Comparison of the Photodegradation of Imazethapyr in Aqueous Solution, on Epicuticular Waxes, and on Intact Corn (Zea Mays) and Soybean (Glycine Max) Leaves.

A direct, controlled comparison of the photodegradation of imazethapyr has been made between imazethapyr in aqueous solutions, imazethapyr on the surface of epicuticular waxes of corn and soybean plants, and imazethapyr on the surface of intact corn and soybean plant leaves. In some experiments, the imazethapyr solutions were allowed to evaporate partially or fully after application to better model environmental conditions. The photodegradation of imazethapyr was fastest in aqueous solutions (k = 0.16 ± 0.02 h-1) and slowest on the surface of corn and soybean plants (kcorn = 0.00048 ± 0.001 h-1 and ksoy = 0.00054 ± 0.003 h-1). Experiments allowing evaporation during irradiation have intermediate rate constants (e.g., kcorn = 0.082 ± 0.005 h-1). Finally, identification of photoproducts was also examined on epicuticular waxes of corn and soybean plants for the first time.

Comparison of video-based and sensor-based head impact exposure.

Previous research has sought to quantify head impact exposure using wearable kinematic sensors. However, many sensors suffer from poor accuracy in estimating impact kinematics and count, motivating the need for additional independent impact exposure quantification for comparison. Here, we equipped seven collegiate American football players with instrumented mouthguards, and video recorded practices and games to compare video-based and sensor-based exposure rates and impact location distributions. Over 50 player-hours, we identified 271 helmet contact periods in video, while the instrumented mouthguard sensor recorded 2,032 discrete head impacts. Matching video and mouthguard real-time stamps yielded 193 video-identified helmet contact periods and 217 sensor-recorded impacts. To compare impact locations, we binned matched impacts into frontal, rear, side, oblique, and top locations based on video observations and sensor kinematics. While both video-based and sensor-based methods found similar location distributions, our best method utilizing integrated linear and angular position only correctly predicted 81 of 217 impacts. Finally, based on the activity timeline from video assessment, we also developed a new exposure metric unique to American football quantifying number of cross-verified sensor impacts per player-play. We found significantly higher exposure during games (0.35, 95% CI: 0.29-0.42) than practices (0.20, 95% CI: 0.17-0.23) (p<0.05). In the traditional impacts per player-hour metric, we observed higher exposure during practices (4.7) than games (3.7) due to increased player activity in practices. Thus, our exposure metric accounts for variability in on-field participation. While both video-based and sensor-based exposure datasets have limitations, they can complement one another to provide more confidence in exposure statistics.

Detection of American Football Head Impacts Using Biomechanical Features and Support Vector Machine Classification.

Accumulation of head impacts may contribute to acute and long-term brain trauma. Wearable sensors can measure impact exposure, yet current sensors do not have validated impact detection methods for accurate exposure monitoring. Here we demonstrate a head impact detection method that can be implemented on a wearable sensor for detecting field football head impacts. Our method incorporates a support vector machine classifier that uses biomechanical features from the time domain and frequency domain, as well as model predictions of head-neck motions. The classifier was trained and validated using instrumented mouthguard data from collegiate football games and practices, with ground truth data labels established from video review. We found that low frequency power spectral density and wavelet transform features (10~30 Hz) were the best performing features. From forward feature selection, fewer than ten features optimized classifier performance, achieving 87.2% sensitivity and 93.2% precision in cross-validation on the collegiate dataset (n = 387), and over 90% sensitivity and precision on an independent youth dataset (n = 32). Accurate head impact detection is essential for studying and monitoring head impact exposure on the field, and the approach in the current paper may help to improve impact detection performance on wearable sensors.

Statistical analysis of the photodegradation of imazethapyr on the surface of extracted soybean (Glycine max) and corn (Zea mays) epicuticular waxes.

The photodegradation rate of the herbicide imazethapyr on epicuticular waxes of soybean and corn plants was investigated. Plant age, relative humidity, temperature, and number of light banks were varied during plant growth, analyzed statistically, and examined to determine if these factors had an effect on the photodegradation of imazethapyr. Through ultraviolet/visible (UV-Vis) and fluorescence spectroscopy, epicuticular wax characteristics of soybean and corn plants were explored, were used to confirm observations determined statistically, and explain correlations between the rate constants and the composition of the epicuticular waxes. Plant age, the interaction between plant age and light, and the quadratic dependence on temperature were all determined to have a significant impact on the photodegradation rate of imazethapyr on the epicuticular waxes of soybean plants. As for the photodegradation rate on the epicuticular waxes of corn plants, the number of light banks used during growing and temperature were significant factors.

Analysis of the Photodegradation of the Imidazolinone Herbicides Imazamox, Imazapic, Imazaquin, and Imazamethabenz-methyl in Aqueous Solution.

