965 resultados para CROSS-COUPLING REACTION


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The majority of Escherichia coli strains isolated from urinary tract infections have the potential to express multiple fimbriae. Two of the most common fimbrial adhesins are type 1 fimbriae and pyelonephritis-associated pili (Pap). Previous research has shown that induced, plasmid-based expression of a Pap regulator, papB, and its close homologues can prevent inversion of the fim switch controlling the expression of type 1 fimbriae. The aim of the present study was to determine if this cross-regulation occurs when PapB is expressed from its native promoter in the chromosome of E. coli K-12 and clinical isolates. The regulation was examined in three ways: (1) mutated alleles of the pap regulatory region, including papB and papI, that maintain the pap promoter in either the off or the on phase were exchanged into the chromosome of both E. coli K-12 and the clinical isolate E. coli CFT073, and the effect on type 1 fimbrial expression was measured; (2) type 1 fimbrial expression was determined using a novel fimS : : gfp+ reporter system in mutants of the clinical isolate E. coli 536 in which combinations of complete fimbrial clusters had been deleted; (3) type 1 fimbrial expression was determined in a range of clinical isolates and compared with both the number of P clusters and their expression. All three approaches demonstrated that P expression represses type 1 fimbrial expression. Using a number of novel genetic approaches, this work extends the initial finding that PapB inhibits FimB recombination to the impact of this regulation in clinical isolates.

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Polymorphisms of glutathione transferases (GST) are important genetic determinants of susceptibility to environmental carcinogens (Rebbeck, 1997). The GSTs are a multigene family of dimeric enzymes involved in detoxification, and, in a few cases, the bioactivation of a variety of xenobiotics (Hayes et al., 1995). The cytosolic GST enzyme family consists of four major classes of enzymes, referred to as alpha, mu, pi and theta. Several members of this family (for example, GSTM1, GSTT1 and GSTP1) are polymorphic in human populations (Wormhoudt et al., 1999). Molecular epidemiology studies have examined the role of GST polymorphisms as susceptibility factors for environmentally and/or occupationally induced cancers (Wormhoudt et al., 1999). In particular, case-control studies showed a relationship between the GSTM1 null genotype and the development of cancer in association with smoking habits, which has been shown for cancers of the respiratory and gastrointestinal tracts as well as other cancer types (Miller et al., 1997). Only a few molecular epidemiological studies addressed the role of GSTT1 and GSTP1 polymorphisms in cancer susceptibility. Since GSTP1 is a key player in biotransformation/bioactivation of benzo(a)pyrene, GSTP1 may be even more important than GSTM1 in the prevention of tobacco-induced cancers (Harries et al., 1997; Harris et al., 1998). To date, this relationship has not been sufficiently addressed in humans. Comprehensive molecular epidemiological studies may add to the current knowledge of the role of GST polymorphisms in cancer susceptibility and extent of the knowledge gained from approaches that used phenotyping, such as GSTM1 activity as it relates to trans-stilbene oxide, or polymerase chain reaction (PCR) based genotyping of polymorphic isoenzymes (Bell et al., 1993; Pemble et al., 1994; Harries et al., 1997).

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Reactive oxygen species are generated during ischaemia-reperfusion of tissue. Oxidation of thymidine by hydroxyl radicals (HO) leads to the formation of 5,6-dihydroxy-5,6-dihydrothymidine (thymidine glycol). Thymidine glycol is excreted in urine and can be used as biomarker of oxidative DNA damage. Time dependent changes in urinary excretion rates of thymidine glycol were determined in six patients after kidney transplantation and in six healthy controls. A new analytical method was developed involving affinity chromatography and subsequent reverse-phase high-performance liquid chromatography (RP-HPLC) with a post-column chemical reaction detector and endpoint fluorescence detection. The detection limit of this fluorimetric assay was 1.6 ng thymidine glycol per ml urine, which corresponds to about half of the physiological excretion level in healthy control persons. After kidney transplantation the urinary excretion rate of thymidine glycol increased gradually reaching a maximum around 48 h. The excretion rate remained elevated until the end of the observation period of 10 days. Severe proteinuria with an excretion rate of up to 7.2 g of total protein per mmol creatinine was also observed immediately after transplantation and declined within the first 24 h of allograft function (0.35 + 0.26 g/mmol creatinine). The protein excretion pattern, based on separation of urinary proteins on sodium dodecyl sulphate-polyacrylamide gel electrophorosis (SDS-PAGE), as well as excretion of individual biomarker proteins, indicated nonselective glomerular and tubular damage. The increased excretion of thymidine glycol after kidney transplantation may be explained by ischaemia-reperfusion induced oxidative DNA damage of the transplanted kidney.

