productivity and soil heterotrophic respiration also were simulated to be spatially more homogeneous compared to simulation with water routing. When averaged for the entire watershed, however, differences in simulated water and carbon fluxes are not significant between the two simulations. Overall, the study demonstrated that consideration of water routing enabled R-RHESSys to better capture our preconception of the spatial patterns of water table depth and saturation deficit across the watershed. Because the spatial pattern of soil moisture is fundamental to water efflux from land to the atmosphere, forest productivity and soil microbial activity, ecosystem and carbon cycle models, therefore, need to explicitly represent water routing in order to accurately quantify the magnitudes and patterns of water and carbon fluxes in terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

Global Circulation Model values of mean daily air temperature, wind speed and solar radiation for the 2081-2100 period are used to produce change factors that are applied to a 39 year record of local meteorological data to produce future climate scenarios. These climate scenarios are used to drive two separate, but coupled models: the Generalized Watershed Loading Functions-Variable Source Area model in order to simulate reservoir tributary inflows, and a one-dimensional reservoir hydrothermal model used to evaluate changes in reservoir thermal structure in response to changes in meteorological forcing and changes in simulated inflow. Comparisons between simulations based on present-day climate data (baseline conditions) and future simulations (change-factor adjusted baseline conditions) are used to evaluate the development and breakdown of thermal stratification, as well as a number of metrics that describe reservoir thermal structure, stability and mixing. Both epilimnion and hypolimnion water temperatures are projected to increase. Indices of mixing and stability show changes that are consistent with the simulated changes in reservoir thermal structure. Simulations suggest that stratification will begin earlier and the reservoir will exhibit longer and more stable periods of thermal stratification under future climate conditions. [ABSTRACT FROM AUTHOR]

A simple bio-optical model, with parameter values derived from measurements of the inherent optical properties (IOPs) and optically active substances that are known to influence the IOPs, has been developed. A large historical dataset of measurements of the concentration of chlorophyll a and phaeophytine a (Chl), suspended particulate inorganic material (SPIM) and the absorption coefficient of Coloured Dissolved Organic Matter (CDOM), spanning more than 25 years, has been used together with the model to develop algorithms for the retrieval of these water quality parameters, for a site in Lake Malaren, Sweden. The model takes as input the optically active substances and outputs a reflectance spectrum just above the water surface. From the modelled reflectance, algorithms were derived for Chl, SPIM and CDOM absorption at 420 nm. The algorithms were applied to atmospherically corrected remote sensing data, which were collected by the Compact Airborne Spectrographic Imager, CASI. The radiative transfer code 6S was used for the atmospheric correction of the data. Distribution maps for the three retrieved parameters were constructed and Chl and SPIM were validated by continuous field measurements of fluorescence and beam attenuation. The continuous data were calibrated with water analysis results from nine water samples. The time lag between the image acquisition and the ground data measurements was never more than 3 hours. Even though the model parameter values were collected at different times from that of the CASI over-flight, and from a larger geographic region of Lake Malaren than that used for the CASI measurements, the independently developed algorithms predicted the concentrations of the optically active substances within a reasonable level of accuracy, allowing spatial variations in the substances to be predicted. [ABSTRACT FROM AUTHOR]

Brian Crucian,1 Adriana Babiak-Vazquez,2 Smith Johnston,1 Duane L Pierson,1 C Mark Ott,1 Clarence Sams1 1Biomedical Research and Environmental Sciences Division, NASA-Johnson Space Center, 2Epidemiology/Lifetime Surveillance of Astronaut Health, KBR-Wyle, Houston, TX, USA Background: The environment of spaceflight may elevate an astronaut’s clinical risk for specific diseases. The purpose of this study was to derive, as accurately as currently possible, an assessment of in-flight clinical “incidence” data, based on observed clinical symptoms in astronauts on board the International Space Station (ISS).Methods: Electronic medical records were examined from 46 long-duration ISS crew members, each serving approximately a 6-month mission on board the ISS, constituting 20.57 total flight years. Incidence for immunological-related adverse health events or relevant clinical symptoms was tabulated in a non-identifiable fashion. Event categories included infectious diseases, allergies, and rashes/hypersensitivities. A subsequent re-evaluation of more notable events, either of prolonged duration or unresponsive to treatment, was performed.Results: For the disease/symptom categories used in this evaluation, the ISS incidence rate was 3.40 events per flight year. Skin rashes were the most reported event (1.12/flight year) followed by upper respiratory symptoms (0.97/flight year) and various other (non-respiratory) infectious processes. During flight, 46% of crew members reported an event deemed “notable”. Among the notable events, 40% were classified as rashes/hypersensitivities. Characterization of on-orbit rashes manifested as redness with irritation, and could present on a variety of body locations.Conclusion: Based on reported symptoms, astronauts experience adverse medical events of varying severity during long-duration spaceflights. The data suggests caution, from both a vehicle design and biomedical countermeasures perspective, as space agencies plan for prolonged deep space exploration missions. Keywords: spaceflight, immunity, clinical incidence, astronauts, gravity, clinical risk, disease

The Space Shuttle has a once-through water system that is initially filled on the ground, partially drained before launch and then refilled with fuel-cell generated water on orbit. The microbiological standard for the Space Shuttle potable water system during this study period allowed only 1 microbe of any kind per 100mL and no detectable coliforms. Contamination episodes in more than 15 years of Shuttle operation have been rare; however, for the past 24 missions, bacterial contamination has been detected in 33% of the samples collected 3d before launch. These samples have had on average 55CFU/100mL of bacteria, with the median less than ICFU/100mL. Burkholderia cepacia has been the primary contaminant of the Shuttle water supply system both before and after flight. Water samples assessed during the STS-70 mission aboard the Space Shuttle Discovery were found to be contaminated (lt;20CFU/100mL) with B. cepacia and B. pickettii. In 1991, waste and water lines were removed from the Space Shuttle Columbia and the waste lines were found to harbor biofilms containing Bacillus spp. Nevertheless, the water systems of the four Space Shuttle vehicles provide extremely pure water. [ABSTRACT FROM AUTHOR]

Abstract Background Extra-cellular shear force is an important environmental parameter that is significant both medically and in the space environment. Escherichia coli cells grown in a low-shear modeled microgravity (LSMMG) environment produced in a high aspect rotating vessel (HARV) were subjected to transcriptional and physiological analysis. Results Aerobic LSMMG cultures were grown in rich (LB) and minimal (MOPS + glucose) medium with a normal gravity vector HARV control. Reproducible changes in transcription were seen, but no specific LSMMG responsive genes were identified. Instead, absence of shear and a randomized gravity vector appears to cause local extra-cellular environmental changes, which elicit reproducible cellular responses. In minimal media, the majority of the significantly up- or down-regulated genes of known function were associated with the cell envelope. In rich medium, most LSMMG down-regulated genes were involved in translation. No observable changes in post-culture stress responses and antibiotic sensitivity were seen in cells immediately after exposure to LSMMG. Comparison with earlier studies of Salmonella enterica serovar Typhimurium conducted under similar growth conditions, revealed essentially no similarity in the genes that were significantly up- or down-regulated. Conclusion Comparison of these results to previous studies suggests that different organisms may dramatically differ in their responses to medically significant low-shear and space environments. Depending on their specific response, some organisms, such as Salmonella, may become preadapted in a manner that predisposes them to increased virulence.