Fundamentals of soft thermofluidic system design.

The soft composition of many natural thermofluidic systems allows them to effectively move heat and control its transfer rate by dynamically changing shape (e.g. dilation or constriction of capillaries near our skin). So far, making analogous deformable "soft thermofluidic systems" has been limited by the low thermal conductivity of materials with suitable mechanical properties. By remaining soft and stretchable despite the addition of filler, elastomer composites with thermal conductivity enhanced by liquid-metal micro-droplets provide an ideal material for this application. In this work, we use these materials to develop an elementary thermofluidic system consisting of a soft, heat generating pipe that is internally cooled with flow of water and explore its thermal behavior as it undergoes large shape change. The transient device shape change invalidates many conventional assumptions employed in thermal design making analysis of this devices' operation a non-trivial undertaking. To this end, using time scale analysis we demonstrate when the conventional assumptions break down and highlight conditions under which the quasi-static assumption is applicable. In this gradual shape modulation regime the actuated devices' thermal behavior at a given stretch approaches that of a static device with equivalent geometry. We validate this time scale analysis by experimentally characterizing thermo-fluidic behavior of our soft system as it undergoes axial periodic extension-retraction at varying frequencies during operation. By doing so we explore multiple shape modulation regimes and provide a theoretical foundation to be used in the design of soft thermofluidic systems undergoing transient deformation.

An innovative educational clinical experience promoting geriatric exercise.

Formal educational training in physical activity promotion is relatively sparse throughout the medical education system. The authors describe an innovative clinical experience in physical activity directed at medical clinicians on a geriatrics rotation. The experience consists of a single 2 1/2 hour session, in which learners are partnered with geriatric patients engaged in a formal supervised exercise program. The learners are guided through an evidence-based exercise regimen tailored to functional status. This experience provides learners with an opportunity to interact with geriatric patients outside the hospital environment to counterbalance the typical geriatric rotation in which geriatric patients are often seen in clinics or hospitals. In this experience, learners are exposed to fit and engaged geriatric patients successfully living in the community despite chronic or disabling conditions. A survey of 105 learners highlighted positive responses to the experience, with 96% of survey respondents indicating that the experience increased their confidence in their ability to serve as advocates for physical activity for older adults, and 89.5% of responders to a follow-up survey indicating that the experience changed their perception of geriatric patients. Modifications to the experience, implemented at partnering facilities are described. The positive feedback from this experience warrants consideration for implementation in other settings.

The impact of the affordable care act on breast cancer care in the USA: A multi-institutional analysis.

There are less data available on the effect of the ACA on breast cancer care beyond the screening level. A retrospective review at participating iCaRe2/BCCR institutions was completed before and after ACA. Post-ACA, patients were older, more urban, and more likely to be insured through Medicaid. Increased imaging use was noted post-ACA. These patients were less likely to be diagnosed with late-stage cancers, received fewer mastectomies, and were more likely to have radiation.

Mobility Improvements are Found in Older Veterans After 6-Months of Gerofit Regardless of BMI Classification.

Veterans represent a unique population of older adults as they are more likely to self-report disability and be overweight or obese compared to the general population. We sought to compare changes in mobility function across the obesity spectrum in older Veterans participating in six-months of Gerofit, a clinical exercise program. 270 Veterans completed baseline, three, and six-month functional assessment and were divided post-hoc into groups: normal weight, overweight, and obese. Physical function assessment included: ten-meter walk time, six-minute walk distance, 30-second chair stands, and eight-foot up-and-go time. No significant weight x time interactions were found for any measure. However, significant (P<0.02) improvements were found for all mobility measures from baseline to three-months and maintained at six-months. Six-months of participation in Gerofit, if enacted nationwide, appears to be one way to improve mobility and function in older Veterans at high risk for disability regardless of weight status.

Droplet-train induced spatiotemporal swelling regimes in elastomers.

In this work, we perform a combined experimental and numerical analysis of elastomer swelling dynamics upon impingement of a train of solvent droplets. We use time scale analysis to identify spatiotemporal regimes resulting in distinct boundary conditions that occur based on relative values of the absorption timescale and the droplet train period. We recognize that when either timescale is significantly larger than the other, two cases of quasi-uniform swelling occur. In contrast, when the two timescales are comparable, a variety of temporary geometrical features due to localized swelling are observed. We show that the swelling feature and its temporal evolution depends upon geometric scaling of polymer thickness and width relative to the droplet size. Based on this scaling, we identify six cases of localized swelling and experimentally demonstrate the swelling features for two cases representing limits of thickness and width. A finite element model of local swelling is developed and validated with experimental results for these two cases. The model is subsequently used to explore the swelling behavior in the rest of the identified cases. We show that depending upon the lateral dimension of the sample, swelling can locally exhibit mushroom, mesa, and cap like shapes. These deformations are magnified during the droplet-train impact but dissipate during post-train polymer equilibration. Our results also show that while swelling shape is a function of lateral dimensions of the sample, the extent of swelling increases with the elastomer sample thickness.

