Heme redox potentials hold the key to reactivity differences between nitric oxide reductase and heme-copper oxidase.

Despite high structural homology between NO reductases (NORs) and heme-copper oxidases (HCOs), factors governing their reaction specificity remain to be understood. Using a myoglobin-based model of NOR (FeBMb) and tuning its heme redox potentials (E°') to cover the native NOR range, through manipulating hydrogen bonding to the proximal histidine ligand and replacing heme b with monoformyl (MF-) or diformyl (DF-) hemes, we herein demonstrate that the E°' holds the key to reactivity differences between NOR and HCO. Detailed electrochemical, kinetic, and vibrational spectroscopic studies, in tandem with density functional theory calculations, demonstrate a strong influence of heme E°' on NO reduction. Decreasing E°' from +148 to -130 mV significantly impacts electronic properties of the NOR mimics, resulting in 180- and 633-fold enhancements in NO association and heme-nitrosyl decay rates, respectively. Our results indicate that NORs exhibit finely tuned E°' that maximizes their enzymatic efficiency and helps achieve a balance between opposite factors: fast NO binding and decay of dinitrosyl species facilitated by low E°' and fast electron transfer facilitated by high E°'. Only when E°' is optimally tuned in FeBMb(MF-heme) for NO binding, heme-nitrosyl decay, and electron transfer does the protein achieve multiple (>35) turnovers, previously not achieved by synthetic or enzyme-based NOR models. This also explains a long-standing question in bioenergetics of selective cross-reactivity in HCOs. Only HCOs with heme E°' in a similar range as NORs (between -59 and 200 mV) exhibit NOR reactivity. Thus, our work demonstrates efficient tuning of E°' in various metalloproteins for their optimal functionality.

Dissolvable Template Nanoimprint Lithography: A Facile and Versatile Nanoscale Replication Technique.

Nanoimprinting lithography (NIL) is a next-generation nanofabrication method, capable of replicating nanostructures from original master surfaces. Here, we develop highly scalable, simple, and nondestructive NIL using a dissolvable template. Termed dissolvable template nanoimprinting lithography (DT-NIL), our method utilizes an economic thermoplastic resin to fabricate nanoimprinting templates, which can be easily dissolved in simple organic solvents. We used the DT-NIL method to replicate cicada wings which have surface nanofeatures of ∼100 nm in height. The master, template, and replica surfaces showed a >∼94% similarity based on the measured diameter and height of the nanofeatures. The versatility of DT-NIL was also demonstrated with the replication of re-entrant, multiscale, and hierarchical features on fly wings, as well as hard silicon wafer-based artificial nanostructures. The DT-NIL method can be performed under ambient conditions with inexpensive materials and equipment. Our work opens the door to opportunities for economical and high-throughput nanofabrication processes.

Nitric Oxide Reductase Activity in Heme-Nonheme Binuclear Engineered Myoglobins through a One-Electron Reduction Cycle.

FeBMbs are structural and functional models of native bacterial nitric oxide reductases (NORs) generated through engineering of myoglobin. These biosynthetic models replicate the heme-nonheme diiron site of NORs and allow substitutions of metal centers and heme cofactors. Here, we provide evidence for multiple NOR turnover in monoformyl-heme-containing FeBMb1 proteins loaded with FeII, CoII, or ZnII metal ions at the FeB site (FeII/CoII/ZnII-FeBMb1(MF-heme)). FTIR detection of the ν(NNO) band of N2O at 2231 cm-1 provides a direct quantitative measurement of the product in solution. A maximum number of turnover is observed with FeII-FeBMb1(MF-heme), but the NOR activity is retained when the FeB site is loaded with ZnII. These data support the viability of a one-electron semireduced pathway for the reduction of NO at binuclear centers in reducing conditions.

Manganese and Cobalt in the Nonheme-Metal-Binding Site of a Biosynthetic Model of Heme-Copper Oxidase Superfamily Confer Oxidase Activity through Redox-Inactive Mechanism.

