617 research outputs found
An Empirical Analysis of a Model for Student Success using a Case Study Approach
Historically black colleges and universities (HBCUs) play a critical role in the national college completion agenda within the United States of America (U.S.). With high enrolments of minority, first-generation, and economically disadvantaged students, HBCUs serve as essential access points to higher education and the American dream. Given the high needs student population of HBCUs, these institutions can serve as national and international models for improving college completion and demonstrating efficacy in promoting access to higher education among students from diverse backgrounds
Application of Confocal Laser Scanning Microscopy to Cytocompatibility Testing of Potential Orthopaedic Materials in Immortalised Osteoblast-Like Cell Lines
Confocal laser scanning microscopy (CLSM) was used in conjunction with in vitro cell culture to investigate cellular interactions with orthopaedic biomaterials. Transfected rat and human osteoblasts were seeded on two potential isoelastic hip prosthesis materials, carbon fibre reinforced polyetheretherketone (PEEK) and epoxy. Titanium 318 alloy was employed as a control. Determination of the material surface contour, an important factor influencing cellular adhesion, proliferation and function, was performed using the industry standard Talysurf® and compared to analogous results obtained using the CLSM. The latter technique consistently gave higher values of material roughness but offers the advantage that it can be used to correlate roughness with cell distribution on the same samples, whereas Talysurf® measurement of roughness requires clean rigid samples. Image analysis and processing, performed on cells after attachment and culture on the materials for 48 hours, provided cell morphology data. Cells cultured on titanium were larger, with a higher percentage of cytoplasm, than those grown on either of the other materials. The macroscopic surface of epoxy resulted in smaller cells with altered morphology, which orientated themselves along carbon fibres. In conclusion, we believe CLSM offers great potential for investigating the cellular interactions of biomaterials involving minimal sample preparation, non-invasive optical sectioning of samples and minimal opportunity for generation of cellular deformation and sample preparation artefacts
Noncommutative generalizations of theorems of Cohen and Kaplansky
This paper investigates situations where a property of a ring can be tested
on a set of "prime right ideals." Generalizing theorems of Cohen and Kaplansky,
we show that every right ideal of a ring is finitely generated (resp.
principal) iff every "prime right ideal" is finitely generated (resp.
principal), where the phrase "prime right ideal" can be interpreted in one of
many different ways. We also use our methods to show that other properties can
be tested on special sets of right ideals, such as the right artinian property
and various homological properties. Applying these methods, we prove the
following noncommutative generalization of a result of Kaplansky: a (left and
right) noetherian ring is a principal right ideal ring iff all of its maximal
right ideals are principal. A counterexample shows that the left noetherian
hypothesis cannot be dropped. Finally, we compare our results to earlier
generalizations of Cohen's and Kaplansky's theorems in the literature.Comment: 41 pages. To appear in Algebras and Representation Theory. Minor
changes were made to the numbering system, in order to remain consistent with
the published versio
Program Spending to Increase Adherence: South African Cervical Cancer Screening
Background: Adherence is crucial for public health program effectiveness, though the benefits of increasing adherence must ultimately be weighed against the associated costs. We sought to determine the relationship between investment in community health worker (CHW) home visits and increased attendance at cervical cancer screening appointments in Cape Town, South Africa. Methodology/Principal Findings: We conducted an observational study of 5,258 CHW home visits made in 2003–4 as part of a community-based screening program. We estimated the functional relationship between spending on these visits and increased appointment attendance (adherence). Increased adherence was noted after each subsequent CHW visit. The costs of making the CHW visits was based on resource use including both personnel time and vehicle-related expenses valued in 2004 Rand. The CHW program cost R194,018, with 1,576 additional appointments attended. Adherence increased from 74% to 90%; 55% to 87%; 48% to 77%; and 56% to 80% for 6-, 12-, 24-, and 36-month appointments. Average per-woman costs increased by R14–R47. The majority of this increase occurred with the first 2 CHW visits (90%, 83%, 74%, and 77%; additional cost: R12–R26). Conclusions/Significance: We found that study data can be used for program planning, identifying spending levels that achieve adherence targets given budgetary constraints. The results, derived from a single disease program, are retrospective, and should be prospectively replicated
Block sequential adriamycin CMF – optimal non-myeloablative chemotherapy for high risk adjuvant breast cancer?
After the publication of the 10-year survival data from Milan on the adjuvant use of the block sequential regimen consisting of four cycles of adriamycin followed by eight cycles of intravenous CMF, many centres adopted this as standard of care for high risk, multiple node-positive breast cancer. For this reason it was identified as the standard arm for the Anglo-Celtic adjuvant high-dose chemotherapy trial. This study reports on the experience of this regimen in 329 women with early breast cancer involving at least four axillary nodes, who were treated outside any adjuvant chemotherapy trial. At a median follow-up of 3 years, the overall 5-year disease-free survival is 61%, and the overall survival is 70%. These data confirm the efficacy of this regimen in non-trial patients, and, for the same high risk subgroup, indicate that this approach offers an outcome at least as good as that seen in the CALGB 9344 AC-Taxol arm, and the NCIC days 1 and 8 CEF
The effectiveness of emergency obstetric referral interventions in developing country settings : a systematic review
Peer reviewedPublisher PD
Tail probabilities of St. Petersburg sums, trimmed sums, and their limit
We provide exact asymptotics for the tail probabilities as , for fix , where is the -trimmed
partial sum of i.i.d. St. Petersburg random variables. In particular, we prove
that although the St. Petersburg distribution is only O-subexponential, the
subexponential property almost holds. We also determine the exact tail behavior
of the -trimmed limits.Comment: 24 pages, 2 figure
Cancer-selective, single agent chemoradiosensitising gold nanoparticles
Two nanometre gold nanoparticles (AuNPs), bearing sugar moieties and/or thiol-polyethylene glycol-amine (PEG-amine), were synthesised and evaluated for their in vitro toxicity and ability to radiosensitise cells with 220 kV and 6 MV X-rays, using four cell lines representing normal and cancerous skin and breast tissues. Acute 3 h exposure of cells to AuNPs, bearing PEG-amine only or a 50:50 ratio of alpha-galactose derivative and PEG-amine resulted in selective uptake and toxicity towards cancer cells at unprecedentedly low nanomolar concentrations. Chemotoxicity was prevented by co-administration of N-acetyl cysteine antioxidant, or partially prevented by the caspase inhibitor Z-VAD-FMK. In addition to their intrinsic cancer-selective chemotoxicity, these AuNPs acted as radiosensitisers in combination with 220 kV or 6 MV X-rays. The ability of AuNPs bearing simple ligands to act as cancer-selective chemoradiosensitisers at low concentrations is a novel discovery that holds great promise in developing low-cost cancer nanotherapeutics
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