13 research outputs found
Thermo elastic Problem of a Thick Circular Plate due to Heat Generation
No full textAbstract-In this paper, an attempt has been made to study thermoelastic response of a thick circular plate occupying the space due to heat generation with radiation type boundary conditions. Here we apply integral transform techniques to find the thermoelastic solution
On B- Covariant Derivative of First Order for Some Tensors in different Spaces
Get PDFIn this paper, we study the relationship between Cartan's second curvature tensor and torsion tensor in sense of Berwald. Moreover, we discuss the necessary and sufficient condition for some tensors which satisfy a recurrence property in -, -Like--, -- and -reducible-
Genomic and proteomic approaches to elucidate polyethylene and polystyrene degradation by the gut microbiome of Plodia interpunctella and Tenebrio molitor larvae respectively
No full textPolyethylene (PE) and polystyrene (PS) are two plastic polymers that are globally used as raw materials in the industry, in everyday items, and as packaging material in various forms. The durability of these two polymers have made it difficult for natural degradation to occur, creating a global disposal problem. Most of the current recycling and disposal practices involve high energy requirements and result in low recovery rates of PE and PS monomers. The past few decades have seen scientists study the effectiveness of microbial degradation of PE and PS polymers in an attempt to solve the disposal issue in a sustainable manner. More recently, the gut microbiomes of different insect larvae are able to degrade either PE, PS, or both. The gut microbiome of Plodia interpunctella larvae can degrade polyethylene while that of Tenebrio molitor can degrade polystyrene. However, the mechanism of degradation in the gut microbiome of these larvae, the microbial families involved, and regulation of both microbial community structure, composition, and protein expression in response to the degradation is poorly understood.
In the second chapter of dissertation, I investigated the change in microbial community composition occurring when Plodia interpunctella larvae feed on PE and Tenebrio molitor larvae feed on PS to identify microbial families involved in either degradation processes using 16S amplicon sequencing. In case of PE degradation, the microbial community in the larval gut showed a significant increase in relative abundance of families Clostridiaceae, Pseudomonadaceae and Caulobacteraceae. When compared to the microbial community of larvae from the control group (bran-glycerol diet), these families increased to represent ~50% of the P. interpunctella gut in larvae fed with only PE as their diet. Interestingly, in T. molitor larvae, the native gut microbiota could degrade PS as the sole diet without changing the structure or composition of their community, indicating an inherent degradative ability against this polymer. Amplicon-based functional prediction via PICRUSt2 analysis showed the presence of fatty acid degradative enzymes in the test groups for both larvae.
To determine the proteins and enzymes involved in polyethylene degradation, I set up enrichment cultures with either glycerol or sterilized PE pieces as the carbon source and inoculated them with microbes extracted from P. interpunctella larvae fed either bran-glycerol or only PE as their diet. Mass spectrometry analysis revealed 61 significantly expressed proteins in the test cultures (with PE as sole source of carbon) and enzymes such as acetyl-CoA acetyltransferase, acetyl-CoA synthetase as well as malate dehydrogenase and enolase were upregulated in the test samples. These enzymes form part of fatty acid degradation and the glycolysis cycle, suggesting that these are the preferred pathways for PE degradation by the gut microbiome of P. interpunctella larvae.
The proteomic analysis of polystyrene degradation by the gut microbiota of T. molitor larvae is detailed in chapter 4, where I followed a similar procedure to set up enrichment cultures. Here, the control media contained starch and test media had sterilized pieces of PS as the sole source of carbon. Fifty-five proteins were significantly expressed in the test media, mainly representing enzymes from fatty acid degradation and the glycolysis cycle. The main proteins of interest were PTS system mannose-specific EAIIB component and mannose permease II-D component pointing to the potential oxidation of PS into mannose. Enzymes such as malate dehydrogenase, isocitrate dehydrogenase, succinate-CoA ligase, and phosphoglucose isomerase among others support degradation via glycolysis and Krebs cycle. Finally, fatty acid oxidation enzymes oleate hydratase, 3-ketoacyl-CoA thiolase, and fatty acid oxidation complex subunit alpha corroborate PS degradation through this pathway.
Overall, the identification of different microbial families as well as the proteomics behind PE and PS degradation provides vital information allowing a mechanistic view of polymer degradation in the gut microbiome of these two larvae. It provides protein candidates for bioengineering and mass production, and on a larger scale for application in current plastic disposal practices, facilitating sustainable solutions for the global plastic problem.Embargo status: Restricted until 09/2027. To request the author grant access, click on the PDF link to the left
Loud Speaker Equalization Project
No full textElec 301 Project. Equalizing the frequency response of a speaker using an inverse filter.This work was created using the Connexions authoring platform. This platform will be retired as of the end of 2021. This work has been migrated to PDF format for continuous access to the educational content, however any embedded links within the text to the legacy platform may no longer be accessible
On B- Covariant Derivative of First Order for Some Tensors in Different Spaces
No full textIn this paper, we study the relationship between Cartan's second curvature tensor and torsion tensor in sense of Berwald. Moreover, we discuss the necessary and sufficient condition for some tensors which satisfy a recurrence property in -, -Like--, -- and -reducible-
Fractional Differential Equation of LC and LR Electrical Circuit
No full textThe fractional derivative isused to calculate the current and charge at any time t in LC,RC and LR circuits by using Laplace Transform of fractional derivatives.
