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It is essential to monitor tissue perfusion during and after reconstructive surgery, as restricted blood flow can result in graft failures. Current clinical procedures are insufficient to monitor tissue perfusion, as they are intermittent and often subjective. To address this unmet clinical need, a compact, low-cost, multimodal diffuse correlation spectroscopy and diffuse reflectance spectroscopy system was developed. We verified system performance via tissue phantoms and experimental protocols for rigorous bench testing. Quantitative data analysis methods were employed and tested to enable the extraction of tissue perfusion parameters. This design verification study assures data integrity in future in vivo studies.

The smallest flying insects commonly possess wings with long bristles. Little quantitative information is available on the morphology of these bristles, and their functional importance remains a mystery. In this study, we (1) collected morphological data on the bristles of 23 species of Mymaridae by analyzing high-resolution photographs and (2) used the immersed boundary method to determine via numerical simulation whether bristled wings reduced the force required to fling the wings apart while still maintaining lift. The effects of Reynolds number, angle of attack, bristle spacing and wing-wing interactions were investigated. In the morphological study, we found that as the body length of Mymaridae decreases, the diameter and gap between bristles decreases and the percentage of the wing area covered by bristles increases. In the numerical study, we found that a bristled wing experiences less force than a solid wing. The decrease in force with increasing gap to diameter ratio is greater at higher angles of attack than at lower angles of attack, suggesting that bristled wings may act more like solid wings at lower angles of attack than they do at higher angles of attack. In wing-wing interactions, bristled wings significantly decrease the drag required to fling two wings apart compared with solid wings, especially at lower Reynolds numbers. These results support the idea that bristles may offer an aerodynamic benefit during clap and fling in tiny insects., (© 2016. Published by The Company of Biologists Ltd.)

The superior manoeuvrability of hummingbirds emerges from complex interactions of specialized neural and physiological processes with the unique flight dynamics of flapping wings. Escape manoeuvring is an ecologically relevant, natural behaviour of hummingbirds, from which we can gain understanding into the functional limits of vertebrate locomotor capacity. Here, we extend our kinematic analysis of escape manoeuvres from a companion paper to assess two potential limiting factors of the manoeuvring performance of hummingbirds: (1) muscle mechanical power output and (2) delays in the neural sensing and control system. We focused on the magnificent hummingbird (Eugenes fulgens, 7.8 g) and the black-chinned hummingbird (Archilochus alexandri, 3.1 g), which represent large and small species, respectively. We first estimated the aerodynamic forces, moments and the mechanical power of escape manoeuvres using measured wing kinematics. Comparing active-manoeuvring and passive-damping aerodynamic moments, we found that pitch dynamics were lightly damped and dominated by the effect of inertia, while roll dynamics were highly damped. To achieve observed closed-loop performance, pitch manoeuvres required faster sensorimotor transduction, as hummingbirds can only tolerate half the delay allowed in roll manoeuvres. Accordingly, our results suggested that pitch control may require a more sophisticated control strategy, such as those based on prediction. For the magnificent hummingbird, we estimated that escape manoeuvres required muscle mass-specific power 4.5 times that during hovering. Therefore, in addition to the limitation imposed by sensorimotor delays, muscle power could also limit the performance of escape manoeuvres., (© 2016. Published by The Company of Biologists Ltd.)

Hummingbirds are nature's masters of aerobatic manoeuvres. Previous research shows that hummingbirds and insects converged evolutionarily upon similar aerodynamic mechanisms and kinematics in hovering. Herein, we use three-dimensional kinematic data to begin to test for similar convergence of kinematics used for escape flight and to explore the effects of body size upon manoeuvring. We studied four hummingbird species in North America including two large species (magnificent hummingbird, Eugenes fulgens, 7.8 g, and blue-throated hummingbird, Lampornis clemenciae, 8.0 g) and two smaller species (broad-billed hummingbird, Cynanthus latirostris, 3.4 g, and black-chinned hummingbirds Archilochus alexandri, 3.1 g). Starting from a steady hover, hummingbirds consistently manoeuvred away from perceived threats using a drastic escape response that featured body pitch and roll rotations coupled with a large linear acceleration. Hummingbirds changed their flapping frequency and wing trajectory in all three degrees of freedom on a stroke-by-stroke basis, likely causing rapid and significant alteration of the magnitude and direction of aerodynamic forces. Thus it appears that the flight control of hummingbirds does not obey the 'helicopter model' that is valid for similar escape manoeuvres in fruit flies. Except for broad-billed hummingbirds, the hummingbirds had faster reaction times than those reported for visual feedback control in insects. The two larger hummingbird species performed pitch rotations and global-yaw turns with considerably larger magnitude than the smaller species, but roll rates and cumulative roll angles were similar among the four species., (© 2016. Published by The Company of Biologists Ltd.)

The paths animals take while moving through their environments affect their likelihood of encountering food and other resources; thus, models of foraging behavior abound. To collect movement data appropriate for comparison with these models, we used time-lapse photography to track movements of a small, hardy, and easy-to-obtain organism, Aquilonastra anomala sea stars. We recorded the sea stars in a tank over many hours, with and without a food cue. With food present, they covered less distance, as predicted by theory; this strategy would allow them to remain near food. We then compared the paths of the sea stars to three common models of animal movement: Brownian motion, Lévy walks, and correlated random walks; we found that the sea stars' movements most closely resembled a correlated random walk. Additionally, we compared the search performance of models of Brownian motion, a Lévy walk, and a correlated random walk to that of a model based on the sea stars' movements. We found that the behavior of the modeled sea star walk was similar to that of the modeled correlated random walk and the Brownian motion model, but that the sea star walk was slightly more likely than the other walks to find targets at intermediate distances. While organisms are unlikely to follow an idealized random walk in all details, our data suggest that comparing the effectiveness of an organism's paths to those from theory can give insight into the organism's actual movement strategy. Finally, automated optical tracking of invertebrates proved feasible, and A. anomala was revealed to be a tractable, 2D-movement study system.

Background: Pneumatosis intestinalis (PI) presents a challenging dilemma for surgeons given its association with both benign and life threatening conditions. As such, the need for surgical intervention is oftentimes difficult to discern. We hypothesize that a clinical nomogram can be used to predict the need for surgical intervention in patients with PI., Methods: We performed a retrospective review of 217 consecutive cases with PI on abdominal computed tomography over a 10-year period at a tertiary care hospital. Bivariable and multivariable analysis were conducted to assess the statistical significance of the association between patient factors and need for surgical intervention, defined as positive findings at surgery., Results: There were 217 patients with PI identified during the study, of which 178 were treated with curative intent. Of these, 82 patients underwent surgical exploration, and 96 patients were managed conservatively. Forty-four percent of patients who had radiographic evidence of PI were managed conservatively and did well, whereas an additional 6% underwent nontherapeutic laparotomies. Multivariable analysis demonstrated that patients with tenderness on examination, lactic acidosis, and tachycardia had significantly higher likelihood of the need for surgical intervention, whereas patients with diabetes had a lower likelihood of surgical intervention. These and other selected patient characteristics can be used to efficiently and reliably estimate the probability of ischemic bowel at laparotomy., Conclusions: The presence of PI does not always warrant surgical intervention. We present a nomogram to assist with clinical decision-making based on the presence of clinical factors., (Copyright © 2015 Elsevier Inc. All rights reserved.)

