The purpose of this study was to gain a better quantitative understanding of bioadhesion, more specifically, the attractive chemistry between biomolecules and surfaces. A Digital Instruments Nanoscope IIIa Multimode atomic force microscope operated in tapping mode was used to image the adsorption of earthworm hemoglobin (EHb) due to the easily distinguishable shape and orientation of this biomolecule. Imaging was performed on a mica substrate in two different environments: air and fluid. In the air experiments, the proteins were imaged as functions of (a) concentration and (b) time under ambient conditions.
Images of three different sample concentrations were captured to explore the concentration effect: i.e. undiluted samples and dilutions of 1:10 and 1:100 made from pH 7 salt buffer (PIPES, MgCl2, and CaCl2). In these samples, in terms of the mean particle and aggregate counts, the number of EHb seen per µm² decreased nonlinearly as the dilutions increased. For the deposition effect as a function of time allotted to incubate before spin-coating, both undiluted and variously diluted samples were used and imaging was performed after 1, 30, 60, and 500 seconds, respectively. In these latter experiments, as deposition time was increased, there was an overall increase per µm² in the mean aggregate count, whereas an overall decrease was observed in the number of individual particles. Samples that had yielded the best images were those that originated from an undiluted standard. One could clearly make out the distinct 6-fold symmetry and "dimple" center of these biomolecules in those runs.
A plausible reason for the poor-quality appearance of images prepared from diluted samples was denaturation of protein complexes at the air-liquid interface. An effective technique of filter paper manipulation (i.e. smash/blotting) onto the sample to remove the denatured protein film on the interface was initiated, resulting in improved and more credible height images. Nanoscope software was utilized to perform height analyses of all AFM data collected to confirm that the images obtained were in fact corresponded to EHb molecules and not to salt particles, dirt, or other contaminants. AFM experimentation was also carried out in fluid with the goal of measuring on and off rates of EHb particles in their native aqueous environment. Four series of different EHb sample concentrations, made from pH 6.11 salt buffer, were sequentially injected into a fluid cell of the AFM and imaged. While EHb particles seemed to be present, no compelling trend was observed to describe the adhesion of these proteins onto mica as a function of concentration. In fact, it was found that carbon-coated mica was a much more effective substrate for biological AFM imaging in fluid. This work was supported by the WISE-Battelle Summer Research Fellowship Program.

Development of Fast Homogenous Catalysts for Hydrogen Purification
Nathan Hould, Stony Brook University; Devinder Mahajan, Energy Sceinces & Technology Department, Brookhaven National Laboratory and Materials Science & Engineering Department, Stony Brook University

Fuel cells are on the edge of reinventing the way that America uses energy. Fuel cells that utilize hydrogen as a fuel offer the potential of highly efficient zero emission power, but a number of engineering and cost issues need to be solved in order to make them economical. Proton exchange membrane (PEM) fuel cells are attractive because they operate at a lower temperature (T < 100oC) and have multiple applications. The hydrogen feed for PEM fuel cells is commercially manufactured by steam reforming of hydrocarbons and typically contains, among other impurities, about 5% carbon monoxide (CO) that severely poisons the expensive platinum electrode. The Water Gas Shift (WGS) reaction [Reaction 1] is used to remove CO:

CO(g) + H2O(l) = CO2(aq) + H2(g) [1]

Current WGS technology is based on a high temperature, low efficiency reaction over heterogeneous catalysts. The aim of this study was to develop a low temperature catalyst that would operate in a homogenous mode and yield fast reaction rates to affect Reaction 1. I designed several potential catalysts based on selective transition metals, RhCl3.3H20, CoCl2.6H2O, and CuCl, and evaluated them as catalysts to drive the WGS. The goal was to achieve the fastest WGS rate and minimum CO (< 50 ppm) in the product.
Our evaluation of potential catalysts was carried out in a customized 0.3 L stainless steel Parr batch reactor rated @ Pmax = 3000 psi and Tmax = 573K. The reactor had the following features: 1) heating mantle via a Parr controller to attain isothermal conditions, 2) a magnedrive stirrer to ensure gas/liquid mixing, 3) a digital pressure readout ( 1 psi precision), 4) ports for collecting liquid and gas samples. Gas samples from the reactor were analyzed on Gow Mac 580 gas chromatographs for CO, CO2, H2, and CH4. In a typical run, 1 mmol catalyst, 2 mmol N-donor ligands, 0.1 mol potassium hydroxide were dissolved in a solvent mixture (50% H2O and 50% glycol or methanol (volume/volume)) and heated at 120oC and pressurized with 200 psig gas mixture of 66% H2/34% CO. The pressure was monitored as a function of time and the gaseous and liquid contents were periodically analyzed.
Of the three metal catalysts evaluated, our results show that CoCl2.6H2O showed the best activity. All catalysts showed a sharp PH drop. The PH drop is expected due to the reaction of CO or CO2 with the base to yield formate and bicarbonate anions respectively. The formate formation is an important step during the base-catalyzed WGS reaction. We are analyzing the data to further refine our catalyst design strategy to develop a viable WGS catalyst that can be commercially used to further the Hydrogen Economy.

