Development of a biodegradation model for the prediction of metabolites in soil

The awareness of air, soil and water pollution has driven the search for better methods for the assessment of the environmental fate of industrial chemicals. This paper is focused on the simulation of formation and transformation of metabolites in soil. The key challenges in the development of a simulator for predicting metabolic fate of chemicals in soil are the complexity of the soil compartment and incompleteness of metabolic information. Based on the collected data for metabolic fate of 183 chemicals a set of soil specific transformations were defined and used to develop a simulator for metabolism in soil. The analysis of outliers showed that the low predictability for some chemicals is due to: 1) incomplete documented metabolic pathways with missing intermediates and/or 2) reactions of condensation that are not simulated in the current version of the model. Hence, further improvement of the model requires expanding the metabolism database and further refinement of the logic of metabolic transformations used in the simulator.     

Capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry as an alternative proteomics platform to ultraperformance liquid chromatography-electrospray ionization-tandem mass spectrometry for samples of intermediate complexity

We demonstrate the use of capillary zone electrophoresis with an electrokinetically pumped sheath-flow electrospray interface for the analysis of a tryptic digest of a sample of intermediate protein complexity, the secreted protein fraction of Mycobacterium marinum. For electrophoretic analysis, 11 fractions were generated from the sample using reverse-phase liquid chromatography; each fraction was analyzed by CZE-ESI-MS/MS, and 334 peptides corresponding to 140 proteins were identified in 165 min of mass spectrometer time at 95% confidence (FDR < 0.15%). In comparison, 388 peptides corresponding to 134 proteins were identified in 180 min of mass spectrometer time by triplicate UPLC-ESI-MS/MS analyses, each using 250 ng of the unfractionated peptide mixture, at 95% confidence (FDR < 0.15%). Overall, 62% of peptides identified in CZE-ESI-MS/MS and 67% in UPLC-ESI-MS/MS were unique. CZE-ESI-MS/MS favored basic and hydrophilic peptides with low molecular masses. Combining the two data sets increased the number of unique peptides by 53%. Our approach identified more than twice as many proteins as the previous record for capillary electrophoresis proteome analysis. CE-ESI-MS/MS is a useful tool for the analysis of proteome samples of intermediate complexity.     

Alignment Method for Spectrograms of DNA Sequences

DNA spectrograms express the periodicities of each of the four nucleotides A, T, C, and G in one or several genomic sequences to be analyzed. DNA spectral analysis can be applied to systematically investigate DNA patterns, which may correspond to relevant biological features. As opposed to looking at nucleotide sequences, spectrogram analysis may detect structural characteristics in very long sequences that are not identifiable by sequence alignment. Alignment of DNA spectrograms can be used to facilitate analysis of very long sequences or entire genomes at different resolutions. Standard clustering algorithms have been used in spectral analysis to find strong patterns in spectra. However, as they use a global distance metric, these algorithms can only detect strong patterns coexisting in several frequencies. In this paper, we propose a new method and several algorithms for aligning spectra suitable for efficient spectral analysis and allowing for the easy detection of strong patterns in both single frequencies and multiple frequencies.      

A novel methodology for controlled migration of antifog from thin polyolefin films

Transparent plastic films are widely used in agriculture as greenhouses covering and in the food industry as packaging films. The films are usually prepared by hydrophobic low polarity thermoplastics such as polyethylene (PE). In a greenhouse, the temperature and humidity are usually higher than the outside temperature and fog will appear on the inner surface of the PE film. Anti‐fogging (AF) additives are tensoactive materials, mainly nonionic surfactants, equalizing the PE and water surface tensions, thus creating a thin, continuous film of water rather than discrete droplets. In the present work, a new method of controlled migration of AF is described, by grafting AF molecules to the surface of submicron inorganic particles. Glycerides and fatty acids are used as AF. During the grafting reaction two fractions are formed: attached AF fraction to the inorganic particles' surface, a fraction which cannot be detached by extraction, and an unreacted, thus unattached AF fraction. Solvent extraction, FTIR and TGA measurements have confirmed the existence of the grafted AF molecules to the inorganic particle's surfaces. Aging tests, developed in the present work, have shown a significant decrease of the AF migration rate, thus confirming an extended duration of the anti‐fog's activity. POLYM. ENG. SCI., 54:2023–2028, 2014. © 2013 Society of Plastics Engineers     

