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340 result(s) for "Walker, Alexander D."
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A Randomized Hybrid‐Effectiveness Trial Comparing Pharmacogenomics (PGx) to Standard Care: The PGx Applied to Chronic Pain Treatment in Primary Care (PGx‐ACT) Trial
This trial aimed to identify the effects of providing pharmacogenomic (PGx) results and recommendations for patients with chronic pain treated in primary care practices compared to standard care. An open‐label, prospective, largely virtual, type‐2 hybrid effectiveness trial randomized participants to PGx or standard care arms. Adults with pain ≥ 3 months who were treated with tramadol, codeine, or hydrocodone enrolled. Alternative analgesics were recommended for CYP2D6 intermediate or poor metabolizers (IM/PMs). Prescribing decisions were at providers' discretion. The trial randomized 253 participants. A modified intent‐to‐treat primary analysis assessed change in pain intensity over 3 months among IM/PMs (PGx: 49; Standard care: 57). The PGx and standard care arms showed no difference in pain intensity change (−0.10 ± 0.63 vs. −0.21 ± 0.75 standard deviation; p = 0.74) or PGx‐aligned care (69% vs. 63%; standardized difference [SD] = 0.13). In IM/PMs, secondary analyses of pain intensity change suggested improvements with PGx‐aligned (n = 70; −0.21 ± 0.70) vs. unaligned care (n = 36; −0.06 ± 0.69) (SD = −0.22), with this difference increasing when examining IM/PMs with an analgesic change (aligned: n = 31, −0.28 ± 0.76; unaligned: n = 36, −0.06 ± 0.69; SD = −0.31). This approach to PGx implementation for chronic pain was not associated with different prescribing (i.e., similar proportions of PGx‐aligned care) or clinical outcomes. Secondary analyses suggest that prescribing aligned with PGx recommendations showed a small improvement in pain intensity. However, the proportion of patients with a clinically meaningful improvement (≥ 30%) in pain intensity was similar. Future efforts should identify effective implementation methods.
Choosing between an Apple and a Chocolate Bar: the Impact of Health and Taste Labels
Increasing the consumption of fruit and vegetables is a central component of improving population health. Reasons people give for choosing one food over another suggest health is of lower importance than taste. This study assesses the impact of using a simple descriptive label to highlight the taste as opposed to the health value of fruit on the likelihood of its selection. Participants (N=439) were randomly allocated to one of five groups that varied in the label added to an apple: apple; healthy apple; succulent apple; healthy and succulent apple; succulent and healthy apple. The primary outcome measure was selection of either an apple or a chocolate bar as a dessert. Measures of the perceived qualities of the apple (taste, health, value, quality, satiety) and of participant characteristics (restraint, belief that tasty foods are unhealthy, BMI) were also taken. When compared with apple selection without any descriptor (50%), the labels combining both health and taste descriptors significantly increased selection of the apple ('healthy & succulent' 65.9% and 'succulent & healthy' 62.4%), while the use of a single descriptor had no impact on the rate of apple selection ('healthy' 50.5% and 'succulent' 52%). The strongest predictors of individual dessert choice were the taste score given to the apple, and the lack of belief that healthy foods are not tasty. Interventions that emphasize the taste attributes of healthier foods are likely to be more effective at achieving healthier diets than those emphasizing health alone.
Effects of Uncoupled Motion on Performance
Objectives: To determine whether human exposure to vehicle motion specifically affects performance on a similar, yet uncorrelated, driving task and to observe the motion/simulator sickness symptoms that were associated with the real vehicle motion and the driving task. Background: Past research has shown uncoupled motion can affect a person's performance on a task as well as induce motion sickness. Methods: Ten participants (age range = 19-25 years) completed an uncorrelated driving task while seated in a stationary real vehicle and a moving real vehicle. Results: The results show participants took longer to complete the motion condition, t(9) = 1.96, p < .05, and were less accurate, t(9) = 3.73, p < .05. Scores for the Motion Sickness Assessment Questionnaire, t(9) = 3.37, p < .05, and the Simulator Sickness Questionnaire, t(9) = 3.30, p < .05, were significantly higher during the motion condition. Conclusions: Performance on the task was degraded and motion sickness heightened during the motion condition. Application: This research has potential implications for military-related tasks such as operating a command and control station or controlling a remote vehicle while simultaneously being a passenger in a real vehicle, as well as for civilian applications such as interacting with a moving map navigation system while driving a car.