While prior studies of swallow manoeuvering have focused on slow-speed flight and obstacle avoidance in still air, swallows survive by foraging at high speeds in windy environments. Recent advances in field-portable, high-speed video systems, coupled with precise anemometry, permit measures of high-speed aerial performance of birds in a natural state. We undertook the present study to test: (i) the manner in which barn swallows (Hirundo rustica) may exploit wind dynamics and ground effect while foraging and (ii) the relative importance of flapping versus gliding for accomplishing high-speed manoeuvers. Using multi-camera videography synchronized with wind-velocity measurements, we tracked coursing manoeuvers in pursuit of prey. Wind speed averaged 1.3-2.0 m s(-1) across the atmospheric boundary layer, exhibiting a shear gradient greater than expected, with instantaneous speeds of 0.02-6.1 m s(-1) While barn swallows tended to flap throughout turns, they exhibited reduced wingbeat frequency, relying on glides and partial bounds during maximal manoeuvers. Further, the birds capitalized on the near-earth wind speed gradient to gain kinetic and potential energy during both flapping and gliding turns; providing evidence that such behaviour is not limited to large, fixed-wing soaring seabirds and that exploitation of wind gradients by small aerial insectivores may be a significant aspect of their aeroecology.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'., (© 2016 The Author(s).)

Ecological, behavioral and biomechanical studies often need to quantify animal movement and behavior in three dimensions. In laboratory studies, a common tool to accomplish these measurements is the use of multiple, calibrated high-speed cameras. Until very recently, the complexity, weight and cost of such cameras have made their deployment in field situations risky; furthermore, such cameras are not affordable to many researchers. Here, we show how inexpensive, consumer-grade cameras can adequately accomplish these measurements both within the laboratory and in the field. Combined with our methods and open source software, the availability of inexpensive, portable and rugged cameras will open up new areas of biological study by providing precise 3D tracking and quantification of animal and human movement to researchers in a wide variety of field and laboratory contexts., Competing Interests: The authors declare no competing or financial interests., (© 2016. Published by The Company of Biologists Ltd.)

Objective: To examine implementing an enhanced recovery after surgery (ERAS) protocol for women undergoing major gynecologic surgery at an academic institution and compare surgical outcomes before and after implementation., Methods: Two ERAS protocols were developed: a full pathway using regional anesthesia for open procedures and a light pathway without regional anesthesia for vaginal and minimally invasive procedures. Enhanced recovery after surgery pathways included extensive preoperative counseling, carbohydrate loading and oral fluids before surgery, multimodal analgesia with avoidance of intravenous opioids, intraoperative goal-directed fluid resuscitation, and immediate postoperative feeding and ambulation. A before-and-after study design was used to compare clinical outcomes, costs, and patient satisfaction. Complications and risk-adjusted length of stay were drawn from the American College of Surgeons' National Surgical Quality Improvement Program database., Results: On the ERAS full protocol, 136 patients were compared with 211 historical controls and the median length of stay was reduced (2.0 compared with 3.0 days; P=.007) despite an increase in National Surgical Quality Improvement Program-predicted length of stay (2.5 compared with 2.0 days; P=.009). Reductions were seen in median intraoperative morphine equivalents (0.3 compared with 12.7 mg; P<.001), intraoperative (285 compared with 1,250 mL; P<.001) and total intravenous fluids (-917.5 compared with 1,410 mL; P<.001), immediate postoperative pain scores (3.7 compared with 5.0; P<.001), and total complications (21.3% compared with 40.2%; P=.004). On the ERAS light protocol, 249 patients were compared with 324 historical controls and demonstrated decreased intraoperative and postoperative morphine equivalents (0.0 compared with 13.0 mg; P<.001 and 15.0 compared with 23.6 mg; P<.001) and decreased intraoperative and overall net intravenous fluids (P<.001). Patient satisfaction scores showed a marked and significant improvement on focus questions regarding pain control, nurses keeping patients informed, and staff teamwork; 30-day total hospital costs were significantly decreased in both ERAS groups., Conclusion: Implementation of ERAS protocols in gynecologic surgery was associated with a substantial decrease in intravenous fluids and morphine administration coupled with reduction in length of stay for open procedures combined with improved patient satisfaction and decreased hospital costs.

Biological systems consistently outperform autonomous systems governed by engineered algorithms in their ability to reactively avoid collisions. To better understand this discrepancy, a collision avoidance algorithm was applied to frames of digitized video trajectory data from bats, swallows and fish (Myotis velifer, Petrochelidon pyrrhonota and Danio aequipinnatus). Information available from visual cues, specifically relative position and velocity, was provided to the algorithm which used this information to define collision cones that allowed the algorithm to find a safe velocity requiring minimal deviation from the original velocity. The subset of obstacles provided to the algorithm was determined by the animal's sensing range in terms of metric and topological distance. The algorithmic calculated velocities showed good agreement with observed biological velocities, indicating that the algorithm was an informative basis for comparison with the three species and could potentially be improved for engineered applications with further study., (© 2016 The Author(s).)

Introduction: Our group has previously demonstrated an upward shift from junior to senior resident participation in common general surgery operations, traditionally performed by junior-level residents. The objective of this study was to evaluate if this trend would correct over time. We hypothesized that junior resident case volume would improve., Methods: A sample of essential laparoscopic and open general surgery procedures (appendectomy, inguinal herniorrhaphy, cholecystectomy, and partial colectomy) was chosen for analysis. The American College of Surgeons National Surgical Quality Improvement Program Participant Use Files were queried for these procedures between 2005 and 2012. Cases were stratified by participating resident post-graduate year with "junior resident" defined as post-graduate year1-3. Logistic regression was performed to determine change in junior resident participation for each type of procedure over time., Results: A total of 185,335 cases were included in the study. For 3 of the operations we considered, the prevalence of laparoscopic surgery increased from 2005-2012 (all p < 0.001). Cholecystectomy was an exception, which showed an unchanged proportion of cases performed laparoscopically across the study period (p = 0.119). Junior resident participation decreased by 4.5%/y (p < 0.001) for laparoscopic procedures and by 6.2%/y (p < 0.001) for open procedures. The proportion of laparoscopic surgeries performed by junior-level residents decreased for appendectomy by 2.6%/y (p < 0.001) and cholecystectomy by 6.1%/y (p < 0.001), whereas it was unchanged for inguinal herniorrhaphy (p = 0.75) and increased for partial colectomy by 3.9%/y (p = 0.003). A decline in junior resident participation was seen for all open surgeries, with appendectomy decreasing by 9.4%/y (p < 0.001), cholecystectomy by 4.1%/y (p < 0.002), inguinal herniorrhaphy by 10%/y (p < 0.001) and partial colectomy by 2.9%/y (p < 0.004)., Conclusions: Along with the proliferation of laparoscopy for common general surgical procedures there has been a concomitant reduction in the participation of junior-level residents. As previously thought, familiarity with laparoscopy has not translated to redistribution of basic operations from senior to junior residents. This trend has significant implications for general surgery resident education., (Copyright © 2016 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.)

We present a computational study of flapping-wing aerodynamics of a calliope hummingbird (Selasphorus calliope) during fast forward flight. Three-dimensional wing kinematics were incorporated into the model by extracting time-dependent wing position from high-speed videos of the bird flying in a wind tunnel at 8.3 m s(-1). The advance ratio, i.e. the ratio between flight speed and average wingtip speed, is around one. An immersed-boundary method was used to simulate flow around the wings and bird body. The result shows that both downstroke and upstroke in a wingbeat cycle produce significant thrust for the bird to overcome drag on the body, and such thrust production comes at price of negative lift induced during upstroke. This feature might be shared with bats, while being distinct from insects and other birds, including closely related swifts.

