Quantitative proteomics: a review of different methodologies

The present review attempts to cover the vast array of methods which have appeared in the last few years for performing quantitative proteome analysis. These methods are divided into two classes: those applicable to conventional two-dimensional map analysis, coupling orthogonally a charge-based step (isoelectric focusing) to a size-based separation [sodium dodecylsulfate (SDS)-electrophoresis] and those applicable to two-dimensional chromatographic protocols. The first method, although being by and large the most popular approach, can offer differential display of paired samples with relatively few methods, the oldest one being based on statistical analysis performed on sets of gels via powerful software packages, such as the MELANIE, PDQuest, Z3 and Z4000, Phoretix and Progenesis. Recent developments comprise analysis performed on a single gel containing mixed samples differentially labeled, either with fluorophors (Cy3 and Cy5) or with d(0)/d(3) acrylamide. Conversely, chromatographic approaches, which mostly rely on analysis not of intact proteins but of their tryptic digests, offer a panoply of differential labeling protocols, most of which rely on stable isotope tagging. Essentially, all possible reactions have been described, such as those involving Lys, Asp, Glu, Cys residues, as well as a number of methods exploiting differential derivatization of amine and carboxyl groups generated during proteolysis. All such methods are described and evaluated.     

The Ã1A1-X̃1A1 two-photon fluorescence excitation spectrum of 1,2-difluorobenzene

The two-photon fluorescence excitation spectrum of 1,2-difluorobenzene was obtained with a tunable dye laser calibrated using a combination of the neon optogalvanic spectrum and etalon fringes. The spectrum consists only of A₁-A₁ bands but the use of linear and circular polarization divides the bands into two types. The 0⁰₀ type retains its intensity in circular polarization and, rotationally, shows little or no zero-rank contribution. The 5¹₀ (or 14¹₀) type loses much of its intensity in circular polarization and, rotationally, shows a large zero-rank contribution. These observations all accord with the trace of the two-photon transition tensor being close to zero for the 0⁰₀ type and large for the 5¹₀ type, the latter type being involved in vibronic interaction which mixes the $\text{A}\text{?}$ and $\text{X}\text{?}$ states. There is strong evidence for Fermi resonance between the 5¹ and 6¹10¹ levels. Parts of the one-photon absorption spectrum have been photographed to aid sequence identification and also to look for the 5¹₀, A₁-A₁ transition. This transition is not observed: nor is there any evidence for intensity stealing by b₂ vibrations.     

Wavelet and chaos analysis of irregularities of vortex shedding

This paper reports the potential of using two types of wavelets namely; the Mexican hat and the modulated Gaussian wavelets to analyze the frequency of vortex shedding from a single cylinder in a cross flow. Furthermore, the paper examines the chaotic behaviors of the vortex shedding signals of various positions along the cylinder span. It is found that the signals along the cylinder are characterized by high-energy contents in the low frequency range below the Strouhal frequency.     

Roughness and turbulence intensity effects on the induced flow oscillation of a single cylinder

The effects of the surface roughness and the turbulence intensity on the dynamic characteristics of the flow induced oscillations of an elastically supported single circular cylinder in a cross flow in the vortex shedding and fluid elastic regions were experimentally investigated. The results of these experiments indicate that, for the vortex shedding region, increasing the surface roughness results in a reduction of the amplitude of oscillation, while in the fluid elastic region, increasing the surface roughness tends to enhance the oscillations. A similar trend for the dynamic response of the cylinder in the vortex shedding region was also observed when the free stream turbulence intensity was varied, while in the fluid elastic region variations in the free stream turbulence intensity were observed to have no drastic effect on the dynamic response of the cylinder.     