Effect of Anion Substitution on Properties of Ionic Liquids
Kimberly Odynocki, Stony Brook University; Alison Funston and James Wishart, Chemistry Department, Brookhaven National Laboratory

The purpose of this project was to continue the research on the synthesis of new ionic liquids with different anions. This involved total synthesis and purification and measuring the effects of the modifications on the properties of the liquids. Ionic liquids are salts that have low melting points (below 100ºC) and no vapor pressure, which prevents them from evaporating. The reason ionic liquids are being so widely studied is because they would be safer, more environmentally friendly solvents for reactions than the volatile organic solvents used today. However, some ionic liquids are too viscous to be used effectively in industry, which is why anion substitutions were studied. It had been observed anecdotally that substitutions of the bis(trifluoromethylsulfonyl)imide anion (NTf2) and dicyanoamide (DCA) anion can lower the viscosity and melting point of an ionic liquid without significantly changing other properties, and this project was designed to quantify this effect. Four ionic liquids were synthesized, namely:
(1) 1-methyl-1butylpyrrolidinum bromide (P14 Br)
(2) 1-methyl-1pentylpyrrolidinuim bromide (P15 Br)
(3) 1-methyl-1-methoxyethylpyrrolidinium bromide (P1EOM Br)
(4) 1-methyl-1-ethoxyethylpyrrolidinium bromide (P1EOE Br)
To synthesize an ionic liquid, the reactants (1-methylpyrrolidine and alkyl halides) were refluxed in acetonitrile under a blanket of nitrogen gas at 45º C for 24 hours. Metathesis reactions to convert the bromide salts to either the NTf2 or DCA salts were generally done by mixing aqueous solutions of the cation halide and lithium NTf2 or silver DCA, respectively. After creating the NTf2 salt, the alkali metal salt remained in the water solution apart from the desired ionic liquid phase which was then purified. The DCA metathesis created solid silver bromide which was filtered off, leaving the ionic liquid dissolved in water. After synthesizing new ionic liquids, it became clear that addition of the NTf2 or DCA anions results in ionic liquids with lower melting points and lower viscosities. This project was funded by the Battelle Summer Research Fellowship Program.

The Effects of Methylphenidate on Sustained Attention in Rats: A Behavioral and Neurocytostructural Analysis
Jason-Flor V. Sisante, Panayotis K. Thanos, Seth N. Rivera, Brenda J. Anderson, & Nora D. Volkow, Behavioral Pharmacology Lab, Department of Medicine, Brookhaven National Lab, Upton, NY 11973

The visual discrimination task (VST) is a sustained attention task that signals the formation of a habit (by taking into account hits, misses, false alarms, and correct rejections) therefore, animals that are trained in this task are very reluctant to unlearn the behavior (Himmelbemer et al. 1997). Damos & Parker (1994) showed that high-false alarm rates might indicate recreational drug use in humans. In addition, ecstasy users have done poorly when compared to non-users in attention, memory-learning tasks (Gouzoulis-Mayfrank et al. 2000). Recently, it was shown that cocaine had effects on sustained attention processing in children that had been prenataly exposed to cocaine (Bandstra et al., 2001). Methylphenidate (MP) has increased accuracy in visual sustained attention tasks (Jonkman et al. 1997). In a rat condition position responding (CPR) discrimination task, MP had similar effects to d-amphetamine (Mayorga et al. 2000) and cocaine, which increased accuracy in rats during a sustained attention task (Grilly et al. 1989). The present study assessed the behavioral effects MP had on sustained attention accuracy using a VST and spontaneously hypertensive (SHR) rats. SHR rats are an excellent rodent model for ADHD because they have behavioral and neurochemical characteristics similar to ADHD. Preadolescent (age 2weeks) male SHR (n=36) and Wistar (n=36) rats were tested on a food VST [using four shaping cue-light intervals (1-s, 500 ms, 50 ms, and 25 ms)] and after baseline criteria were exposed to either: a) 2 mg/kg MP b) 1 mg/kg MP or c) vehicle for 2 weeks. Finally we assessed the histomorphometric effects of MP on these rats using the Golgi-Cox staining method, which demonstrates dendritic density, and branching. This work was supported by the NIDA, DA06891-06, & the US Department of EnergyDE-AC02-98CH10886

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