442 research outputs found
The Longitudinal Effects of STEM Identity and Gender on Flourishing and Achievement in College Physics
Background. Drawing on social identity theory and positive psychology, this study investigated womenâs responses to the social environment of physics classrooms. It also investigated STEM identity and gender disparities on academic achievement and flourishing in an undergraduate introductory physics course for STEM majors. 160 undergraduate students enrolled in an introductory physics course were administered a baseline survey with self-report measures on course belonging, physics identification, flourishing, and demographics at the beginning of the course and a post-survey at the end of the academic term. Students also completed force concept inventories and physics course grades were obtained from the registrar.
Results. Women reported less course belonging and less physics identification than men. Physics identification and grades evidenced a longitudinal bidirectional relationship for all students (regardless of gender) such that when controlling for baseline physics knowledge: (a) students with higher physics identification were more likely to earn higher grades; and (b) students with higher grades evidenced more physics identification at the end of the term. Men scored higher on the force concept inventory than women, although no gender disparities emerged for course grades. For women, higher physics (versus lower) identification was associated with more positive changes in flourishing over the course of the term. High-identifying men showed the opposite pattern: negative change in flourishing was more strongly associated with high identifiers than low identifiers.
Conclusions. Overall, this study underlines gender disparities in physics both in terms of belonging and physics knowledge. It suggests that strong STEM identity may be associated with academic performance and flourishing in undergraduate physics courses at the end of the term, particularly for women. A number of avenues for future research are discussed
Synergistic up-regulation of CXCL10 by virus and IFN Îł in human airway epithelial cells.
Airway epithelial cells are the first line of defense against viral infections and are instrumental in coordinating the inflammatory response. In this study, we demonstrate the synergistic stimulation of CXCL10 mRNA and protein, a key chemokine responsible for the early immune response to viral infection, following treatment of airway epithelial cells with IFN Îł and influenza virus. The synergism also occurred when the cells were treated with IFN Îł and a viral replication mimicker (dsRNA) both in vitro and in vivo. Despite the requirement of type I interferon (IFNAR) signaling in dsRNA-induced CXCL10, the synergism was independent of the IFNAR pathway since it wasn't affected by the addition of a neutralizing IFNAR antibody or the complete lack of IFNAR expression. Furthermore, the same synergistic effect was also observed when a CXCL10 promoter reporter was examined. Although the responsive promoter region contains both ISRE and NFÎșB sites, western blot analysis indicated that the combined treatment of IFN Îł and dsRNA significantly augmented NFÎșB but not STAT1 activation as compared to the single treatment. Therefore, we conclude that IFN Îł and dsRNA act in concert to potentiate CXCL10 expression in airway epithelial cells via an NFÎșB-dependent but IFNAR-STAT independent pathway and it is at least partly regulated at the transcriptional level
Exposure to celebrity- endorsed small cigar promotions and susceptibility to use among young adult cigarette smokers
Small cigar smoking among young adult cigarette smokers may be attributed to their exposure to its advertisements and promotions. We examined the association between exposure to a celebrity music artistâs endorsement of a specific brand of small cigars and young adult cigarette smokersâ susceptibility to smoking that brand. Venue-based sampling procedures were used to select and survey a random sample of 121 young adult cigarette smokers, aged 18â35. Fourteen percent reported exposure to the artistâs endorsement of the small cigar and 45.4% reported an intention to smoke the product in the future. The odds of small cigar smoking susceptibility increased threefold for those who reported exposure to the endorsement compared to those not exposed (OR = 3.64, 95% CI 1.06 to 12.54). Past 30-day small cigar use (OR = 3.30, 95% CI 1.24 to 8.74) and past 30-day cigar use (OR = 5.08, 95% CI 1.23, 21.08) were also associated with susceptibility to smoke a small cigar. An association between young adult cigarette smokersâ exposure to the music artistâs small cigar endorsement and their susceptibility to smoke small cigars was found. This association underscores the importance of monitoring small cigar promotions geared toward young people and their impact on small cigar product smoking
A simple methodology to assess endolysosomal protease activity involved in antigen processing in human primary cells
Background: Endolysosomes play a key role in maintaining the homeostasis of the cell. They are made of a complex set of proteins that degrade lipids, proteins and sugars. Studies involving endolysosome contribution to cellular functions such as MHC class I and II epitope production have used recombinant endolysosomal proteins, knockout mice that lack one of the enzymes or purified organelles from human tissue. Each of these approaches has some caveats in analyzing endolysosomal enzyme functions. Results: In this study, we have developed a simple methodology to assess endolysosomal protease activity. By varying the pH in crude lysate from human peripheral blood mononuclear cells (PBMCs), we documented increased endolysosomal cathepsin activity in acidic conditions. Using this new method, we showed that the degradation of HIV peptides in low pH extracts analyzed by mass spectrometry followed similar kinetics and degradation patterns as those performed with purified endolysosomes. Conclusion: By using crude lysate in the place of purified organelles this method will be a quick and useful tool to assess endolysosomal protease activities in primary cells of limited availability. This quick method will especially be useful to screen peptide susceptibility to degradation in endolysosomal compartments for antigen processing studies, following which detailed analysis using purified organelles may be used to study specific peptides
A novel prosthesis presentation test to screen for cognitive and functional decline
Objectives and background
To validate a novel screening test for cognitive and functional decline in older patients rehabilitated with complete removable dental prostheses (CRDPs).