The presence of a nonheme metal, such as copper and iron, in the heme-copper oxidase (HCO) superfamily is critical to the enzymatic activity of reducing O2 to H2O, but the exact mechanism the nonheme metal ion uses to confer and fine-tune the activity remains to be understood. We herein report that manganese and cobalt can bind to the same nonheme site and confer HCO activity in a heme-nonheme biosynthetic model in myoglobin. While the initial rates of O2 reduction by the Mn, Fe, and Co derivatives are similar, the percentages of reactive oxygen species (ROS) formation are 7%, 4%, and 1% and the total turnovers are 5.1 ± 1.1, 13.4 ± 0.7, and 82.5 ± 2.5, respectively. These results correlate with the trends of nonheme-metal-binding dissociation constants (35, 22, and 9 µM) closely, suggesting that tighter metal binding can prevent ROS release from the active site, lessen damage to the protein, and produce higher total turnover numbers. Detailed spectroscopic, electrochemical, and computational studies found no evidence of redox cycling of manganese or cobalt in the enzymatic reactions and suggest that structural and electronic effects related to the presence of different nonheme metals lead to the observed differences in reactivity. This study of the roles of nonheme metal ions beyond the Cu and Fe found in native enzymes has provided deeper insights into nature's choice of metal ion and reaction mechanism and allows for finer control of the enzymatic activity, which is a basis for the design of efficient catalysts for the oxygen reduction reaction in fuel cells.

Effect of Outer-Sphere Side Chain Substitutions on the Fate of the trans Iron-Nitrosyl Dimer in Heme/Nonheme Engineered Myoglobins (Fe(B)Mbs): Insights into the Mechanism of Denitrifying NO Reductases.

Denitrifying NO reductases are transmembrane protein complexes that utilize a heme/nonheme diiron center at their active sites to reduce two NO molecules to the innocuous gas N2O. Fe(B)Mb proteins, with their nonheme iron sites engineered into the heme distal pocket of sperm whale myoglobin, are attractive models for studying the molecular details of the NO reduction reaction. Spectroscopic and structural studies of Fe(B)Mb constructs have confirmed that they reproduce the metal coordination spheres observed at the active site of the cytochrome c-dependent NO reductase from Pseudomonas aeruginosa. Exposure of Fe(B)Mb to excess NO, as examined by analytical and spectroscopic techniques, results primarily in the formation of a five-coordinate heme-nitrosyl complex without N2O production. However, substitution of the outer-sphere residue Ile107 with a glutamic acid (i.e., I107E) decreases the formation rate of the five-coordinate heme-nitrosyl complex and allows for the substoichiometric production of N2O. Here, we aim to better characterize the formation of the five-coordinate heme-nitrosyl complex and to explain why the level of N2O production increases with the I107E substitution. We follow the formation of the five-coordinate heme-nitrosyl inhibitory complex through the sequential exposure of Fe(B)Mb to different NO isotopomers using rapid-freeze-quench resonance Raman spectroscopy. The data show that the complex is formed by the displacement of the proximal histidine by a new NO molecule after the weakening of the Fe(II)-His bond in the intermediate six-coordinate low-spin (6cLS) heme-nitrosyl complex. These results lead us to explore diatomic migration within the scaffold of myoglobin and whether substitutions at residue 107 can be sufficient to control access to the proximal heme cavities. Results on a new Fe(B)Mb construct with an I107F substitution (Fe(B)Mb3) show an increased rate for the formation of the five-coordinate low-spin heme-nitrosyl complex without N2O production. Taken together, our results suggest that production of N2O from the [6cLS heme {FeNO}(7)/{Fe(B)NO}(7)] trans iron-nitrosyl dimer intermediate requires a proton transfer event facilitated by an outer-sphere residue such as E107 in Fe(B)Mb2 and E280 in P. aeruginosa cNOR.

Pathways to Health: Association Between Trail Use, Weight Status, and Self-Rated Health Among Adults in Greenville County, South Carolina, 2014.

