100 research outputs found
Characterizations of algebras of rapidly decreasing generalized functions
The well-known characterizations of Schwartz space of rapidly
decreasing functions is extended to the algebra of
rapidly decreasing generalized functions and to the algebra of regular rapidly decreasing generalized functions
Improving public service delivery through marketing
Thesis (MPA)--Stellenbosch University, 2000.ENGLISH ABSTRACT: The hypothesis explored in this thesis is that the application of marketing in the
public sector will improve public service delivery.
Three different areas of academic enquiry are examined in an effort to prove a
beneficial relationship between marketing and public service delivery. These
three areas are Public Management, Marketing, and Services Management.
Certain challenges for improving service delivery are identified in each of these
disciplines, and the current status of public sector marketing is described.
The study is applied to the Cape Metropolitan Area, and specifically the Cape
Metropolitan Council. This does however not rule out the application of the
findings of the study to other areas.
Additional to the normal literature study, research for the thesis involves personal
interviews with public managers, and on-line questionnaires on the Internet and
the Intranet of the Cape Metropolitan Council.
Combining the results of the literature study and the physical research with the
argument constructed in the thesis, it is found that many of the challenges
identified in the three disciplines address each other, and that marketing can
definitely prove useful as a tool with which to improve public service delivery.
A model for marketing-oriented public service delivery is proposed.AFRIKAANSE OPSOMMING: Die hipotese wat in hierdie tesis aangespreek word is dat die toepassing van
bemarking in die openbare sektor sal meebring dat openbare dienslewering sal
verbeter.
Drie studievelde word verken om te bepaal of enige afleidings gemaak kan word
oor die positiewe invloed van bemarking op dienslewering. Die drie studievelde
is Openbare Bestuur, Bemarking, en Dienstebestuur.
Sekere uitdagings om dienslewering te verbeter word in elke veld geïdentifiseer,
en die huidige status van openbare bemarking word verduidelik.
Die studie word toegepas op die Kaapse Metropolitaanse Gebied, met spesifieke
verwysing na die Kaapse Metropolitaanse Raad. Die toepassing van die
bevindings van die studie op ander gebiede word egter nie hierdeur uitgesluit nie.
Bykomend tot die literatuurstudie word persoonlike onderhoude met openbare
sektor bestuurders en vraelyste op die Internet en die Intranet van die Kaapse
Metropolitaanse Raad as deel van die navorsingspoging gebruik.
Deur die resultate van die navorsing en die literatuurstudie te vergelyk met die
argument in die tesis, word dit bevind dat die uitdagings uit die verskillende velde
mekaar aanvul. Dit word bevind dat bemarking aansienlik sal kan bydra tot die
verbetering van dienslewering in die openbare sektor.
'n Model vir bemarkings-georiënteerde openbare dienslewering word voorgestel
Asymptotic Almost Automorphy of Functions and Distributions
This work aims to introduce and to study asymptotic almost automorphy in the context of Sobolev–Schwartz distributions. Applications to linear ordinary differential equation and neutral difference differential equations are also given
Mechanisms of HTLV-1 persistence and transformation
Adult T-cell leukaemia (ATL) is caused by the human T-cell lymphotropic virus type 1 (HTLV-1). HTLV-1 has elaborated strategies to persist and replicate in the presence of a strong immune response. In this review, we summarise these mechanisms and their contribution to T-cell transformation and ATL development
Simvastatin and purine analogs have a synergic effect on apoptosis of chronic lymphocytic leukemia cells
Despite many therapeutic regimens introduced recently, chronic lymphocytic leukemia (CLL) is still an incurable disorder. Thus, there is an urgent need to discover novel, less toxic and more effective drugs for CLL patients. In this study, we attempted to assess simvastatin, widely used as a cholesterol-lowering drug, both as a single agent and in combination with purine analogs—fludarabine and cladribine—in terms of its effect on apoptosis and DNA damage of CLL cells. The experiments were done in ex vivo short-term cell cultures of blood and bone marrow cells from newly diagnosed untreated patients. We analyzed expression of active caspase-3 and the BCL-2/BAX ratio as markers of apoptosis and the expression of phosphorylated histone H2AX (named γH2AX) and activated ATM kinase (ataxia telangiectasia mutated kinase), reporters of DNA damage. Results of our study revealed that simvastatin induced apoptosis of CLL cells concurrently with lowering of BCL-2/BAX ratio, and its pro-apoptotic effect is tumor-specific, not affecting normal lymphocytes. We observed that combinations of simvastatin+fludarabine and simvastatin+cladribine had a synergic effect in inducing apoptosis. Interestingly, the rate of apoptosis caused by simvastatin alone and in combination was independent of markers of disease progression like ZAP-70 and CD38 expression or clinical stage according to Rai classification. We have also seen an increase in γH2AX expression in parallel with activation of ATM in most of the analyzed samples. The results suggest that simvastatin can be used in the treatment of CLL patients as a single agent as well as in combination with purine analogs, being equally effective both in high-risk and good-prognosis patients. One of the mechanisms of simvastatin action is inducing DNA damage that ultimately leads to apoptosis
Resveratrol increases rate of apoptosis caused by purine analogues in malignant lymphocytes of chronic lymphocytic leukemia