Total proctocolectomy with ileal pouch-anal anastomosis (IPAA) allows restoration of continence in select patients with ulcerative colitis but is associated with significant morbidity. Well-known complications following IPAA include pouchitis, anastomotic leak, and small bowel obstruction. Obstruction secondary to ileal pouch volvulus is exceedingly rare. We report a case of ileal pouch volvulus, which occurred secondary to internal hernia. Radiographic and endoscopic identification of volvulus allowed for early operative management and pouch salvage.

We used videography to investigate direct lateral maneuvers, i.e. 'sideslips', of the hawkmoth Manduca sexta. M. sexta sideslip by rolling their entire body and wings to reorient their net force vector. During sideslip they increase net aerodynamic force by flapping with greater amplitude, (in both wing elevation and sweep), allowing them to continue to support body weight while rolled. To execute the roll maneuver we observed in sideslips, they use an asymmetric wing stroke; increasing the pitch of the roll-contralateral wing pair, while decreasing that of the roll-ipsilateral pair. They also increase the wing sweep amplitude of, and decrease the elevation amplitude of, the contralateral wing pair relative to the ipsilateral pair. The roll maneuver unfolds in a stairstep manner, with orientation changing more during downstroke than upstroke. This is due to smaller upstroke wing pitch angle asymmetries as well as increased upstroke flapping counter-torque from left-right differences in global reference frame wing velocity about the moth's roll axis. Rolls are also opposed by stabilizing aerodynamic moments from lateral motion, such that rightward roll velocity will be opposed by rightward motion. Computational modeling using blade-element approaches confirm the plausibility of a causal linkage between the previously mentioned wing kinematics and roll/sideslip. Model results also predict high degrees of axial and lateral damping. On the time scale of whole and half wing strokes, left-right wing pair asymmetries directly relate to the first, but not second, derivative of roll. Collectively, these results strongly support a roll-based sideslip with a high degree of roll damping in M. sexta., (© 2016. Published by The Company of Biologists Ltd.)

We used computational fluid dynamics to determine whether lift- or drag-based mechanisms generate the most vertical force in the flight of the smallest insects. These insects fly at Re on the order of 4-60 where viscous effects are significant. Detailed quantitative data on the wing kinematics of the smallest insects is not available, and as a result both drag- and lift-based strategies have been suggested as the mechanisms by which these insects stay aloft. We used the immersed boundary method to solve the fully-coupled fluid-structure interaction problem of a flexible wing immersed in a two-dimensional viscous fluid to compare three idealized hovering kinematics: a drag-based stroke in the vertical plane, a lift-based stroke in the horizontal plane, and a hybrid stroke on a tilted plane. Our results suggest that at higher Re, a lift-based strategy produces more vertical force than a drag-based strategy. At the Re pertinent to small insect hovering, however, there is little difference in performance between the two strategies. A drag-based mechanism of flight could produce more vertical force than a lift-based mechanism for insects at Re<5; however, we are unaware of active fliers at this scale., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background: Surgical site infection is common following colorectal surgery, yet the incidence varies widely. CDC criteria include "diagnosis by attending physician," which can be subjective. Alternatively, the ASEPSIS score is an objective scoring system based on the presence of clinical findings., Objective: The aim of this study is to compare the interrater reliability of the ASEPSIS score vs CDC definitions in identifying surgical site infection., Design: This 24-month prospective study used serial photography of the wound. Three attending surgeons independently reviewed blinded photographic/clinical data., Settings: This study was conducted at an academic institution., Patients: Patients undergoing elective colorectal surgery were selected., Interventions: Surgeons assigned an ASEPSIS score and identified surgical site infection by using CDC definitions. The interrater reliability of ASEPSIS and the CDC criteria were compared by using the κ statistic. These data were also compared with the institutional National Surgical Quality Improvement Program database., Results: One hundred seventy-one patients were included. Four surgical site infections (2.4%) were identified by the National Surgical Quality Improvement Program. Data from the surgeons demonstrated significantly higher yet discrepant rates of infection by the CDC criteria, at 6.2%, 7.4%, and 14.1% with a κ of 0.55 indicating modest interrater agreement. Alternatively, the ASEPSIS assessments demonstrated excellent interrater agreement between surgeons with 96% agreement (2.4%, 2.4%, and 3.6%) and a κ of 0.83., Limitations: This was a single-institution study., Conclusions: This study demonstrates the relatively poor reliability of CDC definitions for surgical site infections in comparison with an objective scoring system. These findings could explain the wide variability in the literature and raise concern for the comparison of institutional surgical site infection rates as a quality indicator. Alternatively, an objective scoring system, like the ASEPSIS score, may yield more reliable measures for comparison.

Background: Population-based studies historically report underutilization of a resection in patients with colorectal metastases to the liver. Recent data suggest limitations of the methods in the historical analysis. The present study examines trends in a hepatic resection and survival among Medicare recipients with hepatic metastases., Methods: Medicare recipients with incident colorectal cancer diagnosed between 1991 and 2009 were identified in the SEER(Surveillance, Epidemiology and End Results)-Medicare dataset. Patients were stratified into historical (1991-2001) and current (2002-2009) cohorts. Analyses compared treatment, peri-operative outcomes and survival., Results: Of 31.574 patients with metastatic colorectal cancer to the liver, 14,859 were in the current cohort treated after 2002 and 16,715 comprised the historical control group. The overall proportion treated with a hepatic resection increased significantly during the study period (P < 0.001) with pre/post change from 6.5% pre-2002 to 7.5% currently (P < 0.001). Over time, haemorrhagic and infectious complications declined (both P ≤ 0.047), but 30-day mortality was similar (3.5% versus 3.9%, P = 0.660). After adjusting for predictors of survival, the use of a hepatic resection [hazard ratio (HR) = 0.40, 95% confidence interval (CI): 0.38-0.42, P < 0.001] and treatment after 2002 (HR = 0.88, 95% CI: 0.86-0.90, P < 0.001) were associated with a reduced risk of death., Conclusions: Case identification using International Classification of Diseases, 9th Revision (ICD-9) codes is imperfect; however, comparison of trends over time suggests an improvement in multimodality therapy and survival in patients with colorectal metastases to the liver., (© 2015 International Hepato-Pancreato-Biliary Association.)

Despite intense study by physicists and biologists, we do not fully understand the unsteady aerodynamics that relate insect wing morphology and kinematics to lift generation. Here, we formulate a force partitioning method (FPM) and implement it within a computational fluid dynamic model to provide an unambiguous and physically insightful division of aerodynamic force into components associated with wing kinematics, vorticity, and viscosity. Application of the FPM to hawkmoth and fruit fly flight shows that the leading-edge vortex is the dominant mechanism for lift generation for both these insects and contributes between 72-85% of the net lift. However, there is another, previously unidentified mechanism, the centripetal acceleration reaction, which generates up to 17% of the net lift. The centripetal acceleration reaction is similar to the classical inviscid added-mass in that it depends only on the kinematics (i.e. accelerations) of the body, but is different in that it requires the satisfaction of the no-slip condition, and a combination of tangential motion and rotation of the wing surface. Furthermore, the classical added-mass force is identically zero for cyclic motion but this is not true of the centripetal acceleration reaction. Furthermore, unlike the lift due to vorticity, centripetal acceleration reaction lift is insensitive to Reynolds number and to environmental flow perturbations, making it an important contributor to insect flight stability and miniaturization. This force mechanism also has broad implications for flow-induced deformation and vibration, underwater locomotion and flows involving bubbles and droplets.

