505 research outputs found
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Interactions of Human Immune Responses with Lipid Metabolism and the Skin Microbiome in Acne Vulgaris
Acne vulgaris is a great example to study the interaction among the environment, microbes, and host immune response. Acne vulgaris is a highly prevalent chronic inflammatory skin disease thought to be caused by increased in sebum secretion, bacterial colonization by the ubiquitous bacterium Cutibacterium acnes (C. acnes), and host inflammatory response. As a major factor implicated acne pathology, sebum and its composition, squalene, are unique to humans. Sebaceous lipids accumulate in the follicular duct are oxidized by C. acnes lipase leading to bacterial proliferation. The direct cause-and-effect relationship between the bacteria has been difficult to establish given that C. acnes is a ubiquitous bacterium and that there was no quantitative difference in the number of bacteria between subjects with and without acne. Recent genomic and phenotypic analyses on acne clinical samples revealed different phylotypes of C. acnes coexist in the pilosebaceous unit with other Cutibacterium spp. included C. granulosum and C. humerusii. Studies also showed strains phylotype IA1 are more abundant with the skin on acne patients (CA) and phylotype II are more associated with healthy skin (CH). However, the mechanisms underlying the lipid and bacterial interaction to cause the onset of inflammation and subsequent development of acne are still not understood. This dissertation begins with a detailed analysis using single cell RNA-seq to deconstruct the genetic and molecular profiles of individual cells to study differences in lesional and non-lesional skin of acne patients. Particularly we were interested in changes within the same cell types to understand how normal skin becomes inflamed acne skin. We identified that a TREM2 macrophage subpopulation, expressing a lipid gene metabolism program, is associated with acne lesions. We further discovered that squalene induces TREM2+ macrophages in vitro to have enhanced phagocytosis but minimal antimicrobial activity against C. acnes. As a result, the squalene induced TREM2+ macrophage perpetuates inflammation linking the excess lipid production in acne to inflammation in acne. Next, we investigated clinical strains of C. acnes, CA and CH, to understand how the microbiome interact in acne lesions. These strains differ in their ability to trigger inflammation with CA induces higher pro-inflammatory cytokine secretion compared to CH in cell culture and mouse infection model. However, the virulence factor that accounts for the differences in immune response between CA and CH are still unknown. In this study, we showed that C. acnes activates the innate immune system through RNA species that are usually reserved for viral detection. Interestingly, RNA species from CA and CH have different bioanalyzer profiles and can trigger distinct immune response as seen with live bacteria. We also showed that CA RNA stimulate the immune response through a TLR-8/IL-18/IL-12p40 pathway. Our in vitro data correlates well with our scRNA-seq data showing the abundance of IFN- and TLR-8 in acne lesions.Taken together, the results enhanced our understanding of the impact of squalene, a sebum lipid, and resident microbes on the immunological functions of the skin. This work advanced our knowledge of the environment-microbe-host interplay occurring at the pilosebaceous follicle and introduced a novel way of thinking about the mechanisms underlying the initiation and pathogenesis of acne vulgaris and inflammatory skin conditions
MATLAB/Simulink Implementation and Analysis of Three Pulse-Width-Modulation (PWM) Techniques
With advances in solid-state power electronic devices and microprocessors, various pulse-width-modulation (PWM) techniques have been developed for industrial applications. For example, PWM-based three-phase voltage source inverters (VSI) convert DC power to AC power with variable voltage magnitude and variable frequency.
This thesis discusses the advantages and drawbacks of three different PWM techniques: the sinusoidalPWM(SPWM) technique, the third-harmonic-injection PWM(THIPWM) technique, and the space-vector PWM (SVPWM) technique. These three methods are compared by discussing their ease of implementation and by analyzing the output harmonic spectra of various output voltages (poles voltages, line-to-neutral voltages, and line-to-line voltages) and their total harmonic distortion (THD).
