Structural characterization of bacterial lipopolysaccharides with mass spectrometry and on‐ and off‐line separation techniques

The focus of this review is the application of mass spectrometry to the structural characterization of bacterial lipopolysaccharides (LPSs), also referred to as “endotoxins,” because they elicit the strong immune response in infected organisms. Recently, a wide variety of MS‐based applications have been implemented to the structure elucidation of LPS. Methodological improvements, as well as on‐ and off‐line separation procedures, proved the versatility of mass spectrometry to study complex LPS mixtures. Special attention is given in the review to the tandem mass spectrometric methods and protocols for the analyses of lipid A, the endotoxic principle of LPS. We compare and evaluate the different ionization techniques (MALDI, ESI) in view of their use in intact R‐ and S‐type LPS and lipid A studies. Methods for sample preparation of LPS prior to mass spectrometric analysis are also described. The direct identification of intrinsic heterogeneities of most intact LPS and lipid A preparations is a particular challenge, for which separation techniques (e.g., TLC, slab‐PAGE, CE, GC, HPLC) combined with mass spectrometry are often necessary. A brief summary of these combined methodologies to profile LPS molecular species is provided. © 2012 Wiley Periodicals, Inc., Mass Spec Rev 32:90–117, 2013     

Preparation of PTFE/graphene nanocomposites by compression moulding and free sintering: A guideline

This work was aimed at preparing polytetrafluoroethylene (PTFE) nanocomposites filled with graphene nanoplatelets and investigating how the graphene nanoplatelets and the preparation techniques influenced the physical properties. Graphene was incorporated up to 4 vol % of the total PTFE system by dry and solvent assisted blending. The powder compaction was evaluated using the Kawakita/Ludde model to describe the compressibility of the powder blends. The nanocomposite billets were prepared using cold compression moulding by applying preform pressures between 12.7 and 140 MPa and the preform billets were sintered at 380°C using a specific sintering cycle. The changes in the physical dimensions, billet mass, density, and void content of the billets, pre and post sintering, were analyzed with experimental design to evaluate the influence of the precompaction pressure and graphene loading. From the evaluation it was concluded that the ideal compaction pressure was at 12.7 MPa and the solvent assisted blending was superior to the mechanical blending method. Furthermore, the compression creep tests confirmed the ideal processing temperature and graphene loading range to improve the mechanical properties. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43369.     

The effect of graphene nanoplatelet thickness on the fracture toughness of Si3N4 composites

Si₃N₄ composites with 3 and 5?wt% of graphene nanoplatelet (GNP) additions were prepared by spark plasma sintering. We used both commercially available GNPs and thinner few-layer graphene nanoplatelets (FL-GNPs) prepared by further exfoliation through ball milling with melamine addition. We found that by employing thinner FL-GNPs as filler material a 100% increase in the fracture toughness of Si₃N₄/3?wt% FL-GNP composites (10.5?±?0.2?MPa?m^1/2) can be achieved as compared to the monolithic Si₃N₄ samples (5.1?±?0.3?MPa?m^1/2), and 60% increase compared to conventional Si₃N₄/3?wt% GNP composites (6.6?±?0.4?MPa?m^1/2). For 5?wt% filler content the increase of the fracture toughness was near 50% for both GNP and FL-GNP fillers. The hardness of the composites decreased with increasing GNP content. However, composites reinforced with 5?wt% of FL-GNPs displayed 30% higher Vickers hardness (12.8?±?0.2?GPa) than their counterparts comprising conventional GNP fillers (9.8?±?0.2?GPa). We attribute the enhanced mechanical properties obtained with thinner FL-GNPs to their higher aspect ratio leading to a more homogeneous dispersion, higher interface area, as well as smaller pores in the ceramic matrix.     

