Where the rubber meets the road: Emerging environmental impacts of tire wear particles and their chemical cocktails

About 3 billion new tires are produced each year and about 800 million tires become waste annually. Global dependence upon tires produced from natural rubber and petroleum-based compounds represents a persistent and complex environmental problem with only partial and often-times, ineffective solutions. Tire emissions may be in the form of whole tires, tire particles, and chemical compounds, each of which is transported through various atmospheric, terrestrial, and aquatic routes in the natural and built environments. Production and use of tires generates multiple heavy metals, plastics, PAH's, and other compounds that can be toxic alone or as chemical cocktails. Used tires require storage space, are energy intensive to recycle, and generally have few post-wear uses that are not also potential sources of pollutants (e.g., crumb rubber, pavements, burning). Tire particles emitted during use are a major component of microplastics in urban runoff and a source of unique and highly potent toxic substances. Thus, tires represent a ubiquitous and complex pollutant that requires a comprehensive examination to develop effective management and remediation. We approach the issue of tire pollution holistically by examining the life cycle of tires across production, emissions, recycling, and disposal. In this paper, we synthesize recent research and data about the environmental and human health risks associated with the production, use, and disposal of tires and discuss gaps in our knowledge about fate and transport, as well as the toxicology of tire particles and chemical leachates. We examine potential management and remediation approaches for addressing exposure risks across the life cycle of tires. We consider tires as pollutants across three levels: tires in their whole state, as particulates, and as a mixture of chemical cocktails. Finally, we discuss information gaps in our understanding of tires as a pollutant and outline key questions to improve our knowledge and ability to manage and remediate tire pollution.

Muscle Damage, Inflammation, and Muscular Performance following the Physical Ability Test in Professional Firefighters

Proper monitoring of fatigue and muscular damage may be used to decrease the high levels of cardiovascular disease, overuse musculoskeletal injuries, and workers compensation claims within the profession of firefighting. The purpose of this study was to examine muscle damage, muscular fatigue, and inflammation responses following a typical firefighting shift. Twenty-four professional firefighters completed two Physical Ability Tests to standardize the tasks typically performed in a day of work, and to elicit similar physiological responses. Participants were then monitored for 48 h. Prior to, and 48 h following the Physical Ability Tests, participants were evaluated for changes in strength, power, range-of-motion, as well as blood markers including myoglobin and c-reactive protein. Following the Physical Ability Tests, significant differences in myoglobin (p < 0.05), grip strength (p < 0.05), vertical jump (p < 0.05), and sit-and-reach (p < 0.05) were observed. No difference in c-reactive protein was observed (p > 0.05). After 24 hours following a shift, firefighters exhibited decreased strength, power, and range-of-motion. This may lead to decreases in performance and an increased risk of injury.

Acute Supplementation with Cannabidiol Does Not Attenuate Inflammation or Improve Measures of Performance following Strenuous Exercise

Supplementation with cannabidiol (CBD) may expedite recovery when consumed after exercise. The purpose of this study was to determine if supplementation with CBD reduces inflammation and enhances performance following strenuous eccentric exercise in collegiate athletes. Twenty-four well-trained females (age = 21.2 ± 1.8 years, height = 166.4 ± 8 cm, weight = 64.9 ± 9.1 kg) completed 100 repetitions of unilateral eccentric leg extension to induce muscle damage. In this crossover design, participants were randomized to receive 5 mg/kg of CBD in pill form or a placebo 2 h prior to, immediately following, and 10 h following muscle damage. Blood was collected, and performance and fatigue were measured prior to, and 4 h, 24 h, and 48 h following the muscle damage. Approximately 28 days separated treatment administration to control for the menstrual cycle. No significant differences were observed between the treatments for inflammation, muscle damage, or subjective fatigue. Peak torque at 60°/s (p = 0.001) and peak isometric torque (p = 0.02) were significantly lower 24 h following muscle damage, but no difference in performance was observed between treatments at any timepoint. Cannabidiol supplementation was unable to reduce fatigue, limit inflammation, or restore performance in well-trained female athletes.