We examined associations between adults' use of a prominent rail-trail and their weight status and self-rated health. In 2014, a random-digit-dial survey of Greenville County, South Carolina, residents (n = 639) was used to collect data on trail use, height and weight, self-rated health, and demographics. Trail users were half as likely to be overweight or obese as trail nonusers (odds ratio [OR] = 0.56; 95% confidence interval [CI], 0.33-0.95). Similarly, trail users were significantly more likely to report high self-rated health than were trail nonusers (OR = 1.83; 95% CI, 1.13-2.97). Findings suggest that trail use is associated with healthier weight status and higher self-rated health and supports the development, maintenance, and promotion of trail resources.

Binuclear Cu(A) Formation in Biosynthetic Models of Cu(A) in Azurin Proceeds via a Novel Cu(Cys)2His Mononuclear Copper Intermediate.

Cu(A) is a binuclear electron transfer (ET) center found in cytochrome c oxidases (CcOs), nitrous oxide reductases (N2ORs), and nitric oxide reductase (NOR). In these proteins, the Cu(A) centers facilitate efficient ET (kET > 104s⁻¹) under low thermodynamic driving forces (10-90 mV). While the structure and functional properties of Cu(A) are well understood, a detailed mechanism of the incorporation of copper into the protein and the identity of the intermediates formed during the Cu(A) maturation process are still lacking. Previous studies of the Cu(A) assembly mechanism in vitro using a biosynthetic model Cu(A) center in azurin (Cu(A)Az) identified a novel intermediate X (Ix) during reconstitution of the binuclear site. However, because of the instability of Ix and the coexistence of other Cu centers, such as Cu(A)' and type 1 copper centers, the identity of this intermediate could not be established. Here, we report the mechanism of Cu(A) assembly using variants of Glu114XCuAAz (X = Gly, Ala, Leu, or Gln), the backbone carbonyl of which acts as a ligand to the Cu(A) site, with a major focus on characterization of the novel intermediate Ix. We show that Cu(A) assembly in these variants proceeds through several types of Cu centers, such as mononuclear red type 2 Cu, the novel intermediate Ix, and blue type 1 Cu. Our results show that the backbone flexibility of the Glu114 residue is an important factor in determining the rates of T2Cu → Ix formation, suggesting that Cu(A) formation is facilitated by swinging of the ligand loop, which internalizes the T2Cu capture complex to the protein interior. The kinetic data further suggest that the nature of the Glu114 side chain influences the time scales on which these intermediates are formed, the wavelengths of the absorption peaks, and how cleanly one intermediate is converted to another. Through careful understanding of these mechanisms and optimization of the conditions, we have obtained Ix in ∼80-85% population in these variants, which allowed us to employ ultraviolet-visible, electron paramagnetic resonance, and extended X-ray absorption fine structure spectroscopic techniques to identify the Ix as a mononuclear Cu(Cys)(2)(His) complex. Because some of the intermediates have been proposed to be involved in the assembly of native Cu(A), these results shed light on the structural features of the important intermediates and mechanism of Cu(A) formation.

Recent advances in biosynthetic modeling of nitric oxide reductases and insights gained from nuclear resonance vibrational and other spectroscopic studies.

This Forum Article focuses on recent advances in structural and spectroscopic studies of biosynthetic models of nitric oxide reductases (NORs). NORs are complex metalloenzymes found in the denitrification pathway of Earth's nitrogen cycle where they catalyze the proton-dependent two-electron reduction of nitric oxide (NO) to nitrous oxide (N2O). While much progress has been made in biochemical and biophysical studies of native NORs and their variants, a clear mechanistic understanding of this important metalloenzyme related to its function is still elusive. We report herein UV-vis and nuclear resonance vibrational spectroscopy (NRVS) studies of mononitrosylated intermediates of the NOR reaction of a biosynthetic model. The ability to selectively substitute metals at either heme or nonheme metal sites allows the introduction of independent (57)Fe probe atoms at either site, as well as allowing the preparation of analogues of stable reaction intermediates by replacing either metal with a redox inactive metal. Together with previous structural and spectroscopic results, we summarize insights gained from studying these biosynthetic models toward understanding structural features responsible for the NOR activity and its mechanism. The outlook on NOR modeling is also discussed, with an emphasis on the design of models capable of catalytic turnovers designed based on close mimics of the secondary coordination sphere of native NORs.

