The choice of the white clover population alters overyielding of mixtures with perennial ryegrass and chicory and underlying processes.

Legume-based forage plant mixtures are known to increase biomass production over the mixture species grown as pure stands (overyielding), which has partly been attributed to enhanced nitrogen availability by legumes. However, the relative importance of underlying processes of these positive diversity effects and their drivers are not fully understood. Here we assessed if outcome and causes of diversity effects depend on the legume-species genetic identity. Over five years, we cultivated different white clover (Trifolium repens) populations, a grass and forb species in pure stands and clover-based mixtures and recorded biomass yield. Complementarity and selection effects of mixtures and relative yields of mixture species were calculated based on both unfertilized and nitrogen-fertilized non-leguminous pure stands. Results showed that the clover population altered the overall strength of diversity effects as well as the direction and magnitude of their temporal trends, at least for the grass component of mixtures. Differences in diversity effects between clover populations diminished when fertilized instead of unfertilized non-leguminous pure stands were considered. Hence, a part of these differences likely results from dissimilar effects of clover populations on nitrogen availability. The findings reveal the possibility to improve overyielding of legume-based forage plant mixtures by decisions on legume-species genetic identity.

Healthcare career intervention with youth in a predominantly Latinx rural community: a pilot study of a creative approach.

The present study discusses a pilot intervention for youth in a predominantly Latinx rural community in the U.S. The intervention incorporated multimodal creative activities into the social cognitive career theory-based healthcare career program. Participants (N = 75) were assessed for healthcare career self-efficacy, outcome expectations, and interests (pre-/post-intervention). Their healthcare career task self-efficacy and interests scores significantly increased overall. By race/ethnicity groups, however, only White students reported an increase in healthcare interests, and only students of color an increase in healthcare career task self-efficacy. This provides preliminary evidence for the effectiveness of the proposed intervention. Implications for services and research are discussed.

Intervention de carrière dans le domaine des soins de santé auprès des jeunes dans une communauté rurale à prédominance latine: Une étude pilote d'une approche créative La présente étude porte sur une intervention pilote destinée aux jeunes d'une communauté rurale à prédominance latine aux États-Unis. L'intervention a intégré des activités créatives multimodales dans le programme de carrière en soins de santé basé sur la théorie sociale cognitive des carrières. Les participant·e·s (N = 75) ont été évalué·e·s sur leur sentiment d'efficacité personnelle dans les soins, leurs attentes en matière de résultats et leurs intérêts (avant et après l'intervention). Les résultats du sentiment d'efficacité personnelle des tâches et des intérêts de leur carrière dans le domaine de la santé ont augmenté de manière significative dans l'ensemble. Toutefois, par groupe racial ou ethnique, seul·e·s les étudiant·e·s blancs ont signalé une augmentation de leurs intérêts pour les soins de santé, et seul·e·s les étudiant·e·s de couleur ont signalé une augmentation de leur sentiment d'efficacité personnelle dans les tâches liées aux soins de santé. Cela fournit des preuves préliminaires de l'efficacité de l'intervention proposée. Les implications pour les services et la recherche sont discutées.

Intervención en la carrera de atención médica con jóvenes en una comunidad rural predominantemente latina: un estudio piloto de un enfoque creativo El presente estudio analiza una intervención piloto para jóvenes en una comunidad rural predominantemente latina en los EE. UU. La intervención incorporó actividades creativas multimodales en el programa de carrera de atención médica basado en el enfoque socio-cognitivo de la carrera. Se evaluó a los participantes (N = 75) en cuanto a la percepción de la autoeficacia para la carrera sanitaria, las expectativas de resultados y los intereses (antes y después de la intervención). Sus puntuaciones de percepción de autoeficacia e intereses en las tareas de la carrera sanitaria aumentaron significativamente en general. Sin embargo, por grupos de raza / etnia, solo los estudiantes blancos mostraron un aumento en los intereses relacionados con la atención médica, y solo en los estudiantes de color se observó un incremento en la percepción de autoeficacia para las tareas profesionales de la salud. Esto proporciona evidencia preliminar de la efectividad de la intervención propuesta. Se discuten las implicaciones para los servicios y la investigación.