Focused Microbiome Shifts in Reconstructed Wetlands Correlated with Elevated Copper Concentrations Originating from Micronized Copper Azole-Treated Wood

Micronized copper (Cu) azole (MCA) wood preservative formulations include Cu in nano form, and relatively little is known about longer term effects of Cu leached from MCA into wetland ecosystems. We tested the hypothesis that changes in soil microbiomes within reconstructed freshwater wetlands will be associated with exposure to elevated Cu concentrations originating from immersed MCA-treated wood stakes. Eight replicate communities were assembled with Willamette Valley (OR, USA) flood plain soil and clonally propagated wetland plants within mesocosms. Inundated communities were equilibrated for 5 months before installation of MCA or control southern yellow pine stakes (n = 4 communities/experimental group). Soil samples were collected for 16S and internal transcribed spacer amplicon sequencing to quantify responses in prokaryotes and eukaryotes, respectively, at 15 time points, spanning two simulated seasonal dry downs, for up to 678 days. Physiochemical properties of water and soil were monitored at 20 and 12 time points respectively, over the same period. For both taxonomic groups of organisms, phylogenetic diversity increased and was positively correlated with elapsed days. Furthermore, there was significant divergence among eukaryotes during the second year based on experimental group. Although the composition of taxa underwent succession over time, there was significantly reduced relative abundance of sequence variants from Gomphonema diatoms and Scutellinia fungi in communities where MCA wood stakes were present compared with the controls. These focused microbiome shifts were positively correlated with surface water Cu and soil Cu concentrations, which were significantly elevated in treated communities. The reconstructed communities were effective systems for assessing potential impacts to wetland microbiomes after exposure to released copper. The results further inform postcommercialization risk assessments on MCA-treated wood. Environ Toxicol Chem 2021;40:3351-3368. Published 2021. This article is a U.S. Government work and is in the public domain in the USA.

Transformation and release of micronized Cu used as a wood preservative in treated wood in wetland soil

Micronized Cu (μ-Cu) is used as a wood preservative, replacing toxic chromated copper arsenate (CCA). Micronized Cu is malachite [Cu₂CO₃(OH)₂] that has been milled to micron/submicron particles, with many particle diameters less than 100 nm, mixed with biocides and then used to treat wood. In addition to concerns about the fate of the Cu from μ-Cu, there is interest in the fate of the nano-Cu (n-Cu) constituents. We examined movement of Cu from μ-Cu-treated wood after placing treated-wood stakes into model wetland ecosystems. Release of Cu into surface and subsurface water was monitored. Surface water Cu reached maximum levels 3 days after stake installation and remained elevated if the systems remained inundated. Subsurface water Cu levels were 10% of surface water levels at day 3 and increased gradually thereafter. Sequential filtering indicated that a large portion of the Cu in solution was associating with soluble organics, but there was no evidence for n-Cu in solution. After 4 months, Cu in thin-sections of treated wood and adjacent soil were characterized with micro X-ray absorption fine structure spectroscopy (μ-XAFS). Localization and speciation of Cu in the wood and adjacent soil using μ-XAFS clearly indicated that Cu concentrations decreased over time in the treated wood and increased in the adjacent soil. However, n-Cu from the treated wood was not found in the adjacent soil or plant roots. The results of this study indicate that Cu in the μ-Cu-treated wood dissolves and migrates into adjacent soil and waters primarily in ionic form (i.e., Cu²⁺) and not as nano-sized Cu particles. A reduced form of Cu (Cu₂S) was identified in deep soil proximal to the treated wood, indicating strong reducing conditions. The formation of the insoluble Cu₂S effectively removes some portion of dissolved Cu from solution, reducing movement of Cu²⁺ to the water column and diminishing exposure.

Exercise-Induced Improvements in Insulin Sensitivity Are Not Attenuated by a Family History of Type 2 Diabetes

Introduction: A family history of type 2 diabetes (FH+) is a major risk factor for the development of insulin resistance and type 2 diabetes. However, it remains unknown whether exercise-induced improvements in insulin sensitivity and metabolic flexibility are impacted by a FH+. Therefore, we investigated whether improvements in insulin sensitivity, metabolic flexibility, body composition, aerobic fitness and muscle strength are limited by a FH+ following eight weeks of combined exercise training compared to individuals without a family history of type 2 diabetes (FH-). Methods: Twenty (n = 10 FH-, n = 10 FH+) young, healthy, sedentary, normoglycemic, Mexican-American males (age: FH- 22.50 ± 0.81, FH+ 23.41 ± 0.86 years; BMI: FH- 27.91 ± 1.55, FH+ 26.64 ± 1.02 kg/m²) underwent eight weeks of combined aerobic and resistance exercise training three times/week (35 min aerobic followed by six full-body resistance exercises). Insulin sensitivity was assessed via hyperinsulinemic euglycemic clamps. Metabolic flexibility was assessed by the change in respiratory quotient from fasted to insulin-stimulated states. Body composition was determined using dual-energy x-ray absorptiometry. Aerobic fitness was determined by a graded exercise test, and upper- and lower-body strength were assessed via one-repetition maximum bench press and leg strength dynamometer, respectively. Results: Insulin sensitivity, metabolic flexibility, aerobic fitness and strength were not different between groups (p > 0.05). Eight weeks of combined aerobic and resistance exercise training improved insulin sensitivity (FH- p = 0.02, FH+ p = 0.002), increased fat free mass (FH- p = 0.006, FH+ p = 0.001), aerobic fitness (FH- p = 0.03, FH+ p = 0.002), and upper- (FH- p = 0.0001, FH+ p = 0.0001) and lower-body strength (FH- p = 0.0009, FH+ p = 0.0003), but did not change metabolic flexibility (p > 0.05) in both groups. Exercise-induced improvements in metabolic outcomes were similar between groups. Conclusions: Insulin sensitivity, metabolic flexibility, aerobic fitness and strength were not compromised by a FH+. Additionally, a FH+ is not a limiting factor for exercise-induced improvements in insulin sensitivity, aerobic fitness, body composition, and strength in normoglycemic young Mexican-American men.