Spectroscopic and computational study of a nonheme iron nitrosyl center in a biosynthetic model of nitric oxide reductase.

A major barrier to understanding the mechanism of nitric oxide reductases (NORs) is the lack of a selective probe of NO binding to the nonheme FeB center. By replacing the heme in a biosynthetic model of NORs, which structurally and functionally mimics NORs, with isostructural ZnPP, the electronic structure and functional properties of the FeB nitrosyl complex was probed. This approach allowed observation of the first S=3/2 nonheme {FeNO}(7) complex in a protein-based model system of NOR. Detailed spectroscopic and computational studies show that the electronic state of the {FeNO}(7) complex is best described as a high spin ferrous iron (S=2) antiferromagnetically coupled to an NO radical (S=1/2) [Fe(2+)-NO(.)]. The radical nature of the FeB -bound NO would facilitate N-N bond formation by radical coupling with the heme-bound NO. This finding, therefore, supports the proposed trans mechanism of NO reduction by NORs.

Travel to, and use of, twenty-one Michigan trails.

OBJECTIVE AND METHODS: This study examined trail use among 857 trail users on 21 trails in Michigan from 2008 to 2011 using a valid and reliable intercept survey. RESULTS: Most of the 857 participants traveled to the trail from their home (92.6%), lived within 15 min of the trails (74.8%), and used active transport to travel to the trails 69.7%. The odds of active transport to the trails were greater among those who had not graduated high school (OR=3.49; 95% CI=1.02, 11.99) and high school graduates (OR=7.432; 95% CI=2.02, 27.30) compared to college graduates. Whites and adults also had greater odds of active transport than non-Whites (OR=3.160, 95% CI: 1.65, 6.05), and older adults (OR=1.75; 95% CI: 1.20, 2.54). The majority of respondents (89.7%) reported using trails for recreational purposes. A significantly greater proportion of females (73.3%) compared to males (64.7%) reported using the trail with others. CONCLUSIONS: The findings from this study might enable health and parks and recreation professionals to better promote physical activity on trails.

Trail user demographics, physical activity behaviors, and perceptions of a newly constructed greenway trail.

To better understand and promote physical activity on a newly constructed trail, the present study examined the demographic characteristics and physical activity behaviors of trail users; the demographic characteristics of trail users compared to the demographic profile Greenville County, South Carolina residents; trail users' purpose for using the trail; the distance trail users traveled to access the trail from their homes; channels through which trail users learned about the trail; and trail characteristics liked by trail users. Using a valid and reliable intercept survey, 1,148 trail users were interviewed. Trail users were mostly white (93.1%), male (59.1%) adults (84.2%) who reported using the trail for exercise (91%). Significant associations were identified between trail user demographic characteristics and how trail users learned about the trail and trail characteristics liked by trail users. The findings may contribute to the development of targeted health promotion efforts to promote physical activity on this and similar trails.

Demographic characteristics and physical activity behavior of park-visitors versus non-visitors.

To examine physical activity (PA) behaviors among park visitors versus non-visitors by select demographic variables of a large city park. A sample of 251 respondents participated in a random digit dial survey. PA was measured using the Behavioral Risk Factor Surveillance System (BRFSS) PA module. The majority of respondents reported meeting PA recommendations (70.5 %) and being park visitors (60.2 %). A greater proportion of adults were park visitors (65.6 %) compared to the proportion of older adults who were park visitors (49.2 %). All persons who identified as being a race other than white and reported meeting the national PA recommendations through vigorous PA were park visitors. Environmental interventions that increase the availability of city parks may impact PA behavior among racial minority groups. There is also an opportunity to promote park usage among older adults.

Demographic characteristics and physical activity behaviors in sixteen Michigan parks.