The simulation results show that both the THIPWM and SVPWM techniques have lower total harmonic distortion than the SPWM technique. The THIPWM and SVPWM techniques in the under-modulation region can both increase the fundamental output voltage by 15.5% over the SPWM technique. Moreover, the SVPWM technique can increase the fundamental output by about 5% in each of the overmodulation regions 1 and 2, respectively
Some Impact of the English Competence Assessment Test Based on Output Standards on English Teaching at Tan Trao University
The standardized English proficiency assessment has yielded significant and positive impacts on the English teaching and learning processes at Tan Trao University. This assessment not only serves as a tool to evaluate students' English proficiency but also constitutes an integral component of the educational process, encompassing curriculum design and instructional methodologies. One of the paramount effects of this assessment is the establishment of clear standards regarding proficiency levels and requisite skills. This initiative provides educators and students with a precise understanding of the competencies required for English language acquisition. Consequently, the university can devise tailored language programs that ensure students are equipped with the necessary skills to thrive in academic and professional environments. Furthermore, the assessment instills a sense of pressure on students as they prepare and engage in a high-stakes testing environment. However, this pressure serves as a motivator for students to enhance their individual English proficiency. Consequently, students are propelled towards autonomy and responsibility in their English language learning endeavors, whether through supplemental coursework or independent study. the assessment fosters improvements in the quality of English language instruction at the university. Educators must possess comprehensive knowledge of the assessment's content and requisite skills, prompting them to explore and implement effective pedagogical strategies. This results in a diversification of teaching methodologies, ranging from the utilization of extensive learning resources to the organization of practical activities and classroom discussions. 
Perfectionism, motivational orientation and academic performance
The present study examined the association between perfectionism and academic
performance, as well as how motivational orientations (fear of failure and achievement
motivation) and achievement goals (performance-approach, performance-avoidance, and
mastery goals) are interrelated in predicting marks. Two hundred and eight university
students completed a questionnaire package that included eight perfectionism subscales,
and measures of achievement motivation, trait test anxiety, and achievement goal scales
early in the fall semester. Marks in Introduction to Psychology (December exam) were
used as a measure of academic performance. Perfectionism made independent
contributions to the prediction of marks above and beyond that accounted for by
motivational orientations and achievement goals, with significant unique contributions
made by the personal standards, parental expectations, and organization perfectionism
subscales. Students who had higher personal standards, lower parental expectations and
lower organization attained higher marks. In addition, those who had a fear of failure
orientation, as well as those who endorsed performance-avoidance goals generally
obtained lower grades
Funktionelle Auswirkungen der 77C→G Mutation im Exon A des CD45-Gens des Menschen
[no abstract
Help or Hurt? The Impact of ESG on Firm Performance in S&P 500 Non-Financial Firms
The paper aims to investigate the impact of ESG practice on firms’ financial performance in the context of U.S. market from 2018 to 2020. The paper examines a sample of 57 U.S. non-financial firms belonging to the S&P 500. The Two-Stage Least Squares (2SLS) estimation is employed with an instrumental variable - the political views of the states where the studied firms are located. The paper shows that having a better practice of ESG could enhance firms’ financial performance measured by ROA, ROE, and TobinQ. These findings are consistent with the stakeholder-focused theory instead of shareholder-focus perspective. In addition, the magnitude of the influence of the ESG practice on TobinQ is significantly higher than that of the ESG-ROA and ESG-ROE relations. It reveals that the ESG benefits could make the firms appear more attractive to investors, creating higher market values of the firms’ assets and then higher TobinQ ratio. Not as the TobinQ enhancement, the significant improvement in ROA and ROE would be realized in the long run rather than short term. The low managerial ownership in the U.S. market may increase the chance of ESG overinvestment by the firms’ managers, hence reducing firm value. However, under the pressure of the investors’ strong demand for socially responsible investing, the U.S. firms tend to become involved in ESG activities, obtaining a strong stakeholder commitment and thus creating additional firm value in the long run
Increasing the Level of Agreement of Taxpayers on Tax Audit Conclusions-Recommendations to Vietnamese Tax Authorities
A person’s agreement on a decision usually attaches to their own benefits. However, in most situations, a single decision will impact on different people with different benefits, therefore, a person’s judgment regarding fairness will decide their agreement. Basing on the fact that tax audit conclusions usually impact on economic benefits of taxpayers and a theory of “awareness of fairness”, we would like to apply the quantitative method to identify and verify different drivers of taxpayer’s agreement on tax audit conclusions by assessing reliability and suitability of different scales; verifying research model and research hypothesis, and determining drivers’ impact through questionnaires given to 256 firms. As a result, we propose recommendations to Vietnamese tax authorities in terms of restructuring procedures, completing auditing method and enhancing tax supervising activities in order to increase the level of agreement of taxpayers on tax audit conclusions, improving Vietnamese tax audit effectiveness. Keywords: Tax audit, taxpayers’ agreement, tax audit conclusions, drivers
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