Materials and methods
Edentate old inâpatients rehabilitated with CRDPs were included in this study. Participants were requested to remove their prostheses before their intraoral examinations. The prostheses were then presented in an inverted orientation. Participants had to correct the orientation of the prostheses and insert them in the appropriate jaws. The test was repeated after the intraoral exam. Appropriate statistical models were used (âșâ=â.05) to associate the test results with the participants' miniâmental state examination (MMSE) score, functional independence measure (FIM), age and sex.
Results
Among the 86 participants (meanâage: 85.4â±â6.4âyears; mean MMSE: 19.8â±â5.5; mean FIM: 77.9â±â20.8), 21 (24.4%) failed to correctly insert the prosthesis. The prosthesis presentation test (PPT) was associated with the FIM but not the MMSE. Regression models further confirmed an association with age (Pâ=â.043), but not sex. Additional analyses revealed the PPT test is associated with the FIM's cognitive subâsets of memory, problem solving and social interaction.
Conclusion
The PPT is a novel, simple and quick screening tool that can help detect functional difficulties in older people. It can easily be performed during an oral examination. Future studies are needed to determine whether the PPT can be used to detect deficits in executive function, as a complement to the MMSE and also as a first assessment of a patient's ability to manage dentures independently
Social Connectedness in Physical Isolation: Online Teaching Practices That Support Under-Represented Undergraduate Studentsâ Feelings of Belonging and Engagement in STEM
The COVID-19 outbreak spurred unplanned closures and transitions to online classes. Physical environments that once fostered social interaction and community were rendered inactive. We conducted interviews and administered surveys to examine undergraduate STEM studentsâ feelings of belonging and engagement while in physical isolation, and identified online teaching modes associated with these feelings. Surveys from a racially diverse group of 43 undergraduate students at a Hispanic Serving Institution (HSI) revealed that interactive synchronous instruction was positively associated with feelings of interest and belonging, particularly for students of color, while noninteractive instruction reduced social belonging, but was related to more cognitive engagement. Small group and one-on-one interviews with 23 of these students suggest that students derived feelings of connectedness from their instructors, peers, and prior experiences and relied on their sense of competency to motivate themselves in the course and feel a sense of belonging. Two embedded cases of students in physics classrooms are compared to highlight the range of student feelings of connectedness and competency during the lockdown. Findings reaffirm that social interaction tends to support belonging and engagement, particularly for under-represented (Black or African American and Hispanic) racial groups in STEM. STEM instructors who aim to support feelings of belonging and engagement in virtual learning environments should consider increasing opportunities for studentâstudent and studentâteacher interactions, as well as taking a flexible approach that validates and integrates student voice into instruction. Future research is needed to further explore the themes of relatedness and competency that emerged as aspects of course belonging
Rat Strain and Housing Conditions Alter Oxidative Stress and Hormone Responses to Chronic Intermittent Hypoxia
Sleep apnea has been associated with elevated risk for metabolic, cognitive, and cardiovascular disorders. Further, the role of hypothalamicâpituitaryâadrenal (HPA) activation in sleep apnea has been controversial in human studies. Chronic intermittent hypoxia (CIH) is a rodent model, which mimics the hypoxemia experienced by patients with sleep apnea. Most studies of CIH in rats have been conducted in the Sprague Dawley rat strain. Previously published literature suggests different strains of rats exhibit various responses to disease models, and these effects can be further modulated by the housing conditions experienced by each strain. This variability in response is similar to what has been observed in clinical populations, especially with respect to the HPA system. To investigate if strain or housing (individual or pair-housed) can affect the results of CIH (AHI 8 or 10) treatment, we exposed individual and pair-housed Sprague Dawley and Long-Evans male rats to 7 days of CIH treatment. This was followed by biochemical analysis of circulating hormones, oxidative stress, and neurodegenerative markers. Both strain and housing conditions altered oxidative stress generation, hyperphosphorylated tau protein (tau tangles), circulating corticosterone and adrenocorticotropic hormone (ACTH), and weight metrics. Specifically, pair-housed Long-Evans rats were the most sensitive to CIH, which showed a significant association between oxidative stress generation and HPA activation under conditions of AHI of 8. These results suggest both strain and housing conditions can affect the outcomes of CIH
