Retirement Plan Contributions and Withdrawals

Qualified retirement plans provide for tax deferral, but they are also subject to a 15% excise tax on excess distributions or accumulations, potentially higher marginal income tax rates on plan withdrawals, mandatory contributions for employers, estate taxes at death, and possible substantial income tax liability for plan beneficiaries. Three possible planning strategies to optimize return on funds available for contributions to a qualified plan include investment in alternative assets, lifetime gifts, and accelerated plan withdrawals. While the 3-year suspension of excess distribution excise taxes under the Small Business Job Protection Act may favor plan withdrawals, in certain situations participants are often best served by leaving the full amount in the plan to take advantage of the tax deferrals

Fluorescence Measurements of Aromatic Amino Acids in the Presence of Lipid Membranes

Amphiphilic peptides are capable of finding their way to, and occasionally through, cellular membranes using a mechanism that includes specific amino acid sequences. Physical measurements of amino acid-lipid interactions are of interest for a quantitative description of peptide affinities to biological membranes. In this study, we investigate small peptide-lipid interactions using the fluorescence of the aromatic amino acids tyrosine (Tyr), tryptophan (Trp) and phenylalanine (Phe). Reference spectra in deuterated isopropanol solutions are obtained to mimic hydrophobic environments and are used to quantify the interaction of Lys-Tyr-Lys, Trp-Gly, and Gly-Phe with 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and palmitoyl-oleoyl phosphatidylserine (POPS) lipid membranes. These fluorescence data complement previously reported UV absorption data and have the advantage of eliminating background and scatter from solution. Together with NMR data, these results can be used to more fully characterize lipid-aromatic amino residue interactions

Targeting the Role of Tyrosine in Amot Protein-Lipid Binding Events

poster abstractAngiomotins (Amots) are a family of adaptor proteins that have been shown to control cell proliferation and differentiation. Amots can selectively bind with high affinity to phosphoinositol containing membranes through the Amot coiled-coil homology (ACCH) domain. This binding event is linked to endocytosis, changes in cellular polarity, and apical membrane sequestration of nuclear transcription factors associated with development of cancerous phenotypes. Although the lipid selectivity of the protein has been well characterized, the residues involved in the ACCH domain binding these membranes have not been fully described. Understanding the structure-function relationship may provide pathways to modulate protein sorting and downstream signaling events inducing cellular differentiation, cancer cell proliferation, and migration. The fluorescent properties of the ACCH domain were previously used to characterize the binding event. However, the relative proximity of the five native tyrosines to the membrane may have led to differences in perceived lipid binding affinities based on fluorescence resonance energy transfer with fluorescently tagged lipids. A variety of short peptides correlating to the amino acid sequence of Amot surrounding these tyrosines were assayed and observed in different membrane mimicking environments. This was done to determine if each tyrosine had the ability to bury into the hydrophobic region of the membrane mimicked by the carbon chain lengths (alcohol study), or simply interacted with the hydrophilic head groups of the lipid (liposome study). In addition, the full length Amot80 ACCH domains (wild-type and tyrosine-to-phenylalanine mutants) were screened for trends in the varying environments. Interactions were characterized by shifts in maximum wavelengths for absorbance, excitation and emission peaks. A characterization of these shifts with respect to what is seen with the various tyrosine and phenalanine mutants may further our understanding of whether each tyrosine is buried within the protein or interacts with the head groups of the membrane

The red edge in arid region vegetation: 340-1060 nm spectra

The remote sensing study of vegetated regions of the world has typically been focused on the use of broad-band vegetation indices such as NDVI. Various modifications of these indices have been developed in attempts to minimize the effect of soil background, e.g., SAVI, or to reduce the effect of the atmosphere, e.g., ARVI. Most of these indices depend on the so-called 'red edge,' the sharp transition between the strong absorption of chlorophyll pigment in visible wavelengths and the strong scattering in the near-infrared from the cellular structure of leaves. These broadband indices tend to become highly inaccurate as the green canopy cover becomes sparse. The advent of high spectral resolution remote sensing instrument such as the Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) has allowed the detection of narrow spectral features in vegetation and there are reports of detection of the red edge even for pixels with very low levels of green vegetation cover by Vane et al. and Elvidge et al., and to characterize algal biomass in coastal areas. Spectral mixing approaches similar to those of Smith et al. can be extended into the high spectral resolution domain allowing for the analysis of more endmembers, and potentially, discrimination between material with narrow spectral differences. Vegetation in arid regions tends to be sparse, often with small leaves such as the creosote bush. Many types of arid region vegetation spend much of the year with their leaves in a senescent state, i.e., yellow, with lowered chlorophyll pigmentation. The sparseness of the leaves of many arid region plants has the dual effect of lowering the green leaf area which can be observed and of allowing more of the sub-shrub soil to be visible which further complicates the spectrum of a region covered with arid region vegetation. Elvidge examined the spectral characteristics of dry plant materials showing significant differences in the region of the red edge and the diagnostic ligno-cellulose absorptions at 2090 nm and 2300 nm. Ray et al. detected absorption at 2100 nm in AVIRIS spectra of an abandoned field known to be covered by a great deal of dead plant litter. In order to better study arid region vegetation remote sensing data, it is necessary to better characterize the reflectance spectra of in situ, living, arid region plants

