The effects of fungal-infested fescue and zeranol on testicular development in the bull

Two experiments were conducted to determine the effect of fescue infestation with the endophytic fungus, Acremonium coenophialum plus zeranol and endophyte-infested fescue alone on testicular development and hormonal secretions in the bull. Bulls were assigned to pastures infested with the fungus at control (0%), Low (50-70%), and High (80-84%) levels. In the first experiment, bulls were implanted at birth with zeranol and every 90 days thereafter. Assessment of the effects of treatment on testicular development and the ability of the pituitary and testis to respond to GnRH challenges were determined. Gonadotropin releasing hormone (GnRH) challenges were effected when the bulls were 3, 5, and 8 months of age. In the second experiment bulls were removed from the pastures when they were 8 months old and injected with GnRH at 12 months of age to determine the late effects of the fungus. Jugular blood was collected at 0, 1, and 2 hours after GnRH injection and plasma was assayed for follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T), androstenedione (δ4A) and prolactin (PRL). Bulls were castrated at 7 months of age in the first experiment, in the second experiment bulls were hemicastrated at either 3 or 8 months of age. Testis were weighed, measured, and prepared for histological evaluation. Cross-sections of seminiferous tubules were evaluated for the number of Sertoli cells (SC) and number of A-spermatogonia. In the 8 month-old testis, sections were evaluated for percentage of tubular cross sections occupied by the various generations of germ cells. PRL secretions were significantly reduced (P\u3c0.05) by fungal infestation in the zeranol and nonzeranol implanted bulls. Serum LH levels were significantly reduced (P\u3c.01) by fungal infestation when the bulls were implanted with zeranol. FSH levels were also reduced by fungal infestation in the zeranol-treated bulls (P\u3c0.06). Gonadotropins in the nonzeranol treated bulls may have been reduced by the fungus (P\u3e0.10). Testosterone levels were not affected by fungal infestation except at 3 months of age, where they were significantly reduced (P\u3c0.01) in the nonzeranol treated bulls. Androstenedione levels were not affected by the fungus at any age studied. Testicular weights were significantly lower in bulls treated with zeranol (P\u3c0.07) and a trend toward lowered testes weights was seen in the nonzeranol treated bulls (P\u3e0.10). Sertoli cell number was significantly reduced in both the zeranol treated bulls (P\u3c0.01) and nonzeranol treated bulls (P\u3c0.05). Number of A-spermatogonia was not affected by the endophyte but percentage of cross sections with mature spermatids were significantly (P\u3c0.03) higher in the control group. It is concluded that feeding infested fescue significantly reduced PRL levels in the bull. Fungal infestation significantly affected gonadotropins secretion in the zeranol treated bulls and they also reduced in the nonzeranol treated bulls but the difference was not significant. Testosterone secretion was reduced in the treated bull in the early prepubertal period in the nonzeranol treated bulls. Testicular weights and Sertoli cell number were decreased by fungal ingestion both with and without zeranol. Also, testicular development was delayed by fungus as evidenced by the histological evaluation. Decrements in number of Sertoli cells could lead to a permanent impairment of testicular function

Utilizing Diffusion and Temperature as a Means of Band-Gap Modulation for Conjugated Polymers

First, the effect of monomer feed ratios when two electroactive monomers diffuse towards each other as a means of modulating the band gap by creating different copolymers is presented. From two homopolymers, having a high and low energy band gap, a set of conjugated copolymers with different energy bang gaps were prepared in a single run using diffusion fundamentals. . Hence, a combination of the two monomers is used to generate solid state electrochromic devices of any color. Second, the preparation and characterization of conductive fabric using a conjugated polymer is introduced. The electrical properties, morphology, and the effect of temperature on conductive fabric resistance over a wide range of temperature were investigated. It was found that the conductive fabric had low sheet resistance with passage of high current. The material exhibited metallic behavior at a specific temperature due to the modulation in the band gap from the semiconductor to metal rang

The Influence of Participation in Socially Engaging or Complex Physical Activities on Executive Function Among Older Adults

