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1.
Psychol Sport Exerc ; 69: 102505, 2023 11.
Article in English | MEDLINE | ID: mdl-37665940

ABSTRACT

Positive youth development is a popular guiding framework for studying the psychosocial development of youth. In sport research, for more than two decades, this framework has enhanced our understanding of the mechanisms involved in successful shifts from youth to adulthood. Nonetheless, scholars have recently taken a more critical stance on the positive youth development framework by elucidating some of its shortcomings. To help determine whether it may be warranted to plan for a transition from the positive youth development framework in sport research, a critical commentary is offered. The purpose of this commentary lies in situating three ontologically distinct arguments that depict the shortcomings of the positive youth development framework, namely the operationalization argument, the social justice argument, and the posthumanist argument. This paper is offered as an open invitation to instigate dialogue on what may come next for youth development in sport research and whether planning for a transition is warranted.


Subject(s)
Dissent and Disputes , Sports , Adolescent , Humans , Personality , Research Design , Social Justice
2.
J Am Coll Health ; : 1-6, 2023 Apr 24.
Article in English | MEDLINE | ID: mdl-37094249

ABSTRACT

Objective: The purpose of this study was to measure college student athletes' nutrition knowledge and behavior before and after a text message-based educational intervention. Participants: Athletes (n = 35) participated by completing a pre- and post-intervention survey. Methods: This survey gathered information on ability to identify carbohydrate and protein food sources, pre-and post-workout intake, and behavior. Text messages were sent during the 4-week intervention and included information regarding the importance of carbohydrate consumption before training, and a carbohydrate-protein mixture for recovery. Results: Dependent t-tests revealed a lack of statistically significant increases in total knowledge (p = 0.156) or behavior (p = 0.177), but an increase in the behavior questions regarding efficacy of carbohydrate before training (p = 0.026) and carbohydrate and protein after training (p = 0.016). Conclusion: This suggests the text message educational intervention did influence behavioral outcomes. Future research should focus on the effectiveness, length, and frequency of the text message intervention, and investigate the athletes' willingness to change dietary behaviors.

3.
Am Surg ; 89(5): 1798-1806, 2023 May.
Article in English | MEDLINE | ID: mdl-35285298

ABSTRACT

BACKGROUND: The high rate of work-related musculoskeletal disorders (WMSD) among surgeons is well-documented and found to factor into medical students' interest in surgical specialties. Ergonomic techniques can reduce musculoskeletal pain in surgeons. Access to ergonomics education in residency is minimal and the ergonomics education offered in medical school has not been characterized. METHODS: An anonymous, online survey was distributed to 210 administrators in medical education and curriculum at all accredited US allopathic medical schools. They were asked about their knowledge of ergonomics, assessment of potential benefits of ergonomics education to their students, and the ergonomics education offered at their institution. RESULTS: A total of 71 surveys were completed (33.8% response rate). 82% of schools reported familiarity with the study of ergonomics and 81% thought it would be beneficial to the future careers of their students to receive ergonomics education. Respondents estimated 43% of surgeons experience WMSDs and those that did not think ergonomics education would be beneficial to their students' future careers had a statistically significantly lower estimate of WMSD burden amongst practicing surgeons. Only one respondent reported that students at their institution receive greater than three hours of ergonomics education, while 98% reported their students will receive less than three hours. Considering this, 81% of respondents reported that students do have access to other resources that encourage ergonomic practices, such as gym access, yoga classes, and surgical simulation labs. DISCUSSION: Medical schools should increase access to ergonomics education and integrate it into their curriculum as early as possible.


Subject(s)
Musculoskeletal Pain , Students, Medical , Surgeons , Humans , Ergonomics/methods , Surveys and Questionnaires , Schools, Medical
4.
Molecules ; 27(12)2022 Jun 09.
Article in English | MEDLINE | ID: mdl-35744823

ABSTRACT

We report the first total synthesis of 5-phenyl preacinetobactin and its characterization. The route was developed for the synthesis of preacinetobactin, the siderophore critical to the Gram-negative pathogen A. baumannii. It leverages a C5-substituted benzaldehyde as a key starting material and should enable the synthesis of similar analogs. 5-Phenyl preacinetobactin binds iron in a manner analogous to the natural siderophore, but it did not rescue growth in a strain of A. baumannii unable to produce preacinetobactin.


