Candidate control design metrics for an agile fighter

Success in the fighter combat environment of the future will certainly demand increasing capability from aircraft technology. These advanced capabilities in the form of superagility and supermaneuverability will require special design techniques which translate advanced air combat maneuvering requirements into design criteria. Control design metrics can provide some of these techniques for the control designer. Thus study presents an overview of control design metrics and investigates metrics for advanced fighter agility. The objectives of various metric users, such as airframe designers and pilots, are differentiated from the objectives of the control designer. Using an advanced fighter model, metric values are documented over a portion of the flight envelope through piloted simulation. These metric values provide a baseline against which future control system improvements can be compared and against which a control design methodology can be developed. Agility is measured for axial, pitch, and roll axes. Axial metrics highlight acceleration and deceleration capabilities under different flight loads and include specific excess power measurements to characterize energy meneuverability. Pitch metrics cover both body-axis and wind-axis pitch rates and accelerations. Included in pitch metrics are nose pointing metrics which highlight displacement capability between the nose and the velocity vector. Roll metrics (or torsion metrics) focus on rotational capability about the wind axis

ISSLS PRIZE IN BIOENGINEERING SCIENCE 2019: biomechanical changes in dynamic sagittal balance and lower limb compensatory strategies following realignment surgery in adult spinal deformity patients.

Study designA longitudinal cohort study.ObjectiveTo define a set of objective biomechanical metrics that are representative of adult spinal deformity (ASD) post-surgical outcomes and that may forecast post-surgical mechanical complications. Current outcomes for ASD surgical planning and post-surgical assessment are limited to static radiographic alignment and patient-reported questionnaires. Little is known about the compensatory biomechanical strategies for stabilizing sagittal balance during functional movements in ASD patients.MethodsWe collected in-clinic motion data from 15 ASD patients and 10 controls during an unassisted sit-to-stand (STS) functional maneuver. Joint motions were measured using noninvasive 3D depth mapping sensor technology. Mathematical methods were used to attain high-fidelity joint-position tracking for biomechanical modeling. This approach provided reliable measurements for biomechanical behaviors at the spine, hip, and knee. These included peak sagittal vertical axis (SVA) over the course of the STS, as well as forces and muscular moments at various joints. We compared changes in dynamic sagittal balance (DSB) metrics between pre- and post-surgery and then separately compared pre- and post-surgical data to controls.ResultsStandard radiographic and patient-reported outcomes significantly improved following realignment surgery. From the DSB biomechanical metrics, peak SVA and biomechanical loads and muscular forces on the lower lumbar spine significantly reduced following surgery (- 19 to - 30%, all p < 0.05). In addition, as SVA improved, hip moments decreased (- 28 to - 65%, all p < 0.05) and knee moments increased (+ 7 to + 28%, p < 0.05), indicating changes in lower limb compensatory strategies. After surgery, DSB data approached values from the controls, with some post-surgical metrics becoming statistically equivalent to controls.ConclusionsLongitudinal changes in DSB following successful multi-level spinal realignment indicate reduced forces on the lower lumbar spine along with altered lower limb dynamics matching that of controls. Inadequate improvement in DSB may indicate increased risk of post-surgical mechanical failure. These slides can be retrieved under Electronic Supplementary Material

Establishment of invasive Black Carp (\u3ci\u3eMylopharyngodon piceus\u3c/i\u3e) in the Mississippi River basin: identifying sources and year classes contributing to recruitment