Hummingbirds are known to defend food resources such as nectar sources from encroachment by competitors (including conspecifics). These competitive intraspecific interactions provide an opportunity to quantify the biomechanics of hummingbird flight performance during ecologically relevant natural behavior. We recorded the three-dimensional flight trajectories of Ruby-throated Hummingbirds defending, being chased from and freely departing from a feeder. These trajectories allowed us to compare natural flight performance to earlier laboratory measurements of maximum flight speed, aerodynamic force generation and power estimates. During field observation, hummingbirds rarely approached the maximal flight speeds previously reported from wind tunnel tests and never did so during level flight. However, the accelerations and rates of change in kinetic and potential energy we recorded indicate that these hummingbirds likely operated near the maximum of their flight force and metabolic power capabilities during these competitive interactions. Furthermore, although birds departing from the feeder while chased did so faster than freely-departing birds, these speed gains were accomplished by modulating kinetic and potential energy gains (or losses) rather than increasing overall power output, essentially trading altitude for speed during their evasive maneuver. Finally, the trajectories of defending birds were directed toward the position of the encroaching bird rather than the feeder.

Few vertebrates run on water. The largest animals to accomplish this feat are western and Clark's grebes (Aechmophorus occidentalis and Aechmophorus clarkii). These birds use water running to secure a mate during a display called rushing. Grebes weigh an order of magnitude more than the next largest water runners, basilisk lizards (Basilicus basiliscus), and therefore face a greater challenge to support their body weight. How do these birds produce the hydrodynamic forces necessary to overcome gravity and sustain rushing? We present the first quantitative study of water running by grebes. High-speed video recordings elucidate the hindlimb movements of grebes rushing in the wild. We complement these findings with laboratory experiments using physical models and a preserved grebe foot to estimate how slapping the water surface contributes to weight support. Our results indicate that grebes use three novel tactics to successfully run on water. First, rushing grebes use exceptionally high stride rates, reaching 10 Hz. Second, grebe foot size and high water impact speed allow grebes to generate up to 30-55% of the required weight support through water slap alone. Finally, flattened foot bones reduce downward drag, permitting grebes to retract each foot from the water laterally. Together, these mechanisms outline a water-running strategy qualitatively different from that of the only previously studied water runner, the basilisk lizard. The hydrodynamic specializations of rushing grebes could inform the design of biomimetic appendages. Furthermore, the mechanisms underlying this impressive display demonstrate that evolution can dramatically alter performance under sexual selection., (© 2015. Published by The Company of Biologists Ltd.)

Background: Colorectal surgery is associated with considerable morbidity and prolonged length of stay (LOS). Recognizing the need for improvement, we implemented an enhanced recovery (ER) protocol for all patients undergoing elective colorectal surgery at an academic institution., Study Design: A multidisciplinary team implemented an ER protocol based on: preoperative counseling with active patient participation, carbohydrate loading, multimodal analgesia with avoidance of intravenous opioids, intraoperative goal-directed fluid resuscitation, immediate postoperative feeding, and ambulation. Discharge requirements remained identical throughout. A before and after study design was undertaken comparing patients before (August 2012 to February 2013) and after implementation of an ER protocol (August 2013 to February 2014). Risk stratification was performed using the NSQIP risk calculator to calculate the predicted LOS for each patient based on 23 variables., Results: One hundred and nine consecutive patients underwent surgery within the ER protocol compared with 98 consecutive historical controls (conventional). The risk-adjusted predicted LOS was similar for each group at 5.1 and 5.2 days. Substantial reductions were seen in LOS, morphine equivalents, intravenous fluids, return of bowel function, and overall complications with the ER group. There was a $7,129/patient reduction in direct cost, corresponding to a cost savings of $777,061 in the ER group. Patient satisfaction as measured by Press Ganey improved considerably during the study period., Conclusions: Implementation of an ER protocol led to improved patient satisfaction and substantial reduction in LOS, complication rates, and costs for patients undergoing both open and laparoscopic colorectal surgery. These data demonstrate that small investments in the perioperative environment can lead to large returns., (Copyright © 2015 American College of Surgeons. Published by Elsevier Inc. All rights reserved.)

Intraoperative wound classification is a predictor of postoperative infection. Therefore, accurately assigning the correct classification to a surgical wound is of particular importance. Our institution participates in the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP), a national outcomes database that collects wound classification for all qualifying operative procedures, and we noted discrepancies when comparing ACS NSQIP wound classification coding with perioperative coding in our electronic medical record. We tested the effectiveness of an intervention that included staff educational sessions, informational posters, and postoperative debriefings on improving the accuracy of documented intraoperative wound classification. The χ(2) test was used to compare proportions of wound classification miscodings before and after educational sessions and debriefings commenced. Baseline data revealed misclassification of wounds occurred 21 per cent (30 of 141) of the time in predominately colorectal procedures performed by two surgeons from April through August 2012. Errors decreased to 9 per cent (13 of 147) from August to December 2012, after our intervention of education sessions with operating room staff and the surgeons incorporating a statement confirming the wound classification at the end of the case debriefing. The χ(2) statistic was 8.7589. The P value was significant at 0.003. Ensuring concordance of classification between the surgeon and nurse during a postprocedure debriefing as well as education of perioperative nursing staff through posters and seminars significantly improved the accuracy of intraoperative wound classification coding.

In hovering flight, hummingbirds reverse the angle of attack of their wings through pitch reversal in order to generate aerodynamic lift during both downstroke and upstroke. In addition, the wings may pitch during translation to further enhance lift production. It is not yet clear whether these pitching motions are caused by the wing inertia or actuated through the musculoskeletal system. Here we perform a computational analysis of the pitching dynamics by incorporating the realistic wing kinematics to determine the inertial effects. The aerodynamic effect is also included using the pressure data from a previous three-dimensional computational fluid dynamics simulation of a hovering hummingbird. The results show that like many insects, pitch reversal of the hummingbird is, to a large degree, caused by the wing inertia. However, actuation power input at the root is needed in the beginning of pronation to initiate a fast pitch reversal and also in mid-downstroke to enable a nose-up pitching motion for lift enhancement. The muscles on the wing may not necessarily be activated for pitching of the distal section. Finally, power analysis of the flapping motion shows that there is no requirement for substantial elastic energy storage or energy absorption at the shoulder joint.

The aerodynamics of flapping flight for the smallest insects such as thrips is often characterized by a 'clap and fling' of the wings at the end of the upstroke and the beginning of the downstroke. These insects fly at Reynolds numbers (Re) of the order of 10 or less where viscous effects are significant. Although this wing motion is known to augment the lift generated during flight, the drag required to fling the wings apart at this scale is an order of magnitude larger than the corresponding force acting on a single wing. As the opposing forces acting normal to each wing nearly cancel during the fling, these large forces do not have a clear aerodynamic benefit. If flight efficiency is defined as the ratio of lift to drag, the clap and fling motion dramatically reduces efficiency relative to the case of wings that do not aerodynamically interact. In this paper, the effect of a bristled wing characteristic of many of these insects was investigated using computational fluid dynamics. We performed 2D numerical simulations using a porous version of the immersed boundary method. Given the computational complexity involved in modeling flow through exact descriptions of bristled wings, the wing was modeled as a homogeneous porous layer as a first approximation. High-speed video recordings of free-flying thrips in take-off flight were captured in the laboratory, and an analysis of the wing kinematics was performed. This information was used for the estimation of input parameters for the simulations. Compared with a solid wing (without bristles), the results of the study show that the porous nature of the wings contributes largely to drag reduction across the Re range explored. The aerodynamic efficiency, calculated as the ratio of lift to drag coefficients, was larger for some porosities when compared with solid wings., (© 2014. Published by The Company of Biologists Ltd.)