The Building Healthy Communities (BHC) initiative addresses inadequate physical activity in Michigan using a population-based approach to prevent chronic disease. Eighteen local health departments through 2010 received $1,505,179 to plan and implement community-based interventions to increase physical activity among low-income and minority populations. This paper examines park user demographics, compares park user demographics to the demographic characteristics and examines physical activity behaviors of park users in these parks. BHC Park usage was examined from 2008 to 2010 using the System for Observing Play and Recreation in Communities (SOPARC). One sample binomial tests were used to examine if the proportion of male and female park users was different than the proportion of males and females in Michigan and to examine if the proportion of white and other park users was different than the proportion of whites and others in Michigan. A chi-square goodness-of-fit test was used to examine whether the observed proportions for age groups observed using the park differed from the actual proportions for age groups in Michigan. The majority of BHC park users were white. More children were observed than other age groups. Park users were most often observed engaging in walking or vigorous activity rather than sedentary activities. When comparing the proportion of whites (54.7%) and others (42.8%) observed using the parks to the proportion of whites (79%) and others (21%) residing in Michigan, there was a significant difference (P < 0.001) with a greater proportion of whites and smaller proportion of persons of other ethnicities expected to be observed using the parks. This chi square goodness of fit test showed a significant difference in the observed and expected number of persons observed using the trail in each age group (χ(2) = 4,897.707, df = 3, P < 0.001) with a greater number of children (n = 1,939) and teens (n = 1,116) observed than the number of children (n = 828) and teens (n = 305) expected based on 2010 Michigan census data. A greater proportion of non-whites (compared to whites) were observed using the park than would be expected. In Michigan, 60% of blacks, 37% of Hispanics, and 53% of other minority groups do not meet national physical activity recommendations. Perhaps developing additional parks in Michigan can increase physical activity behaviors among minorities.

The association of natural elements and trail use by adults.

We used the System for Observing Play and Recreation in Communities to examine the association between variations in natural elements (ie, season, weather, and temperature) and adults' use of a rail-trail in South Carolina (2006-2009). Most (62%) of the 4,468 trail users observed were walkers; 38% were observed participating in vigorous physical activity. Adults were most often observed using the trail during the summer (32%), sunny weather (78%), and moderate temperatures (54%). When promoting trail use among adults, natural elements should be considered.

Associations between sociodemographic characteristics and perceptions of the built environment with the frequency, type, and duration of physical activity among trail users.

INTRODUCTION: Rail trails are elements of the built environment that support the Task Force on Community Preventive Services' recommendation to create, or enhance access to, places for physical activity (PA). The purpose of this study was to examine the associations between sociodemographic characteristics and perceptions of the built environment with the frequency, type, and duration of PA among users of an urban, paved rail trail segment. METHODS: Interviewers conducted intercept surveys with 431 rail trail users and analyzed data by using logistic regression to estimate odds ratios between sociodemographic characteristics and perceptions of the built environment on the frequency, type, and duration of PA performed on the trail. RESULTS: Adults who used the trail in the cool months, traveled to the trail by a motorized vehicle, used the trail with others, and had some graduate school education visited the trail less often. Younger adults, men, whites, and those with some graduate school education were more likely to engage in vigorous activities on the trail. Adults who traveled to the trail by a motorized vehicle spent more time engaged in PA on the trail. CONCLUSION: Our results suggest that the most frequent users of a rail trail for PA are those who use the trail alone and travel to the trail by bicycle or on foot. Trails are an aspect of the built environment that supports active lifestyles, and future studies should evaluate different types of trails among more diverse populations and locations.

Daily Physical Education Linked to Higher Youth Aerobic Fitness Levels: A 4-Year Longitudinal Study.