Pilot study: an acute bout of high intensity interval exercise increases 12.5 h GH secretion

The purpose of this study was to test the hypothesis that high‐intensity interval exercise (HIE) significantly increases growth hormone (GH) secretion to a greater extent than moderate‐intensity continuous exercise (MOD) in young women. Five young, sedentary women (mean ± SD; age: 22.6±1.3 years; BMI: 27.4±3.1 kg/m²) were tested during the early follicular phase of their menstrual cycle on three occasions. For each visit, participants reported to the laboratory at 1700 h, exercised from 1730–1800 h, and remained in the laboratory until 0700 h the following morning. The exercise component consisted of either 30‐min of moderate‐intensity continuous cycling at 50% of measured peak power (MOD), four 30‐s “all‐out” sprints with 4.5 min of active recovery (HIE), or a time‐matched sedentary control using a randomized, cross‐over design. The overnight GH secretory profile of each trial was determined from 10‐min sampling of venous blood from 1730–0600 h, using deconvolution analysis. Deconvolution GH parameters were log transformed prior to statistical analyses. Calculated GH AUC (0–120 min) was significantly greater in HIE than CON (P = 0.04), but HIE was not different from MOD. Total GH secretory rate (ng/mL/12.5 h) was significantly greater in the HIE than the CON (P = 0.05), but MOD was not different from CON or HIE. Nocturnal GH secretion (ng/mL/7.5 h) was not different between the three trials. For these women, in this pilot study, a single bout of HIE was sufficient to increase 12.5 h pulsatile GH secretion. It remains to be determined if regular HIE may contribute to increased daily GH secretion.

Daily Physical Activity by Occupational Classification in US Adults: NHANES 2005-2006

BACKGROUND

Little is known about the daily physical activity (PA) levels of people employed in different occupational categories.

METHODS

Nine ActiGraph accelerometer-derived daily PA variables are presented and ranked for adults (N = 1465, 20-60 y) working in the 22 occupational categories assessed by NHANES 2005-2006. A composite score was generated for each occupational category by summing the rankings of 3 accelerometer-derived daily PA variables known to have strong associations with health outcomes (total activity counts [TAC], moderate to vigorous PA minutes per week in modified 10-minute bouts [MVPA 10], and percentage of time spent in sedentary activity [SB%]).

RESULTS

Classified as high-activity occupational categories, "farming, fishing, forestry," and "building & grounds cleaning, maintenance" occupations had the greatest TAC (461 996 and 449 452), most MVPA 10 (149.6 and 97.8), most steps per day (10 464 and 11 602), and near the lowest SB% (45.2% and 45.4%). "Community, social services" occupations, classified as low-activity occupational categories, had the second lowest TAC (242 085), least MVPA 10 (12.1), fewest steps per day (5684), and near the highest SB% (64.2%).

CONCLUSIONS

There is a strong association between occupational category and daily activity levels. Objectively measured daily PA permitted the classification of the 22 different occupational categories into 3 activity groupings.

Classification of occupational activity categories using accelerometry: NHANES 2003-2004

Background

An individual’s occupational activity (OA) may contribute significantly to daily physical activity (PA) and sedentary behavior (SB). However, there is little consensus about which occupational categories involve high OA or low OA, and the majority of categories are unclassifiable with current methods. The purpose of this study was to present population estimates of accelerometer-derived PA and SB variables for adults (n = 1112, 20–60 years) working the 40 occupational categories collected during the 2003–2004 National Health and Nutrition Examination Survey (NHANES).