Subject(s)
Acinetobacter baumannii , Siderophores , Acinetobacter baumannii/metabolism , Imidazoles/metabolism , Iron/metabolism , Oxazoles/metabolism , Siderophores/metabolism
5.
Methods Enzymol ; 663: 99-130, 2022.
Article in English | MEDLINE | ID: mdl-35168799

ABSTRACT

Antimicrobial peptides will be an essential component in combating the escalating issue of antibiotic resistance. Identifying synergistic combinations of two or more substances will increase the value of these peptides further. Several potential pitfalls in conducting synergy testing with peptides are discussed in detail. As case studies, we describe observations of AMP synergy with peptides, antibiotics, and metal ions as well as some of the mechanistic details that have been uncovered. The Bliss and Loewe models for synergy are presented prior to recommending protocols for conducting checkerboard, minimal inhibitory concentration, and time-kill assays. Establishing mechanisms of action and exploring the potential for resistance will be crucial to translate these studies into the clinic.


Subject(s)
Anti-Bacterial Agents , Antimicrobial Peptides , Anti-Bacterial Agents/pharmacology , Biology , Drug Synergism , Microbial Sensitivity Tests
6.
Am J Emerg Med ; 51: 397-400, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34837886

ABSTRACT

BACKGROUND: Necrotizing fasciitis (NF) is a severe, life-threatening soft tissue infection requiring prompt diagnosis and immediate surgical debridement. Imaging, including a computed tomography (CT) scan, can often aid in the diagnosis, though it can prolong time to treatment and diagnosis. Point-of-care ultrasound (POCUS) is often used in the ED to identify soft tissue infections. The objective of this study is to evaluate the use of POCUS to identify NF in patients presenting to the emergency department. METHODS: We prospectively enrolled patients who presented to the emergency department (ED) with suspected soft tissue infection who received a computed tomography and/or surgical consult. POCUS images of the suspected site of infection were obtained by the emergency medicine physician and interpreted based on sonographic findings of NF. These findings were compared with CT scan or surgical impression. RESULTS: We enrolled 64 patients in this study. Eight were determined to be at high risk of having NF based on CT scan and/or surgical impression. All of these patients also had POCUS images interpreted as concerning for NF. Furthermore, 56 patients were classified as being low risk for having NF based on CT scan and/or surgical impression. All but one of these patients had POCUS images interpreted as not concerning for NF. CONCLUSIONS: Our data indicates that POCUS can be used to identify NF with a high sensitivity and specificity.


Subject(s)
Fasciitis, Necrotizing/diagnostic imaging , Point-of-Care Systems , Ultrasonography , Adolescent , Adult , Aged , Aged, 80 and over , Emergency Service, Hospital , False Negative Reactions , Fasciitis, Necrotizing/diagnosis , Female , Humans , Male , Middle Aged , Prospective Studies , ROC Curve , Sensitivity and Specificity , Tomography, X-Ray Computed , Young Adult
8.
Inorg Chem ; 59(20): 14866-14870, 2020 Oct 19.
Article in English | MEDLINE | ID: mdl-32993282

ABSTRACT

Antimicrobial photodynamic therapy (APDT) has gained increased attention because of its broad spectrum activity and lower likelihood to elicit bacterial resistance. Although many photosensitizers excel at eradicating Gram-positive bacterial infections, they are generally less potent when utilized against Gram-negative bacteria. We hypothesized that conjugating the DNA-targeting, antimicrobial peptide buforin II to a metal-based photosensitizer would result in a potent APDT agent. Herein, we present the synthesis and characterization of a buforin II-[Ru(bpy)3]2+ bioconjugate (1). The submicromolar activity of 1 against the multidrug-resistant strains Escherichia coli AR 0114 and Acinetobacter baumannii Naval-17 indicates strong synergy between the ruthenium complex and buforin II. Our mechanistic studies point to an increased rate of DNA damage by 1 compared to [Ru(bpy)3]2+. These results suggest that conjugating metal complexes to antimicrobial peptides can lead to potent antimicrobial agents.


