74 research outputs found
Financing Internal Buyouts of Private Companies: SCIN Attractive If Valuation Issues Can Be Resolved
In planning for succession of ownership, oftentimes the owner of a private business seeks to sell the business to either family members or employees. Arranging outside financing may be difficult or costly, making internal financing attractive. Self-cancelling installment notes (SCINs) provide an opportunity to finance the transfer of ownership at a favorable interest rate and to obtain income and estate tax advantages. However, to pass muster with the Internal Revenue Service, the SCIN must include a risk premium for the cancellation feature. In this paper, we provide a mathematical model for computation of the required risk premium associated with the cancellation provision. The premium may be in the form of either an interest premium or a principal premium and the computations for both are demonstrated in this paper. Appendix A provides an example of the use of the formulas
A DNA nanoswitch incorporating the fluorescent base analogue 2-aminopurine detects single nucleotide mismatches in unlabelled targets
DNA nanoswitches can be designed to detect unlabelled nucleic acid targets and have been shown to discriminate between targets which differ in the identity of only one base. This paper demonstrates that the fluorescent base analogue 2-aminopurine (AP) can be used to discriminate between nanoswitches with and without targets and to discriminate between matched and mismatched targets. In particular, we have used both steady-state and time-resolved fluorescence spectroscopy to determine differences in AP environment at the branchpoint of nanoswitches assembled using complementary targets and targets which incorporate single base mismatches
Fluorescence Lifetime Imaging of Quantum Dot Labeled DNA Microarrays
Quantum dot (QD) labeling combined with fluorescence lifetime imaging microscopy is proposed as a powerful transduction technique for the detection of DNA hybridization events. Fluorescence lifetime analysis of DNA microarray spots of hybridized QD labeled target indicated a characteristic lifetime value of 18.8 ns, compared to 13.3 ns obtained for spots of free QD solution, revealing that QD labels are sensitive to the spot microenvironment. Additionally, time gated detection was shown to improve the microarray image contrast ratio by 1.8, achieving femtomolar target sensitivity. Finally, lifetime multiplexing based on Qdot525 and Alexa430 was demonstrated using a single excitation-detection readout channel
Fast DNA and protein microarray tests for the diagnosis of hepatitis C virus infection on a single platform
Hepatitis C virus (HCV) is a major cause of chronic liver disease and liver cancer, and remains a large health care burden to the world. In this study we developed a DNA microarray test to detect HCV RNA and a protein microarray to detect human anti-HCV antibodies on a single platform. A main focus of this study was to evaluate possibilities to reduce the assay time, as a short time-to-result (TTR) is a prerequisite for a point-of-care test. Significantly reducing hybridisation and washing times did not impair the assay performance. This was confirmed first using artificial targets and subsequently using clinical samples from an HCV seroconversion panel derived from a HCV-infected patient. We were able to reduce the time required for the detection of human anti-HCV antibodies to only 14 min, achieving nanomolar sensitivity. The protein microarray exhibited an analytical sensitivity comparable to that of commercial systems. Similar results were obtained with the DNA microarray using a universal probe which covered all different HCV genotypes. It was possible to reduce the assay time after PCR from 150 min to 16 min without any loss of sensitivity. Taken together, these results constitute a significant step forward in the design of rapid, microarray-based diagnostics for human infectious disease, and show that the protein microarray is currently the most favourable candidate to fill this role
Peptide-tags for enhanced DNA microarray performance
DNA microarrays are powerful tools for gene expression analysis and genotyping studies in research and diagnostic applications. A high sensitivity and short time-to-result are prerequisites for their practical application in the clinic. The hybridization efficiency of DNA microarrays depends on the probe density and the probe orientation and thus their accessibility for target molecules. In order to find an optimal probe immobilization procedure a set of different oligonucleotide modifications was tested on epoxy silane functionalized glass slides. It was found that histidine-tagged oligonucleotides resulted in the highest amount of bound probe and by far the best hybridization efficiencies. The detection limit obtained with histidine-tagged probes was up to two orders of magnitude lower compared to commonly used probe modifications. In order to further investigate the binding mechanism of histidine-tags towards functionalized glass substrates a set of different peptide-tags with and without free terminal amino-groups and with different amino acid compositions was tested. The results indicate an impact of the terminal amino group on the covalent surface binding and of aromatic amino acid residues on the enhanced hybridisation efficiency