Methods

ActiGraph accelerometer-derived total activity counts/day (TAC), activity counts/minute, and proportion of wear time spent in moderate-to-vigorous PA [MVPA], lifestyle, and light PA organized by occupational category were ranked in ascending order and SB was ranked in descending order. Summing the ranks of the six accelerometer-derived variables generated a summary score for each occupational category, which was re-ranked in ascending order. Higher rankings indicated higher levels of OA, lower rankings indicated lower levels of OA. Tertiles of the summary score were used to establish three mutually exclusive accelerometer-determined OA groupings: high OA, intermediate OA, and low OA.

Results

According to their summary score, ‘farm and nursery workers’ were classified as high OA and ‘secretaries, stenographers, and typists’ were classified as low OA. Consistent with previous research, some low OA occupational categories (e.g., ‘engineers, architects, and scientists’, ‘technicians and related support occupations’, ‘management related occupations’, ‘executives, administrators, and managers’, ‘protective services’, and ‘writers, artists, entertainers, and athletes’) associated with higher education and income had relatively greater amounts of MVPA compared to other low OA occupational categories, likely due to the greater percentage of men in those occupations and/or the influence of higher levels of leisure time PA. Men had more TAC, activity counts/minute and time in MVPA, but similar proportions of SB compared to women in all three OA groupings.

Conclusions

Objectively measured PA allowed for a more precise estimate of the amount of PA and SB associated with different occupations and facilitated systematic classification of the 40 different occupational categories into three distinct OA groupings. This information provides new opportunities to explore the relationship between OA and health outcomes.

Potential for metal contamination by direct sonication of nanoparticle suspensions

While conducting toxicity tests with nano titanium dioxide, the authors found that test suspensions were being contaminated with aluminum and titanium from tip erosion during direct sonication. The contaminating alloy particles had a measurable size distribution and zeta potential using dynamic light scattering, which changed the measured characteristics of the suspensions. Caution should be used when employing direct sonication for preparing test suspensions due to potential interferences of these particles in toxicological assessments.

Outcomes of a peer mentor implemented fitness program in older adults: a quasi-randomized controlled trial

OBJECTIVES

To investigate the effectiveness of different applications of mentoring in an older adult exercise program, this study compared the physical fitness scores, the retention and participation rates of older adults trained by student mentors, peer mentors, peer mentors working independently of the researchers, and a non-exercising control group.

METHODS

106 older adults were recruited and assigned to one of the groups using quasi-randomization. All three experimental groups completed a 14-week intervention. Pre- and post-training assessments of fitness were completed, and retention and participation rates were compared.

RESULTS

High retention and participation rates, as well as significant improvements in fitness scores from baseline to post-test were observed in all three mentored groups. While the control group showed improvement only in one fitness test, subjects in the mentored groups improved similarly in all measures, regardless of the type of mentoring received.

DISCUSSION

These findings indicated effectiveness of the peer mentor model and suggested that with adequate preparation peer mentors may be capable of guiding older adult participants effectively without assistance from professional staff.

Adiponectin is associated with risk of the metabolic syndrome and insulin resistance in women

The purpose of this study was to examine insulin resistance, markers of the metabolic syndrome, cardiovascular disease (CVD) risk, and serum adiponectin concentrations in pre-menopausal Hispanic and non-Hispanic White (NHW) women. This cross-sectional study examined 119 pre-menopausal women (76 Hispanic, 45 NHW) for markers of the metabolic syndrome (ATP III criteria), level of insulin resistance (HOMA-IR), CVD risk factors, and serum total adiponectin concentrations. Relationships between variables were assessed using Student's t-tests, Pearson's and Spearman's Rho correlations, and stepwise multiple regression analysis. Hispanic women had significantly lower adiponectin concentrations than NHW women, even after controlling for body fat (%) (P < 0.01). Number of markers of the metabolic syndrome was inversely related to total adiponectin concentration for all women combined and for NHW women (P ≤ 0.04), but not for Hispanic women. Insulin resistance was inversely related to adiponectin for all women and for NHW women (P < 0.01), but not significantly associated in Hispanic women. Adiponectin concentration was not significantly associated with number of CVD risk factors for these women. While adiponectin was associated with markers of metabolic syndrome and insulin resistance for all women of this study and despite lower adiponectin concentrations for Hispanic women than NHW women, the role of adiponectin to these conditions among Hispanics remains unclear. There was no significant association between adiponectin and CVD risk for these women. Future research should focus on understanding mechanisms for up-regulating adiponectin secretion and if ethnicity affects adiponectin gene expression and secretion given the beneficial effects derived from elevated adiponectin levels.

