Application of Visual Basic for Automation of LC-MS Analysis

An approach to customizing the data acquisition and interpretation process of liquid chromatography electrospray mass spectrometry (LC-MS) analysis of compound libraries is presented. Macro programs, using Microsoft Visual Basic, were applied to allow the seamless flow of data from the sample synthesis stage through data acquisition/interpretation and reporting, with minimum user interaction. Logical functions were also incorporated into the macros to allow automated actions to be performed based on experimental results. The application of this approach as a universal method for supplementing the automation process of other instruments controlled by the Microsoft Windows PC platform is also discussed.     

The production of naturally fermented fish silage using various lactobacilli and different carbohydrate sources

The suitability for fish silage-making of eight different Lactobacillus cultures was investigated. The industrial by-products whey powder and molasses, as well as refined sugar, were tested as fermentation substrates. Using the information obtained two batches of fish silage were made at local white fish processing plants on a semi-commercial basis and subsequently successfully used on local cattle and pig farms.     

A Flexible,High-Performance FPGA Implementation of a Feed-Forward Equalizer for Optical Interconnects up to 112 Gb/s

Commodity optoelectronic components and multi-level modulation formats are combined nowadays in optical networks to increase their throughput while decreasing their cost. To overcome the inherent limitations of such interconnects, research focuses on digital equalizers that compensate for the effects of the developed channels. The current paper proposes the use of FPGAs to enhance the speed, power and flexibility of digital equalization for the next generation 100 Gb/s rack-to-rack optical links in datacenters. We present the high-performance hardware architecture of a flexible feed-forward equalizer (FFE) with multiple reconfigurations. We describe parallelization techniques to accelerate FFE, accuracy analysis for various FFE scenarios, as well as a design space exploration leading to a fine-tuned and platform-dependent FFE customization. Our final implementation on a single Xilinx XC7VH580T FPGA device with GTZ transceivers can support a single link of up to 112 Gbps (56 GSa/s with PAM-4 modulation) and 2.26?10^?6 Bit-Error-Rate.     

Interchain ion formation in secondary ion mass spectrometry resulting from the double-helical structure of isotactic poly(methyl methacrylate) in adsorbed monolayers

Results from time-of-flight secondary ion mass spectra (TOF-SIMS) of Langmuir-Blodgett monolayers of various isomers (isotactic and syndiotactic) of poly(methyl methacrylate) (PMMA) are reported. A detailed analysis of the repeating pattern of fragment ion clusters yields very different patterns for isotactic PMMA LB layers than for the syndiotactic and atactic forms. This is attributed to the resulting double-helical tertiary structure of isotactic PMMA, a structure that does not form for the syndiotactic and atactic PMMA polymer monolayers. The double-helical structure of isotactic PMMA monolayers is verified using reflection absorption Fourier transform infrared spectroscopy. The repeating patterns of cluster ions in syndiotactic and atactic PMMA monolayers can be explained using statistical chain-breaking models for fragmentation of single isolated polymer chains. The repeating ion patterns from the TOF-SIMS of the isotactic PMMA monolayers are analyzed by considering bond breaking and ion formation between adjacent polymer chains, resulting in a newly proposed ion formation model due to the tertiary structure of the double-helical form. A rearrangement mechanism consistent with all ions that are formed is proposed.     

Identification of biomarkers of whole Coxiella burnetii phase I by MALDI-TOF mass spectrometry

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) specific biomarkers have been shown to be an effective tool for identifying microorganisms. In this study, we demonstrate the feasibility of using this technique to detect the obligate intracellular bacterium Coxiella burnetii, a category B bioterrorism agent. Specific biomarkers were detected in C. burnetii Nine Mile phase I (NMI) strain purified from embryonated egg yolk sac preparations. Whole organisms were applied directly to the MALDI target. MALDI-TOF MS analysis of C. burnetii NMI grown and purified at different times and places revealed a group of unique, characteristic, and reproducible spectral markers in the mass range of 1000-25000 Da. Statistical analysis of the averaged centroided masses uncovered at least 24 peptides or biomarkers. Three biomarkers observed in the MALDI-TOF MS spectrum consistently matched proteins that had been previously described in C. burnetii, one of them being the small cell variant protein A. MALDI-TOF MS analysis of whole organisms represents a sensitive and specific option for characterizing C. burnetii isolates, especially when coupled with antigen capture techniques. The method also has potential for several applications in basic microbial research, including regulation of gene expression.     

The modified Pascal polynomial approximation and filter design method

Polynomial approximations are extensively used in analog and IIR digital filter design. In this paper, a comprehensive filter design and an optimization procedure are presented explicitly using a filter‐appropriate modified Pascal polynomial. The so‐designed all‐pole Pascal filters exhibit non‐equiripple passband and monotonic transition and stopband responses. The order of the new Pascal filters is calculated from the order inequality which, although it cannot be analytically solved, leads to a nomograph that has been created and is presented here. Inevitably, the mathematical complexity introduced by the nature of the Pascal polynomials makes the analytical expression of the poles of the transfer function unfeasible and for that reason poles are given by means of appropriate tables. The design method is demonstrated in several detailed examples and Pascal filters are compared with their all‐pole counterparts, Butterworth and Chebyshev, over which they reveal certain advantages and disadvantages. Copyright © 2010 John Wiley & Sons, Ltd.     

Absolute surface coverage of tungsten-alumina catalysts

Absolute surface coverages (θ) of a series of tungsten-alumina catalysts prepared by the equilibrium adsorption method were determined by ion scattering spectroscopy (ISS) and low-temperature CO adsorption. The θ_CO values for the W catalysts were very similar to those obtained with the ISS method, for a given W loading. A linear increase in W coverage with increasing W loading, reaching ~55% coverage for the 13.1% W solid, was observed. The calculated W cross-sections (22.0- 24.5Ų/W) were in agreement with other reports in the literature. Due to the inherent limitations of each method, the combined use of ISS and low-temperature CO adsorption is recommended for estimating absolute surface coverages in tungsten-alumina catalysts.     

Pervaporative transport mechanisms in phosphonium ionic liquid-based supported liquid membrane and its stability with actual fermentation broth feed

The pervaporative transport interactions between trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide ionic liquid-based membrane and the components of ABE fermentation broth were elucidated in this study. Acetone has a suggested viscosity decreasing effect on the ionic liquid and exhibited coupling effect with 1-butanol. Temperature increase consistently caused increase on 1-butanol permeance. The presence of acetic and butyric acids has no observed effect on 1-butanol and water permeation. No permeation of ethanol and acetic acid was noted, while butyric acid permeation can be suppressed by pH control. The membrane was proven stable in separating 1-butanol from actual fermentation broth for long period of time.