A three-dimensional computational fluid dynamics simulation is performed for a ruby-throated hummingbird (Archilochus colubris) in hovering flight. Realistic wing kinematics are adopted in the numerical model by reconstructing the wing motion from high-speed imaging data of the bird. Lift history and the three-dimensional flow pattern around the wing in full stroke cycles are captured in the simulation. Significant asymmetry is observed for lift production within a stroke cycle. In particular, the downstroke generates about 2.5 times as much vertical force as the upstroke, a result that confirms the estimate based on the measurement of the circulation in a previous experimental study. Associated with lift production is the similar power imbalance between the two half strokes. Further analysis shows that in addition to the angle of attack, wing velocity and surface area, drag-based force and wing-wake interaction also contribute significantly to the lift asymmetry. Though the wing-wake interaction could be beneficial for lift enhancement, the isolated stroke simulation shows that this benefit is buried by other opposing effects, e.g. presence of downwash. The leading-edge vortex is stable during the downstroke but may shed during the upstroke. Finally, the full-body simulation result shows that the effects of wing-wing interaction and wing-body interaction are small., (© 2014 The Author(s) Published by the Royal Society. All rights reserved.)

Background: Increasingly, surgical site infection (SSI) is being tied to quality of care. The incidence of SSI after colorectal surgery differs widely. We hypothesize that it is difficult to define SSI reliably and reproducibly when adhering to the U.S. Centers for Disease Control and Prevention (CDC) definitions., Methods: Elective intra-abdominal colorectal procedures via a clean-contaminated incision performed at a single institution between January 1 and May 1, 2011 were queried. Three attending surgeons examined all patients' records retrospectively for documentation of SSI. These data were compared with the institutional National Surgeon Quality Improvement Program (NSQIP) data with regard to deep and superficial incisional SSI., Results: Seventy-one cases met the inclusion criteria. There were six SSIs identified by NSQIP, representing 8.4% of cases. Review of the three attending surgeons demonstrated a significantly higher incidence of SSI, at 27%, 38%, and 23% (p=0.002). The percent of overall agreement between all reviewers was 82.16 with a kappa of 0.64, indicating only modest inter-rater agreement. Lack of attending surgeon documentation and subjective differences in chart interpretation accounted for most discrepancies between the surgeon and NSQIP SSI capture rates., Conclusions: This study highlights the difficulty in defining SSI in colon and rectal surgery, which oftentimes is subjective and difficult to discern from the medical record. According to these preliminary data from our institution, there is poor reliability between clinical reviewers in defining SSI on the basis of the CDC criteria, which has serious implications. The interpretation of clinical trials may be jeopardized if we cannot define SSI accurately. Furthermore, according to current CDC definitions and infection tracking strategies, these data suggest that the institutional incidence of SSI may not be a reliable measure by which to compare institutions. Better methods for defining SSI should be implemented if these data are made publicly available and tied to performance measures.

Cliff swallows (Petrochelidon pyrrhonota) are highly maneuverable social birds that often forage and fly in large open spaces. Here we used multi-camera videography to measure the three-dimensional kinematics of their natural flight maneuvers in the field. Specifically, we collected data on tandem flights, defined as two birds maneuvering together. These data permit us to evaluate several hypotheses on the high-speed maneuvering flight performance of birds. We found that high-speed turns are roll-based, but that the magnitude of the centripetal force created in typical maneuvers varied only slightly with flight speed, typically reaching a peak of ~2 body weights. Turning maneuvers typically involved active flapping rather than gliding. In tandem flights the following bird copied the flight path and wingbeat frequency (~12.3 Hz) of the lead bird while maintaining position slightly above the leader. The lead bird turned in a direction away from the lateral position of the following bird 65% of the time on average. Tandem flights vary widely in instantaneous speed (1.0 to 15.6 m s(-1)) and duration (0.72 to 4.71 s), and no single tracking strategy appeared to explain the course taken by the following bird., (© 2014. Published by The Company of Biologists Ltd.)

Stereo videography is a powerful technique for quantifying the kinematics and behavior of animals, but it can be challenging to use in an outdoor field setting. We here present a workflow and associated software for performing calibration of cameras placed in a field setting and estimating the accuracy of the resulting stereoscopic reconstructions. We demonstrate the workflow through example stereoscopic reconstructions of bat and bird flight. We provide software tools for planning experiments and processing the resulting calibrations that other researchers may use to calibrate their own cameras. Our field protocol can be deployed in a single afternoon, requiring only short video clips of light, portable calibration objects., (© 2014. Published by The Company of Biologists Ltd.)

Vertical vortex systems such as tornadoes dramatically affect the flight control and stability of aircraft. However, the control implications of smaller scale vertically oriented vortex systems for small fliers such as animals or micro-air vehicles are unknown. Here we examined the flapping kinematics and body dynamics of hawkmoths performing hovering flights (controls) and maintaining position in three different whirlwind intensities with transverse horizontal velocities of 0.7, 0.9 and 1.2 m s(-1), respectively, generated in a vortex chamber. The average and standard deviation of yaw and pitch were respectively increased and reduced in comparison with hovering flights. Average roll orientation was unchanged in whirlwind flights but was more variable from wingbeat to wingbeat than in hovering. Flapping frequency remained unchanged. Wingbeat amplitude was lower and the average stroke plane angle was higher. Asymmetry was found in the angle of attack between right and left wings during both downstroke and upstroke at medium and high vortex intensities. Thus, hawkmoth flight control in tornado-like vortices is achieved by a suite of asymmetric and symmetric changes to wingbeat amplitude, stroke plane angle and principally angle of attack.

Background: There is a mounting body of evidence that suggests worsened postoperative outcomes at the extremes of BMI, yet few studies investigate this relationship in patients undergoing proctectomy for rectal cancer., Objective: We aimed to examine the relationship between BMI and short-term outcomes after proctectomy for cancer., Design: This was a retrospective study comparing the outcomes of patients undergoing proctectomy for rectal cancer as they relate to BMI., Settings: The American College of Surgeons-National Surgical Quality Improvement Program database was queried for this study., Patients: Patients included were those who underwent proctectomy for rectal neoplasm between 2005 and 2011., Main Outcome Measures: Study end points included 30-day mortality and overall morbidity, including the receipt of blood transfusion, venous thromboembolic disease, wound dehiscence, renal failure, reintubation, cardiac complications, readmission, reoperation, and infectious complications (surgical site infection, intra-abdominal abscess, pneumonia, and urinary tract infection). Univariate logistic regression was used to analyze differences among patients of varying BMI ranges (kg/m; ≤20, 20-24, 25-29, 30-34, and ≥35). When significant differences were found, multivariable logistic regression, adjusting for preoperative demographic and clinical variables, was performed., Results: A total of 11,995 patients were analyzed in this study. The incidences of overall morbidity, wound infection, urinary tract infection, venous thromboembolic event, and sepsis were highest in those patients with a BMI of ≥35 kg/m (OR, 1.63, 3.42, 1.47, 1.64, and 1.50). Wound dehiscence was also significantly more common in heavier patients. Patients with a BMI <20 kg/m had significantly increased rates of mortality (OR, 1.72) and sepsis (OR, 1.30)., Limitations: This study was limited by its retrospective design. Furthermore, it only includes patients from the American College of Surgeons-National Surgical Quality Improvement Program database, limiting its generalizability to nonparticipating hospitals., Conclusions: Obese and underweight patients undergoing proctectomy for neoplasm are at a higher risk for postoperative complications and death.