Overweight and obese humans overeat away from home

The built environment has been implicated in the development of the epidemic of obesity. We investigated the differences in the meal patterns of normal weight vs. overweight/obese individuals occurring at home vs. other locations. The location of meals and their size in free-living participants were continuously recorded for 7 consecutive days. Study 1: 81 males and 84 females recorded their intake in 7-day diet diaries and wore a belt that contained a GPS Logger to record their location continuously for 7 consecutive days. Study 2: 388 males and 621 females recorded their intake in diet diaries for 7 consecutive days. In both studies, compared to eating at home, overweight/obese participants ate larger meals away from home in both restaurants and other locations than normal weight participants. Overweight/obese individuals appear to be more responsive to environmental cues for eating away from home. This suggests that the influence of the built environment on the intake of overweight/obese individuals may contribute to the obesity epidemic.

Social participation of youths with cerebral palsy differed based on their self-perceived competence as a friend

BACKGROUND

Social participation with friends fosters development of meaningful relationships, life skills and psychosocial well-being. Youths with cerebral palsy (CP) face challenges to establishing social relationships with friends. The aim of this study was to explore whether social participation with friends differs among youths with CP based on their self-perceived competence as a friend.

METHODS

A total of 135 youths with CP, 13-21 years old (mean age 16 years, 50% were male), completed the measures Fulfillment in Social Roles and Children's Assessment of Participation and Enjoyment. Youths were assigned to high, middle and low groups defined by their self-perceived competence as a friend. Differences among the three groups in the number, total frequency and enjoyment of activities done with friends was examined by Kruskal-Wallis one-way analyses of variance. Post hoc analysis of significant effects was performed using a Mann-Whitney U-test or Kolmogorov-Smirnov test.

RESULTS

The number (χ(2) = 17.07, d.f. = 2, P < 0.001) and total frequency (χ(2) = 18.35, d.f. = 2, P < 0.001) of activities done with friends differed based on youths' self-perceived competence as a friend. Youths with high self-perceived competence as a friend did the greatest number of activities and participated most often with friends. Youths with low self-perceived competence did the fewest activities and participated least often with friends. No differences were found in the enjoyment of activities done with friends among the three groups (χ(2) = 1.86, d.f. = 2, P > 0.05).

CONCLUSIONS

For youths with CP, the number and frequency of activities done with friends differed based on self-perceived competence as a friend, but not enjoyment of activities. The results suggest a positive link between social participation and self-perceived competence. Healthcare providers have a role to support youths' efforts to engage with friends by enhancing community opportunities, developing and providing interventions in natural social environments and incorporating peer support into service delivery.

Comparing the effectiveness of peer mentoring and student mentoring in a 35-week fitness program for older adults

To investigate the applicability and effectiveness of a peer-mentored exercise program, this study compared the retention and participation rates, and physical improvements of older adults trained by peer mentors (PM) to a group trained by young qualified student mentors (SM). A group of older adults were prepared as peer mentors through a 30-week preparation program. Later, 60 older adults (mean ± SD age: 68.7 ± 6.1 years) were recruited and randomly assigned to either the PM or SM group. Both groups completed an identical 35-week fitness program. Pre-, midterm- and post-training assessments of fitness were completed and rates of participation and retention were documented. The same retention rates were observed in the two groups, but SM group had higher participation. Both groups improved significantly in all measures of fitness and there were no significant post-test differences between the groups in the fitness measures. Findings suggest that the peer mentor model is applicable in an older adult exercise program and may be as effective as a program mentored by young professionals.

Effects of manual resistance training on fitness in adolescents

Manual resistance training (MRT), an alternative to traditional resistance training, requires minimal equipment and may be effective when applied in school-based physical education (PE) classes. The purpose of this study was to document the physical changes in adolescents (n = 222) using MRT in school-based PE settings. Six fitness tests from the Fitnessgram assessment tool were selected to assess students' cardiovascular and muscular fitness, and skinfold tests were used to assess body composition. One control and 2 experimental groups were defined. The control group of students (n = 129) attended regular PE classes. One experimental group (n = 63) attended PE that was complemented by the MRT system. A second experimental group (n = 30) attended PE complemented by MRT and cardiovascular endurance training. With use of the selected Fitnessgram tests, post-test measurements were performed after 9 and 18 weeks of PE. At baseline, there were no significant differences among the 3 groups for most measures. Compared with baseline, the experimental groups improved significantly in all 6 fitness measures and showed more improvements than the control group in most fitness measures both at 9 and 18 weeks. None of the groups showed significant improvement in body composition. The results documented that an MRT-complemented PE program was effective in improving adolescents' muscular fitness. An 18-week combined MRT and cardiovascular endurance training program effectively improved cardiovascular and muscular fitness but was ineffective in improving adolescent body composition. An MRT-based exercise session requires minimal equipment and set-up and can be performed in a short period of time, and therefore it is suitable for application in regular PE settings.

