Determination of methionine and selenomethionine in yeast by species-specific isotope dilution GC/MS

A method for the simultaneous determination of methionine (Met) and selenomethionine (SeMet) in yeast using species-specific isotope dilution (ID) gas chromatography/mass spectrometry (GC/MS) is described. Samples were digested by refluxing for 16 h with 4 M methanesulfonic acid. Analytes were derivatized with methyl chloroformate and extracted into chloroform for GC/MS analysis. In addition to use of commercially available 13C-enriched Met and SeMet spikes for species specific ID analysis, a 74Se-enriched SeMet spike was also available for comparison of results. In selective ion monitoring mode, the intensities of ions at m/z 221, 222, 269, 270, and 263 were used to calculate the 221/222, 269/270, and 269/263 ion ratios for quantification of Met and SeMet. Concentrations of 5959 +/- 33 and 3404 +/- 12 microg g(-1) (one standard deviation, n = 6) with relative standard deviations of 0.55 and 0.36% for Met and SeMet, respectively, were obtained using 13C-enriched spikes. A concentration of 3417 +/- 8 microg g(-1) (one standard deviation, n = 6) was obtained using the 74Se-enriched SeMet spike. The concentration of SeMet measured in the yeast is equivalent to 66.43 +/- 0.24% of total Se and 30.31 +/- 0.11% of total Met is in the form of SeMet. Method detection limits (three times the standard deviation) of 3.4 and 1.0 microg g(-1) were estimated for Met and SeMet, respectively, based on a 0.25-g subsample of yeast with 1 mL of extract used for derivatization. A similar concentration of 5930 +/- 29 microg g(-1) (one standard deviation, n = 4) for Met and a lower concentration of 2787 +/- 49 microg g(-1) (one standard deviation, n = 4) for SeMet were obtained for this yeast sample using species-specific ID analysis based on GC/MS with 13C-enriched Met and SeMet spikes when a 2-h open microwave digestion approach using 8 M methanesulfonic acid was used.     

Particle size dependent chemistry from laser ablation of brass

The proportion of zinc and copper in particles formed by laser ablation of brass was found to vary with the particle diameter. Energy-dispersive X-ray analysis showed that smaller particles were zinc enhanced while larger particles were composed mostly of copper. A model based on condensation of vapor onto large droplets ejected from a melted liquid layer is proposed to describe the change in particle composition versus size.     

Static Scene Illumination Estimation from Videos with Applications

We present a system that automatically recovers scene geometry and illumination from a video, providing a basis for various applications. Previous image based illumination estimation methods require either user interaction or external information in the form of a database. We adopt structure-from-motion and multi-view stereo for initial scene reconstruction, and then estimate an environment map represented by spherical harmonics (as these perform better than other bases). We also demonstrate several video editing applications that exploit the recovered geometry and illumination, including object insertion (e.g., for augmented reality), shadow detection, and video relighting.     

Free volume theory of diffusion: Method of predicting activation energies of diffusion for gases in elastomers

It is well established that diffusion and relaxation processes in polymers above T_g are closely related in that they are both governed by the polymer segmental motions, which are believed to be determined by the free volume present in the system. The diffusion coefficients of gases in elastomers can be accounted for by the WLF equation using the “universal values” of constants A and B. The parameter K = B_D/B_η of Frisch and Rogers is used as a correction factor. An analysis has been made of the diffusion of five gases in nine elastomers, from data found in the literature. K and log D_g are shown to vary with the penetrant but not with the polymer. Therefore, once the values of K and log D_g of gases are determined, their diffusion coefficients in any elastomers of known T_g at a variety of temperatures can be estimated. From the Arrhenius and the WLF relationships, an equation is derived to predict the activation energy of diffusion directly from the temperature of diffusion, the glass transition temperature of the amorphous polymer, the predetermined value of K, and the universal constants A and B. In the systems studied, the predictions agree on the average to within 11–17% of the values calculated from the experimental data.     

Paclitaxel‐Loaded Polymer Nanoparticles for the Reversal of Multidrug Resistance in Breast Cancer Cells

Novel paclitaxel‐loaded polymer nanoparticles were developed for circumventing multidrug resistance (MDR) of malignant cancerous diseases, which is an unsolved clinical problem in cancer chemotherapy. In many cases, MDR is due to the intrinsic or acquired expression of an efflux pump, the P‐170 glycoprotein (P‐gp). By encapsulating paclitaxel in a water‐soluble and biocompatible synthetic polyampholyte using a solid‐state reaction the highly water‐soluble paclitaxel‐loaded nanoparticles are formed. The resulting paclitaxel nanoparticles with an average diameter of 250 nm show a significant reversal of chemoresistance in the drug‐resistant variants (MCF7/ADR, MT3/ADR) by a factor of 100 or more. The novel paclitaxel nanoparticles enter MDR breast cancer cells by adsorptive endocytosis bypassing the P‐gp, preventing the efflux of paclitaxel and thus restoring the anti‐proliferative effect of paclitaxel.     

Probing the Relationship of Long-Range Order in Nanodomain FeCo Alloys with Ternary Additions Using Neutron Diffraction

The effects of tailoring FeCo alloys with addition of ternary elements Pt, Pd, Mn, Ir, and Re have been investigated. In the composition range of 30 to 70 pct Co, FeCo alloys undergo a continuous order-disorder phase transition at a maximum temperature of 730 °C at the equiatomic composition. The effects of temperature and composition on the degree of long-range order in six alloys (Fe₇₀Co₃₀, Fe₆₇Co₃₀Pt₃, Fe₆₇Co₃₀Pd₃, Fe₆₇Co₃₀Mn₃, Fe₆₇Co₃₀Ir₃, and Fe₆₇Co₃₀Re₃; at. pct) were compared using neutron diffraction. The transition goes along with growing of antiphase domains during the heating process.     

Treatment of Cancer with Radio-Immunotherapy: What We Currently Know and What the Future May Hold

Radiotherapy and immunotherapy are most effective as cancer therapies in the setting of low-volume disease. Although initial studies of radio-immunotherapy in patients with metastatic cancer have not confirmed the efficacy of this approach, the role of radio-immunotherapy in patients with limited metastatic burden is unclear. We propose that further investigation of radio-immunotherapy in metastatic patients should focus upon patients with oligometastatic disease.     

A generalized model for Kalman filtering of motion information in video compression

In this paper, we tackle the problem of motion estimation in video compression. Since Full Search Algorithms (FSA) present the disadvantage of adding a high computational burden to the encoder, fast search techniques have been used in conjunction with predictive filtering, in such a way to guarantee an acceptable quality with an affordable complexity. The aim of this work is to propose a novel framework for Kalman filtering of motion information in compressed video sequences. The merits of our new framework are twofold: First, using an appropriate formulation of the system equations, several shortcomings inherent with former models in the literature are greatly counteracted. Secondly, it is constructed using a generalized structure in such a way to enclose a large variety of prediction models. Therefore, it can adapt to different types of motion activities in video sequences, without the need for a different formulation in each prediction model, as was the case in previous studies. Furthermore, we propose an adaptive motion compensation technique that permits an additional improvement to the decoded video quality. Our framework permits a considerable gain in the average performance compared to previous models and even to the FSA technique.