Objectives: To investigate the role of sex on cytokine expression and mortality in critically ill patients., Design: A cohort of patients admitted to were enrolled and followed over a 5-year period., Setting: Two university-affiliated hospital surgical and trauma ICUs., Patients: Patients 18 years old and older admitted for at least 48 hours to the surgical or trauma ICU., Interventions: Observation only., Measurements and Main Results: Major outcomes included admission cytokine levels, prevalence of ICU-acquired infection, and mortality during hospitalization conditioned on trauma status and sex. The final cohort included 2,291 patients (1,407 trauma and 884 nontrauma). The prevalence of ICU-acquired infection was similar for men (46.5%) and women (44.5%). All-cause in-hospital mortality was 12.7% for trauma male patient and 9.1% for trauma female patient (p = 0.065) and 22.9% for nontrauma male patients and 20.6% for nontrauma female patients (p = 0.40). Among trauma patients, logistic regression analysis identified female sex as protective for all-cause mortality (odds ratio, 0.57). Among trauma patients, men had significantly higher admission serum levels of interleukin-2, interleukin-12, interferon-γ, and tumor necrosis factor-α, and among nontrauma patients, men had higher admission levels of interleukin-8 and tumor necrosis factor-α., Conclusions: The relationship between sex and outcomes in critically ill patients is complex and depends on underlying illness. Women appear to be better adapted to survive traumatic events, while sex may be less important in other forms of critical illness. The mechanisms accounting for this gender dimorphism may, in part, involve differential cytokine responses to injury, with men expressing a more robust proinflammatory profile.

Shedding of vortices is a common phenomenon in the atmosphere over a wide range of spatial and temporal scales. However, it is unclear how these vortices of varying scales affect the flight performance of flying animals. In order to examine these interactions, we trained seven hawkmoths (Manduca sexta) (wingspan ~9 cm) to fly and feed in a wind tunnel under steady flow (controls) and in the von Kármán vortex street of vertically oriented cylinders (two different cylinders with diameters of 10 and 5 cm) at speeds of 0.5, 1 and 2 m s(-1). Cylinders were placed at distances of 5, 25 and 100 cm upstream of the moths. Moths exhibited large amplitude yaw oscillations coupled with modest oscillations in roll and pitch, and slight increases in wingbeat frequency when flying in both the near (recirculating) and middle (vortex dominated) wake regions. Wingbeat amplitude did not vary among treatments, except at 1 m s(-1) for the large cylinder. Yaw and roll oscillations were synchronized with the vortex shedding frequencies in moths flying in the wake of the large cylinder at all speeds. In contrast, yaw and pitch were synchronized with the shedding frequency of small vortices at speeds ≤1 m s(-1). Oscillations in body orientation were also substantially smaller in the small cylinder treatment when compared with the large cylinder, regardless of temporal or non-dimensional spatial scale. Moths flying in steady conditions reached a higher air speed than those flying into cylinder wakes. In general, flight effects produced by the cylinder wakes were qualitatively similar among the recirculating and vortex-dominated wake regions; the magnitude of those effects, however, declined gradually with downstream distance.

Colovesical fistula involving the sigmoid colon is the most common fistulous communication between the gastrointestinal tract and the urinary bladder. These tracts are most commonly associated with diverticulitis but might arise secondary to a neoplasm, inflammatory bowel disease, iatrogenic injuries, radiation therapy, trauma, or foreign bodies. We describe a patient who developed a fistula between the sigmoid colon and bladder secondary to an ingested chicken bone that lodged in a colonic diverticulum. A portion of the foreign body was removed by direct visualization on colonoscopy; the remaining fragment passed spontaneously per urethra after hospital discharge., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Caring for patients with constipation and pelvic outlet obstruction can be challenging, requiring skill, patience, and empathy on the part of the medical professional. The mainstay of treatment is behavioral with surgery reserved for a select group of patients. The evaluation, diagnostic, and treatment modalities of both constipation and pelvic outlet with a focus on current advancements and technology are explored in depth., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Colonic Crohn disease is a complicated disease entity that requires a multidisciplinary effort on the part of the surgeon, gastroenterologist, and pathologist. Crohn disease affects ∼500,000 people in North America with nearly 300,000 people suffering from colonic manifestations. This represents a significant portion of the patient population in the typical colorectal surgeon's practice. As such, an intimate understanding of the disease process, presentation, and treatment options is imperative. In this article, the authors review the clinical manifestations, diagnosis, and medical and surgical treatment options with a focus on current strategies for surgical management.

Background: Surgical site infection is one of the most common and significant morbidities following colon and rectal surgery, representing a marker of institutional quality. Various measures have been implemented to lower its incidence. However, the level of incidence remains unacceptable in many reports., Objective: This study addresses whether surgical site infections can be accurately predicted in an outpatient clinical setting among patients undergoing elective colon and rectal surgery., Design: This investigation was designed as a retrospective cohort study with the use of logistic regression modeling., Settings: Data for this study were extracted from the American College of Surgeons National Surgical Quality Improvement Program Participant user data file., Patients: Patients undergoing elective intraabdominal colorectal surgery during 2009 were included., Main Outcome Measures: The primary outcome measured was the probability of 30-day surgical site infection (superficial and deep incisional)., Results: A total of 18,403 records for patients with colorectal surgery were identified. Superficial incisional surgical site infections were identified in 1447 records (7.86%). Deep incisional surgical site infections were identified in 278 records (1.51%). Body mass index, preoperative hematocrit, open approach, ASA classification level, smoking, alcohol use, functional status before surgery, and age more than 75 years were identified as likely independent predictors of deep and superficial surgical site infections. Multivariable logistic regression analysis was used to develop a series of predictive models. Reduced versions of the models were then developed that included only highly statistically significant predictors of infection in the corresponding full models (age, alcohol abuse, ASA classification, stoma closure, open approach, BMI, and hematocrit). Nomograms representing the final reduced model equations are presented., Limitations: This study was limited by the use of an administrative database and its retrospective design., Conclusions: Surgical site infection is common morbidity following colon and rectal surgery. Nomograms using key patient characteristics can be used to accurately calculate a patients' risk of surgical site infection. This tool could be applied in the clinical setting to prospectively identify patients at highest risk of surgical site infection.

The Model for End-stage Liver Disease (MELD) score was previously shown to predict perioperative mortality in patients with cirrhosis undergoing a variety of nontransplant surgical procedures. We sought to determine its usefulness in predicting postoperative mortality in patients undergoing colorectal procedures. National Surgical Quality Improvement Program data were gathered for adult patients undergoing elective and emergent colorectal procedures (Current Procedural Terminology codes 44005 through 45563 excluding appendectomy) during 2005 and 2006 at participating centers. The preoperative MELD score was calculated for all patients and assessed using logistic regression modeling. A total of 10,033 patients met study inclusion criteria. Overall 30-day mortality was 6.6 per cent. In all patients undergoing colorectal surgery, MELD was an independent predictor of mortality (2.95 [2.27 to 3.84]). Other independent predictors included age, functional status, American Society of Anesthesiologists classification, ascites, esophageal varices, disseminated cancer, chronic steroid use, cardiac disease, renal failure, malnutrition, sepsis, emergency, and ventilator dependence. The MELD score is an independent predictor of mortality in patients undergoing colorectal procedures. These data can be used to assign risk and assist in clinical decision-making.