Microscale Mechanism of Age Dependent Wetting Properties of Prickly Pear Cacti (Opuntia).

Cacti thrive in xeric environments through specialized water storage and collection tactics such as a shallow, widespread root system that maximizes rainwater absorption and spines adapted for fog droplet collection. However, in many cacti, the epidermis, not the spines, dominates the exterior surface area. Yet, little attention has been dedicated to studying interactions of the cactus epidermis with water drops. Surprisingly, the epidermis of plants in the genus Opuntia, also known as prickly pear cacti, has water-repelling characteristics. In this work, we report that surface properties of cladodes of 25 taxa of Opuntia grown in an arid Sonoran climate switch from water-repelling to superwetting under water impact over the span of a single season. We show that the old cladode surfaces are not superhydrophilic, but have nearly vanishing receding contact angle. We study water drop interactions with, as well as nano/microscale topology and chemistry of, the new and old cladodes of two Opuntia species and use this information to uncover the microscopic mechanism underlying this phenomenon. We demonstrate that composition of extracted wax and its contact angle do not change significantly with time. Instead, we show that the reported age dependent wetting behavior primarily stems from pinning of the receding contact line along multilayer surface microcracks in the epicuticular wax that expose the underlying highly hydrophilic layers.

A naturally occurring epigenetic mutation in a gene encoding an SBP-box transcription factor inhibits tomato fruit ripening.

A major component in the regulatory network controlling fruit ripening is likely to be the gene at the tomato Colorless non-ripening (Cnr) locus. The Cnr mutation results in colorless fruits with a substantial loss of cell-to-cell adhesion. The nature of the mutation and the identity of the Cnr gene were previously unknown. Using positional cloning and virus-induced gene silencing, here we demonstrate that an SBP-box (SQUAMOSA promoter binding protein-like) gene resides at the Cnr locus. Furthermore, the Cnr phenotype results from a spontaneous epigenetic change in the SBP-box promoter. The discovery that Cnr is an epimutation was unexpected, as very few spontaneous epimutations have been described in plants. This study demonstrates that an SBP-box gene is critical for normal ripening and highlights the likely importance of epialleles in plant development and the generation of natural variation.

The effects of natural cigarette claims on adolescents' brand-related beliefs, attitudes, and intentions.

The marketing of natural cigarettes has been widely criticized by consumer advocates and public policymakers. The present research is designed to inform the ongoing policy debate by examining the effects of natural cigarette claims on adolescents' brand impressions. The authors report the results of an experiment in which high school students viewed images of cigarette packages for three different brands. Findings indicate that including natural claims on cigarette packages can weaken beliefs that the cigarettes cause diseases. Results also reveal that skepticism toward marketing claims may play an important role in undermining brand attitudes and trial intentions toward cigarette brands promoted with natural claims. Policy implications and suggestions for further research are provided.

Longitudinal analysis of physical function in older adults: The effects of physical inactivity and exercise training.

Lack of exercise contributes to systemic inflammation and is a major cause of chronic disease. The long-term impact of initiating and sustaining exercise in late life, as opposed to sustaining a sedentary lifestyle, on whole-body health measures such as physical performance is not well known. This is an exploratory study to compare changes in physical performance among older adults initiating exercise late in life versus inactive older adults. Data from two observational cohorts were included in this analysis, representing two activity groups. The Active group cohort comprises older adults (n = 318; age 72.5 ± 7.2 years) enrolled in a supervised exercise program, "Gerofit." The inactive group comprises older adults (n = 146; age 74.5 ± 5.5 years) from the Italian study "Act on Ageing" (AOA) who self-reported being inactive. Participants in both groups completed physical performance battery at baseline and 1-year including: 6-min walk test, 30-s chair stand, and timed up-and-go. Two-sample t-tests measured differences between Gerofit and AOA at baseline and 1-year across all measures. Significant between-group effects were seen for all performance measures (ps = 0.001). The AOA group declined across all measures from baseline to 1 year (range -18% to -24% change). The Gerofit group experienced significant gains in function for all measures (range +10% to +31% change). Older adults who initiated routine, sustained exercise were protected from age-related declines in physical performance, while those who remained sedentary suffered cumulative deficits across strength, aerobic endurance, and mobility. Interventions to reduce sedentary behaviors and increase physical activity are both important to promote multi-system, whole-body health.

