Periodontitis is one of the most prevalent bacterial diseases affecting man with up to 90% of the global population affected. Its severe form can lead to the tooth loss in 10-15% of the population worldwide. The disease is caused by a dysbiosis of the local microbiota and one organism that contributes to this alteration in the bacterial population is Prophyromonas gingivalis. This organism possesses a range of virulence factors that appear to contribute to its growth and survival at a periodontal site amongst which is its ability to invade oral epithelial cells. Such an invasion strategy provides a means of evasion of host defence mechanisms, persistence at a site and the opportunity for dissemination to other sites in the mouth. However, previous studies have demonstrated that invasion of the mammalian cells in a population by P. gingivalis is heterogenous, with some cells becoming heavily invaded while others harbour no or only a few bacteria. An understanding of this heterogeneity may throw light on the mechanisms involved and we hypothesised that the phase of the host cell cycle may explain this phenomenon. In an attempt to study the factors influencing P. gingivalis invasion and the cell response to that invasion, a standard antibiotic protection assay was employed and an oral keratinocyte cell line, H357. The results showed that P. gingivalis NCTC 11834 invasion was significantly increased with increasing time of exposure to the cells and the cell density. This may reflect an increased host cell surface area available for bacterial attachment. No effect on invasion of P. gingivalis invasion was observed by the bacterial growth phase, H357 cell passage number or whether cells were pre-incubated with P. gingivalis lipopolysaccharide. Epithelial cells did, however, respond to the presence of P. gingivalis in a number of ways. For example, the mRNA expression of endothelin-1 and urokinase receptor were upregulated with increasing P. gingivalis infection time, suggesting that these proteins could act as inflammatory mediators and possibly as useful markers of the severity of periodontal disease or in the diagnosis and treatment of periodontitis. iii Secondly, in an attempt to investigate the reason for the observed heterogeneous P. gingivalis invasion of H357 cell populations, the effect of cell cycle phase on P. gingivalis invasion was investigated. H357 cells were synchronized by serum starvation. On re-introduction of serum, characterisation of cell cycle phase distribution was performed by flow cytometry following staining with propidium idodide (PI) or by immunofluorescence using bromodeoxyuridine (BrdU), which specifically identifies cells in S-phase. The effect of cell cycle phases on P. gingivalis invasion was measured using the antibiotic protection assay, immunofluorescence and flow cytometry and these were correlated with gene and surface expression of the urokinase receptor and the α5-integrin subunit, which is thought to mediate P. gingivalis invasion. Results showed that the percentage invasion was enhanced with increasing serum re-introduction time, and positively correlated with the number of cells in S-phase. In addition, flow cytometry data showed that the highest association of fluorescent P. gingivalis was with PI positive S-phase cells. Moreover, BrdU positive S-phase cells were 3 times more likely to be invaded and contained 10 times more P. gingivalis than cells in other phases. Also, α5-integrin was more highly expressed in cells in S-phase than other phases, which could explain the mechanism underlying this enhanced invasion. Data presented here have suggested that P. gingivalis targeting of cells in S- phase could, in vivo, allow preferential invasion of the junctional epithelial cells which turns over rapidly. The data presented in this thesis suggest that P. gingivalis invasion is greatly dependent on several factors attributed to the host, the bacteria itself, and to the environment which the bacteria reside in. The invasion occurs within a population of host cells in a heterogeneous fashion, and is dependent on the cell cycle phase, specifically S-phase. This novel finding, in addition to the previously reported mechanisms of P. gingivalis invasion, increases our understanding of this virulence trait and suggests that such a strategy is a highly organised process which the bacteria can follow to ensure its survival within the host. Furthermore, knowledge of these mechanisms could provide novel approaches to treatment of periodontal diseases.
The research aims to know the relation between positive thinking and self academic motivation, trend towards teaching profession. So a sample of (344) male and female student of the morning study of education colleges from the two universities of Baghdad and al Mustansria for the academic year 2012-2013.
So three tools had been used to achieve the procedures of the research which are: the scale of positive thinking constracted by Abdal satar Ibrahim year 2010, the scale of self academicmotivation constracted by (Gottfried) and adapted by Hanan Hussan year 2010, the scale of teaching profession trend constracted by Enayat Zaki year 1974.