Subject(s)
Anti-Bacterial Agents/pharmacology , Coordination Complexes/pharmacology , Drug Resistance, Bacterial/drug effects , Drug Resistance, Multiple/drug effects , Photosensitizing Agents/pharmacology , Proteins/pharmacology , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/radiation effects , Coordination Complexes/chemical synthesis , Coordination Complexes/radiation effects , DNA Damage/drug effects , DNA, Superhelical/drug effects , Gram-Negative Bacteria/drug effects , Microbial Sensitivity Tests , Photosensitizing Agents/chemical synthesis , Photosensitizing Agents/radiation effects , Proteins/chemical synthesis , Ruthenium/chemistry , Ruthenium/radiation effects , Singlet Oxygen/metabolism
10.
ACS Infect Dis ; 6(5): 1250-1263, 2020 05 08.
Article in English | MEDLINE | ID: mdl-32251582

ABSTRACT

Gram-negative bacteria are some of the biggest threats to public health due to a large prevalence of antibiotic resistance. The difficulty in treating bacterial infections, stemming from their double membrane structure combined with efflux pumps in the outer membrane, has resulted in a much greater need for antimicrobials with activity against these pathogens. Tunicate host defense peptide (HDP), Clavanin A, is capable of not only inhibiting Gram-negative growth but also potentiating activity in the presence of Zn(II). Here, we provide evidence that the improvements of Clavanin A activity in the presence of Zn(II) are due to its novel mechanism of action. We employed E. coli TD172 (ΔrecA::kan) and the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay to show in cellulae that DNA damage occurs upon treatment with Clavanin A. In vitro assays demonstrated that Zn(II) ions are required for the nuclease activity of the peptide. The quantum mechanics/molecular mechanics (QM/MM) calculations were used to investigate the mechanism of DNA damage. In the rate-determining step of the proposed mechanism, due to its Lewis acidity, the Zn(II) ion activates the scissile P-O bond of DNA and creates a hydroxyl nucleophile from a water molecule. A subsequent attack by this group to the electrophilic phosphorus cleaves the scissile phosphoester bond. Additionally, we utilized bacterial cytological profiling (BCP), circular dichroism (CD) spectroscopy in the presence of lipid vesicles, and surface plasmon resonance combined with electrical impedance spectroscopy in order to address the apparent discrepancies between our results and the previous studies regarding the mechanism of action of Clavanin A. Finally, our approach may lead to the identification of additional Clavanin A like HDPs and promote the development of antimicrobial peptide based therapeutics.


Subject(s)
Antimicrobial Cationic Peptides , Blood Proteins/pharmacology , DNA Damage , Escherichia coli/drug effects , Gram-Negative Bacteria/drug effects , Antimicrobial Cationic Peptides/pharmacology , Molecular Dynamics Simulation
11.
ACS Infect Dis ; 4(11): 1623-1634, 2018 11 09.
Article in English | MEDLINE | ID: mdl-30141623

ABSTRACT

Copper (Cu) ions are critical in controlling bacterial infections, and successful pathogens like Mycobacterium tuberculosis (Mtb) possess multiple Cu resistance mechanisms. We report, as proof of concept, that a novel Cu hypersensitivity phenotype can be generated in mycobacteria, including Mtb, through a peptide, DAB-10, that is able to form reactive oxygen species (ROS) following Cu-binding. DAB-10 induces intramycobacterial oxidative stress in a Cu-dependent manner in vitro and during infection. DAB-10 penetrates murine macrophages and encounters intracellular mycobacteria. Significant intracellular Cu-dependent protection was observed when Mtb-infected macrophages were treated with DAB-10 alongside a cell-permeable Cu chelator. Treatment with the Cu chelator reversed the intramycobacterial oxidative shift induced by DAB-10. We conclude that DAB-10 utilizes the pool of phagosomal Cu ions in the host-Mtb interface to augment the mycobactericidal activity of macrophages while simultaneously exploiting the susceptibility of Mtb to ROS. DAB-10 serves as a model with which to develop next-generation, multifunctional antimicrobials.


