Clostridium difficile infection (CDI) is a major healthcare-associated disease with high recurrence rates. Host colonization is critical for the infectious process, both in first episodes and in recurrent disease, with biofilm formation playing a key role. The ability of C. difficile to form a biofilm on abiotic surfaces is established, but has not yet been confirmed in the intestinal tract. Here, four different isolates of C. difficile, which are in vitro biofilm producers, were studied for their ability to colonize germ-free mice. The level of colonization achieved was similar for all isolates in the different parts of the murine gastrointestinal tract, but pathogen burden was higher in the cecum and colon. Confocal laser scanning microscopy revealed that C. difficile bacteria were distributed heterogeneously over the intestinal tissue, without contact with epithelial cells. The R20291 strain, which belongs to the Ribotype 027 lineage, displayed a unique behavior compared to the other strains by forming numerous aggregates. By immunochemistry analyses, we showed that bacteria were localized inside and outside the mucus layer, irrespective of the strains tested. Most bacteria were entrapped in 3-D structures overlaying the mucus layer. For the R20291 strain, the cell-wall associated polysaccharide PS-II was detected in large amounts in the 3-D structure. As this component has been detected in the extrapolymeric matrix of in vitro C. difficile biofilms, our data suggest strongly that at least the R20291 strain is organized in the mono-associated mouse model in glycan-rich biofilm architecture, which sustainably maintains bacteria outside the mucus layer.

No description available.

Phthalates are industrial plasticizers with a wide range of applications. Di-(2-ethylhexyl) phthalate (DEHP) is one of the most highly produced and frequently studied phthalates. Its metabolite, mono-(2-ethylhexyl) phthalate (MEHP) is known as a testicular toxicant. The objective of this study was to examine expression of the genes of interest in testicular germ cells exposed to MEHP in a dose- and time-dependent manner at concentrations of 1µM, 10µM, and 100µM at 24, 48, 72 and 96hr time points. The genes consisted of Testisin, GSPT1, and MGMT genes which are a tumor suppressors, phase II xenobiotic metabolizing enzyme and DNA repair gene respectively. These genes were analyzed by Quantitative Real Time PCR (RT-PCR). The results revealed an overall down-regulation for each gene as the concentration and/or time increased. Testisin was the focus of the gene expression analysis. Testisin is epigenetically silenced in testicular germ cell tumors (TGCT) by DNA methylation at the 5’CpG island of the gene. To investigate if MEHP is capable of DNA hypermethylation, a co-exposure with 5-azacytidine (demethylating agent) was conducted. Compared with the 5-azacytidine treatment alone, there was a significant down-regulation of the Testisin gene in the co-exposure. This suggests that MEHP may down-regulate Testisin gene expression by DNA methylation. These findings provide evidence that MEHP can alter the expression of Testisin, GSTP1 and MGMT, genes that are associated in the risk of developing testicular germ cell tumors. In addition, results indicated that MEHP may cause DNA methylation leading to the down-regulation/silencing of genes such as Testisin.

Researchers use interviews as one of the means of collecting the information that is surrounding people. Interviewing is an important instrument of collecting data during a research. Although the collection of particular data is not guaranteed, interviews render an opportunity for collection of that data. Reasons for successful collection and/ or failure to collect the targeted data are various. Cultural formation of the interview situation might be one of those various reasons. This study focused on selected cultural dimensions, namely race, gender and language as possible causative dimensions influencing the generation of data in terms of volume, expression, range, content and content formulation. Data collected during culturally formulated interviews were presented. The influence that the three dimensions might have had on the generation of data was emphasized. A Response Process Model was utilized in this study to interpret the responding process that an individual might go through before yielding a response to the posed question. Coupled with the demands of meeting the question’s objective, an individual might be bombarded by extraneous and internal cues that might be exacerbated by the cross-cultural formation of the interview situation and therefore imposing extra demands on the individual and ultimately affecting the response given. The response processes were indicated in this study that at times were altered to possibly suit the cross-cultural interview situation. / Dissertation (MEd (Educational Psychology))--University of Pretoria, 2006. / Educational Psychology / unrestricted