The photodegradation of the imidazolinone herbicides imazamox, imazapic, imazaquin, and imazamethabenz-methyl has been investigated in phosphate-buffered solutions and buffered solutions containing natural organic matter (NOM). The hydrolysis of imazamethabenz-methyl, the only imidazolinone herbicide susceptible to hydrolysis, was also examined. The rate of hydrolysis of imazamethabenz-methyl increased with increasing pH, with the para isomer degrading more rapidly than the meta isomer. All photodegradation rate constants increased with pH and plateaued after pH 5.2. All imidzaolinones degraded more quickly under 253.7 nm lamps as compared to degradation under 310 nm lamps. Imazamox and imazapic degraded more rapidly than imazaquin at all pH values and had higher quantum yields. In addition, imazamox and imazapic quantum yields increased as a function of pH, whereas imazaquin quantum yields showed no trend as a function of pH. Photodegradation reaction rate constants decreased as the concentration of NOM was increased in the solutions due to the effect of light screening. Formulas for the proposed photoproducts for imazamox, imazapic, and imazaquin in pH 7 phosphate buffers were identified, and structures for the photoproducts are proposed.

Seventy day safety assessment of an orally ingested, l-glutamine-containing oat and yeast supplement for horses.

We describe a safety assessment of an oral supplement designed to nutritionally support the gastrointestinal system of horses. The supplement comprised a mixture of essential (l-threonine) and conditionally essential (l-glutamine) amino acids, polar lipids, oat bran rich in beta glucans and yeast extract. Young (1-2years) horses of both sexes were allocated to control (n=7) and treatment groups (n=7) and studied for 9weeks. Horses in the treatment group received the supplement daily for 8weeks. After 8weeks of supplementation, horses were studied for one additional week. Outcome measures included body mass, weight gain, results of clinical examination, hematology and plasma chemistry. There were no adverse events associated with supplementation and horses in both groups showed normal weight gain, clinical signs, hematology and chemistry. l-Glutamine, which is not yet listed as GRAS, was considered with respect to its potential for nutritional support and safety when ingested orally. It is concluded that this oral supplement, when ingested by horses at twice the recommended daily level, was safe and does not pose a health risk when used in accordance with good feeding practice.

Test-retest and interrater reliability of the functional movement screen.

CONTEXT: The Functional Movement Screen (FMS) is a popular test to evaluate the degree of painful, dysfunctional, and asymmetric movement patterns. Despite great interest in the FMS, test-retest reliability data have not been published. OBJECTIVE: To assess the test-retest and interrater reliability of the FMS and to compare the scoring by 1 rater during a live session and the same session on video. DESIGN: Cross-sectional study. SETTING: Human performance laboratory in the sports medicine center. PATIENTS OR OTHER PARTICIPANTS: A total of 21 female (age = 19.6 ± 1.5 years, height = 1.7 ± 0.1 m, mass = 64.4 ± 5.1 kg) and 18 male (age = 19.7 ± 1.0 years, height = 1.9 ± 0.1 m, mass = 80.1 ± 9.9 kg) National Collegiate Athletic Association Division IA varsity athletes volunteered. INTERVENTION(S): Each athlete was tested and retested 1 week later by the same rater who also scored the athlete's first session from a video recording. Five other raters scored the video from the first session. MAIN OUTCOME MEASURE(S): The Krippendorff α (K α) was used to assess the interrater reliability, whereas intraclass correlation coefficients (ICCs) were used to assess the test-retest reliability and reliability of live-versus-video scoring. RESULTS: Good reliability was found for the test-retest (ICC = 0.6), and excellent reliability was found for the live-versus-video sessions (ICC = 0.92). Poor reliability was found for the interrater reliability (K α = .38). CONCLUSIONS: The good test-retest and high live-versus-video session reliability show that the FMS is a usable tool within 1 rater. However, the low interrater K α values suggest that the FMS within the limits of generalization should not be used indiscriminately to detect deficiencies that place the athlete at greater risk for injury. The FMS interrater reliability may be improved with better training for the rater.

Prevention of cartilage degeneration and gait asymmetry by lubricin tribosupplementation in the rat following anterior cruciate ligament transection.