Subject(s)
Chelating Agents/pharmacology , Copper/chemistry , Mycobacterium tuberculosis/drug effects , Peptides/pharmacology , Phagosomes/chemistry , Animals , Anti-Bacterial Agents/pharmacology , Chelating Agents/chemistry , Host-Pathogen Interactions , Macrophages/microbiology , Mice , Oxidation-Reduction , Oxidative Stress , Peptides/chemistry , Proof of Concept Study , RAW 264.7 Cells , Tuberculosis/microbiology
12.
Biochemistry ; 56(10): 1403-1414, 2017 03 14.
Article in English | MEDLINE | ID: mdl-28226206

ABSTRACT

Tunicates have been used as primitive models for understanding cell-mediated and humoral immunity. Clavanin A (ClavA) is one member of a family of antimicrobial peptides produced by the solitary tunicate Styela clava. In this work, we demonstrate that ClavA utilizes Zn2+ ions to potentiate its antimicrobial activity not only by reducing the concentration at which the peptide inhibits the growth of bacteria but also by increasing the rate of killing. Membrane depolarization, ß-galactosidase leakage, and potassium leakage assays indicate that ClavA is membrane active, forms small pores, but induces cell death by targeting an intracellular component. ClavA and ClavA-Zn2+ added to Escherichia coli and imaged by confocal microscopy translocate across the cell membrane. E. coli mutants lacking the functional Zn2+ import system are less susceptible to ClavA, suggesting that the synergistic activity between ClavA and Zn2+ has a cytoplasmic target, which is further supported by its nucleolytic activity. Overall, these studies identify a remarkable new mechanism by which zinc contributes to the immune response in the tunicate S. clava.


Subject(s)
Antimicrobial Cationic Peptides/immunology , Blood Proteins/immunology , Escherichia coli/drug effects , Immune System , Urochordata/immunology , Zinc/pharmacology , Amino Acid Sequence , Animals , Antimicrobial Cationic Peptides/biosynthesis , Antimicrobial Cationic Peptides/chemical synthesis , Antimicrobial Cationic Peptides/pharmacology , Bacterial Proteins/metabolism , Biological Transport , Blood Proteins/biosynthesis , Blood Proteins/chemical synthesis , Blood Proteins/pharmacology , Cell Membrane/chemistry , Cell Membrane/drug effects , Cell Membrane/metabolism , Cytoplasm/chemistry , Cytoplasm/drug effects , Cytoplasm/metabolism , Drug Synergism , Escherichia coli/chemistry , Escherichia coli/metabolism , Gene Expression , Hemocytes/chemistry , Hemocytes/immunology , Microbial Sensitivity Tests , Potassium/metabolism , Protein Binding , Solid-Phase Synthesis Techniques , Urochordata/genetics , Urochordata/microbiology , Zinc/metabolism , beta-Galactosidase/metabolism
13.
J Comp Neurol ; 525(4): 885-900, 2017 Mar 01.
Article in English | MEDLINE | ID: mdl-27560718