Detecting Counterfeit Pharmaceuticals through UV Spectrophotometry

poster abstractAccording to the World Health Organization between 10%-30% of medicines, in Africa, Asia and South America, are counterfeit or sub-standard, affecting the health of millions of people. Currently, there is no effective way to check the quality of a medicine at the point of care, leaving many with treatable diseases at risk. The goal of this study is to identify UV-Vis (240nm - 500nm) absorbance patterns that would indicate if a drug is sub-standard or counterfeit. UV-Vis spectroscopy was selected as the method for testing due to the maturity and availability of the technology. Pure Acetaminophen and Tylenol were used as controls for proof of concept. Samples were prepared by dissolving different combinations of the pure active ingredient and adulterants such as cement, rice flour, vitamin C and lactose in three different types of solvents (H2O, 0.1 M HCl, 0.1 NaOH). Various concentrations (ranging from 0.01mg/ml to 0.04mg/ml) and mixing ratios were analyzed using a UV-Vis Spectrophotometer. It was found that adulterants significantly decrease the absorption of acetaminophen at 245nm by interacting with its benzene ring, while showing a slight increase in other parts of the spectrum. UV-Vis scans show that the amount of change in absorbance at specific wavelengths, coupled with characteristic wavelength shifts produced by different solvents, can be used for detection of counterfeit drugs. The methods presented here could be used for quality control of medicines at or near the point of care in parts of the world at higher risk of encountering defective pharmaceuticals

Finding Active Ingredients in Pharmaceuticals by UV Spectrophotometry

The active ingredient in any pharmaceutical is the chemical that will ultimately deliver the desired effect on a patient. Knowing the quality and the quantity of the active ingredient in a pill right before ingestion is of paramount importance for the patient’s health and the desired results. Unfortunately drugs only undergo quality control testing at the manufacturing plant but not at the point of sale. Moreover, to an untrained eye, one pill may not appear different from another and if the wrong pill or the wrong dose is taken, adverse health effects may arise. Indeed, manufacturers of counterfeit drugs rely on these two points of appearance and testing. In this study we examine whether ultra violet (UV) spectrophotometry absorbance can be used to separate an active ingredient’s UV peaks from the combination of peaks generated by the inactive ingredients of the tablet. A well-understood active ingredient, acetaminophen, was used for this study. Samples were prepared by crushing Tylenol tablets, dissolving the powder in different solvents (0.1M HCl, 0.1M NaOH, and H2O) at various concentrations and mixed by vortex. After preparation, the samples were measured by UV Spectroscopy. Experimental results were compared to standard UV curves for the pure active ingredient to correlate the observed changes in absorbance within the relevant UV wavelength range. We observe that more than one solvent is needed to identify the active ingredient. Development of a simple method to accurately identify the quality of the active ingredient will provide an additional safeguard to consumers, particularly in regions where counterfeit drugs are prevalent

SOLUTION STRUCTURE OF THE TOXIC E. COLI PEPTIDE, TISB

poster abstractAntibiotics act by interfering in bacterial metabolism. Thus, antibiotics are only effective against metabolically active bacteria while dormant cells are highly tolerant to antibiotics. Such persistent bacterial cells may be the main culprits in chronic infectious diseases resistance to antimicrobial thera-py. In Escherichia coli, expression of a toxic peptide, TisB, sends cells into dormancy by decreasing the proton motive force thus decreasing ATP levels. TisB is a 29 amino acid residue peptide with 70% hydrophobic residues. It has a predicted alpha helical transmembrane domain spanning residues 6 - 28. In membrane channel studies, ion transport is observed with TisB and with some TisB mutants. As a preliminary to combining multi-dimensional NMR spectroscopy with circular dichroism to determine the structure of the TisB membrane ion transport complex in lipid micelles, NMR spectroscopy is used to determine the structure of TisB in ethanol

Laparoscopic Colectomy: Does the Learning Curve Extend Beyond Colorectal Surgery Fellowship?

Colorectal fellowship training adequately surpasses the learning curve with regard to safety and outcome; however, the surgeon continues to increase operative efficiency during the first year of practice