Black Carp (Mylopharyngodon piceus) was imported to the USA to control aquaculture pond snails. This species has escaped captivity and occurs in parts of the Mississippi River, several tributaries, and floodplain lakes, which is concerning due to potential competition with native fishes and predation on native mussels, many of which are imperiled. However, Black Carp captures have primarily been incidental by commercial fishers, and evidence of reproduction in the wild is limited. The objectives of this study were to assess relative abundance of aquaculture- origin and wild Black Carp using ploidy and otolith stable isotope analysis, identify spatial extent of natural reproduction using otolith microchemistry, assess age distributions of wild and aquaculturesource Black Carp to infer years in which natural reproduction occurred and timing of aquaculture escapement or introductions, and estimate size and age at maturation to assess whether recruitment to adulthood has occurred. Results revealed that Black Carp are established in parts of the Mississippi River basin based on findings that: (1) non-captive Black Carp primarily consist of fertile, naturally-reproduced fish, (2) reproduction has occurred in several rivers, (3) multiple year classes of wild fish are present, and (4) wild fish have recruited to adulthood. Multiple introductions or escapements of aquaculture-source fish into the wild, including both fertile and functionally sterile individuals, were also inferred. Individual growth appears to be rapid, although considerable variation was observed among fish. Additional study is suggested to refine understanding of where and when Black Carp reproduction is occurring in the Mississippi River basin

Increased brain activation during working memory processing after pediatric mild traumatic brain injury (mTBI).

Purpose: The neural substrate of post-concussive symptoms following the initial injury period after mild traumatic brain injury (mTBI) in pediatric populations remains poorly elucidated. This study examined neuropsychological, behavioral, and brain functioning in adolescents post-mTBI to assess whether persistent differences were detectable up to a year post-injury. Methods: Nineteen adolescents (mean age 14.7 years) who experienced mTBI 3–12 months previously (mean 7.5 months) and 19 matched healthy controls (mean age 14.0 years) completed neuropsychological testing and an fMRI auditory-verbal N-back working memory task. Parents completed behavioral ratings. Results: No between-group differences were found for cognition, behavior, or N-back task performance, though the expected decreased accuracy and increased reaction time as task difficulty increased were apparent. However, the mTBI group showed significantly greater brain activation than controls during the most difficult working memory task condition. Conclusion: Greater working memory task-related activation was found in adolescents up to one year post-mTBI relative to controls, potentially indicating compensatory activation to support normal task performance. Differences in brain activation in the mTBI group so long after injury may indicate residual alterations in brain function much later than would be expected based on the typical pattern of natural recovery, which could have important clinical implications

Pioglitazone Treatment Following Spinal Cord Injury Maintains Acute Mitochondrial Integrity and Increases Chronic Tissue Sparing and Functional Recovery

Pioglitazone is an FDA-approved PPAR-γ agonist drug used to for treat diabetes, and it has demonstrated neuroprotective effects in multiple models of central nervous system (CNS) injury. Acute treatment after spinal cord injury (SCI) in rats is reported to suppress neuroinflammation, rescue injured tissues, and improve locomotor recovery. In the current study, we additionally assessed the protective efficacy of pioglitazone treatment on acute mitochondrial respiration, as well as functional and anatomical recovery after contusion SCI in adult male C57BL/6 mice. Mice received either vehicle or pioglitazone (10 mg/kg) at either 15 min or 3 hr after injury (75 kDyn at T9) followed by a booster at 24 hr post-injury. At 25 hr, mitochondria were isolated from spinal cord segments centered on the injury epicenters and assessed for their respiratory capacity. Results showed significantly compromised mitochondrial respiration 25 hr following SCI, but pioglitazone treatment that was initiated either at 15 min or 3 hr post-injury significantly maintained mitochondrial respiration rates near sham levels. A second cohort of injured mice received pioglitazone at 15 min post injury, then once a day for 5 days post-injury to assess locomotor recovery and tissue sparing over 4 weeks. Compared to vehicle, pioglitazone treatment resulted in significantly greater recovery of hind-limb function over time, as determined by serial locomotor BMS assessments and both terminal BMS subscores and gridwalk performance. Such improvements correlated with significantly increased grey and white matter tissue sparing, although pioglitazone treatment did not abrogate long-term injury-induced inflammatory microglia/macrophage responses. In sum, pioglitazone significantly increased functional neuroprotection that was associated with remarkable maintenance of acute mitochondrial bioenergetics after traumatic SCI. This sets the stage for dose-response and delayed administration studies to maximize pioglitazone’s efficacy for SCI while elucidating the precise role that mitochondria play in governing its neuroprotection; the ultimate goal to develop novel therapeutics that specifically target mitochondrial dysfunction