Choosing between an Apple and a Chocolate Bar: the Impact of Health and Taste Labels: e77500
Increasing the consumption of fruit and vegetables is a central component of improving population health. Reasons people give for choosing one food over another suggest health is of lower importance than taste. This study assesses the impact of using a simple descriptive label to highlight the taste as opposed to the health value of fruit on the likelihood of its selection. Participants (N=439) were randomly allocated to one of five groups that varied in the label added to an apple: apple; healthy apple; succulent apple; healthy and succulent apple; succulent and healthy apple. The primary outcome measure was selection of either an apple or a chocolate bar as a dessert. Measures of the perceived qualities of the apple (taste, health, value, quality, satiety) and of participant characteristics (restraint, belief that tasty foods are unhealthy, BMI) were also taken. When compared with apple selection without any descriptor (50%), the labels combining both health and taste descriptors significantly increased selection of the apple ('healthy & succulent' 65.9% and 'succulent & healthy' 62.4%), while the use of a single descriptor had no impact on the rate of apple selection ('healthy' 50.5% and 'succulent' 52%). The strongest predictors of individual dessert choice were the taste score given to the apple, and the lack of belief that healthy foods are not tasty. Interventions that emphasize the taste attributes of healthier foods are likely to be more effective at achieving healthier diets than those emphasizing health alone.
Predicting team workload and performance using team autonomic activity
The development of a team measure of autonomic activity has a wide variety of applications. During team training, an index of team autonomic activity could potentially have added value for real-time feedback, team selection and performance evaluation. The primary purpose of this study was to investigate the relation between autonomic activity measures, workload, and performance, on both an individual and team level. Specifically, this study sought to determine whether changes in workload could be detected in measures of autonomic activity and whether changes in the autonomic measures related to changes in performance. 34 teams of two (35 males, 33 females) completed a processing plant simulation during 4 varying levels of individual and team difficulty. Sympathetic and parasympathetic nervous system activity was measured throughout the task using an electrocardiogram (ECG) and an impedance cardiogram (ICG), in addition to the NASA-TLX. SNS and PNS measures were combined to produce a team autonomic activity measure that was used to predict team workload and performance. Results showed that workload and performance varied across the task difficulty levels with higher difficulty producing higher workload and worse performance. Regressions conducted predicting team performance from team autonomic activity showed that team autonomic activity accounted for 10% of the variance in team performance scores. Further exploratory analyses showed interesting relations between autonomic activity and performance when examining the task difficulty levels separately. These analyses discovered that during the mixed individual difficulty levels, one team member’s physiology was consistently correlated with the other team member’s performance. In conclusion, the current study showed that team performance can be predicted from team autonomic activity, and that individual team member physiology has the potential to provide an index of team related behaviors (e.g. mutual performance monitoring and back-up behaviors).
The role of head movements in simulator sickness generated by a virtual environment
Virtual environments (VEs) are being used in a variety of applications, including training, rehabilitation and clinical treatment. To effectively utilize VEs in these situations it is important to try to understand some of the effects of VE exposure. The purpose of this study was to investigate head and body movements in virtual and real environments during building clearing and the relationship between these movements and simulator sickness. The data for the current study were drawn from a larger team training study which investigated the use of VEs for training building clearing. The goal of the first part of this study was to compare head movements made in a real world (RW) environment to head movements made in a VE (Analysis I). The goal of second part of this study was to examine the relationship between head movements and simulator sickness in a VE (Analysis II). The first analysis used two independent samples t-tests to examine the differences between head movements made in a VE and head movements made in a RW environment. The t-tests showed that subjects in the VE moved their heads less, t(23.438)=12.690, p<0.01, and less often, t(46)=8.682, p<0.05, than subjects in the RW. In the second analysis, a 3 x 20 ANOVA found a significant difference between groups with low, med, and high simulator sickness scores, F(2,21)=4.221, p <0.05, [special characters omitted]2 =0.287, where subjects who reported being the most sick tended to restrict their head movements more than the other two groups. For VEs to progress as a useful tool, whether for training, therapy, etc., it will be necessary to identify the variable(s) that cause people to become motion sick and restrict their head movement during VE exposure. Future studies should seek to investigate more continuous measures of sickness, perhaps psychophysiological measures, and possible effects of a negative transfer of training due to the restriction of head movements in VEs.