And by using the statistical means of person
... Show MoreThe study aims to follow modern methods in teaching rhythmic gymnastics skills by directing learners to develop their perceptions and absorb what the world deals with today and develop intelligence among learners, the researchers searched for the strengths of the learner by providing them with an opportunity to form their kinetic formation, hence the problem came by introducing a method of self-intelligence and social to guide the learner in the search for ways and solutions to overcome boredom and economy Time and effort in the educational process in learning and give them the freedom to express their ideas And their skills and here came the role of social and self-intelligence to teach the individual and collective kinetic formati
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The study aims to identify the cognitive bias and the level of emotional thinking among university students, besides, identifying the significant differences between male and female students regarding those two variables, and determine if there is a correlation between cognitive bias and emotional thinking. To this end, two scales were adopted to collect needed data: cognitive bias scale designed by (Al-any, 2015), composed of (14) items, and emotional thinking scale designed by (Abdu Allah, 2017), consisted of (27) items. These two scales were administered to (140) students composed the study sample. They were chosen from four different colleges at Al-mustansiriyah University for the academic year (2017-1018). The findings revealed that
... Show MoreThere is no doubt that leadership is a social phenomenon , and human activity does not take place , but remained in the family cohesive have a common goal Alaho instil confidence in the same of her sons to be better , and the importance of this subject Arta researchers to identify the extent to which children in this phenomenon and to identify the causes and extent of its spread in the community , has been directing an open question (Appendix 1) to a group of kindergarten teachers , to learn about the characteristics of leadership that can be enjoyed by kindergarten children . The current research aims to:
1. Detect levels of leadership qualities among kindergarten children in the light of the characteristics of leadership skills
2
Mindfulness is considered a process to draw an image of the active event and to creat new social varieties which leaves the individuals open to modernity and to be sensitive towards the context. in contrast, when individuals act with less attention, they need to be more determined concerning the varieties and events of the past . and as a result , they become unaware of the characteristics that creat the individual condition .The problem of the current study is represented in asking about the nature of the possible relationship between mindfulness and self-regulated learning within specific demographic frame of an importantsocial category represented in university students where no previous researches nor theories have agreed on the natu
... Show MoreThis study aims to identify the forgiveness level among gifted students and its relation to the self-awareness. The study sample consisted of (207) students were randomly chosen, they are integrated in secondary schools in Abha / Saudi Arabia. The correlative, analytical descriptive method was adopted. Two scales were adopted by the researcher: The forgiveness scale prepared by Rye et al (2001) which translated to Arabic by Al-Mahasneh (2017) and the self-awareness scale which prepared by Al-Ghezwani (2017). The study results indicated the following: the forgiveness level among the talented students was high, the self-awareness level among talented students was high, and there is a positive statistically significant relationship
... Show MoreThe study aims to identify the extent of the availability of administrative empowerment and the implementation of remote supervision in relation to two variables with respect to the employees of the Saudi Ministry of Education. The study included (456) male and female supervisors. The questionnaire has been administrated to collected data related to the research aims. The results indicated that both the extent of the availability of administrative empowerment and the implementation of remote supervision is of an average degree. There is a significant correlation relationship (p<0.05) between administrative empowerment and remote supervision of the educational supervisors of the Saudi Ministry of Education. The research recommends that
... Show MorePVC membrane sensor for the selective determination of Mefenamic acid (MFA) was constructed. The sensor is based on ion association of MFA with Dodecaphospho molybdic acid (PMA) and Dodeca–Tungstophosphoric acid(PTA) as ion pairs. Nitro benzene (NB) and di-butyl phthalate (DBPH) were used as plasticizing agents in PVC matrix membranes. The specification of sensor based on PMA showed a linear response of a concentration range 1.0 × 10–2 –1.0 × 10–5 M, Nernstian slopes of 17.1-18.86 mV/ decade, detection limit of 7 × 10-5 -9.5 × 10 -7M, pH range 3 – 8 , with correlation coefficients lying between 0.9992 and 0.9976, respectively. By using the ionphore based on PTA gives a concentration range of 1.0 × 10–4 –1.0 × 10–5 M,
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This study was conducted for the purpose of exploring the relationship between positive thinking and academic achievement in art history. And it relates to the student’s personality, intelligence, abilities and economic and social level. The sample of the study consisted of (40) male and female students from the first stage students - Department of Art Education in the Faculty of Fine Arts / Morning Study, A positive thinking questionnaire was applied to them, and the study found that there is no positive relationship between positive thinking and academic achievement in art history.
Research summary: The current research aims to identify:
1-Mental wandering among university students 2- Attentioncontrol among universitey students. 3- The relationship between mental wandering and attention control among university students. 4- The difference in the relationship among university students: accoerding to a- the gender variable (males - females) b- according to the specialization variable) Scientific-human), and the results of the current research reached the following: 1- University students have mental wandering associated with the task, and mental wandering that is not related to the task. 2- University students have attentive control 3- There is no relationship between mental wandering associated with task and
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