Decreased cerebral blood flow in chronic pediatric mild TBI: an MRI perfusion study

We evaluated cerebral blood flow (CBF) in chronic pediatric mild traumatic brain injury (mTBI) using arterial spin labeling (ASL) magnetic resonance imaging perfusion. mTBI patients showed lower CBF than controls in bilateral frontotemporal regions, with no between-group cognitive differences. Findings suggest ASL may be useful to assess functional abnormalities in pediatric mTBI

Quantification of intracellular payload release from polymersome nanoparticles

Polymersome nanoparticles (PMs) are attractive candidates for spatio-temporal controlled delivery of therapeutic agents. Although many studies have addressed cellular uptake of solid nanoparticles, there is very little data available on intracellular release of molecules encapsulated in membranous carriers, such as polymersomes. Here, we addressed this by developing a quantitative assay based on the hydrophilic dye, fluorescein. Fluorescein was encapsulated stably in PMs of mean diameter 85 nm, with minimal leakage after sustained dialysis. No fluorescence was detectable from fluorescein PMs, indicating quenching. Following incubation of L929 cells with fluorescein PMs, there was a gradual increase in intracellular fluorescence, indicating PM disruption and cytosolic release of fluorescein. By combining absorbance measurements with flow cytometry, we quantified the real-time intracellular release of a fluorescein at a single-cell resolution. We found that 173 ± 38 polymersomes released their payload per cell, with significant heterogeneity in uptake, despite controlled synchronisation of cell cycle. This novel method for quantification of the release of compounds from nanoparticles provides fundamental information on cellular uptake of nanoparticle-encapsulated compounds. It also illustrates the stochastic nature of population distribution in homogeneous cell populations, a factor that must be taken into account in clinical use of this technology.</p

Mitochondria Exert Age-Divergent Effects on Recovery from Spinal Cord Injury

The extent that age-dependent mitochondrial dysfunction drives neurodegeneration is not well understood. This study tested the hypothesis that mitochondria contribute to spinal cord injury (SCI)-induced neurodegeneration in an age-dependent manner by using 2,4-dinitrophenol (DNP) to uncouple electron transport, thereby increasing cellular respiration and reducing reactive oxygen species (ROS) production. We directly compared the effects of graded DNP doses in 4- and 14-month-old (MO) SCI-mice and found DNP to have increased efficacy in mitochondria isolated from 14-MO animals. In vivo, all DNP doses significantly exacerbated 4-MO SCI neurodegeneration coincident with worsened recovery. In contrast, low DNP doses (1.0-mg/kg/day) improved tissue sparing, reduced ROS-associated 3-nitrotyrosine (3-NT) accumulation, and improved anatomical and functional recovery in 14-MO SCI-mice. By directly comparing the effects of DNP between ages we demonstrate that mitochondrial contributions to neurodegeneration diverge with age after SCI. Collectively, our data indicate an essential role of mitochondria in age-associated neurodegeneration

Associations between cardiorespiratory fitness, physical activity and clustered cardiometabolic risk in children and adolescents: the HAPPY study

Clustering of cardiometabolic risk factors can occur during childhood and predisposes individuals to cardiometabolic disease. This study calculated clustered cardiometabolic risk in 100 children and adolescents aged 10-14 years (59 girls) and explored differences according to cardiorespiratory fitness (CRF) levels and time spent at different physical activity (PA) intensities. CRF was determined using a maximal cycle ergometer test, and PA was assessed using accelerometry. A cardiometabolic risk score was computed as the sum of the standardised scores for waist circumference, blood pressure, total cholesterol/high-density lipoprotein ratio, triglycerides and glucose. Differences in clustered cardiometabolic risk between fit and unfit participants, according to previously proposed health-related threshold values, and between tertiles for PA subcomponents were assessed using ANCOVA. Clustered risk was significantly lower (p < 0.001) in the fit group (mean 1.21 ± 3.42) compared to the unfit group (mean -0.74 ± 2.22), while no differences existed between tertiles for any subcomponent of PA. Conclusion These findings suggest that CRF may have an important cardioprotective role in children and adolescents and highlights the importance of promoting CRF in youth