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Laboratory and Clinical Predictors of Disease Progression following Initiation of Combination Therapy in HIV-Infected Adults in Thailand
Background: Data on determinants of long-term disease progression in HIV-infected patients on antiretroviral therapy (ART) are limited in low and middle-income settings. Methods: Effects of current CD4 count, viral load and haemoglobin and diagnosis of AIDS-defining events (ADEs) after start of combination ART (cART) on death and new ADEs were assessed using Poisson regression, in patient aged â„18 years within a multi-centre cohort in Thailand. Results: Among 1,572 patients, median follow-up from cART initiation was 4.4 (IQR 3.6â6.3) years. The analysis of death was based on 60 events during 6,573 person-years; 30/50 (60%) deaths with underlying cause ascertained were attributable to infections. Analysis of new ADE included 192 events during 5,865 person-years; TB and Pneumocystis jiroveci pneumonia were the most commonly presented first new ADE (35% and 20% of cases, respectively). In multivariable analyses, low current CD4 count after starting cART was the strongest predictor of death and of new ADE. Even at CD4 above 200 cells/mm3, survival improved steadily with CD4, with mortality rare at â„500 cells/mm3 (rate 1.1 per 1,000 person-years). Haemoglobin had a strong independent effect, while viral load was weakly predictive with poorer prognosis only observed at â„100,000 copies/ml. Mortality risk increased following diagnosis of ADEs during cART. The decline in mortality rate with duration on cART (from 21.3 per 1,000 person-years within first 6 months to 4.7 per 1,000 person-years at â„36 months) was accounted for by current CD4 count. Conclusions: Patients with low CD4 count or haemoglobin require more intensive diagnostic and treatment of underlying causes. Maintaining CD4â„500 cells/mm3 minimizes mortality. However, patient monitoring could potentially be relaxed at high CD4 count if resources are limited. Optimal ART monitoring strategies in low-income settings remain a research priority. Better understanding of the aetiology of anaemia in patients on ART could guide prevention and treatment
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Variable Processing and Cross-presentation of HIV by Dendritic Cells and Macrophages Shapes CTL Immunodominance and Immune Escape
Dendritic cells (DCs) and macrophages (MĂžs) internalize and process exogenous HIV-derived antigens for cross-presentation by MHC-I to cytotoxic CD8+ T cells (CTL). However, how degradation patterns of HIV antigens in the cross-presentation pathways affect immunodominance and immune escape is poorly defined. Here, we studied the processing and cross-presentation of dominant and subdominant HIV-1 Gag-derived epitopes and HLA-restricted mutants by monocyte-derived DCs and MĂžs. The cross-presentation of HIV proteins by both DCs and MĂžs led to higher CTL responses specific for immunodominant epitopes. The low CTL responses to subdominant epitopes were increased by pretreatment of target cells with peptidase inhibitors, suggestive of higher intracellular degradation of the corresponding peptides. Using DC and MĂž cell extracts as a source of cytosolic, endosomal or lysosomal proteases to degrade long HIV peptides, we identified by mass spectrometry cell-specific and compartment-specific degradation patterns, which favored the production of peptides containing immunodominant epitopes in all compartments. The intracellular stability of optimal HIV-1 epitopes prior to loading onto MHC was highly variable and sequence-dependent in all compartments, and followed CTL hierarchy with immunodominant epitopes presenting higher stability rates. Common HLA-associated mutations in a dominant epitope appearing during acute HIV infection modified the degradation patterns of long HIV peptides, reduced intracellular stability and epitope production in cross-presentation-competent cell compartments, showing that impaired epitope production in the cross-presentation pathway contributes to immune escape. These findings highlight the contribution of degradation patterns in the cross-presentation pathway to HIV immunodominance and provide the first demonstration of immune escape affecting epitope cross-presentation
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