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23083号 / 医博第4710号 / 新制||医||1049(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 中島 貴子, 教授 近藤 玄, 教授 小杉 眞司 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

A series of Fischer mono- and biscarbene complexes of the type [MLn{C=(XR)R'}] was synthesized and characterized. The redox behavior of the complexes was studied by different techniques, including cyclic voltammetry, spectroelectrochemistry, ESR and computational methods. Different transition metals (M) and carbene substituents (XR, R') were employed to compare both the effect of the central metal atom as well as the carbene substituent. Thienyl, furyl and ferrocenyl chromium(0) mono- and biscarbene complexes with ethoxy and amino substituents were electrochemically studied in CH2Cl2. Results were mutually consistent with computational data showing that the carbene double bond of all complexes is reduced pseudo reversibly to an anion radical, -Cr-C•. The Cr centers are oxidized in two successive one electron transfer steps to Cr(II) via the Cr(I) intermediate. For all ferrocenyl carbene complexes the Fe(II) is oxidized after the first oxidation of Cr. It was found that with respect to the aryl substituents the donating effect decreases from Fc>Fu>Th. Stabilization from the XR substituent, where XR = NHR, also resulted in lower redox potentials compared to their OEt analogues. The inclusion of ferrocene in the carbene substituent was done, as its redox activity and increased donating effect are well known. Mono- and biscarbene complexes with ethoxy and amino substituents of both chromium and tungsten were electrochemically studied. Again experimental data were supported by computational studies. Similar to the ethoxy chromium complexes, reduction of the W=C fragment to -W-C• was observed. However oxidation of the Fc group occurred first before the electrochemically irreversible oxidation process for W(0) involving a three electron-mediated process as seen in chronocoulometric analyses. The tungsten oxidation was restricted to a W0/II, consistent with computational studies, by the use of the electrolyte [NnBu4][B(C6F5)4]. The short-lived W(II) species were calculated to be stabilized by agostic CH···W interactions, similar to the chromium analogues. To extend linkers between the metal-carbene termini and investigate metal-metal interaction, biferrocenyl and 2,5-thienylbiferrocenyl tungsten(0) mono-and biscarbene complexes were synthesized and studied by spectroelectrochemistry. A metal-metal charge transfer transition between the tungsten carbonyl increment and the biferrocenyl / 2,5-thienylbiferrocenyl unit was confirmed by infrared spectroelectrochemical studies. The electronic interaction in the corresponding cationic species can be described as weakly coupled class II systems according to Robin and Day. The cymantrenyl moiety, Mn(η5-C5H4)(CO)3, provides an interesting alternative to ferrocene as an organometallic molecular tag, however the instability of the radical cation impairs its use. Improved stability of the cation, monitored by electrochemical measurements, was accomplished by substituting a carbonyl with a ferrocenyl Fischer carbene ligand resulting in Mn(I) oxidation occuring at lower potentials than ferrocenyl oxidation. These uncommon Fischer carbene complexes is the first organometallic multi-tags reported. The mono cationic species, [CpMn(CO)2{=C(OEt)Fc}][PF6], could be isolated and characterized with ESR analysis. Finally, transmetallation from the tungsten(0) Fischer carbene complexes yielded examples of rare acyclic alkoxy- and aminocarbene complexes of gold(I). Single x-ray structures for all complexes could be obtained including the novel ferrocenophane dinuclear biscarbene Au(I) complex. All structures display unsupported aurophilic interactions, while the bridging biscarbene shows a semi-supported Au-Au interaction. In the case of the furanyl/thienyl methoxy monocarbene complexes, extended Au-Au interactions result in oligomeric structures. Although this study is of a fundamental nature, it is imperative for the understanding and design of gold compounds with specific applications. / Thesis (PhD)--University of Pretoria, 2013. / gm2014 / Chemistry / unrestricted