Synthesis of Carbon–Metal Multi-Strand Nanocomposites by Discharges in Heptane Between Two Metallic Electrodes

We studied composite wires assembled from electric field-driven nanoparticles in a dielectric liquid (heptane) to elucidate the exact processes and controlling factors involved in the synthesis of the multi-phase nanocomposites. Filamentary wires are synthesized by a two-step process: (1) abundant nanoparticle production, mostly of carbonaceous types, from heptane decomposition by spark discharge and of metal nanoparticles by electrode erosion and (2) assembly of hydrogenated amorphous carbonaceous nano-clusters with incorporated metal nanoparticles forming wires by dielectrophoretic transport while maintaining a high electric field between electrodes kept sufficiently separated to avoid breakdown. Four types of nanocomposites products are identified to form at different steps in distinctive zones of the setup. The black carbonaceous agglomerates with metal spherules made by electrode erosion represent the pyrolytic residues of heptane decomposition by spark discharge during step 1. The filamentary wires grown in the interelectrode gap during step 2 get assembled by dielectrophoretic transport and chaining forces. Their great stability is shown to express the concurrent effect of polymerization favoured by the abundance of metal catalysts. The nature, abundance, and transformation of solid particles from the source materials versus discharge conditions control the morphological and compositional diversity of the wires. The production of mineral and metal nano-particles traces the efficiency of dielectrophoresis to separate compound particle mixtures by size and to co-synthesize nanostructured microcrystals and nanocomposites. The link between impurities and the variability from nano- to micro-scales of the synthesized products provides an innovative contribution to the knowledge of nanocomposite synthesis triggered by electric field.     

Dehydration and dehydrogenation of cyclohexanol over AlPO4-5 based molecular sieves

The role of incorporated divalent metal (Mn, Mg, Co and Zn) incorporated into the framework of AlPO₄-5 in conversion of cyclohexanol has been examined. The influence of these metals to cyclohexene and cyclohexanone selectivities was correlated to the acidity and basicity properties of these molecular sieves. Possible mechanism for the dehydration and dehydrogenation for cyclohexanol was proposed.     

Post-Harvest Operations to Generate High-Quality Medicinal Cannabis Products: A Systemic Review

The traditional Cannabis plant as a medicinal crop has been explored for many thousands of years. The Cannabis industry is rapidly growing; therefore, optimising drying methods and producing high-quality medical products have been a hot topic in recent years. We systemically analysed the current literature and drew a critical summary of the drying methods implemented thus far to preserve the quality of bioactive compounds from medicinal Cannabis. Different drying techniques have been one of the focal points during the post-harvesting operations, as drying preserves these Cannabis products with increased shelf life. We followed or even highlighted the most popular methods used. Drying methods have advanced from traditional hot air and oven drying methods to microwave-assisted hot air drying or freeze-drying. In this review, traditional and modern drying technologies are reviewed. Each technology will have different pros and cons of its own. Moreover, this review outlines the quality of the Cannabis plant component harvested plays a major role in drying efficiency and preserving the chemical constituents. The emergence of medical Cannabis, and cannabinoid research requires optimal post-harvesting processes for different Cannabis strains. We proposed the most suitable method for drying medicinal Cannabis to produce consistent, reliable and potent medicinal Cannabis. In addition, drying temperature, rate of drying, mode and storage conditions after drying influenced the Cannabis component retention and quality.     

Thermodynamic analytical model of a loop heat pipe

A thermodynamics analytical model is developed to explore different parameters effects on a loop heat pipe (LHP). The LHP is a two-phase device with extremely high effective thermal conductivity that utilizes the thermodynamic pressure difference to circulate a cooling fluid. The effects of pipe length, pipe diameter, condenser temperature, and heat load are reported. As pipe length increases and/or pipe diameter decreases, a higher temperature is expected in the evaporator.     

Production of SiC Nanoparticles in Carbon Network by Pulsed Electrical Discharges in Liquid Hexamethyldisilazane with Gaseous Bubbles

Plasma Chemistry and Plasma Processing - Discharges in liquid can efficiently produce nanoparticles via electrode erosion and (or) liquid decomposition. Although in-liquid spark discharges promote...