Buccolingual Inclination of Canine and First and Second Molar Teeth and the Curve of Wilson in Different Sagittal Skeletal Patterns of Adults Using Cone-Beam Computed Tomography.

OBJECTIVES: This study aimed to assess the buccolingual inclination of canine and first and second molar teeth and the curve of Wilson in different sagittal skeletal patterns in untreated adults using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: Sixty-six CBCT scans of adults (mean age: 28.74 ± 5.25 years) were evaluated in this cross-sectional study. The images were standardized using the Frankfurt horizontal plane and the interorbital line. The sagittal skeletal pattern was determined using the ANB angle and Wits appraisal. Inclination angles were measured by NNT Viewer and Mimics software. The curve of Wilson was measured by connecting the tips of mesiobuccal and mesiolingual cusps of maxillary first and second molars along the buccal groove and measuring the formed angle. Data were analyzed using ANOVA. RESULTS: The intraobserver agreement was 0.969. The mean inclination of maxillary first and second molars in class I and III patients was significantly higher than that in class II patients (P < 0.05). The mean inclination of mandibular first and second molars in class II patients was significantly higher than that in class I and III patients (P < 0.05). The difference in inclination of maxillary and mandibular canine teeth was not significant (P > 0.05). The mean curve of Wilson in second molars of class II patients was significantly higher than that in class I patients (P < 0.05). CONCLUSION: In different sagittal skeletal patterns, a compensatory relationship exists between the opposing teeth, which, along with the standards of crowns, can be used to determine the appropriate position of teeth in dental arch.

Enhancing effects of acute exposure to cannabis smoke on working memory performance.

Numerous preclinical studies show that acute cannabinoid administration impairs cognitive performance. Almost all of this research has employed cannabinoid injections, however, whereas smoking is the preferred route of cannabis administration in humans. The goal of these experiments was to systematically determine how acute exposure to cannabis smoke affects working memory performance in a rat model. Adult male (n = 15) and female (n = 16) Long-Evans rats were trained in a food-motivated delayed response working memory task. Prior to test sessions, rats were exposed to smoke generated by burning different numbers of cannabis or placebo cigarettes, using a within-subjects design. Exposure to cannabis smoke had no effect on male rats' performance, but surprisingly, enhanced working memory accuracy in females, which tended to perform less accurately than males under baseline conditions. In addition, cannabis smoke enhanced working memory accuracy in a subgroup of male rats that performed comparably to the worst-performing females. Exposure to placebo smoke had no effect on performance, suggesting that the cannabinoid content of cannabis smoke was critical for its effects on working memory. Follow-up experiments showed that acute administration of either Δ9-tetrahydrocannabinol (0.0, 0.3, 1.0, 3.0 mg/kg) or the cannabinoid receptor type 1 antagonist rimonabant (0.0, 0.2, 0.6, 2.0 mg/kg) impaired working memory performance. These results indicate that differences in the route, timing, or dose of cannabinoid administration can yield distinct cognitive outcomes, and highlight the need for further investigation of this topic.

Functional Connectivity of Chronic Cocaine Use Reveals Progressive Neuroadaptations in Neocortical, Striatal, and Limbic Networks.

Brain imaging studies indicate that chronic cocaine users display altered functional connectivity between prefrontal cortical, thalamic, striatal, and limbic regions; however, the use of cross-sectional designs in these studies precludes measuring baseline brain activity prior to cocaine use. Animal studies can circumvent this limitation by comparing functional connectivity between baseline and various time points after chronic cocaine use. In the present study, adult male Long-Evans rats were trained to self-administer cocaine intravenously for 6 h sessions daily over 14 consecutive days. Two additional groups serving as controls underwent sucrose self-administration or exposure to the test chambers alone. Functional magnetic resonance imaging was conducted before self-administration and after 1 and 14 d of abstinence (1d and 14d Abs). After 1d Abs from cocaine, there were increased clustering coefficients in brain areas involved in reward seeking, learning, memory, and autonomic and affective processing, including amygdala, hypothalamus, striatum, hippocampus, and thalamus. Similar changes in clustering coefficient after 1d Abs from sucrose were evident in predominantly thalamic brain regions. Notably, there were no changes in strength of functional connectivity at 1 or 14 d after either cocaine or sucrose self-administration. The results suggest that cocaine and sucrose can change the arrangement of functional connectivity of brain regions involved in cognition and emotion, but that these changes dissipate across the early stages of abstinence. The study also emphasizes the importance of including baseline measures in longitudinal functional neuroimaging designs seeking to assess functional connectivity in the context of substance use.