A large portion of the world’s population is multilingual. This trend is reflected in the population with communication disorders, and therefore in people with complex communication needs (CCN). People with CCN may need alternative and augmentative communication (AAC) systems to facilitate their participation in daily life. These systems are often related to the language of the person’s community. Yet, if this person lives in a multilingual community, little current research is available to guide the design of AAC systems that give access to expression in more than one language. This pilot study aimed to determine the ability of typically developing Afrikaans-English bilingual children, between the ages of 4;6 (years;months) and 6;11, to label Picture Communication Symbols (PCS) in both these languages when taught with mono medium (English) versus dual medium (Afrikaans and English) teaching. Four participants, who spoke Afrikaans and English, were included in the study. A withinsubjects crossover design was used. Each participant was taught two sets of symbols, one using mono medium and one dual medium teaching. Treatments were counterbalanced for order and set. Results tentatively showed that the teaching method was successful, with participants being able to label most symbols in English when taught in either mono (English) or dual medium. Participants were also able to label symbols in Afrikaans when taught the symbols by dual medium teaching. Some participants were spontaneously able to translate symbols taught by mono medium teaching (English) to Afrikaans. This pilot study tentatively suggests that this ability is dependent on the child’s receptive vocabulary ability in both languages, as well as their ability to express the concepts depicted by the symbols in both L1 and L2. Future research is needed with studies that include a larger sample size, to be able to draw more robust conclusions. / Mini Dissertation (M(AAC))--University of Pretoria, 2017. / National Research Foundation (NRF) / Centre for Augmentative and Alternative Communication (CAAC) / M(AAC) / Unrestricted

Mono is an open-source implementation of the software development platform .NET. An important application area is the realization of web services. Following some simple examples of web services and appropriate clients a more sophisticated example "crane control" is presented. / Mono ist eine Open-Source-Implementierung der Software-Entwicklungsplattform .NET. Ein wesentliches Anwendungsgebiet ist die Realisierung von Web-Services. Nach einfachen Beispielen für Web-Services und dazugehörigen Klienten wird ein anspruchsvolleres Beispiel "Kranfernsteuerung" vorgestellt.