A SQUAMOSA MADS box gene involved in the regulation of anthocyanin accumulation in bilberry fruits.

Anthocyanins are important health-promoting phytochemicals that are abundant in many fleshy fruits. Bilberry (Vaccinium myrtillus) is one of the best sources of these compounds. Here, we report on the expression pattern and functional analysis of a SQUAMOSA-class MADS box transcription factor, VmTDR4, associated with anthocyanin biosynthesis in bilberry. Levels of VmTDR4 expression were spatially and temporally linked with color development and anthocyanin-related gene expression. Virus-induced gene silencing was used to suppress VmTDR4 expression in bilberry, resulting in substantial reduction in anthocyanin levels in fully ripe fruits. Chalcone synthase was used as a positive control in the virus-induced gene silencing experiments. Additionally, in sectors of fruit tissue in which the expression of the VmTDR4 gene was silenced, the expression of R2R3 MYB family transcription factors related to the biosynthesis of flavonoids was also altered. We conclude that VmTDR4 plays an important role in the accumulation of anthocyanins during normal ripening in bilberry, probably through direct or indirect control of transcription factors belonging to the R2R3 MYB family.

A SEPALLATA gene is involved in the development and ripening of strawberry (Fragaria x ananassa Duch.) fruit, a non-climacteric tissue.

Climacteric and non-climacteric fruits have traditionally been viewed as representing two distinct programmes of ripening associated with differential respiration and ethylene hormone effects. In climacteric fruits, such as tomato and banana, the ripening process is marked by increased respiration and is induced and co-ordinated by ethylene, while in non-climacteric fruits, such as strawberry and grape, it is controlled by an ethylene-independent process with little change in respiration rate. The two contrasting mechanisms, however, both lead to texture, colour, and flavour changes that probably reflect some common programmes of regulatory control. It has been shown that a SEPALLATA(SEP)4-like gene is necessary for normal ripening in tomato. It has been demonstrated here that silencing a fruit-related SEP1/2-like (FaMADS9) gene in strawberry leads to the inhibition of normal development and ripening in the petal, achene, and receptacle tissues. In addition, analysis of transcriptome profiles reveals pleiotropic effects of FaMADS9 on fruit development and ripening-related gene expression. It is concluded that SEP genes play a central role in the developmental regulation of ripening in both climacteric and non-climacteric fruits. These findings provide important information to extend the molecular control of ripening in a non-climacteric fruit beyond the limited genetic and cultural options currently available.

Genetics and epigenetics of fruit development and ripening.

Fruits come in a vast variety of forms with both dry and fleshy types being essential components of the human diet. Elegant studies on the dry fruits of Arabidopsis have identified a suite of transcription factors involved in their development and dehiscence. Recent discoveries in tomato have revealed a hitherto unsuspected regulatory network involved in the developmental regulation of ripening in these fleshy fruits. Intriguingly it has become apparent that tomato shares some elements of its regulatory network in common with those involved in fruit development in Arabidopsis. Furthermore epigenetic variation has been shown to influence tomato ripening. These discoveries are likely to have a major impact on strategies for crop improvement in fruit bearing species.

Impact of Supervised Exercise on One-Year Medication Use in Older Veterans with Multiple Morbidities.

Exercise is touted as the ideal prescription to treat and prevent many chronic diseases. We examined changes in utilization and cost of medication classes commonly prescribed in the management of chronic conditions following participation in 12-months of supervised exercise within the Veterans Affairs Gerofit program. Gerofit enrolled 480 veterans between 1999 and 2017 with 12-months participation, with 453 having one or more active prescriptions on enrollment. Active prescriptions overall and for five classes of medications were examined. Changes from enrollment to 12 months were calculated, and cost associated with prescriptions filled were used to estimate net cost changes. Active prescriptions were reduced for opioids (77 of 164, 47%), mental health (93 of 221, 42%), cardiac (175 of 391, 45%), diabetes (41 of 166, 25%), and lipid lowering (56 of 253, 22%) agents. Cost estimates resulted in a net savings of $38,400. These findings support the role of supervised exercise as a favorable therapeutic intervention that has impact across chronic conditions.

Rapid Transition to Telehealth Group Exercise and Functional Assessments in Response to COVID-19.