OBJECTIVE: To investigate whether cartilage degeneration is prevented or minimized in a rat model of anterior cruciate ligament (ACL) injury following a single dose-escalated intraarticular injection of lubricin derived from human synoviocytes in culture. METHODS: Unilateral ACL transection (ACLT) of the right hind limb was performed in Lewis rats (n = 56). Control animals underwent a capsulotomy alone, leaving the ACL intact (n = 11). Intraarticular injections (50 µl/injection) of phosphate buffered saline (PBS; n = 14 rats) and human synoviocyte lubricin (1,600 µg/ml; n = 14 rats) were performed on day 7 postsurgery. Animals were killed on day 70 postsurgery. Histologic specimens were immunoprobed for lubricin and sulfated glycosaminoglycans. Urinary C-telopeptide of type II collagen (CTX-II) levels were measured on days 35 and 70 postsurgery. Hind limb maximum applied force was determined using a variable resistor walkway to monitor quadruped gait asymmetries. RESULTS: Increased immunostaining for lubricin in the superficial zone and on the surface of cartilage was observed in lubricin-treated and control animals but not in PBS-treated or untreated animals with ACLT. On days 35 and 70 after surgery, urinary CTX-II levels in human synoviocyte lubricin-treated animals were lower than in untreated and PBS-treated animals (P < 0.005 and P < 0.001, respectively). Animals with ACLT treated with human synoviocyte lubricin and control animals distributed their weight equally between hind limbs compared to PBS-treated or untreated animals (P < 0.01). CONCLUSION: Our findings indicate that a single intraarticular injection of concentrated lubricin following ACLT reduces type II collagen degradation and improves weight bearing in the affected rat joint. These findings support the practice of tribosupplementation with lubricin for retarding cartilage degeneration and possibly the development of posttraumatic osteoarthritis.

Prevention of cartilage degeneration and restoration of chondroprotection by lubricin tribosupplementation in the rat following anterior cruciate ligament transection.

OBJECTIVE: To investigate whether cartilage degeneration is prevented or minimized following intraarticular injections of lubricin derived from human synoviocytes in culture, recombinant human PRG4 (rhPRG4), or human synovial fluid (SF) in a rat model of anterior cruciate ligament (ACL) injury. METHODS: Unilateral ACL transection (ACLT) was performed in Lewis rats (n = 45). Nine animals were left untreated. The remaining rats were given intraarticular injections (50 microl/injection) of either phosphate buffered saline (PBS) (n = 9), human synoviocyte lubricin (200 microg/ml; n = 9), rhPRG4 (200 microg/ml; n = 9), or human SF lubricin (200 microg/ml; n = 9) twice weekly beginning on day 7 after injury. Joints were harvested on day 32 after injury. Histologic analysis was performed using Safranin O-fast green staining, and articular cartilage degeneration was graded using the Osteoarthritis Research Society International (OARSI)-modified Mankin criteria. Histologic specimens were immunoprobed for lubricin and sulfated glycosaminoglycans. A 24-hour urine collection was performed on days 17 and 29 postinjury, and urinary C-terminal telopeptide of type II collagen (CTX-II) levels were measured. RESULTS: Treatment with human synoviocyte lubricin resulted in significantly lower OARSI scores for cartilage degeneration compared with no treatment or PBS treatment (P < 0.05). Increased immunostaining for lubricin in the superficial zone chondrocytes and on the surface of cartilage was observed in lubricin-treated, but not untreated or PBS-treated, joints. On day 17, urinary CTX-II levels in human synoviocyte lubricin- and human SF lubricin-treated animals were significantly lower than those in untreated animals (P = 0.005 and P = 0.002, respectively) and in PBS-treated animals (P = 0.002 and P < 0.001, respectively). CONCLUSION: After treatment with any of the 3 types of lubricin evaluated in this study, a reduction in cartilage damage following ACLT was evident, combined with a reduction in type II collagen degradation. Our findings indicate that intraarticular lubricin injection following an ACL injury may be beneficial in retarding the degeneration of cartilage and the development of posttraumatic OA.

Local delivery of a viral vector mitigates neutralization by antiviral antibodies and results in efficient transduction of rabbit liver.

Antiviral antibodies within the human population remain a barrier to the effective clinical use of viral gene transfer vectors. We have asked whether local, balloon catheter-mediated delivery of a viral vector to the rabbit liver using a hepatic vein might mitigate the neutralizing effects of antiviral antibodies. We have compared directly the ability of adenovirus (Ad2) encoding nuclear-localized beta-galactosidase to infect the rabbit liver after local and systemic delivery in both the presence and the absence of defined anti-Ad2 antibody titers. In naive rabbits, local delivery resulted in higher beta-galactosidase expression compared to systemic delivery. In the presence of passively administered anti-Ad2 antibodies, local delivery resulted in expression levels that were comparable to those obtained in naive rabbits by systemic delivery. Local delivery also resulted in the majority of expression originating from hepatocytes, even in passively immunized animals, a result that could not be duplicated using the systemic approach. Since systemic delivery of adenovirus in naive animal models results in transgene expression levels often regarded as therapeutic, these results predict that local hepatic vein delivery of a viral vector is a clinically practical approach to mitigate neutralizing antiviral antibodies and generate therapeutic levels of transgene expression.