ABSTRACT

Descending projections from the thalamus and related structures to the midbrain are evolutionarily highly conserved. However, the basic organization of this auditory thalamotectal pathway has not yet been characterized. The purpose of this study was to obtain a better understanding of the anatomical and neurochemical features of this pathway. Analysis of the distributions of retrogradely labeled cells after focal injections of retrograde tracer into the inferior colliculus (IC) of the mouse revealed that most of the subcortical descending projections originated in the brachium of the IC and the paralaminar portions of the auditory thalamus. In addition, the vast majority of thalamotectal cells were found to be negative for the calcium-binding proteins calbindin, parvalbumin, or calretinin. Using two different strains of GAD-GFP mice, as well as immunostaining for GABA, we found that a subset of neurons in the brachium of the IC is GABAergic, suggesting that part of this descending pathway is inhibitory. Finally, dual retrograde injections into the IC and amygdala plus corpus striatum as well into the IC and auditory cortex did not reveal any double labeling. These data suggest that the thalamocollicular pathway comprises a unique population of thalamic neurons that do not contain typical calcium-binding proteins and do not project to other paralaminar thalamic forebrain targets, and that a previously undescribed descending GABAergic pathway emanates from the brachium of the IC. J. Comp. Neurol. 525:885-900, 2017. © 2016 Wiley Periodicals, Inc.


Subject(s)
Auditory Pathways/cytology , Inferior Colliculi/cytology , Neurons/cytology , Animals , Female , Image Processing, Computer-Assisted , Male , Mice , Microscopy, Confocal
14.
Cureus ; 7(12): e414, 2015 Dec 17.
Article in English | MEDLINE | ID: mdl-26870618

ABSTRACT

Atypical chronic myeloid leukemia (aCML) and chronic neutrophilic leukemia (CNL) are rare hematologic neoplasms characterized by leukocytosis and a hypercellular bone marrow. Although recurrent mutations in the colony-stimulating factor 3 receptor (CSF3R) are frequently observed in patients with (CNL), the mutational landscape in (aCML) is less well-defined. In this report, we describe an 81-year-old male who was diagnosed with aCML. He presented with leukocytosis and anemia but no significant clinical symptoms. Standard laboratory studies revealed the absence of the Philadelphia chromosome. Massively parallel sequencing demonstrated no mutations in CSF3R, but the presence of a heterozygous NRAS-G12D variant (47% allele frequency). The patient was started on treatment with trametinib, an MEK1/2 inhibitor with Food and Drug Administration approval for malignant melanoma. Therapy with trametinib resulted in exceptional improvements in his blood counts and continued disease control with 14 months of follow-up. This case highlights the need for clinical trials evaluating the safety and efficacy of MEK1/2 as a therapeutic target for the treatment of patients with NRAS-mutated aCML/CNL.

15.
Biochem Biophys Res Commun ; 456(1): 446-51, 2015 Jan 02.
Article in English | MEDLINE | ID: mdl-25482446

ABSTRACT

Antimicrobial peptides (AMPs) are broad spectrum antimicrobial agents that act through diverse mechanisms, this characteristic makes them suitable starting points for development of novel classes of antibiotics. We have previously reported the increase in activity of AMPs upon addition of the Amino Terminal Copper and Nickel (ATCUN) Binding Unit. Herein we synthesized the membrane active peptide, Anoplin and two ATCUN-Anoplin derivatives and show that the increase in activity is indeed due to the ROS formation by the Cu(II)-ATCUN complex. We found that the ATCUN-Anoplin peptides were up to four times more potent compared to Anoplin alone against standard test bacteria. We studied membrane disruption, and cellular localization and found that addition of the ATCUN motif did not lead to a difference in these properties. When helical content was calculated, we observed that ATCUN-Anoplin had a lower helical composition. We found that ATCUN-Anoplin are able to oxidatively damage lipids in the bacterial membrane and that their activity trails the rate at which ROS is formed by the Cu(II)-ATCUN complexes alone. This study shows that addition of a metal binding tripeptide motif is a simple strategy to increase potency of AMPs by conferring a secondary action.