In this study, we attempted to assess the interactions of resveratrol, a natural compound present in various plant species, with the purine analogues fludarabine and cladribine in terms of their effects on DNA damage and apoptosis in chronic lymphocytic leukemia (CLL) cells. The experiments were performed ex vivo using short-term cell cultures of blood and bone marrow cells from newly diagnosed untreated patients. We analyzed the expression of active caspase-3 and the BCL-2/BAX ratio as markers of apoptosis and the expression of phosphorylated histone H2AX (γH2AX) and activated ATM kinase, which are reporters of DNA damage. The results of our study revealed that resveratrol induced apoptosis in CLL cells in a tumor-specific manner but did not affect non-leukemic cells, and apoptosis was associated with a decreased BCL2/BAX ratio. Here, we report for the first time that both resveratrol + fludarabine and resveratrol + cladribine caused a higher rate of apoptosis in comparison to the rate caused by a single drug. The percentage of apoptotic cells induced by resveratrol alone was higher in the group of patients with better prognostic markers than in those with worse prognostic markers. However, the rates of apoptosis caused by resveratrol combined with purine analogues were independent of ZAP-70 and CD38 expression and the clinical state of the disease; they were only dependent on the presence of high-risk cytogenetic abnormalities. We also observed an increase in γH2AX expression together with a rise in activated ATM in most of the analyzed samples. The obtained results indicate that resveratrol might warrant further study as a new therapeutic option for CLL patients. This naturally occurring substance may be used as a single agent, especially in older persons for whom there are some limitations for the use of aggressive treatment. On the other hand, a lower purine analogue dose could potentially be used in combination with resveratrol because of their combined effect. One of the mechanisms of action of resveratrol is the induction of DNA damage, which ultimately leads to apoptosis
Synergistic Interactions between HDAC and Sirtuin Inhibitors in Human Leukemia Cells
Aberrant histone deacetylase (HDAC) activity is frequent in human leukemias. However, while classical, NAD+-independent HDACs are an established therapeutic target, the relevance of NAD+-dependent HDACs (sirtuins) in leukemia treatment remains unclear. Here, we assessed the antileukemic activity of sirtuin inhibitors and of the NAD+-lowering drug FK866, alone and in combination with traditional HDAC inhibitors. Primary leukemia cells, leukemia cell lines, healthy leukocytes and hematopoietic progenitors were treated with sirtuin inhibitors (sirtinol, cambinol, EX527) and with FK866, with or without addition of the HDAC inhibitors valproic acid, sodium butyrate, and vorinostat. Cell death was quantified by propidium iodide cell staining and subsequent flow-cytometry. Apoptosis induction was monitored by cell staining with FITC-Annexin-V/propidium iodide or with TMRE followed by flow-cytometric analysis, and by measuring caspase3/7 activity. Intracellular Bax was detected by flow-cytometry and western blotting. Cellular NAD+ levels were measured by enzymatic cycling assays. Bax was overexpressed by retroviral transduction. Bax and SIRT1 were silenced by RNA-interference. Sirtuin inhibitors and FK866 synergistically enhanced HDAC inhibitor activity in leukemia cells, but not in healthy leukocytes and hematopoietic progenitors. In leukemia cells, HDAC inhibitors were found to induce upregulation of Bax, a pro-apoptotic Bcl2 family-member whose translocation to mitochondria is normally prevented by SIRT1. As a result, leukemia cells become sensitized to sirtuin inhibitor-induced apoptosis. In conclusion, NAD+-independent HDACs and sirtuins cooperate in leukemia cells to avoid apoptosis. Combining sirtuin with HDAC inhibitors results in synergistic antileukemic activity that could be therapeutically exploited
Comparative genomics reveals diversity among xanthomonads infecting tomato and pepper
<p>Abstract</p> <p>Background</p> <p>Bacterial spot of tomato and pepper is caused by four <it>Xanthomonas </it>species and is a major plant disease in warm humid climates. The four species are distinct from each other based on physiological and molecular characteristics. The genome sequence of strain 85-10, a member of one of the species, <it>Xanthomonas euvesicatoria </it>(<it>Xcv</it>) has been previously reported. To determine the relationship of the four species at the genome level and to investigate the molecular basis of their virulence and differing host ranges, draft genomic sequences of members of the other three species were determined and compared to strain 85-10.</p> <p>Results</p> <p>We sequenced the genomes of <it>X. vesicatoria </it>(<it>Xv</it>) strain 1111 (ATCC 35937), <it>X. perforans </it>(<it>Xp</it>) strain 91-118 and <it>X. gardneri </it>(<it>Xg</it>) strain 101 (ATCC 19865). The genomes were compared with each other and with the previously sequenced <it>Xcv </it>strain 85-10. In addition, the molecular features were predicted that may be required for pathogenicity including the type III secretion apparatus, type III effectors, other secretion systems, quorum sensing systems, adhesins, extracellular polysaccharide, and lipopolysaccharide determinants. Several novel type III effectors from <it>Xg </it>strain 101 and <it>Xv </it>strain 1111 genomes were computationally identified and their translocation was validated using a reporter gene assay. A homolog to Ax21, the elicitor of XA21-mediated resistance in rice, and a functional Ax21 sulfation system were identified in <it>Xcv</it>. Genes encoding proteins with functions mediated by type II and type IV secretion systems have also been compared, including enzymes involved in cell wall deconstruction, as contributors to pathogenicity.</p> <p>Conclusions</p> <p>Comparative genomic analyses revealed considerable diversity among bacterial spot pathogens, providing new insights into differences and similarities that may explain the diverse nature of these strains. Genes specific to pepper pathogens, such as the O-antigen of the lipopolysaccharide cluster, and genes unique to individual strains, such as novel type III effectors and bacteriocin genes, have been identified providing new clues for our understanding of pathogen virulence, aggressiveness, and host preference. These analyses will aid in efforts towards breeding for broad and durable resistance in economically important tomato and pepper cultivars.</p
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