Label- and amplification-free electrochemical detection of bacterial ribosomal RNA
Current approaches to molecular diagnostics rely heavily on PCR amplification and optical detection methods which have restrictions when applied to point of care (POC) applications. Herein we describe the development of a label-free and amplification-free method of pathogen detection applied to Escherichia coli which overcomes the bottleneck of complex sample preparation and has the potential to be implemented as a rapid, cost effective test suitable for point of care use. Ribosomal RNA is naturally amplified in bacterial cells, which makes it a promising target for sensitive detection without the necessity for prior in vitro amplification. Using fluorescent microarray methods with rRNA targets from a range of pathogens, an optimal probe was selected from a pool of probe candidates identified in silico. The specificity of probes was investigated on DNA microarray using fluorescently labeled 16S rRNA target. The probe yielding highest specificity performance was evaluated in terms of sensitivity and a LOD of 20 pM was achieved on fluorescent glass microarray. This probe was transferred to an EIS end point format and specificity which correlated to microarray data was demonstrated. Excellent sensitivity was facilitated by the use of uncharged PNA probes and large 16S rRNA target and investigations resulted in an LOD of 50 pM. An alternative kinetic EIS assay format was demonstrated with which rRNA could be detected in a species specific manner within 10-40 min at room temperature without wash steps
Pedagogical memory and the space of the postcolonial classroom : reading Dangarembga's Nervous Conditions
This article addresses issues of the mnemonic space of the literature classroom by
interrogating a classic text of African women’s writing, Tsitsi Dangaremnga’s Nervous
Conditions (1988) for the ways it speaks about education in 1960s and 1970s late-colonial
Rhodesia. The article suggests that the novel reviews and critiques a number of memorial
strategies that were crucial to the colonial educational system, thereby facilitating a reflexive
application of the novel’s concerns to the contexts in which it is often taught, that of today’s
postcolonial classrooms. The article seeks to place Dangarembga’s novel in the context of its
present moment, contemporary South Africa – that of the present critic’s site of practice, both
pedagogical and scholarly, and that of many of this article’s readers. This present moment, in
turn, is made up the many sites, successive and simultaneous, in which the novel’s work of
memory is being re-activated in the minds of students as readers and writers. Via a dialogue
between the textual past and the pedagogical present, one which is often subject to critical
amnesia, the article seeks to inaugurate a debate on the nature of pedagogical memory in the
space of the postcolonial university or high school literature classroom.http://www.informaworld.com/RSCRhb2013gv201
An Analysis of the Tradeoff between Tax Deferred Earnings in Iras and Preferential Capital Gains
This paper extends prior research in evaluating the decision of whether to invest in a mutual fund either outright or through one of the three available IRAs: the deductible IRA, the Roth IRA, and the nondeductible IRA. We provide mathematical models for after-tax accumulations for each of the investments that are a function of return, the percentage of the return currently taxable to the investor, the time horizon of the investment, the capital gain tax rate, and the ordinary income tax rate. The Roth IRA and the deductible IRA always dominate investments in the nondeductible IRA or through outright investment. However, in comparing the nondeductible IRA and outright investments, the outcome is dependent on the investment goals of the mutual fund and whether it generates substantial dividend distributions or capital gain distributions. Mutual funds with small dividend and capital gain distributions may accumulate larger amounts if held outright while mutual funds that pay substantial dividends or make substantial capital gain distributions accumulate larger after-tax amounts when invested in a nondeductible IRA
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