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There are many ways to create a cross-media project, but there are approaches which facilitate a quality implementation. The crucial starting point with any creative project is a great story or game. However, because the cross-media artform is still emerging and many practitioners are new to the area, just how to produce a quality cross-media project is not well known. Based on my work on both small- and large-scale projects, I outline ten approaches that will aid in facilitating a quality cross-media project.

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Background: Nausea can be a debilitating symptom for patients with a life-limiting illness. While addressing reversible components, nonpharmacological strategies and antiemetics are the main therapeutic option. The choice of medication, dose, and route of administration remain highly variable. Objective: The aim of this study was to codify the current clinical approaches and quantify any variation found nationally. Methods: A cross-sectional study utilizing a survey of palliative medicine clinicians examined prescribing preferences for nausea using a clinical vignette. Respondent characteristics, the use of nonpharmacological interventions, first- and second-line antiemetic choices, commencing and maximal dose, and time to review were collected. Results: Responding clinicians were predominantly working in palliative medicine across a range of settings with a 49% response rate (105/213). The main nonpharmacological recommendation was “small, frequent snacks.” Metoclopramide was the predominant first-line agent (69%), followed by haloperidol (26%), while second-line haloperidol was the predominant agent (47%), with wide variation in other nominated agents. Respondents favoring metoclopramide as first-line tended to use haloperidol second-line (65%), but not vice versa. Maximal doses for an individual antiemetic varied up to tenfold. Conclusion: For nausea, a commonly encountered symptom in palliative care, clinicians' favored metoclopramide and haloperidol; however, after these choices, there was large variation in antiemetic selection. While most clinicians recommended modifying meal size and frequency, use of other nonpharmacological therapies was limited.

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The purpose of this cross-sectional study was to identify the prevalence of incontinence and incontinence-associated dermatitis (IAD) in Australian acute care patients and to describe the products worn to manage incontinence, and those provided at the bedside for perineal skin care. Data on 376 inpatients were collected over 2 days at a major Australian teaching hospital. The mean age of the sample group was 62 years and 52% of the patients were male. The prevalence rate of incontinence was 24% (91/376). Urinary incontinence was significantly more prevalent in females (10%) than males (6%) (χ2  = 4·458, df = 1, P = 0·035). IAD occurred in 10% (38/376) of the sample group, with 42% (38/91) of incontinent patients having IAD. Semi-formed and liquid stool were associated with IAD (χ2  = 5·520, df = 1, P = 0·027). Clinical indication of fungal infection was present in 32% (12/38) of patients with IAD. Absorbent disposable briefs were the most common incontinence aids used (80%, 70/91), with soap/water and disposable washcloths being the clean-up products most commonly available (60%, 55/91) at the bedside. Further data are needed to validate this high prevalence. Studies that address prevention of IAD and the effectiveness of management strategies are also needed.

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Purpose This study aims to test service providers’ ability to recognise non-verbal emotions in complaining customers of same and different cultures. Design/methodology/approach In a laboratory study, using a between-subjects experimental design (n = 153), we tested the accuracy of service providers’ perceptions of the emotional expressions of anger, fear, shame and happiness of customers from varying cultural backgrounds. After viewing video vignettes of customers complaining (with the audio removed), participants (in the role of service providers) assessed the emotional state of the customers portrayed in the video. Findings Service providers in culturally mismatched dyads were prone to misreading anger, happiness and shame expressed by dissatisfied customers. Happiness was misread in the displayed emotions of both dyads. Anger was recognisable in the Anglo customers but not Confucian Asian, while Anglo service providers misread both shame and happiness in Confucian Asian customers. Research limitations/implications The study was conducted in the laboratory and was based solely on participant’s perceptions of actors’ non-verbal facial expressions in a single encounter. Practical implications Given the level of ethnic differences in developed nations, a culturally sensitive workplace is needed to foster effective functioning of service employee teams. Ability to understand cultural display rules and to recognise and interpret emotions is an important skill for people working in direct contact with customers. Originality/value This research addresses the lack of empirical evidence for the recognition of customer emotions by service providers and the impact of cross-cultural differences.