PURPOSE: Physical education (PE) provides opportunities for youth physical activity during the school day, yet daily PE policies remain low. This study investigated whether daily PE was linked to youth aerobic capacity across a 4-year period in Greenville (South Carolina). METHODS: Youth in grade levels second to eighth at 2 schools providing daily PE and 2 schools that did not provide daily PE participated in the study (N = 466). The 2 schools used as comparisons provided standard PE outlined by South Carolina, which included one 50-minute session per week (elementary) and daily PE for one semester (middle school). Aerobic fitness was measured using the FITNESSGRAM® Progressive Aerobic Cardiovascular Endurance Run test (May 2011-2015). Number of Progressive Aerobic Cardiovascular Endurance Run laps completed, age, gender, ethnicity, body composition, and school attended were included in multilevel linear regression analyses. RESULTS: Across the sample, aerobic fitness increased with age. Throughout the study, males demonstrated growth in aerobic fitness compared with a slight decline for females (P < .001). Youth participation in daily PE was linked to increases in aerobic fitness compared with youth who did not receive daily PE (P < .001). CONCLUSIONS: Findings suggest that exposure to daily PE may contribute to increased aerobic fitness in youth.

Parents' Perceptions and Engagement Regarding School-Based Physical Activity Promotion.

PURPOSE: This study examined parents' perceived importance of, and engagement in, school-based physical activity (PA) promotion. DESIGN: A cross-sectional, quantitative survey design was employed. SETTING: The survey was conducted in the United States. SUBJECTS: Using a probability-based panel (AmeriSpeak®), a national sample of 3599 parents was randomly recruited to participate in the survey and 1015 participants (28.2%) completed it. Parents or legal guardians of children enrolled in K-12 during the 2017-2018 school year were eligible to participate. MEASURES: The survey was developed and distributed by a national collaborative for active schools with the support of a national research center. ANALYSIS: Data were analyzed using structural equation modeling and path analysis. RESULTS: The data supported a 6-factor solution encompassing perceived importance of PA before, during, and after school, communication with administrators, and volunteering and participating in school-based PA (CFI = .974, RMSEA = .034, SRMR = .056). Path coefficients from perceived importance of PA before/after school to current (ß = .43; 95%CI[.25, .61]) and future communication with administrators (ß = .40; 95%CI[.23, .55]) were statistically significant, as were coefficients from perceived importance of PA before/after school to past (ß = .60; 95%CI[.35, .83]) and current volunteering/participating in school-based PA (ß = .63; 95%CI[.42, .85]). CONCLUSION: Parents' perceived importance of school-based PA opportunities before and after school warrants emphasis in future research and advocacy.

Identification of Effective Programs to Improve Access to and Use of Trails among Youth from Under-Resourced Communities: A Review.

The primary purpose of this paper is to identify and review studies evaluating the effectiveness of programs to increase access to trails and trails use (physical activity) among youth from under-resourced communities. Three additional goals include identifying: (1) Correlates of physical activity/trail use and features of transportation systems and/or built environment and land use destinations, that may inform and support the planning and implementation of programs to promote trail use among youth, (2) benefits associated with trail use, and (3) barriers to trail use. Under-resourced communities are defined as those lacking sufficient resources (i.e., under-funded). METHODS: A review of the literature was conducted to identify, abstract, and evaluate studies related to programs to promote trail use among youth and youth from under-resourced communities. In anticipation of very few studies being published about this topic, studies were also reviewed to identify correlates of transportation systems and built environment and land use destinations related to increases in physical activity, and benefits of, and barriers to trail use. PUBMED, MEDLINE, PsycINFO, Sportdiscus, Annual Reviews, American Trails, and Google Scholar databases were searched using terms including trails, built environment, physical activity, exercise, walking, children, adolescents, and youth to identify studies that potentially related to the purposes for conducting this review. Review methods identified, 5278 studies based on our search terms. A review of study titles, abstracts, and select full article screens determined that 5049 studies did not meet the study inclusion criteria, leaving 221 studies included in this review. RESULTS: No studies were located that evaluated programs designed to promote and increase trail use among youth, including youth from under-resourced communities. Eight studies used longitudinal or quasi-experimental designs to evaluate physical activity and neighborhood characteristics prospectively among adolescent girls (n = 1), the effects of the path or trail development on physical activity behaviors of children, youth, and adults (n = 4), marketing or media campaigns (n = 2), and wayfinding and incremental distance signage (n = 1) to promote increased trail use. Correlates of transportation systems (e.g., trail access, road traffic congestion related to safe active travel, lack of sidewalks, closer proximity to trails, access to transportation), destinations (e.g., park availability and access, park improvements, greenspaces), or both routes and destinations (e.g., perceptions of safety, lighting), were identified. These correlates may support the planning and implementation of programs to increase trail use among youth, or may facilitate the connection of trails or routes to destinations in communities. Barriers to trail use included costs, crime, lack of transportation, lack of role models using trails, and institutional discrimination. CONCLUSIONS: Scientific evidence in support of addressing the underrepresentation of trail use by youth from under-resourced communities is lacking. However, there is a related body of evidence that may inform how to develop programs that support trail use by youth from under-resourced areas. Dedicated, deliberate, and systematic efforts will be required to address research and knowledge gaps, and to evaluate programs and practice related to trail use among youth from low income, often racially or ethnically diverse under-resourced neighborhoods or communities.

