Detection and expression analysis of recombinant proteins in plant-derived complex mixtures using nanoUPLC-MS(E)

The use of mass spectrometry to identify recombinant proteins that are expressed in total soluble proteins (TSPs) from plant extracts is necessary to accelerate further processing steps. For example, the method consists of TSP sample preparation and trypsin digestion prior to the preliminary characterization using nanoUPLC-MS(E) analysis of the recombinant proteins that are expressed in TSP samples of transgenic soybean seeds. A TSP sample as small as 50 μg can be effectively analyzed. In this study, transgenic soybean seeds that expressed recombinant cancer testis antigen (CTAG) were used. The procedure covered 30% of the protein sequence and was quantified at 0.26 ng, which corresponded to 0.1% of the TSP sample. A comparative proteomic profile was generated by the comparison of a negative control and sample that showed a unique expression pattern of CTAG in a transgenic line. The experimental data from the TSP extraction, sample preparation and data analysis are discussed herein.     

Structural characteristics of chalcopyrite from a Cu(Au) ore deposit in the Caraj��s Mineral Province, Brazil

Mössbauer spectra and X-ray diffraction data show a chalcopyrite from the Cristalino Cu(Au) deposit in the Carajás Mineral Province in northern Brazil to consist of a single, tetragonal phase. This is in stark contrast to a previously described chalcopyrite from the Camaquã copper mine in southern Brazil, obviously reflecting differences in mineral (and thus ore deposit) genesis.     

Ion-exchange of monovalent and bivalent cations with NaA zeolite membranes : a molecular dynamics study

Molecular simulations using the method of molecular dynamics have been carried out to study the dynamics and energetics of ion exchanges between monovalent and bivalent cations in supercritical and subcritical (liquid) electrolyte solutions (here Li⁺, and Ca⁺⁺ in aqueous solutions of LiCl and CaCl₂) and an ion exchange membrane (NaA zeolite) using direct simulations of up to a nanosecond or more. NaA zeolites are widely used in many commercial ion-exchange processes including detergents. Results show that with appropriate driving forces, such ion exchange processes can be clearly witnessed and investigated using molecular simulations at these timescales, especially for supercritical solutions. An attempt is made to understand the phenomenon of ion exchange at the molecular level. Results have shown that the ion-exchange process is primarily energetically driven and entropic forces do not appear to be playing a significant role in the exchanges observed. For supercritical LiCl solutions, small differences were found between the energy of the Li⁺ inside and outside the membrane. In contrast, for Na⁺ there was a considerable energetic advantage in being outside the membrane, making the overall exchange process energetically favourable. In subcritical (liquid) LiCl solutions an exchange was found to be more favourable energetically than supercritical solutions. For Ca⁺⁺ similar trends were observed, except the differences in the energies were much larger (compared to the corresponding Li⁺ exchanges), making them more energetically efficient, as has also been observed experimentally. In addition to clarifying the molecular basis for these exchanges, simulations can also potentially be very useful to determine the behaviour (e.g. state dependence, etc.) of hydrodynamic parameters commonly used to characterize ion-exchange processes at a fundamental molecular level, and to determine if the hydrodynamic equations used for ion-exchange processes are applicable to nano-systems that can be studied using simulations.     

Sensitive interferometric detection of ultrasound for minimally invasive clinical imaging applications

Miniaturized optical detectors of ultrasound represent a promising alternative to piezoelectric technology and may enable new minimally invasive clinical applications, particularly in the field of optoacoustic imaging. However, the use of such detectors has so far been limited to controlled lab environments, and has not been demonstrated in the presence of mechanical disturbances, common in clinical imaging scenarios. Additionally, detection sensitivity has been inherently limited by laser noise, which hindered the use of sensing elements such as optical fibers, which exhibit a weak response to ultrasound. In this work, coherence‐restored pulse interferometry (CRPI) is introduced – a new paradigm for interferometric sensing in which shot‐noise limited sensitivity may be achieved alongside robust operation. CRPI is implemented with a fiber‐based resonator, demonstrating over an order of magnitude higher sensitivity than that of conventional 15 MHz intravascular ultrasound probes. The performance of the optical detector is showcased in a miniaturized all‐optical optoacoustic imaging catheter.     

Small and Large Scale Behavior of the Poissonized Telecom Process

The stable Telecom process has infinite variance and appears as a limit of renormalized renewal reward processes. We study its Poissonized version where the infinite variance stable measure is replaced by a Poisson point measure. We show that this Poissonized version converges to the stable Telecom process at small scales and to the Gaussian fractional Brownian motion at large scales. This process is therefore locally as well as asymptotically self-similar. The value of the self-similarity parameter at large scales, namely the self-similarity parameter of the limit fractional Brownian motion, depends on the form the Poissonized Telecom process. The Poissonized Telecom process is a Poissonized mixed moving average. We investigate more general Poissonized mixed moving averages as well.     

Micromechanical computational modeling of expansive porous media

A modified Terzaghi principle is proposed to describe the influence of locally coupled electro-chemo-mechanical processes in highly compacted swelling clays upon the form of the macroscopic modified effective stress principle. The two-scale model is derived using the homogenization procedure to upscale the microscopic behavior of a two-phase system composed of clay particles saturated by a completely dissociated electrolyte aqueous solution. Numerical experiments are performed to illustrate the results in a particular cell geometry. To cite this article: M.A. Murad, C. Moyne, C. R. Mecanique 330 (2002) 865–870.     

Selective plane illumination optical and optoacoustic microscopy for postembryonic imaging

Intravital imaging of large specimens is intrinsically challenging for postembryonic studies. Selective plane illumination microscopy (SPIM) has been introduced to volumetrically visualize organisms used in developmental biology and experimental genetics. Ideally suited for imaging transparent samples, SPIM can offer high frame rate imaging with optical microscopy resolutions and low phototoxicity. However, its performance quickly deteriorates when applied to opaque tissues. To overcome this limitation, SPIM optics were merged with optical and optoacoustic (photoacoustic) readouts. The performance of this hybrid imaging system was characterized using various phantoms and by imaging a highly scattering ex vivo juvenile zebrafish. The results revealed the system's enhanced capability over that of conventional SPIM for high‐resolution imaging over extended depths of scattering content. The approach described here may enable future visualization of organisms throughout their entire development, encompassing regimes in which the tissue may become opaque.

     

Regular multigraphs and their application to the Monte Carlo evaluation of moments of non-linear functions of Gaussian random variables

This paper expands on the multigraph method for expressing moments of non-linear functions of Gaussian random variables. In particular, it includes a list of regular multigraphs that is needed for the computation of some of these moments. The multigraph method is then used to evaluate numerically the moments of non-Gaussian self-similar processes. These self-similar processes are of interest in various applications and the numerical value of their marginal moments yield qualitative information about the behavior of the probability tails of their marginal distributions.