Insect wings can undergo significant chordwise (camber) as well as spanwise (twist) deformation during flapping flight but the effect of these deformations is not well understood. The shape and size of butterfly wings leads to particularly large wing deformations, making them an ideal test case for investigation of these effects. Here we use computational models derived from experiments on free-flying butterflies to understand the effect of time-varying twist and camber on the aerodynamic performance of these insects. High-speed videogrammetry is used to capture the wing kinematics, including deformation, of a Painted Lady butterfly (Vanessa cardui) in untethered, forward flight. These experimental results are then analyzed computationally using a high-fidelity, three-dimensional, unsteady Navier-Stokes flow solver. For comparison to this case, a set of non-deforming, flat-plate wing (FPW) models of wing motion are synthesized and subjected to the same analysis along with a wing model that matches the time-varying wing-twist observed for the butterfly, but has no deformation in camber. The simulations show that the observed butterfly wing (OBW) outperforms all the flat-plate wings in terms of usable force production as well as the ratio of lift to power by at least 29% and 46%, respectively. This increase in efficiency of lift production is at least three-fold greater than reported for other insects. Interestingly, we also find that the twist-only-wing (TOW) model recovers much of the performance of the OBW, demonstrating that wing-twist, and not camber is key to forward flight in these insects. The implications of this on the design of flapping wing micro-aerial vehicles are discussed.

Recent advances in computational methods have made realistic large-scale simulations of animal locomotion possible. This has resulted in numerous mathematical and computational studies of animal movement through fluids and over substrates with the purpose of better understanding organisms' performance and improving the design of vehicles moving through air and water and on land. This work has also motivated the development of improved numerical methods and modeling techniques for animal locomotion that is characterized by the interactions of fluids, substrates, and structures. Despite the large body of recent work in this area, the application of mathematical and numerical methods to improve our understanding of organisms in the context of their environment and physiology has remained relatively unexplored. Nature has evolved a wide variety of fascinating mechanisms of locomotion that exploit the properties of complex materials and fluids, but only recently are the mathematical, computational, and robotic tools available to rigorously compare the relative advantages and disadvantages of different methods of locomotion in variable environments. Similarly, advances in computational physiology have only recently allowed investigators to explore how changes at the molecular, cellular, and tissue levels might lead to changes in performance at the organismal level. In this article, we highlight recent examples of how computational, mathematical, and experimental tools can be combined to ultimately answer the questions posed in one of the grand challenges in organismal biology: "Integrating living and physical systems."

Wing damage is common in flying insects and has been studied using a variety of approaches to assess its biomechanical and fitness consequences. Results of these studies range from strong to nil effect among the variety of species, fitness measurements and damage modes studied, suggesting that not all damage modes are equal and that insects may be well adapted to compensate for some types of damage. Here, we examine the biomechanical and neuromuscular means by which flying insects compensate for asymmetric wing damage, which is expected to produce asymmetric flight forces and torques and thus destabilize the animal in addition to reducing its total wing size. We measured the kinematic and neuromuscular responses of hawkmoths (Manduca sexta) hovering in free flight with asymmetrically damaged wings via high-speed videography and extracellular neuromuscular activity recordings. The animals responded to asymmetric wing damage with asymmetric changes to wing stroke amplitude sufficient to restore symmetry in lift production. These asymmetries in stroke amplitude were significantly correlated with bilateral asymmetries in the timing of activation of the dorsal ventral muscle among and within trials. Correspondingly, the magnitude of wing asymmetry was significantly, although non-linearly, correlated with the magnitude of the neuromuscular response among individuals. The strongly non-linear nature of the relationship suggests that active neural compensation for asymmetric wing damage may only be necessary above a threshold (>12% asymmetry in wing second moment of area in this case) below which passive mechanisms may be adequate to maintain flight stability.

Hummingbirds (Trochilidae) are widely known for their insect-like flight strokes characterized by high wing beat frequency, small muscle strains and a highly supinated wing orientation during upstroke that allows for lift production in both halves of the stroke cycle. Here, we show that hummingbirds achieve these functional traits within the limits imposed by a vertebrate endoskeleton and muscle physiology by accentuating a wing inversion mechanism found in other birds and using long-axis rotational movement of the humerus. In hummingbirds, long-axis rotation of the humerus creates additional wing translational movement, supplementing that produced by the humeral elevation and depression movements of a typical avian flight stroke. This adaptation increases the wing-to-muscle-transmission ratio, and is emblematic of a widespread scaling trend among flying animals whereby wing-to-muscle-transmission ratio varies inversely with mass, allowing animals of vastly different sizes to accommodate aerodynamic, biomechanical and physiological constraints on muscle-powered flapping flight.

The biomechanical properties of an animal's locomotor structures profoundly influence the relationship between neuromuscular inputs and body movements. In particular, passive stability properties are of interest as they may offer a non-neural mechanism for simplifying control of locomotion. Here, we hypothesized that a passive stability property of animal flight, flapping counter-torque (FCT), allows hawkmoths to control planar yaw turns in a damping-dominated framework that makes rotational velocity directly proportional to neuromuscular activity. This contrasts with a more familiar inertia-dominated framework where acceleration is proportional to force and neuromuscular activity. To test our hypothesis, we collected flight muscle activation timing, yaw velocity and acceleration data from freely flying hawkmoths engaged in planar yaw turns. Statistical models built from these data then allowed us to infer the degree to which the moths inhabit either damping- or inertia-dominated control domains. Contrary to our hypothesis, a combined model corresponding to inertia-dominated control of yaw but including substantial damping effects best linked the neuromuscular and kinematic data. This result shows the importance of including passive stability properties in neuromechanical models of flight control and reveals possible trade-offs between manoeuvrability and stability derived from damping.

Background: The neuroimmunologic effect of traumatic head injury remains ill-defined. This study aimed to characterize systemic cytokine profiles among traumatically injured patients to assess the effect of traumatic head injury on the systemic inflammatory response., Study Design: For 5 years, 1,022 patients were evaluated from a multi-institutional Trauma Immunomodulatory Database. Patients were stratified by presence of severe head injury (SHI; head Injury Severity Score ≥4, n = 335) vs nonsevere head injury (NHI; head Injury Severity Score ≤3, n = 687). Systemic cytokine expression was quantified by ELISA within 72 hours of admission. Patient factors, outcomes, and cytokine profiles were compared by univariate analyses., Results: SHI patients were more severely injured with higher mortality, despite similar ICU infection and ventilator-associated pneumonia rates. Expression of early proinflammatory cytokines, interleukin-6 (p < 0.001) and tumor necrosis factor-α (p = 0.02), was higher among NHI patients, and expression of immunomodulatory cytokines, interferon-γ (p = 0.01) and interleukin-12 (p = 0.003), was higher in SHI patients. High tumor necrosis factor-α levels in NHI patients were associated with mortality (p = 0.01), increased mechanical ventilation (p = 0.02), and development of ventilator-associated pneumonia (p = 0.01). Alternatively, among SHI patients, high interleukin-2 levels were associated with survival, decreased mechanical ventilation, and absence of ventilator-associated pneumonia., Conclusions: The presence of severe traumatic head injury significantly alters systemic cytokine expression and exerts an immunomodulatory effect. Early recognition of these profiles can allow for targeted intervention to reduce patient morbidity and mortality., (Copyright © 2012 American College of Surgeons. Published by Elsevier Inc. All rights reserved.)

Flying animals exhibit remarkable degrees of both stability and manoeuvrability. Our understanding of these capabilities has recently been improved by the identification of a source of passive damping specific to flapping flight. Examining how this damping effect scales among different species and how it affects active manoeuvres as well as recovery from perturbations provides general insights into the flight of insects, birds and bats. These new damping models offer a means to predict manoeuvrability and stability for a wide variety of flying animals using prior reports of the morphology and flapping motions of these species. Furthermore, the presence of passive damping is likely to have facilitated the evolution of powered flight in animals by providing a stability benefit associated with flapping.