Relationship between leptin, adiponectin, bone mineral density, and measures of adiposity among pre-menopausal Hispanic and Caucasian women

OBJECTIVE

The purpose of this study was to examine the relationship between fasting serum leptin and adiponectin levels with bone mineral density (BMD) and body composition in pre-menopausal, middle-aged Hispanic and Caucasian women.

OBJECTIVE

Participants' (68 Hispanic and 36 Caucasian) BMD and bone mineral content were measured by dual-energy X-ray absorptiometry, and body density was measured by hydrodensitometry. Serum leptin was determined by enzyme immunoassay and adiponectin by ELISA.

RESULTS

Hispanic women had significantly higher leptin, BMD, and fat mass (FM), and lower adiponectin than Caucasian women. There was no significant correlation between leptin and BMD for Hispanic or Caucasian women; adiponectin was inversely correlated with BMD in Caucasian women only (p = 0.01). In both Hispanic and Caucasian women, lean body mass and adiponectin best explained the variance in BMD (r(2) = 0.25, p < 0.001).

CONCLUSION

These data demonstrate no significant relationship between leptin and BMD of pre-menopausal, middle-aged Hispanic and Caucasian women, and a significant inverse relationship between adiponectin and BMD in Caucasian women. The role of adipocytokines in the regulation of BMD remains inconclusive and may vary across ethnic groups.

Relationship of leptin, resting metabolic rate, and body composition in premenopausal hispanic and non-Hispanic White women

OBJECTIVE

The purpose was to evaluate the relationships between fasting serum leptin, resting metabolic rate (RMR), and body composition in premenopausal Hispanic and non-Hispanic White (White) women.

METHODS

Participants were 67 Hispanic and 43 White women who arrived at the laboratory in a fasted state for measurement of RMR by indirect calorimetry, bone mineral content measured by dual-energy X-ray absorptiometry, and body density measured by hydrodensitometry. Serum leptin levels were determined by EIA.

RESULTS

Multiple regression analysis revealed that body mass and lean body mass were the best predictors of RMR. Leptin was not a significant predictor of RMR.

CONCLUSION

Further research needs to be done to examine the role of leptin on metabolism, especially in ethnic groups predisposed to development of obesity and related disorders.

Alginate concentration: a key factor in growth of temperature-sensitive baculovirus-infected insect cells in microcapsules

The desire to increase cell density and product concentration has been the primary driving force for the development of better animal cell culture processes. In the technique used in our laboratory-microencapsulation-insect cells (Spodoptera frugiperda), infected with a temperature-sensitive mutant of the Autographa californica nuclear polyhedrosis virus (AcNPV), were cultured in multiple membrane alginate-polylysine (PLL) microcapsules which had a controlled membrane molecular-weight cutoff and an intracapsular alginate concentration which was ca. 16% lower than that obtained in the commercially available single-membrane system. Cell culture experiments indicated that the intracapsular alginate concentration appears to be a key factor in achieving good cell growth. It was possible to obtain intracapsular cell densities of 8 x 10(7) cells/mL capsules and virus concentrations to 10(9) IFU/mL capsules. The virus litre in the supernatant was ca. 300 times lower, indicating that virtually all of the virus was retained within the capsules.

The effects of manual resistance training on improving muscular strength and endurance

The purpose of this study was to investigate the effects of a manual resistance training (MRT) program on muscular strength and endurance and to compare these effects with those of an identically structured weight resistance training (WRT) program. To do this, 84 healthy college students were randomly assigned to either an MRT (n = 53, mean +/- SD: age 25.6 +/- 6.0 years, height 170.1 +/- 8.1 cm, body mass 73.9 +/- 16.0 kg, and body fat 24.6 +/- 8.7%) or WRT (n = 31, mean +/- SD: age 25.5 +/- 5.2 years; height 169.6 +/- 10.1 cm, body mass 75.0 +/- 17.4 kg, and body fat 24.7 +/- 8.5%) group and engaged in a 14-week training program. Each participant's performance was assessed before and immediately after the 14-week training period. Muscular strength was assessed by the one-repetition maximum (1RM) bench press test and the 1RM squat test. Muscular endurance was recorded as the maximum number of repetitions performed with 70% of pretraining 1RM for the bench press and squat exercises. There were no significant differences between the MRT and WRT groups at baseline for muscular strength (p > 0.36) or muscular endurance (p > 0.46). Compared with baseline values, the 14-week training programs produced significant (p < 0.001) improvements in muscular strength and muscular endurance of the MRT and WRT groups. However, no significant difference was observed between the MRT and WRT groups for muscular strength (p > 0.22) or for muscular endurance (p > 0.09) after training. The improvements in muscular strength and muscular endurance after a 14-week MRT program in the present study were similar to those produced by a WRT program, and well-designed MRT exercises seem to be effective for improving muscular fitness.