Twice-exceptionality is the phenomenon of a student with one or more disabilities who is also gifted and talented. Identification of twice-exceptionality is difficult and only recently has there been a greater awareness of the needs of twice-exceptional students. There is empirical research about twice-exceptionality but little research exists on how twice-exceptional individuals perceive and attribute meaning to their lived experiences. The purpose of this qualitative case study was to explore the experiences of one university student identified as gifted and learning disabled to understand how personal experiences influenced his identity development, his perspectives on teaching and education, and, ultimately, his career choice. Five themes emerged from the data analysis: (a) psychosocial challenges, (b) delayed identification, (c) masking effect and school achievement, (d) the importance of support, and (e) motivation for career choice. Individuals with twice-exceptionality often face unique psychosocial challenges including social isolation, low self-esteem, and feelings of worthlessness. Identification and support are often delayed for these individuals as their disability can mask their giftedness and vice versa; each condition affects their school achievement. These challenges affected the study participant; his personal and academic experiences illustrated the impact identification and support had on his education as well as his future goal of becoming a teacher. A key motivating factor for his career choice was to address the needs of future students with twice exceptionality. Findings of this study suggested an interrelationship among the five themes and stressed the critical importance of identifying and supporting students who have unique learning needs

Challenges Facing Gifted Students in Saudi Arabia

Gifted education and general education are inseparable in Saudi Arabia. Gifted students are integrated with other students in public schools. Like regular students, gifted students study the same curriculum, and in many schools they have been taught by non-specialist or untrained teachers of gifted education. In spite of some special programs for gifted children, such as summer enrichment programs and weekend programs, gifted students still face challenges and difficulties in Saudi public schools. This study attempts to explore some of these challenges: a) the nature of the Saudi educational system, (b) the structure of curricula, and (c) the readiness of Saudi teachers to deal with gifted students. The findings show that, though the Saudi educational system has witnessed significant development and has received considerable support from the government, education in Saudi Arabia is still behind global standards. The balance between Islamic and Arabic studies on one hand and scientific subjects (i.e., mathematics and science studies) on the other is still uneven. In addition, the preparation and training programs of Saudi teachers to deal with regular students in general and gifted students in particular need a lot of work from the Ministry of Education and the teachers themselves. The consequences for gifted students as part of the Saudi educational system, as well as further recommendations, are later discussed. Keywords: gifted students, Saudi educational system, difficulties facing gifted students, religious education

The role of tumour vasculature in fluid flow and drug transport in solid tumours

The aberrance of the vasculature in tumours has been linked to increased aggressiveness and poor drug delivery in tumours. Complexities in the microarchitecture of tumour vasculature occurring on microscopic scales can affect fluid flow and drug transport making it difficult to predict tumour response to treatment. Given this, mathematical models can play an important role in understanding the various aspects of the tumour vasculature that can promote invasiveness and limit drug delivery. In this work, computational models are developed to investigate the effect of tumour vasculature on fluid flow and drug distribution and novel imaging methods are assessed for their ability to characterise the tumour vasculature in whole human tumours. A mathematical angiogenesis model is used to generate microscopic details including individual vessel properties on a whole vascular network scale which are coupled with a fluid flow and drug transport model. The interstitial fluid pressure (IFP) in the tumour model was found to be elevated with increased heterogeneity caused by the presence of a necrotic core and heterogenous vessel permeability. Subtle changes to the network on a microscopic scale significantly influenced fluid flow in the tumour vessels and tissue. Delivery of doxorubicin to tumours was found to be highly dependent on the properties of tumour vasculature and blood flow, where regions with excessive branching and vessel tortuosity had reduced drug concentrations due to poor blood flow. Hence, the vascular density was not found to be the main factor in the accumulation of the drug within the tissue space and it’s uptake by cancer cells. An interplay between treatment strategy including dose and administration mode and properties of the vasculature was found by evaluating the spatial intracellular concentration. The fluid flow and drug transport models showed the significant effect of incorporating the microscopic properties of the tumour vasculature which can influence fluid flow and drug distribution on a macroscopic scale. The imaging methods assessed in this work shows that Optical projection tomography combined with fluorescent Immunohistochemistry labelling methods can be used to extract angiogenesis related parameters in whole human tumours. Additionally, the method was able to extract clean network topologies that show promise in application to understanding fluid flow and drug transport in real tumours.Open Acces

Characterization of Phosphorylated G Protein Function and Membrane Culstering by Super Resolution Imaging

