22 research outputs found
Investigation of Chemokine and Microbiome Profiles in Gingival Health and Disease in Humans
No full textThesis (Ph.D.)--University of Washington, 2019Periodontal health is maintained by various host immune mechanisms. Neutrophils are a crucial component of health representing the first line of defense against microbial challenge. The migration and activation of these key effector cells in the gingiva are orchestrated by complex networks of host mediators called chemokines and cytokines. Recently, it has been shown that bacteria have an influential role in the immunomodulation of host mediators and hence host immune response. Indeed, dysregulation of the host immune response, as well as a dysbiosis of the oral microbial community, has been attributed to the pathogenesis of periodontal disease. However, the few investigations into the interaction between the subgingival microbial community and the host immune response have provided limited information to understand this relationship. Therefore, a full assessment of the host-bacterial interaction in health and disease is necessary to further our understandings of the etiology of periodontal disease and identify novel biomarkers of this disease. This thesis investigates the interaction of subgingival microbiome and the host immune response for both health and disease with disease defined as induced gingivitis. A comprehensive evaluation of forty major chemokines and inflammatory mediators in the gingival crevicular fluid (GCF) was achieved by multiplex immunoassay. In parallel, 16S rRNA next-generation sequencing was performed to characterize microbial community composition and structure. Lastly, neutrophil infiltration was assessed by myeloperoxidase (MPO) detection in the GCF to correlate neutrophil recruitment with chemokine expression patterns. The cross-sectional study in healthy adolescents showed inter-individual variability in the chemokine expression patterns and the subgingival microbial profile. Two different chemokine expression patterns were observed among study participants; however, the different groups did not share common microbiome profiles. Additionally, there was no significant concordance between the combined chemokines and microbial profiles in gingival health. Altogether, this data provides a better understanding of the interaction between the immune response and microbiome in the state of clinical health. Findings from the experimental gingivitis study demonstrated that during the initial transition from clinical health to gingivitis, there was a significant shift in the microbial composition that paralleled an alteration in host homeostasis. Despite variable immune responses to plaque accumulation, this alteration was characterized by a decrease in neutrophil chemotactic factors within most patients. Furthermore, patients were able to be separated into three distinct categories with unique microbial and chemokine profiles based on their immune response. The result of this work highlights the influential effect of host response and microbiome in the susceptibility to periodontal disease. In conclusion, this study contributes to our understanding of the host-bacterial interaction in health and the changes which occur during gingivitis induction. The significant alteration of multiple chemotactic factors within the GCF also provides the potential for a novel gingivitis diagnostic tool
Narratives in Mamluk architecture: Spatial and perceptual analyses of the madrassas and their mausoleums
No full textAbstractMamluk sultans were known for their patronage of the arts and architecture. Their educational institutions were among the wide array of architectural projects that linked them as ruling elites to the religious scholars of their times. Their tombs were placed in a mausoleum attached to their educational–religious complexes to attest to their legacy. The evolution of their buildings such that both educational and memorial functions are integrated with the dense surroundings is scrutinized through chronological–spatial analysis. The configuration of the built form, the disposition of its boundaries, its patterns of accessibility, and its visual properties are the features that present the buildings to one’s experience and bring certain perceptions into play. In this study, various spatial descriptor tools of space syntax are employed to analyze the data of 14 Mamluk examples (1260–1517A.D.) and capture the differences in the experience where the expression is preserved. Analyses of the configurational characteristics, axial attributes, visibility structures, and isovists highlight how the spatial and formal properties of the layouts were used to express certain representational relationships. The advantages of combining different spatial investigations allows for understanding historical design principles and how the geometry of forms could hide in its abstract rules, conceptual and perceptual qualities
Integrating Lean and Green Supply Chain Management Systems in Manufacturing
No full textThe attached document may provide the author's accepted version of a published work. See Citation for details of the published work
Protromic and functional study of Acinetobacter abumannii outer membrane vesicles
No full textThe author has granted permission for their work to be available to the general public.<italic>Acinetobacter baumannii<italic>, a gram-negative aerobic bacterium, is one of the most spread bacteria which can be easily isolated from water, soil, and hospital facilities. It may cause various types of diseases such as respiratory tract infection, urinary tract infection, nosocomial pneumonia and bacteremia. It was noticed that <italic>A. baumanii<italic> was existed in the blood stream of military people deployed in Iraq and Afghanistan who suffered with serious injury. The treatment for the infection of <italic>A. baumannii<italic> is limited because it resists to resist nearly 90% of antibiotics. Therefore, to better treat the infection of <italic>A. baumannii<italic>,the mechanism of infection and virulence factors involved in pathogenecity needed to be studied. Similar to other gram-negative bacteria, outer membrane vesicles (OMVs) secreted by A. baumannii consisted of virulence factors. In my study, the <italic>A. baumannii<italic> OMVs were isolated and observed under transmission electron microscopy. The proteomic analysis indicated that <italic>A. baumannii<italic> OMVs consisted of various virulence factors such as OmpA. To understand the function of the <italic>A. baumannii<italic> OMVs, OMVs were incubated with macrophage cells. Results showed the macrophage cells were lysed when incubated with OMVs compared to cells in the control group which were intact. The quantification of cytotoxicity caused by OMVs showed that the mortality rate reached 80% when 0.02 ug/ml OMVs were added.