Contributions of medial prefrontal cortex to decision making involving risk of punishment.

The prefrontal cortex (PFC) plays an important role in several forms of cost-benefit decision making. Its contributions to decision making under risk of explicit punishment, however, are not well understood. A rat model was used to investigate the role of the medial PFC (mPFC) and its monoaminergic innervation in a Risky Decision-making Task (RDT), in which rats chose between a small, "safe" food reward and a large, "risky" food reward accompanied by varying probabilities of mild footshock punishment. Inactivation of mPFC increased choice of the large, risky reward when the punishment probability increased across the session ("ascending RDT"), but decreased choice of the large, risky reward when the punishment probability decreased across the session ("descending RDT"). In contrast, enhancement of monoamine availability via intra-mPFC amphetamine reduced choice of the large, risky reward only in the descending RDT. Systemic administration of amphetamine reduced choice of the large, risky reward in both the ascending and descending RDT; however, this reduction was not attenuated by concurrent mPFC inactivation, indicating that mPFC is not a critical locus of amphetamine's effects on risk taking. These findings suggest that mPFC plays an important role in adapting choice behavior in response to shifting risk contingencies, but not necessarily in risk-taking behavior per se.

Effects of nucleus accumbens amphetamine administration on performance in a delay discounting task.

Chronic administration of cocaine can cause pronounced and enduring cognitive alterations such as increases in impulsive choice. Chronic cocaine can also result in enhanced dopamine (DA) release in the nucleus accumbens (NAc) in response to reward-related cues. It is possible that this enhanced DA release in the NAc is a mechanism by which cocaine increases impulsive choice. To date, however, the specific role of DA in the NAc in impulsive choice is unclear. To begin to address this, rats received acute microinjections of the indirect DA agonist amphetamine directly into the NAc prior to testing in a delay discounting task in which rats chose between a small, immediate and a large, delayed food reward. When delays to the large reward increased within test sessions, amphetamine increased choice of the large reward. When delays decreased within test sessions, however, amphetamine decreased choice of the large reward. These findings suggest that, rather than specifically mediating impulsive choice, DA neurotransmission in the NAc is necessary for flexible adaptation of choice strategies in the presence of shifting reward contingencies. These results further indicate that enhancements in NAc DA release likely do not account for lasting increases in impulsive choice caused by chronic cocaine.

Interaction between troponin and myosin enhances contractile activity of myosin in cardiac muscle.

Ca(2+) signaling in striated muscle cells is critically dependent upon thin filament proteins tropomyosin (Tm) and troponin (Tn) to regulate mechanical output. Using in vitro measurements of contractility, we demonstrate that even in the absence of actin and Tm, human cardiac Tn (cTn) enhances heavy meromyosin MgATPase activity by up to 2.5-fold in solution. In addition, cTn without Tm significantly increases, or superactivates sliding speed of filamentous actin (F-actin) in skeletal motility assays by at least 12%, depending upon [cTn]. cTn alone enhances skeletal heavy meromyosin's MgATPase in a concentration-dependent manner and with sub-micromolar affinity. cTn-mediated increases in myosin ATPase may be the cause of superactivation of maximum Ca(2+)-activated regulated thin filament sliding speed in motility assays relative to unregulated skeletal F-actin. To specifically relate this classical superactivation to cardiac muscle, we demonstrate the same response using motility assays where only cardiac proteins were used, where regulated cardiac thin filament sliding speeds with cardiac myosin are >50% faster than unregulated cardiac F-actin. We additionally demonstrate that the COOH-terminal mobile domain of cTnI is not required for this interaction or functional enhancement of myosin activity. Our results provide strong evidence that the interaction between cTn and myosin is responsible for enhancement of cross-bridge kinetics when myosin binds in the vicinity of Tn on thin filaments. These data imply a novel and functionally significant molecular interaction that may provide new insights into Ca(2+) activation in cardiac muscle cells.