Exercise is critical for health maintenance in late life. The COVID-19 shelter in place and social distancing orders resulted in wide-scale interruptions of exercise therapies, placing older adults at risk for the consequences of decreased mobilization. The purpose of this paper is to describe rapid transition of the Gerofit facility-based group exercise program to telehealth delivery. This Gerofit-to-Home (GTH) program continued with group-based synchronous exercise classes that ranged from 1 to 24 Veterans per class and 1 to 9 classes offered per week in the different locations. Three hundred and eight of 1149 (27%) Veterans active in the Gerofit facility-based programs made the transition to the telehealth delivered classes. Participants' physical performance testing continued remotely as scheduled with comparisons between most recent facility-based and remote testing suggesting that participants retained physical function. Detailed protocols for remote physical performance testing and sample exercise routines are described. Translation to remote delivery of exercise programs for older adults could mitigate negative health effects.

Reflections on E. E. Just, Black Apollo of Science, and the experiences of African American scientists.

The text below is a transcript of the keynote address Kenneth Manning gave at the symposium honoring E. E. Just that was held on the campus of Howard University on November 21, 2008. In his talk, Manning reflects on his experiences researching and writing Black Apollo of Science: The Life of Ernest Everett Just, his prize-winning biography published in 1983. In the process, he retells the fascinating story of the life of E. E. Just. Manning also discusses a number of other topics, including Just's legacy, the role of African Americans in science, and the importance of having minority representation on college campuses.

Role of Scale Wettability on Rain-Harvesting Behavior in a Desert-Dwelling Rattlesnake.

During storms in the southwestern United States, several rattlesnake species have been observed drinking rain droplets collected on their dorsal scales. This process often includes coiling and flattening of the snake's body, presumably to enhance water collection. Here, we explored this rain-harvesting behavior of the Western Diamond-backed Rattlesnake (Crotalus atrox) from the perspective of surface science. Specifically, we compared surface wettability and texture, as well as droplet impact and evaporation dynamics on the rattlesnake epidermis with those of two unrelated (control) sympatric snake species (Desert Kingsnake, Lampropeltis splendida, and Sonoran Gopher Snake, Pituophis catenifer). These two control species are not known to show rain-harvesting behavior. Our results show that the dorsal scales of the rattlesnake aid in water collection by providing a highly sticky, hydrophobic surface, which pins the impacting water droplets. We show that this high pinning characteristic stems from surface nanotexture made of shallow, labyrinth-like channels.

Oxide-Mediated Formation of Chemically Stable Tungsten-Liquid Metal Mixtures for Enhanced Thermal Interfaces.

Modern microelectronics and emerging technologies such as wearable devices and soft robotics require conformable and thermally conductive thermal interface materials to improve their performance and longevity. Gallium-based liquid metals (LMs) are promising candidates for these applications yet are limited by their moderate thermal conductivity, difficulty in surface-spreading, and pump-out issues. Incorporation of metallic particles into the LM can address these problems, but observed alloying processes shift the LM melting point and lead to undesirable formation of additional surface roughness. Here, these problems are addressed by introducing a mixture of tungsten microparticles dispersed within a LM matrix (LM-W) that exhibits two- to threefold enhanced thermal conductivity (62 ± 2.28 W m-1 K-1 for gallium and 57 ± 2.08 W m-1 K-1 for EGaInSn at a 40% filler volume mixing ratio) and liquid-to-paste transition for better surface application. It is shown that the formation of a nanometer-scale LM oxide in oxygen-rich environments allows highly nonwetting tungsten particles to mix into LMs. Using in situ imaging and particle dipping experimentation within a focused ion beam and scanning electron microscopy system, the oxide-assisted mechanism behind this wetting process is revealed. Furthermore, since tungsten does not undergo room-temperature alloying with gallium, it is shown that LM-W remains a chemically stable mixture.

Physical Activity Trackers: Promising Tools to Promote Resilience in Older Surgical Patients.