In my study, the OMVs were isolated and observed. The virulence factors were identified by proteomic analysis and OMVs are toxic to macrophage cells in vitro.Integrative Biolog
Impact of knowledge of the 2017 classification for periodontal and peri-implant diseases on diagnostic accuracy among dental students
No full textBackgroundPeriodontal diseases are a significant global health problem and have been associated with various systemic diseases. The American Academy of Periodontology (AAP) and the European Federation of Periodontology (EFP) introduced a new classification system for periodontal and peri-implant diseases in 2017. However, the complexity of this new classification has presented some challenges in its implementation compared to the 1999 classification system. This study evaluates the impact of dental students’ knowledge of the 2017 classification on their ability to diagnose periodontal diseases accurately.Materials and methodsThis cross-sectional study enrolled 146 fifth- and sixth-year dental students from King Abdulaziz University in Jeddah, Saudi Arabia. A self-reported questionnaire was employed to assess students’ knowledge of the 2017 periodontal classification system and their diagnostic abilities across five clinical cases. Students were classified into low, moderate, and high knowledge groups based on their knowledge questionnaire scores. Statistical analyses assessed the relationship between classification knowledge and diagnostic accuracy and compared these measures across different groups.ResultsIn the study, 41.10% of participants achieved high knowledge scores (14–16 correct answers), while 32.88% and 26.03% were categorized into moderate and low knowledge groups, respectively. There was no significant association between knowledge levels and diagnostic accuracy, except for one specific clinical case. While sixth-year students scored significantly higher in the knowledge assessment than fifth-year students (p = 0.005), their diagnostic accuracy did not significantly differ. The main challenge, as reported by students, was the discrepancy between case complexity and their clinical experience (28.1%).ConclusionThis study found no significant impact of dental students’ knowledge of the 2017 periodontal classification system on diagnostic accuracy. Challenges such as discrepancies between case complexity and clinical experience and teaching inconsistencies underscore the need for enhanced clinical simulations, case-based learning, and targeted educational training to improve diagnostic accuracy and clinical competence
Interdental oral hygiene interventions elicit varying compositional microbiome changes in naturally occurring gingivitis:Secondary data analysis from a clinical trial
No full textAim: To evaluate the effect of different oral irrigators on the sub-gingival microbiome composition in patients with naturally occurring plaque-induced gingivitis. Materials and Methods: Sub-gingival plaque was collected from adults participating in a clinical trial assessing the efficacy of oral hygiene with two different oral irrigators (Waterpik Water Flosser [Group 1] and Oral-B Water Flosser [Group 2]) versus dental flossing (Group 3) for microbiome analysis. Plaque samples were reflective of naturally occurring plaque-induced gingivitis at baseline and of gingival health at the endpoint (4 weeks). Clinical measures of gingival inflammation were collected, and the sub-gingival microbiome was analysed by 16S rRNA sequencing to identify amplicon sequence variants. Results: Oral hygiene instruction with self-performed manual toothbrushing and water-jet irrigation led to significant reductions in inflammation for all groups; both oral irrigators outperformed flossing in bleeding-on-probing reduction (p <.001). Microbiome diversity of sub-gingival plaque remained relatively stable over time, but significant changes were noted in certain taxa, consistent with increases in the relative abundance of commensals and reductions in late colonizers and periodontal pathogens in the water-jet groups. Conclusions: Reduction in gingival inflammation at 4 weeks within the water-jet groups is accompanied by slight but critical changes in microbiome composition. Although biodiversity does not substantially change within 4 weeks during the resolution of naturally induced gingivitis, significant relative increases in commensal early colonizers such as Streptococcus, Veillonella and Fusobacterium were accompanied by a shift towards a less anaerobic microbiota associated with return to health. These changes were contingent upon the type of interdental hygiene, with Group 1 exhibiting more significant alterations in microbiome composition towards a periodontal-health-compatible community.</p
Measuring surface porosity for zirconium enforced by different additive rates of nano-silica by means of image processing
No full textSynthesis and characterization study of n-Bi2O3/p-Si heterojunction dependence on thickness
No full textIndividual face-to-face feedback and the Saudi EFL learners: Evaluating enhancement of writing skills
No full text This research analyzed Saudi undergraduate students’ writing before and after individual face-to-face feedback. The intervention was individual written feedback on Saudi EFL students' paragraph writing. The participants were 31 EFL Saudi students exposed to a pre and post-test across six criteria that targeted to evaluate their writing with individual corrective feedback from the teacher. The intervention was one semester long. The study reported that individual corrective feedback plays an important role in developing students' writing skills.
Thirty-one students participated in the writing tasks. All the participants had studied English as a foreign language being enrolled in the writing course at Qassim University College of Language and Translation. The median age of the participants was 20 years and the group was homogenous in terms of years of learning English, residence type (rural/ urban), GPA scores in the past two semesters, and gender (all males). Though the initial group strength was 31, in the post tests, 8 answers were repeated, so the author deleted them from the analysis. Thus, the actual participants were 23 students. The researcher got an oral consent from the students to participate in the study.
The study clearly established that individual face-to-face corrective feedback played an important role in developing students’ paragraph writing skills. </p