Subject(s)
Antimicrobial Cationic Peptides/chemistry , Copper/chemistry , Reactive Oxygen Species/metabolism , Wasp Venoms/chemistry , Amino Acid Motifs , Bacillus subtilis/metabolism , Cell Membrane/metabolism , Circular Dichroism , Erythrocytes/drug effects , Escherichia coli/metabolism , Humans , Lipid Peroxidation , Microscopy, Confocal , Oxidative Stress , beta-Galactosidase/metabolism
16.
Rehabil Nurs ; 38(2): 80-7, 2013.
Article in English | MEDLINE | ID: mdl-23529946

ABSTRACT

BACKGROUND AND PURPOSE: Violent acts are on rise and rehabilitation providers as caregivers may encounter anger on a daily basis. The purpose of this article is to discuss anger and describe anger management strategies based on behavioral interventions grounded in Choice Theory. CHOICE THEORY: Applying choice theory to anger is the belief that people are internally, not externally motivated, and that outside events do not make people do anything. Thus, what drives people's anger behaviors are internally developed notions of what is important and satisfying for them. CLINICAL RELEVANCE AND CONCLUSION: Anger becomes a choice along with its management. Choosing strategies to manage anger are key to reducing the potential for angry emotions to escalate to the point of aggressive and violent acts that threaten caregivers and clients safety. Anger-free environments promote mental/physical health and establish elements of safe living and working environments in a variety of rehabilitative care settings.


Subject(s)
Adaptation, Psychological , Anger , Choice Behavior , Nursing Theory , Rehabilitation Nursing/methods , Humans
17.
J Am Vet Med Assoc ; 241(7): 927-34, 2012 Oct 01.
Article in English | MEDLINE | ID: mdl-23013507

ABSTRACT

OBJECTIVE: To assess survival-to-discharge rates of mares and foals and postoperative complications and fertility in mares following cesarean section (C-section). DESIGN: Retrospective case series. ANIMALS: 95 mares. PROCEDURES: Medical and breeding records of mares that underwent C-section were reviewed; signalment, surgical technique, complications, survival-to-discharge rate, and pregnancy and foaling rates were recorded and evaluated. Foaling rates in the 3 years after C-section were compared with the cumulative foaling rate before C-section. RESULTS: C-section was performed because of dystocia (n = 71) or concurrent maternal disease (20) or was elective (4). Overall survival-to-discharge rate was 84% (80/95) for mares and 35% (28/80) for foals. Six of 15 mares that had partial fetotomies prior to C-section did not survive. Mares that had dystocia for < 90 minutes had the fewest complications. Cumulative foaling rate before C-section was 77% (394/509). Overall foaling rate for the 3 years after C-section was 52% (30/58) and 68% (13/19) when duration of dystocia was ≥ 90 minutes and < 90 minutes, respectively, and was 31 % (9/29) for mares ≥ 16 years old. Foaling rate was significantly lower for mares bred in the same year as C-section than for mares bred in later years. CONCLUSIONS AND CLINICAL RELEVANCE: Breeding in the same year as C-section, dystocia for ≥ 90 minutes before C-section, and mare age ≥ 16 years were associated with poor foaling rates. Prognosis for delivery of a live foal in years following C-section was good if duration of dystocia was < 90 minutes and the mare was < 16 years old at the time of surgery.


Subject(s)
Cesarean Section/veterinary , Dystocia/veterinary , Horse Diseases/mortality , Horses , Postoperative Complications/veterinary , Age Factors , Animals , Cesarean Section/adverse effects , Dystocia/mortality , Dystocia/surgery , Female , Fertility , Horse Diseases/physiopathology , Pregnancy , Pregnancy Outcome/veterinary , Retrospective Studies , Time Factors
18.
J Sport Exerc Psychol ; 33(6): 779-806, 2011 Dec.
Article in English | MEDLINE | ID: mdl-22262705

ABSTRACT

The purpose of this article was to provide a substantive-methodological synergy of potential importance to future research in sport and exercise psychology. The substantive focus was to improve the measurement of coaching efficacy by developing a revised version of the coaching efficacy scale (CES) for head coaches (N = 557) of youth sport teams (CES II-YST). The methodological focus was exploratory structural equation modeling (ESEM), a methodology that integrates the advantages of exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) within the general structural equation model (SEM). The synergy was a demonstration of how ESEM (as compared with CFA) may be used, guided by content knowledge, to develop (or confirm) a measurement model for the CES II-YST. A single-group ESEM provided evidence for close model-data fit, while a single-group CFA fit significantly worse than the single-group ESEM and provided evidence for only approximate model-data fit. A multiple-group ESEM provided evidence for partial factorial invariance by coach's gender.


