Dynamic Manipulation of Friction in Smart Textile Composites of Liquid-Crystal Elastomers

Smart surfaces that reversibly change the interfacial friction coefficients in response to external stimuli enable a wide range of applications, such as grips, seals, brake pads, packaging films, and fabrics. Here a new concept of such a smart frictional system is reported: a composite film of a plain-weave polyester textile sheet, and a thermo-responsive nematic liquid crystalline elastomer (LCE). The composite is deployed with retractable micro-undulations of the elastomer inside each weave mesh, enabling dramatic changes of the contact interface with the opposing surface on LCE actuation, which is induced e.g. by a change in temperature (T). At ambient T, the protruding viscoelastic parts of LCE in the nematic phase make contact with the opposing flat surface, resulting in a very high friction. At an elevated T (50C, isotropic phase), the undulations of LCE surface are retracted within the thickness of the textile, and the contacts are limited to small regions around overlapping textile fibers, lowering the friction dramatically. This effect is fully reversible on heating/cooling cycles. The surface undulations are spontaneous, i.e. fabricated without any lithographic or alignment techniques. The present composite opens a new way to practical uses of sheets/films with switchable friction enabled by stimuli-responsive LCEs.ERC H2020 AdG No. 786659 JSPS KAKENHI under Grant No. JP17K1886

Paper Session I-A - Development of Technology and Experimental Designs for Plant Growth Studies in Space

Plants will be a critical component of future Bioregenerative Life Support Systems that will be implemented on long duration space missions. We describe here a novel microgravity-rated plant growth apparatus that is targeted for use on the International Space Station (ISS) in the 2004-2005 timeframe. The system contains six modular units capable of utilizing either porous tube and/or substrate-based nutrient delivery approaches. Heat pulse moisture sensors are used to both monitor and control root zone wetness levels. In addition, a fixed-feed water delivery algorithm is available which meters out appropriate levels of water based upon plant life cycle stage. Fifty miniature color cameras will image the plant specimens throughout the experiment, permitting real-time assessments of plant performance over time. Alternative experimental strategies suitable for implementation on the ISS are discussed

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Searching for microbial life remotely: Satellite-to-rover habitat mapping in the Atacama Desert, Chile

The Atacama Desert, one of the most arid landscapes on Earth, serves as an analog for the dry conditions on Mars and as a test bed in the search for life on other planets. During the Life in the Atacama (LITA) 2004 field experiment, satellite imagery and ground-based rover data were used in concert with a `follow-the-water' exploration strategy to target regions of biological interest in two ( 1 coastal, 1 inland) desert study sites. Within these regions, environments were located, studied and mapped with spectroscopic and fluorescence imaging (FI) for habitats and microbial life. Habitats included aqueous sedimentary deposits ( e. g., evaporites), igneous materials ( e. g., basalt, ash deposits), rock outcrops, drainage channels and basins, and alluvial fans. Positive biological signatures ( chlorophyll, DNA, protein) were detected at 81% of the 21 locales surveyed with the FI during the long-range, autonomous traverses totaling 30 km. FI sensitivity in detecting microbial life in extreme deserts explains the high percentage of positives despite the low actual abundance of heterotrophic soil bacteria in coastal (< 1-10(4) CFU/g-soil) and interior (< 1-10(2) CFU/g-soil) desert soils. Remote habitat, microbial and climate observations agreed well with ground-truth, indicating a drier and less microbially rich interior compared to the relatively wetter and abundant biology of the coastal site where rover sensors detected the presence of fog and abundant surface lichens. LITA project results underscore the importance of an explicit focus by all engineering and science disciplines on microbially relevant scales ( mm to nm), and highlight the success of satellite-based and `follow-the-water' strategies for locating diverse habitats of biological promise and detecting the microbial hotspots within them