 
Undergraduates’ reactions to errors mediates the association between growth mindset and study strategies
No full text© The Author(s) 2024. cc-byBackground: Students employ a variety of study strategies to learn and master content in their courses. Strategies vary widely in their effectiveness for promoting deep, long-term learning, yet most students use ineffective strategies frequently. Efforts to educate students about effective study strategies have revealed that knowledge about effective strategies is by itself insufficient for encouraging widespread and lasting changes. An important next step is to uncover factors that influence the decisions students make about study strategy use. We explored the association between beliefs about intelligence (mindset, universality, and brilliance) and study strategies. The most effective study strategies are error-prone, and beliefs about intelligence carry implications for whether errors are a normal and even beneficial part of the learning process (e.g., growth mindset) or signs of insufficient intelligence (e.g., fixed mindset). Therefore, we hypothesized that beliefs about and reactions to errors would mediate a relationship between beliefs about intelligence and study strategies. We tested this hypothesis by surveying 345 undergraduates enrolled in an introductory biology class at a public, research-active university in northwestern United States. Results: Confirmatory factor analysis indicated that the internal structure of all measures functioned as expected in our sample. We fit a structural equation model to evaluate our hypothesized model. We found that mindset, but not universality nor brilliance, predicts variance in both beliefs about errors and reactions to errors. In turn, adaptive reactions to errors (but not beliefs about errors) are associated with the use of highly effective study strategies and spacing study sessions. There was a significant indirect relationship between growth mindset and spacing of study sessions. Conclusions: Our results provide evidence for a mechanism explaining the association between students’ mindset beliefs and academic outcomes: believing that intelligence is improvable is associated with more adaptive reactions to making errors, which correlates with choosing more error-prone and therefore more effective study strategies. Future interventions aimed at improving students’ study strategies may be more effective if they simultaneously target reacting adaptively to errors and emphasize that intelligence is improvable
Strategically creating maximally heterogeneous lab groups did not improve group performance in an introductory biology lab class.
No full textCollaboration is a critical skill for professionals in any field to master, and group work is a prominent component of many lab courses. However, there is conflicting guidance about the best method for forming groups to maximize performance and student experiences. Based on the benefits of cognitive diversity, we hypothesized that creating maximally heterogeneous groups would improve performance on lab activities. We conducted a quasi-experiment in the lab sections of a large-enrollment 2-semester introductory biology for majors course sequence (n = 986). In these large enrollment courses, students simultaneously enroll in smaller-enrollment lab sections. Each semester, we assigned groups randomly in half of the lab sections and in the other half of lab sections we strategically assigned groups to be maximally heterogeneous in terms of race, gender, and prior preparation. We examined the impact of group assignment on students' academic performance (their grade on their collaborative lab report and their overall lab grade), incidence of group conflict, and student attitudes towards group work (i.e., teamwork satisfaction and perceptions of collaborative learning). We found that group formation strategy had no impact on students' grades on either their collaborative lab report or their overall lab grade. Group conflicts were reported so infrequently that we were not able to detect any differences between the two groups. Our measures of groupwork satisfaction and perceptions of collaborative learning failed to demonstrate measurement invariance between the two types of group formation, which prevented us from assessing whether student attitudes differ, but suggest that there is some experiential difference that we were unable to capture
Pediatric radiology in oto-rhino-laryngology
No full textHead and neck diseases in children and adolescents present special diagnostic and differential diagnostic challenges to ENT surgeons as well as to radiologists. Both disciplines have to adapt the latest radiological and interventional technologies to the needs of the pediatric patient in order to enable a minimally invasive but successful diagnostic procedure.High quality sonography by an experienced examiner is often the only imaging technique that is necessary in children and adolescents. Radiographs are rarely indicated in pediatric head and neck diseases. MRI, compared to computed tomography, has the advantage of absent radiation exposure. Additionally, due to current advances in high resolution techniques to delineate very small details or in visualization of different tissue characteristics, it has become an integral part of pre- and postoperative imaging.However, children should not be denied an adequate diagnostic procedure even if it includes sedation, intervention, or exposure to radiation. The responsible use of the diagnostic options under consideration of the therapeutic consequences is essential. It is most likely to be successful in a close interdisciplinary cooperation of pediatric ENT specialists and radiologists as well as pediatric anesthesiologists in selected cases.Although benign diseases predominate in children and adolescents, the possibility of malignancy has to be considered in cases of atypical clinical and radiological findings. In many of these young patients, the outcome and the probability of survival are directly associated with the initial diagnostic and therapeutic strategies, which should therefore be in accordance with the current guidelines of pediatric oncology therapy studies.Our collection of clinical cases consists of representative examples of useful diagnostic approaches in common and age specific diagnoses as well as in rare diseases and malformations. It shows the significance of a special knowledge in embryology and normal postnatal development for the differentiation of normal variants from pathological findings. Only in considering the results of imaging studies in their clinical context, it is possible to succeed in detecting a syndrome behind a single malformation or adequately caring for patients with a chronic disease such as cystic fibrosis