OBJECTIVES: Impending surgery presents a high risk for older adults given their vulnerability to adverse outcomes. New approaches to peri-operative care bring together surgeons, geriatricians, and other Multidisciplinary specialties to co-manage the geriatric surgical patient. However, few have incorporated interventions to promote physical activity (PA) throughout this period. We describe findings from two quality improvement (QI) initiatives that adopted the use of PA trackers to monitor and promote PA during the peri-operative period. METHODS: QI project within Perioperative Optimization of Senior Health (POSH) clinic at two medical centers (Duke and Durham Veterans Healthcare System (VA)) in Durham, North Carolina. Participants included 38 adults, ages 65+. Participants from POSH-at-Duke received PA trackers with one-time bundled advice from the provider team on nutrition, activity, pain management, medications and other relevant education prior to surgery. Participants from POSH-at-VA received the same one time bundled advice in addition to a visit with an exercise health coach who provided PA guidance followed by weekly PA telephone counseling throughout entire peri-operative period to 4-weeks post-surgery. Primary outcome was daily step counts. RESULTS: Ninety three percent of participants approached agreed to use PA trackers. POSH-at-Duke had mean daily step counts of 3,951 at baseline, 4,437 two days prior to surgery, and 1,838 at 4-week post-operative visit as opposed to POSH-at-VA with 2,063 steps at baseline, 5,452 two days prior to surgery, and 4,236 at 4-week post-operative visit, p=0.049 for trajectory differences. CONCLUSION: PA trackers coupled with appropriate continuous PA counseling has a potential utility in promoting resilience in the geriatric surgical candidate.

Should Structured Exercise Be Promoted As a Model of Care? Dissemination of the Department of Veterans Affairs Gerofit Program.

Exercise provides a wide range of health-promoting benefits, but support is limited for clinical programs that use exercise as a means of health promotion. This stands in contrast to restorative or rehabilitative exercise, which is considered an essential medical service. We propose that there is a place for ongoing, structured wellness and health promotion programs, with exercise as the primary therapeutic focus. Such programs have long-lasting health benefits, are easily implementable, and are associated with high levels of participant satisfaction. We describe the dissemination and implementation of a long-standing exercise and health promotion program, Gerofit, for which significant gains in physical function that have been maintained over 5 years of follow-up, improvements in well-being, and a 10-year 25% survival benefit among program adherents have been documented. The program has been replicated at 6 Veterans Affairs Medical Centers. The pooled characteristics of enrolled participants (n = 691) demonstrate substantial baseline functional impairment (usual gait speed 1.05 ± 0.3 m/s, 8-foot up and go 8.7 ± 6.7 seconds, 30-second chair stands 10.7 ± 5.1, 6-minute walk distance 404.31 ± 141.9 m), highlighting the need for such programs. Change scores over baseline for 3, 6, and 12 months of follow-up are clinically and statistically significant (P < .05 all measures) and replicate findings from the parent program. Patient satisfaction ratings of high ranged from 88% to 94%. We describe the implementation process and present 1-year outcomes. We suggest that such programs be considered essential elements of healthcare systems.

A Qualitative Study of Participation in Cardiac Rehabilitation Programs in an Integrated Health Care System.

INTRODUCTION: Despite strong incentives to use cardiac rehabilitation (CR), patient participation is low in the Veterans Health Administration (VHA). This is paradoxical given that VHA is an integrated health care system that offers a range of CR programs which should logically reduce barriers to access to CR participation. The purpose of this study was to better understand the contextual factors that influence patient participation in CR and how patients consider factors together when making decisions about CR participation. MATERIALS AND METHODS: Using a qualitative study design we examined patient and provider perceptions of CR across six VHA medical centers with high- and low-enrollment rates between December 2014 and October 2015. We conducted semistructured interviews with CR eligible patients who had both enrolled and not enrolled in CR (n = 16), cardiology providers who could refer patients to CR and CR staff who provided CR services (n = 15). Data were analyzed using grounded thematic techniques. RESULTS: We identified program and patient-specific factors related to CR participation. The four program factors were: program responsiveness to patient needs, CR schedule, specialized CR program equipment, and the CR program social environment. Program factors were primarily discussed by individuals associated with sites that had high CR enrollment rates. The patient-specific factor that promoted participation was patient perceptions of CR benefits. Disincentives to participation included competing conditions or obligations, logistical/cost challenges, convenience, and fear of exercise. CR participation entailed a complex process in which patients balanced factors that reinforced patient perceptions that CR was beneficial against factors that acted as disincentives to participation. CONCLUSIONS: CR participation was influenced by both program and patient factors. Patients weighed factors that fostered perceptions that CR was beneficial against factors that served as disincentives to CR participation when considering CR participation. High-enrollment sites may be better at countering disincentives to participate and/or improve patient perceptions of CR. Actionable ways to improve CR participation include encouraging providers to strongly and frequently endorse CR, educating patients about the importance and benefits of CR, emphasizing how exercises are individualized, supervised and monitored, educating patients about how CR is safe and effective, how CR offers peer support, and structuring CR programs to be responsive to patient needs in terms of duration, frequency, schedule, and location.