Insects produce a variety of exquisitely controlled manoeuvres during natural flight behaviour. Here we show how hawkmoths produce and control one such manoeuvre, an avoidance response consisting of rapid pitching up, rearward flight, pitching down (often past the original pitch angle), and then pitching up slowly to equilibrium. We triggered these manoeuvres via a sudden visual stimulus in front of free-flying hawkmoths (Manduca sexta) while recording the animals' body and wing movements via high-speed stereo videography. We then recreated the wing motions in a dynamically scaled model to: (1) associate wing kinematic changes with pitch torque production and (2) extract the open-loop dynamics of an uncontrolled moth. Next, we characterized the closed-loop manoeuvring dynamics from the observed flight behaviour assuming that hawkmoths use feedback control based on translational velocity, pitch angle and angular velocity, and then compared these with the open-loop dynamics to identify the control strategy used by the moth. Our analysis revealed that hawkmoths produce active pitch torque via changes in mean wing spanwise rotation angle. Additionally, body translations produce passive translational damping and pitch torque, both of which are linearly dependent on the translational velocity. Body rotations produce similar passive forces and torques, but of substantially smaller magnitudes. Our comparison of closed-loop and open-loop dynamics showed that hawkmoths rely largely on passive damping to reduce the body translation but use feedback control based on pitch angle and angular velocity to control their orientation. The resulting feedback control system remains stable with sensory delays of more than two wingbeats.

Objective: Heparin-induced thrombocytopenia is a common adverse effect of treatment with heparin resulting in paradoxical thromboses. An immunoglobulin G class "heparin-induced thrombocytopenia antibody" attaches to a heparin-platelet factor 4 protein complex. The antibody then binds to the FcγIIa receptor on the surface of a platelet, resulting in activation, consumption, and thrombocytopenia in the clinical syndrome of heparin-induced thrombocytopenia. In contradistinction to other drug-induced thrombocytopenias that lead to a risk of hemorrhage, the state of thrombocytopenia in heparin-induced thrombocytopenia leads to an acquired hypercoagulability syndrome. Bilateral adrenal hemorrhage associated with heparin-induced thrombocytopenia has become an increasingly documented association. The adrenal gland has a vascular construction that lends itself to venous thrombus in the setting of heparin-induced thrombocytopenia and subsequent arterial hemorrhage. A literature search revealed 17 reported cases of bilateral adrenal hemorrhage in the setting of heparin-induced thrombocytopenia uniformly presenting with complete hemodynamic collapse., Data Sources: An Ovid MEDLINE search of the English-language medical literature was conducted, identifying articles describing cases of bilateral adrenal hemorrhage in the setting of heparin-induced thrombocytopenia., Study Selection: All cases with this association were included in the review., Data Extraction and Data Synthesis: A total of 14 articles were identified, describing 17 individual case reports of bilateral adrenal hemorrhage associated with heparin-induced thrombocytopenia. All cases confirmed known characteristics of heparin-induced thrombocytopenia and uniformly revealed hypotension due to adrenal insufficiency. There were five deaths, resulting in an overall mortality rate of 27.8%, and 100% mortality in the three cases where adrenal insufficiency went unrecognized., Conclusions: The secondary complication of adrenal vein thrombosis leading to bilateral adrenal hemorrhage remains insufficiently recognized and undertreated. The nonspecific presentation of adrenal hemorrhage and insufficiency as a complication of heparin-induced thrombocytopenia, coupled with the catastrophic clinical course of untreated adrenal collapse, requires a high index of suspicion to achieve rapid diagnosis and provide life-saving therapy.

Hummingbirds have the smallest body size and highest wingbeat frequencies of all flying vertebrates, so they represent one endpoint for evaluating the effects of body size on sustained muscle function and flight performance. Other bird species vary neuromuscular recruitment and contractile behavior to accomplish flight over a wide range of speeds, typically exhibiting a U-shaped curve with maxima at the slowest and fastest flight speeds. To test whether the high wingbeat frequencies and aerodynamically active upstroke of hummingbirds lead to different patterns, we flew rufous hummingbirds (Selasphorus rufus, 3 g body mass, 42 Hz wingbeat frequency) in a variable-speed wind tunnel (0-10 m s(-1)). We measured neuromuscular activity in the pectoralis (PECT) and supracoracoideus (SUPRA) muscles using electromyography (EMG, N=4 birds), and we measured changes in PECT length using sonomicrometry (N=1). Differing markedly from the pattern in other birds, PECT deactivation occurred before the start of downstroke and the SUPRA was deactivated before the start of upstroke. The relative amplitude of EMG signal in the PECT and SUPRA varied according to a U-shaped curve with flight speed; additionally, the onset of SUPRA activity became relatively later in the wingbeat at intermediate flight speeds (4 and 6 m s(-1)). Variation in the relative amplitude of EMG was comparable with that observed in other birds but the timing of muscle activity was different. These data indicate the high wingbeat frequency of hummingbirds limits the time available for flight muscle relaxation before the next half stroke of a wingbeat. Unlike in a previous study that reported single-twitch EMG signals in the PECT of hovering hummingbirds, across all flight speeds we observed 2.9+/-0.8 spikes per contraction in the PECT and 3.8+/-0.8 spikes per contraction in the SUPRA. Muscle strain in the PECT was 10.8+/-0.5%, the lowest reported for a flying bird, and average strain rate was 7.4+/-0.2 muscle lengths s(-1). Among species of birds, PECT strain scales proportional to body mass to the 0.2 power (infinityM(b)(0.2)) using species data and infinityM(b)(0.3) using independent contrasts. This positive scaling is probably a physiological response to an adverse scaling of mass-specific power available for flight.

Free-flight body dynamics and wing kinematics were collected from recordings of continuous, low-speed, multi-wingbeat yaw turns in hawkmoths (Manduca sexta) using stereo videography. These data were used to examine the effects of rotational damping arising from interactions between the body rotation and flapping motion (flapping counter-torque, FCT) on continuous turning. The moths were found to accelerate during downstroke, then decelerate during upstroke by an amount consistent with FCT damping. Wing kinematics related to turning were then analysed in a simulation of hawkmoth flight; results were consistent with the observed acceleration-deceleration pattern. However, an alternative wing kinematic which produced more continuous and less damped accelerations was found in the simulation. These findings demonstrate that (i) FCT damping is detectable in the dynamics of continuously turning animals and (ii) FCT-reducing kinematics do exist but were not employed by turning moths, possibly because within-wingbeat damping simplifies control of turning by allowing control systems to target angular velocity rather than acceleration.

X-Ray Reconstruction of Moving Morphology (XROMM) comprises a set of 3D X-ray motion analysis techniques that merge motion data from in vivo X-ray videos with skeletal morphology data from bone scans into precise and accurate animations of 3D bones moving in 3D space. XROMM methods include: (1) manual alignment (registration) of bone models to video sequences, i.e., Scientific Rotoscoping; (2) computer vision-based autoregistration of bone models to biplanar X-ray videos; and (3) marker-based registration of bone models to biplanar X-ray videos. Here, we describe a novel set of X-ray hardware, software, and workflows for marker-based XROMM. Refurbished C-arm fluoroscopes retrofitted with high-speed video cameras offer a relatively inexpensive X-ray hardware solution for comparative biomechanics research. Precision for our biplanar C-arm hardware and analysis software, measured as the standard deviation of pairwise distances between 1 mm tantalum markers embedded in rigid objects, was found to be +/-0.046 mm under optimal conditions and +/-0.084 mm under actual in vivo recording conditions. Mean error in measurement of a known distance between two beads was within the 0.01 mm fabrication tolerance of the test object, and mean absolute error was 0.037 mm. Animating 3D bone models from sets of marker positions (XROMM animation) makes it possible to study skeletal kinematics in the context of detailed bone morphology. The biplanar fluoroscopy hardware and computational methods described here should make XROMM an accessible and useful addition to the available technologies for studying the form, function, and evolution of vertebrate animals.