Determination of the diffusion coefficient and solubility of radon in plastics

This paper describes a method for determination of the diffusion coefficient and the solubility of radon in plastics. The method is based on the absorption and desorption of radon in plastics. Firstly, plastic specimens are exposed for controlled time to referent (222)Rn concentrations. After exposure, the activity of the specimens is followed by HPGe gamma spectrometry. Using the mathematical algorithm described in this report and the decrease of activity as a function of time, the diffusion coefficient can be determined. In addition, if the referent (222)Rn concentration during the exposure is known, the solubility of radon can be determined. The algorithm has been experimentally applied for different plastics. The results show that this approach allows the specified quantities to be determined with a rather high accuracy-depending on the quality of the counting equipment, it can be better than 10 %.     

Development of Teachers’ Conceptions Through Learning and Teaching: The Meaning and Potential of Multiple-Solution Tasks

Abstract

This study analyzes development of teachers’ mathematical and pedagogical conceptions in systematic (through learning) and craft (through teaching) modes and the relationships between them. We focus on teachers’ conceptions of the meaning and potential of multiple-solution connecting tasks in school mathematics. We found that in systematic mode teachers increase primarily their shared conceptions and that the development of mathematical conceptions precedes that of pedagogical conceptions. Only in craft mode do they develop new understandings while their mathematical and pedagogical conceptions become integrated and advance each other mutually.     

Analysis and design of high-performance asynchronous sigma-delta Modulators with a binary quantizer

Asynchronous sigma-delta modulators (ASDMs) are closed-loop nonlinear systems that transform the information in the amplitude of their input signal into time information in the output signal, without suffering from quantization noise such as in synchronous sigma-delta modulators. This is an important advantage with many interesting applications. In contrast with their synchronous counterparts, ASDMs have been underexposed. Both conceptually and analytically, they are quite complex. This paper investigates in detail the analysis, design and circuit-implementation aspects of ASDMs with a binary quantizer. In the ASDM, the amplitude-time transformation is done using an inherent self-oscillation denoted as a limit cycle. The oscillation frequency is addressed as the main design parameter that determines the spectral properties of the ASDMs and the quality of the amplitude-time transformation. Analytical and graphical derivations of the limit cycle frequency are treated. The impact of the filter order and the properties of the nonlinear element are elaborated on. Circuit implementations and the tradeoffs in the design are presented for a first- and a second-order ASDM that target the VDSL front-end specifications. Prototypes are implemented in a digital 0.18-/spl mu/m 1.8-V CMOS technology. The measured SFDR is 75dB in a frequency band of 8MHz for the first-order ASDM, and 72dB in a band of 12MHz for the second-order ASDM. The dissipated power is 1.5 mW and 2.2 mW, respectively.     

Antinociceptive activity of metamizol in rats with experimental ureteric calculosis: central and peripheral components

OBJECTIVE AND DESIGN: To study the antinociceptive effects of metamizol in a rat model of ureteric calculosis. Subjects: Adult female Wistar rats (n = 40). TREATMENT: Metamizol was given i.p. 50-100 mg/kg, 3 times daily for 4 days for behavioural testing, and 25-100 mg/kg i.v. whilst recording peristalsis or dorsal horn neurons. METHODS: An artificial stone was induced in one ureter. In 3 separate groups of stone-implanted rats, behaviour was recorded continuously on video tape, ureteric peristalsis or the electrical activity of single nociceptive dorsal horn neurons with ureteric input was recorded under anaesthesia. Data were compared with analysis of variance. RESULTS: Metamizol inhibited the behavioural visceral crises, the abnormal ureteric peristalsis and the activity of nociceptive dorsal horn neurons. CONCLUSIONS: Metamizol has central antinociceptive effects on the pain produced by a ureteric stone, and an additional spasmolytic effect on the hyperperistalsis produced by the stone.     

Video content management in consumer devices

Methods for video content analysis are necessary for the growing amount of video information delivered to consumers today. In this paper, we present a system for video content analysis called Vitamin, which provides management of a home video library. The system presents the user with a visual table of contents that provides an overview of the video content and direct access to particular points in the stored video. In this process, we apply a computationally inexpensive, simple, yet powerful mechanism for cut detection and keyframe filtering. Our initial implementation and results show that this system can perform video content extraction in real time on a low-end platform that matches a visual table of contents extracted by an expert