Engineering T cells to enhance 3D migration through structurally and mechanically complex tumor microenvironments
Defining the principles of T cell migration in structurally and mechanically complex tumor microenvironments is critical to understanding escape from antitumor immunity and optimizing T cell-related therapeutic strategies. Here, we engineered nanotextured elastic platforms to study and enhance T cell migration through complex microenvironments and define how the balance between contractility localization-dependent T cell phenotypes influences migration in response to tumor-mimetic structural and mechanical cues. Using these platforms, we characterize a mechanical optimum for migration that can be perturbed by manipulating an axis between microtubule stability and force generation. In 3D environments and live tumors, we demonstrate that microtubule instability, leading to increased Rho pathway-dependent cortical contractility, promotes migration whereas clinically used microtubule-stabilizing chemotherapies profoundly decrease effective migration. We show that rational manipulation of the microtubule-contractility axis, either pharmacologically or through genome engineering, results in engineered T cells that more effectively move through and interrogate 3D matrix and tumor volumes. Thus, engineering cells to better navigate through 3D microenvironments could be part of an effective strategy to enhance efficacy of immune therapeutics. The mechanics of the migration of T cells into tumours is an important aspect of tumour immunity. Here the authors engineer complex 3D environments to explore functions of microtubules and cell contractility as strategies to enhance T cell migration in tumour microenvironments.
Reviews and syntheses: Changing ecosystem influences on soil thermal regimes in northern high-latitude permafrost regions
Soils in Arctic and boreal ecosystems store twice as much carbon as the atmosphere, a portion of which may be released as high-latitude soils warm. Some of the uncertainty in the timing and magnitude of the permafrost–climate feedback stems from complex interactions between ecosystem properties and soil thermal dynamics. Terrestrial ecosystems fundamentally regulate the response of permafrost to climate change by influencing surface energy partitioning and the thermal properties of soil itself. Here we review how Arctic and boreal ecosystem processes influence thermal dynamics in permafrost soil and how these linkages may evolve in response to climate change. While many of the ecosystem characteristics and processes affecting soil thermal dynamics have been examined individually (e.g., vegetation, soil moisture, and soil structure), interactions among these processes are less understood. Changes in ecosystem type and vegetation characteristics will alter spatial patterns of interactions between climate and permafrost. In addition to shrub expansion, other vegetation responses to changes in climate and rapidly changing disturbance regimes will affect ecosystem surface energy partitioning in ways that are important for permafrost. Lastly, changes in vegetation and ecosystem distribution will lead to regional and global biophysical and biogeochemical climate feedbacks that may compound or offset local impacts on permafrost soils. Consequently, accurate prediction of the permafrost carbon climate feedback will require detailed understanding of changes in terrestrial ecosystem distribution and function, which depend on the net effects of multiple feedback processes operating across scales in space and time.
Pan-Arctic ice-wedge degradation in warming permafrost and its influence on tundra hydrology
Ice wedges are common features of the subsurface in permafrost regions. They develop by repeated frost cracking and ice vein growth over hundreds to thousands of years. Ice-wedge formation causes the archetypal polygonal patterns seen in tundra across the Arctic landscape. Here we use field and remote sensing observations to document polygon succession due to ice-wedge degradation and trough development in ten Arctic localities over sub-decadal timescales. Initial thaw drains polygon centres and forms disconnected troughs that hold isolated ponds. Continued ice-wedge melting leads to increased trough connectivity and an overall draining of the landscape. We find that melting at the tops of ice wedges over recent decades and subsequent decimetre-scale ground subsidence is a widespread Arctic phenomenon. Although permafrost temperatures have been increasing gradually, we find that ice-wedge degradation is occurring on sub-decadal timescales. Our hydrological model simulations show that advanced ice-wedge degradation can significantly alter the water balance of lowland tundra by reducing inundation and increasing runoff, in particular due to changes in snow distribution as troughs form. We predict that ice-wedge degradation and the hydrological changes associated with the resulting differential ground subsidence will expand and amplify in rapidly warming permafrost regions. The polygonal patterns in permafrost regions are caused by the formation of ice wedges. Observations of polygon evolution reveal that rapid ice-wedge melting has occurred across the Arctic since 1950, altering tundra hydrology.