Subject(s)
Exercise/psychology , Mentors , Models, Statistical , Sports/psychology , Adolescent , Adult , Aged , Child , Female , Humans , Male , Middle Aged , Surveys and Questionnaires , United States , Young Adult
19.
J Am Vet Med Assoc ; 236(6): 669-73, 2010 Mar 15.
Article in English | MEDLINE | ID: mdl-20225981

ABSTRACT

OBJECTIVE-To determine the association between results of endoscopic evaluation of arytenoid function (AF) and epiglottic structure (ES) in Thoroughbred yearlings and racing performance at 2 to 4 years of age. DESIGN-Retrospective case series. ANIMALS-2,954 Thoroughbred yearlings. Procedures-Records of yearlings that had endoscopic evaluation of the larynx between 1998 and 2001 were obtained, and results were graded by use of standardized scales. A modified Havemeyer scale (grade I, II.1, II.2, III, or IV) was used to evaluate AF; ES was graded on a scale of 0 to IV. Records were annotated if the epiglottis was subjectively short or narrow. Racing performance data were obtained from an online database. RESULTS-Horses with grade II.2 AF had significantly less earnings at 4 years of age, compared with earnings of horses with AF grades < II.2. Grade III AF was associated with fewer starts and less earnings at 3 and 4 years of age. No horses met the criteria for grade IV AF. Horses with ES grades > II had less earnings at 2 and 4 years of age, compared with earnings of horses with ES grades < II. A short epiglottis was associated with less earnings at 2 and 3 years of age. CONCLUSIONS AND CLINICAL RELEVANCE-Analysis suggested that yearlings with grade III AF had a decrease in athletic potential. Yearlings with grade II.2 AF, an ES grade > II, or a short epiglottis typically had decreases in racing performance. These factors should be evaluated carefully when developing purchase recommendations.


Subject(s)
Arytenoid Cartilage/physiology , Epiglottis/physiology , Horses/physiology , Laryngoscopy/veterinary , Physical Conditioning, Animal , Aging , Animals , Female , Male , Retrospective Studies , Running , Sports
20.
J Agric Food Chem ; 56(1): 213-9, 2008 Jan 09.
Article in English | MEDLINE | ID: mdl-18069796

ABSTRACT

Using a nonionic, alkyl polyoxyethylene surfactant (X-77) in aqueous solutions, sessile droplet spreading, pinning, evaporation, contraction, and post-evaporation deposits are characterized. X-77 is widely used in the agricultural field as a spreader/adherent, intended to optimize pathenogenic agent coverage. Using a single droplet size under monitored temperature conditions, we control humidity, substrate hydrophobicity, and surfactant concentration to mimic varying agricultural conditions. For hydrophilic surfaces, the droplet spreads, reaching and retaining a maximum, stationary size. At this stage, a ring accretion occurs at the maximum spread diameter. During the final stage, the water film retracts, resulting in deposition of small islands of surfactant residue inside the ring. At lower concentrations of surfactant, we discover ring formations that break-up into "ring islands" at late-stage evaporation, accompanied by a distribution of the smaller islands in the interior portion of the substrate contact area. These are promoted by higher relative humidity. At higher concentrations, only a solid ring of surfactant remains, post-evaporation. Increasing surfactant concentration tends to increase the mean of the interior island size and to broaden the overall island size distribution. On sufficiently hydrophobic surfaces, surfactant-laden droplets do not evidence pinning, ring formations, or post-evaporation interior islands. Interestingly, lower humidity increases spreading at higher surfactant concentrations. Such pattern formations of surfactant deposit are reported for the first time and are of significance in projecting how surfactants such as X-77 distribute pesticides or other chemicals on leaf surfaces.


Subject(s)
Polyethylene Glycols/analysis , Surface-Active Agents/analysis , Water/chemistry , Agrochemicals/chemistry , Alkylation , Humidity , Phase Transition , Polyethylene Glycols/chemistry , Temperature
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