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This work makes the case that cross cultural issues are central to the purposes of legal education, and no longer can such issues be seen as an add-on to the traditional curriculum. The authors argue instead for a critical multiculturalism that is attuned to questions of gender, class, sexuality and social justice, and that must inform the whole law school curriculum.

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Cross-talk between microtubule networks and sites of cell-matrix and cell-cell adhesion has profound impact on these structures and is essential for proper cell organization, polarization and motility. Components of adhesion sites can interact directly with microtubules or with proteins that specifically associate with microtubule plus ends and minus ends and in this way capture, stabilize or destabilize microtubules. In their turn, microtubules can serve as routes for delivery of structural and regulatory factors that control adhesion site turnover. In addition, the microtubule lattice or growing microtubule plus ends can serve as diffusional sinks that accumulate and scaffold regulatory molecules, thereby affecting their activity in the vicinity of adhesions. Combination of these mechanisms underlies the functional co-operation between microtubules and adhesion sites and defines their dynamic behavior.

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Nursing was one of the last health professions to be established in the higher education sector. A lingering challence is the integration of bioscience into nursing curriculum. Research suggests that students perceive bioscience teaching to be difficult thereby contributing to heightened anxiety. It has been proposed that high content volume, lack of secondary school science, and predominance of science lectureres without clinical practice experience, may lead to a bioscience disconnet with curricula. To ascertain the extent of this problem, we undertook a cross-sectional designed study of commencing, second and third year undergraduate nursing students (n=566). They were surveyed about perceptions, knowledge and approaches to bioscience learning. Preliminary analysis revealed similar findings between the three different cohorts. Generally, sudents perceived bioscience subjects to be difficult, more challenging and requiring more study hours than clinical nursing subjects. Interestingly, the perception of difficulty and associated anxieties were found in both commencing and existing students. Moreover, students with secondary school biology combined with another science subject perceived bioscience teaching more favourably compared to those who had studied one secondary school science subject. University coursework needs to embed strategies to minimise anxieties about learning bioscience by using innovative deliveries and scaffolded assessments that target the learner's needs.

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This thesis contains a mathematical investigation of the existence of travelling wave solutions to singularly perturbed advection-reaction-diffusion models of biological processes. An enhanced mathematical understanding of these solutions and models is gained via the identification of canards (special solutions of fast/slow dynamical systems) and their role in the existence of the most biologically relevant, shock-like solutions. The analysis focuses on two existing models. A new proof of existence of a whole family of travelling waves is provided for a model describing malignant tumour invasion, while new solutions are identified for a model describing wound healing angiogenesis.

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Objective While home visiting in the early postpartum period appears to have increased, there are limited data defining which women receive a visit and none that include Queensland. We aimed to investigate patterns of postpartum home visiting in the public and private sectors in Queensland. Methods Data were collected via a retrospective cross-sectional survey of women birthing in Queensland between 1st February and 31st May 2010 at 4 months postpartum (N = 6948). Logistic regression was used to assess associations between receiving a home visit and sociodemographic, clinical and hospital variables. Analyses were stratified by public and private birthing sector because of significant differences between sectors. Results Public sector women were more likely to receive a visit from a nurse or midwife (from the hospital or child health sector) within 10 days of hospital discharge (67.2%) than private sector women (7.2%). Length of hospital stay was associated with home visiting in both sectors. Some vulnerable sub-populations in both sectors were more likely to be visited, while others were not. Conclusions Home visiting in Queensland varies markedly between the public and private sector and is less common in some vulnerable populations. Further consideration to improving the equity of community postpartum care in Queensland is needed.