Poverty Status Moderates the Relationship between Cardiorespiratory Fitness and Academic Achievement.

BACKGROUND: The purpose of the study was to examine the associations among cardiorespiratory fitness (CRF), weight status and academic achievement in youth, and to determine if these relationships are moderated by poverty status. METHODS: The sample included 5th (N = 27,791) and 8th grade (N = 16,047) South Carolina students. Academic achievement was assessed using a state-wide assessment and classified into 2 categories (ie, does not meet/approaches standards vs meets/exceeds standards). CRF was assessed and expressed as Healthy Fitness Zone (HFZ) or Needs Improvement/Needs-Improvement-Health Risk. Students' demographics and poverty status were reported. Multilevel logistic regression analyses were used to examine the association between CRF, weight status and academic achievement. Interaction terms were introduced into the final models. Analyses were performed separately by grade level and academic subject. RESULTS: The CRF was significantly associated with the odds of meeting/exceeding academic standards after controlling for covariates and adjusting for weight status. The relationship between CRF and academic achievement varied significantly by poverty status. After adjustment for CRF, weight status was not significantly associated with academic achievement. CONCLUSIONS: The odds of achieving academic standards were significantly higher among students achieving CRF HFZ regardless of poverty status. CRF may partially mitigate the adverse effect of poverty on academic achievement.

Ultrascalable Multifunctional Nanoengineered Copper and Aluminum for Antiadhesion and Bactericidal Applications.

Biofouling disrupts the surface functionality and integrity of engineered substrates. A variety of natural materials such as plant leaves and insect wings have evolved sophisticated physical mechanisms capable of preventing biofouling. Over the past decade, several reports have pinpointed nanoscale surface topography as an important regulator of surface adhesion and growth of bacteria. Although artificial nanoengineered features have been used to create bactericidal materials that kill adhered bacteria, functional surfaces capable of synergistically providing antiadhesion and bactericidal properties remain to be developed. Furthermore, fundamental questions pertaining to the need for intrinsic hydrophobicity to achieve bactericidal performance and the role of structure length scale (nano vs micro) are still being explored. Here, we demonstrate highly scalable, cost-effective, and efficient nanoengineered multifunctional surfaces that possess both antiadhesion and bactericidal properties on industrially relevant copper (Cu) and aluminum (Al) substrates. We characterize antiadhesion and bactericidal performance using a combination of scanning electron microscopy (SEM), atomic force microscopy (AFM), live/dead bacterial staining and imaging, as well as solution-phase and Petrifilm measurements of bacterial viability. Our results showed that nanostructures created on both Cu and Al were capable of physical deformation of adhered Escherichia coli bacteria. Bacterial viability measurements on both Cu and Al indicated a complex interaction between the antiadhesion and bactericidal nature of these materials and their surface topography, chemistry, and structure. Increased superhydrophobicity greatly decreased bacterial adhesion while not significantly influencing surface bactericidal performance. Furthermore, we observed that more densely packed nanoscale structures improved antiadhesion properties when compared to larger features, even over extended time scales of up to 24 h. Our data suggests that the superhydrophobic Al substrate possesses superior antiadhesion and bactericidal effects, even over long time courses. The techniques and insights presented here will inform future work on antiadhesion and bactericidal multifunctional surfaces and enable their rational design.