A Standard Method for Evaluating Radiocarbon Dates of Local Deglaciation: Application to the Deglaciation History of Southern Labrador and Adjacent Québec

Sixty-two radiocarbon dates of marine shells, basal lake sediments, and basal peat deposits from the southeastern part of the Labrador-Ungava Peninsula, Canada, were evaluated for their accuracy and precision in estimating local deglaciation time. A procedure for the consistent evaluation of basal dates of lake sediments was developed after consideration of the problems with dating early-postglacial sediments. Of the 62 dates, 42 were selected to construct the regional déglaciation chronology, interpreted in the context of the glacial geology of the area. Late Wisconsin ice stretched to or beyond the present-day coastline throughout the study area, except in southeastern Labrador where the extreme southeastern coast was probably ice-free during Late Wisconsin time. Déglaciation began in southeastern Labrador by 13.OK. It proceeded slowly at first, and between 9.7K and 10.5K the retreating ice formed the Paradise Moraine, which parallels the southeastern Labrador coastline. In contrast, the coast at Sept-îles was not ice-free until about 9.4K. Shortly thereafter the extensive Québec North Shore Moraine System developed, although its precise age is uncertain. The position of the ice margin at 8.0K is uncertain, but may still have been near the Québec North Shore Moraine System. After 8.0K ice retreat was rapid, although extensive ice persisted at 6.5K in western Labrador and adjacent Québec. Final wastage of ice occurred in two localities in the center of the Labrador-Ungava Peninsula just after 6.OK. The precision of the well-dated glacial isochrones is estimated to be about ± 23 km.

Photofragment slice imaging studies of pyrrole and the Xe⋯pyrrole cluster

The photolysis of pyrrole has been studied in a molecular beam at wavelengths of 250, 240, and 193.3 nm, using two different carrier gases, He and Xe. A broad bimodal distribution of H-atom fragment velocities has been observed at all wavelengths. Near threshold at both 240 and 250 nm, sharp features have been observed in the fast part of the H-atom distribution. Under appropriate molecular beam conditions, the entire H-atom loss signal from the photolysis of pyrrole at both 240 and 250 nm (including the sharp features) disappear when using Xe as opposed to He as the carrier gas. We attribute this phenomenon to cluster formation between Xe and pyrrole, and this assumption is supported by the observation of resonance enhanced multiphoton ionization spectra for the (Xe...pyrrole) cluster followed by photofragmentation of the nascent cation cluster. Ab initio calculations are presented for the ground states of the neutral and cationic (Xe...pyrrole) clusters as a means of understanding their structural and energetic properties.

Long-distance GM pollen movement of creeping bentgrass using modeled wind trajectory analysis

The importance of understanding the role of atmospheric conditions in pollen dispersal has grown in recent years with increased field-testing of genetically modified (GM) crop plants. An atmospheric model was used to characterize wind trajectories at 10 m and 100 m above GM pollen source fields located within a 4452-ha "control" area north of Madras, Oregon, USA, designated by the Oregon Department of Agriculture (ODA). The area was used in 2003 for the growth of GM creeping bentgrass (Agrostis stolonifera) engineered to be resistant to glyphosate herbicide. The presence of the GM gene (CP4 EPSPS) provided a distinct selectable marker for pollen-mediated gene flow to sentinel and resident Agrostis spp. plants. Linkage of GM gene presence with wind flow characteristics over the "control" area became essential to understand the timing and processes leading to long-distance transport of this pollen. Wind trajectories showed a general pattern of northwest to southeast air movement. Trajectory travel distances calculated hourly from 06:00 hours to 15:00 hours during the 2003 pollination period (15 June-15 July) showed movement up to 15 km from the "control" area's center by the first hour. Maximum travel distances increased to 40 and 55 km after two and three hours from release, respectively. Calculated wind trajectory positions corresponded with observed long-distance pollen-mediated gene flow in the seedlings of sentinel and resident plants. The highest correlations were found during the late morning hours. Back-calculated wind trajectories from sentinel and resident locations with GM-gene-positive progeny suggested that most successful fertilizations occurred in the direction of prevailing winds during late June 2003. The occurrence of positive progeny from sentinel plants, upwind of the "control" area during this period, indicated the additional influence of local topography on pollen dispersal.