After the dismantling of apartheid in South Africa, democratic transformation included desegregating mono-ethnic environments, such as schools and higher education institutions, through the integration of learners and students from diverse multilingual and multicultural backgrounds. A further ideal encouraged mother-tongue education. Yet, a growing preference for English as the medium of instruction ensued, especially in multilingual urban areas. This study investigated the degree of ethnocentrism that student teachers studying at a mono-ethnic private higher education institution had and what their attitudes and beliefs about language-in-education issues were since such outlooks could potentially affect their classroom practices. Ethnocentrism, the tendency of an individual to identify strongly with their own ethnicity and to reject others’, draws on the premises of the social identity theory owing to the focus on in-group-out-group distinctions, racism and stereotyping. Using an online questionnaire to generate primarily quantitative data, this embedded mixed-methods study investigated 1 164 student teachers’ reasons for choosing to study at a mono-ethnic higher education institution. Their degree of ethnocentrism as well as their attitudes and beliefs about languages used for social and educational purposes were measured by the standardised Generalised Ethnocentrism and Language Attitudes of Teachers Scale. Key findings from the qualitative data indicated that student teachers chose to study at a particular institution because of a shared mono-ethnic social identity, which strongly relates to a common language (Afrikaans), culture (Afrikaner), religion (Christianity) and possible race (Caucasian). The quantitative data showed a statistically significant relationship between the student teachers’ degree of ethnocentrism and their attitudes and beliefs about language-in-education issues. Overall, in line with the social identity theory, findings pointed to the formation of social identities based on shared ethnic characteristics, such as language, culture, religion and race. The study provides a more comprehensive understanding of how ethnocentrism, social identities and particular perspectives of language-in-education issues exist on a continuum. Unchecked, such attitudes and beliefs may have far-reaching consequences for multilingual classroom practices, especially where English as the medium of instruction is the mother tongue of neither the learners nor the teacher. / Afrikaans: In Suid-Afrika het demokratiese transformasie die desegregasie van mono-etniese omgewings, soos skole en hoëronderwysinstellings, ingesluit. Dit het onder andere meegebring dat leerders en studente uit verskillende taal- en kultuuragtergronde saam in die leeromgewing verkeer. Moedertaalonderrig is ook veral tydens aanvangsonderrig aangemoedig. Tog het daar toenemend ʼn voorkeur vir Engels as onderrigmedium ontstaan, veral in meertalige stedelike gebiede. Hierdie studie stel ondersoek in na die mate van etnosentrisme wat studenteonderwysers openbaar terwyl hulle by ʼn mono-etniese private hoëronderwysinstelling ingeskryf is. Hulle houdings en oortuigings met betrekking tot taalonderrigkwessies is ook vasgestel. Etnosentrisme, die neiging van individue om sterk met hul eie etnisiteit te identifiseer en dié van ander te verwerp, is geskoei op die sosiale identiteitsteorie met ‘n fokus op binnegroep-buitegroeponderskeid, rassisme en stereotipering. ʼn Aanlyn vraelys is gebruik om hoofsaaklik kwantitatiewe data te genereer wat verskaf is deur 1 164 studenteonderwysers. Sowel hulle graad van etnosentrisme as hul houdings en oortuigings oor tale wat vir sosiale en opvoedkundige doeleindes gebruik word, is gemeet aan die hand van die gestandardiseerde Generalised Ethnocentrism en Language Attitudes of Teachers skaal. Sleutelbevindinge uit die kwalitatiewe data dui aan dat studenteonderwysers verkies om aan ʼn spesifieke instelling te studeer waar ʼn gedeelde mono-etniese sosiale identiteit, wat sterk verband hou met ʼn gemeenskaplike taal (Afrikaans), kultuur (Afrikaner), godsdiens (Christendom) en moontlik ras (blank) heers. Die kwantitatiewe data het ʼn statisties beduidende verband getoon tussen die studenteonderwyseres se graad van etnosentrisme en hul houdings en oortuigings rakende taal-in-onderwyskwessies. Die bevindinge dui ook op die ontwikkeling van sosiale identiteite gebaseer op samehorigheidseienskappe soos taal, kultuur, godsdiens en ras. Die studie bied ʼn meer omvattende begrip van hoe etnosentrisme, sosiale identiteite en bepaalde perspektiewe van taal-in-onderwys-kwessies op ʼn kontinuum bestaan. As voornemende onderwysers nie bewus gemaak word van hulle sterk etnosentriese oortuigings nie, kan dit verreikende gevolge vir meertalige praktyke in die klaskamer inhou, veral waar Engels as onderrigmedium gebruik word, maar nie die moedertaal van die leerders of die onderwyser is nie. / Thesis (PhD)--University of Pretoria, 2020. / Humanities Education / PhD / Unrestricted

Even though there is a multitude of observational evidence from cosmology and astrophysics, the standard model does not include a suitable dark matter candidate and therefore physics beyond the standard model is necessary. There are hypotheses of what the particle candidate could be coming from theories such as supersymmetry or extra dimensions. The processes producing these particles are understood very well from the theoretical perspective. The problem is that these processes have not been observed in any detectors. Therefore the nature of the dark matter remains unknown. However, it is clear that the dark matter-particle interacts with ordinary matter through gravity and in general, candidates may also interact through the weak force. These candidates are called Weakly Interacting Massive Particles. Therefore, by studying weak processes (weak in the sense that the processes are interactions mediated by a force weaker than the Electro-Magnetic and Quantum-Chromo dynamical-forces, not necessarily the weak force of the standard model) in the large hadron collider it may be possible to pose constraints on the dark matter signatures. One possible process which specifically involves the standard model electroweak interaction, which will be the model for the project, is the emission of scalar dark matter particles from the Z boson,which would result in a final state characterized by a Z boson and missing transverse energy. Simulations of the model and calculations of the cross section are done for different masses, ranging from 20−680 GeV, of the scalar dark matter particle and then compared to a standard model background process. Investigations are made whether or not it would be possible to detect darkmatter signals in the background. With the assumptions made, the results indicate that a signal from dark matter with a mass of around 40−150 GeV could not be rejected up to 5σ.