Heterotrimeric G proteins play crucial roles in various signal transduction pathways, where they act as molecular switches in transducing a signal from G protein coupled receptors (GPCRs) at the plasma membrane to downstream effectors. Although their mechanism of action is mostly concentrated at the plasma membrane, their dynamic membrane organization and how it is regulated are not understood. Due to the diffraction limited resolution of fluorescence microscopy, studying the precise organization of membrane proteins can be challenging. In this study, we took advantage of super-resolution fluorescence photoactivation localization microscopy (FPALM) to overcome this challenge. Dictyostelium discoideum was used as a cellular model to study G protein function and membrane organization. These cells rely on chemotaxis toward a secreted chemoattractant, cyclic adenosine monophosphate (cAMP) during the development phase of their life cycle. The Gα2 subunit of D. discoideum is required for the chemotactic response. Once activation occurs, Gα2 is known to be phosphorylated on serine 113; however, the role of this phosphorylation remains poorly defined. Exchange of serine residue 113 to alanine causes starved cells to begin the aggregation phase several hours sooner when compared to wild type, while exchanging this serine to aspartic acid (phosphorylation mimic) shows a dramatic decrease in plasma membrane surface localization. At the nanoscale level, images using FPALM show that activation and phosphorylation cause significant changes to Gα2 cluster density in the plasma membrane. Getting these first nanoscale images of G protein provided robust information, which adds to our understanding of the ligand-dependent reorganization and clustering of Gα2 required for precise signaling. Cell fractionation experiments supported this result. In addition, phosphorylation-dependent interaction between phosphorylated Gα2 and D. discoideum 14-3-3 protein was detected

Construct validation of the revised Metacognitive Awareness of Reading Strategies Inventory (MARSI-R) and its relation to learning effort and reading achievement

Language students apply different strategies to learn a second language (L2), especially when they want to attain proficiency in reading. The aim of the present study was to revisit the validity of the Metacognitive Awareness of Reading Strategies Inventory (MARSI-R) among Saudi students using a new statistical method of confirmatory composite analysis (CCA). Past studies modeled MARSI-R as a common factor and applied confirmatory factor analysis (CFA) to test its validity. However, studies struggled to provide support for the validity of the MASRI-R with each suggesting different model. Instead, we treat the inventory as a composite, meaning that the items in MARSI-R form and define the inventory and not the other way around. We use partial least squared structural equation modeling (PLS-SEM) to allow the composite model to be estimated. The results indicated that the constructs of MARSI-R are better operationalized as composites not common factors as supported through CCA exclusively. After confirming the nature of the inventory, we evaluated the extent to which MARSI-R is related to reading proficiency through the mediational mechanism of motivational intensity (i.e., learning effort). Descriptive statistics illustrated that problem-solving strategies are the most used strategy and that females used the strategies more frequently than their male counterparts. Most importantly, the structural model showed that metacognitive reading strategies only exert an indirect effect on reading proficiency, suggesting that the effect of strategies is mediated by motivational intensity (i.e., learning effort). Thus, motivational intensity seems to be mediator in the relationship between metacognitive reading strategies and reading proficiency. Finally, methodological and educational implications are provided

When and how to use confirmatory composite analysis (CCA) in second language research

Alamer, A., Schuberth, F., & Henseler, J. (2024). When and how to use confirmatory composite analysis (CCA) in second language research. Studies in Second Language Acquisition, 46(2), 597–616. Advance online publication. https://doi.org/10.1017/S0272263124000020 --- This work was supported by the Deanship of Scientific Research, Vice Presidency for Graduate Studies and Scientific Research, King Faisal University, Saudi Arabia [Grant No. 5589]. Jörg Henseler acknowledges a financial interest in the composite-based SEM software ADANCO and its distributor, Composite Modeling. Moreover, he gratefully acknowledges financial support from FCT Fundação para a Ciência e a Tecnologia (Portugal), national funding through a research grant from the Information Management Research Center– MagIC/NOVA IMS (UIDB/04152/2020). Moreover, we thank Daniel Ondé and colleagues for giving us permission to use their dataset in our illustrative example. We also thank Alexandra Elbakyan for her efforts in making science accessible.Researchers in second language (L2) and education domain use different statistical methods to assess their constructs of interest. Many L2 constructs emerge from elements/parts, i.e., the elements define and form the construct and not the other way around. These constructs are referred to as emergent variables (also called components, formative constructs, and composite constructs). Because emergent variables are composed of elements/parts, they should be assessed through confirmatory composite analysis (CCA). Elements of emergent variables represent unique facets of the construct. Thus, such constructs cannot be properly assessed by confirmatory factor analysis (CFA) because CFA and its underlying common factor model regard these elements to be similar and interchangeable. Conversely, the elements of an emergent variable uniquely define and form the construct, i.e., they are not similar or interchangeable. Thus, CCA is the preferred approach to empirically validate emergent variables such as language skills L2 students’ behavioral engagement and language learning strategies. CCA is based on the composite model, which captures the characteristics of emergent variables more accurately. Aside from the difference in the underlying model, CCA consists of the same steps as CFA, i.e., model specification, model identification, model estimation, and model assessment. In this paper, we explain these steps. and present an illustrative example using publicly available data. In doing so, we show how CCA can be conducted using graphical software packages such as Amos, and we provide the code necessary to conduct CCA in the R package lavaan.publishersversionpublishe