Evaluation of a foot-to-foot bioelectrical impedance analyser in highly active, moderately active and less active young men

The Tanita TBF-305 (Tanita Corp., Tokyo, Japan) is a commercially available foot-to-foot bioelectrical impedance analysis (BIA) system. The manufacturer-supplied equations incorporate gender, mass, height, activity category and a measured impedance value to determine % body fat (BF). The purpose of the present study was to determine whether the manufacturer-supplied ‘adult’ and ‘athlete’ equations provided an accurate estimate of % BF for a group of young men with varying activity levels. Fifty-seven men (18–35 years old) were categorized into the following groups: (1) highly active (HA) (≥10·0 h aerobic activity/week); (2) moderately active (MA) (2·5–10·0 h aerobic activity/week); (3) less active (LA) (<2·5 h aerobic activity/week). The % BF was measured using the BIA ‘athlete’ and ‘adult’ modes. After BIA measurements, residual volume was measured and hydrostatic weighing (HW) was performed. The amount of activity performed by each group was significantly different (P<0·001). No significant differences were found between the % BF determined by the ‘athlete’ mode and HW for HA (P=0·309) and MA (P=0·091). However, a significant difference was found for LA (P=0·001). The % BF determined by the ‘adult’ mode and HW was not different for LA (P=0·395), but was significantly different for MA (P<0·001) and HA (P<0·001). The choice of activity mode on the foot-to-foot BIA significantly alters prediction of % BF. With careful selection of activity mode, there was no statistical difference between % BF determined by HW and the BIA, but the range of individual error scores was large.

Measuring children's participation in recreation and leisure activities: construct validation of the CAPE and PAC

There is a need for psychometrically sound measures of children's participation in recreation and leisure activities, for both clinical and research purposes. This paper provides information about the construct validity of the Children's Assessment of Participation and Enjoyment (CAPE) and its companion measure, Preferences for Activities of Children (PAC). These measures are appropriate for children and youth with and without disabilities between the ages of 6 and 21 years. They provide information about six dimensions of participation (i.e. diversity, intensity, where, with whom, enjoyment and preference) and two categories of recreation and leisure activities: (i) formal and informal activities; and (ii) five types of activities (recreational, active physical, social, skill-based and self-improvement). This paper presents information about the performance of the CAPE and PAC activity type scores using data from a study involving 427 children with physical disabilities between the ages of 6 and 15 years. Intensity, enjoyment and preference scores were significantly correlated with environmental, family and child variables, in expected ways. Predictions also were supported with respect to differences in mean scores for boys vs. girls, and children in various age groups. The information substantiates the construct validity of the measures. The clinical and research utility of the measures are discussed.

Establishment of transgenic herbicide-resistant creeping bentgrass (Agrostis stoloniferaL.) in nonagronomic habitats

Concerns about genetically modified (GM) crops include transgene flow to compatible wild species and unintended ecological consequences of potential transgene introgression. However, there has been little empirical documentation of establishment and distribution of transgenic plants in wild populations. We present herein the first evidence for escape of transgenes into wild plant populations within the USA; glyphosate-resistant creeping bentgrass (Agrostis stolonifera L.) plants expressing CP4 EPSPS transgenes were found outside of cultivation area in central Oregon. Resident populations of three compatible Agrostis species were sampled in nonagronomic habitats outside the Oregon Department of Agriculture control area designated for test production of glyphosate-resistant creeping bentgrass. CP4 EPSPS protein and the corresponding transgene were found in nine A. stolonifera plants screened from 20,400 samples (0.04 +/- 0.01% SE). CP4 EPSPS-positive plants were located predominantly in mesic habitats downwind and up to 3.8 km beyond the control area perimeter; two plants were found within the USDA Crooked River National Grassland. Spatial distribution and parentage of transgenic plants (as confirmed by analyses of nuclear ITS and chloroplast matK gene trees) suggest that establishment resulted from both pollen-mediated intraspecific hybridizations and from crop seed dispersal. These results demonstrate that transgene flow from short-term production can result in establishment of transgenic plants at multi-kilometre distances from GM source fields or plants. Selective pressure from direct application or drift of glyphosate herbicide could enhance introgression of CP4 EPSPS transgenes and additional establishment. Obligatory outcrossing and vegetative spread could further contribute to persistence of CP4 EPSPS transgenes in wild Agrostis populations, both in the presence or absence of herbicide selection.