Pilot-scale two-phase extraction of canola

An extraction process was developed in our laboratory for rapeseed (canola) with 10% (w/w) ammonia in methanol, containing 5% (vol/vol) water, and hexane to simultaneously produce an improved meal and a high-quality oil. To remove the hazards associated with the use of ammonia, a two-phase solvent extraction, with 0.08% (w/w) sodium hydroxide replacing the ammonia, was tested on a semipilot scale with a Szego mill and a Karr reciprocating-plate extraction column. Flooding curves and appropriate agitation parameters were examined for this system. Then, the effects of polar solvent-to-seed ratio, slurry-to-hexane flow ratio, plate amplitude and plate agitation frequency on extraction efficiency were investigated. The process is technically viable for industrial application. A meal that contained 0.9% residual oil, 44.4% protein and 2.79 mmol/kg glucosinolates (moisture and oil-free basis) and a miscella with 19.5% oil were obtained.     

Peripheral Nerve Injuries and Transplantation of Olfactory Ensheathing Cells for Axonal Regeneration and Remyelination: Fact or Fiction?

Successful nerve regeneration after nerve trauma is not only important for the restoration of motor and sensory functions, but also to reduce the potential for abnormal sensory impulse generation that can occur following neuroma formation. Satisfying functional results after severe lesions are difficult to achieve and the development of interventional methods to achieve optimal functional recovery after peripheral nerve injury is of increasing clinical interest. Olfactory ensheathing cells (OECs) have been used to improve axonal regeneration and functional outcome in a number of studies in spinal cord injury models. The rationale is that the OECs may provide trophic support and a permissive environment for axonal regeneration. The experimental transplantation of OECs to support and enhance peripheral nerve regeneration is much more limited. This chapter reviews studies using OECs as an experimental cell therapy to improve peripheral nerve regeneration.     

Destabilization of Yellow Mustard Emulsion Using Organic Solvents

An aqueous extraction process was developed consisting of aqueous contact with dehulled yellow mustard flour to recover protein followed by dissolution of the released emulsion in dimethylformamide (DMF) or isopropyl alcohol (IPA) to recover the released oil in the form of single-phase oil–solvent miscellae suitable for industrial applications. Only some 38 ± 3 % of the oil in the yellow mustard emulsion was extracted using DMF even at high weight ratios since DMF is widely miscible with water, preventing separation of the oil from the emulsion. A ternary phase diagram of DMF/oil/water was prepared and confirmed the limited solubility of the oil in DMF in the presence of water. The use of 31:1 IPA:oil weight ratio could effectively recover over 94 % of the oil in the emulsion; however, multiple-stage treatment of the emulsion was proven to be more efficient with lower volumes of IPA required to achieve high oil extraction yields. The results suggest that the optimal conditions for multiple-stage process were four stages using 2:1 IPA:oil weight ratio, with 96 ± 1 % oil recovery from the emulsion.     

pCBT/MWCNT Nanocomposites Prepared by In situ Polymerization of CBT After Solid‐Phase High‐Energy Ball Milling of CBT with MWCNT

pCBT/MWCNT nanocomposites were prepared by in situ polymerization of CBT after solid‐phase HEBM of the polymerization catalyst containing CBT with MWCNT. The crystallinity and crystallization behavior of the pCBT nanocomposites were studied by WAXS and DSC. The MWCNTs did not affect the crystallinity of the isothermally produced pCBT significantly, but acted as nucleation agents during the crystallization of pCBT from its melt. pCBT/MWCNT nanocomposites were subjected to DMTA, static flexure, and dynamic Charpy impact tests. The flexural modulus, strength, and impact strength from these tests all went through a maximum as a function of the MWCNT content. Optimum properties were found in the MWCNT range of 0.25–0.5 wt.‐%.

     

Decoding skills in nonverbal communication and perceived interviewer effectiveness.

Examined the relationship between decoding ability in nonverbal communication and characteristic verbal and nonverbal behavior of beginning counselors during interviews. There were 17 "good" decoders and 17 "poor" decoders who conducted short interviews with a client; the decoders were assessed by the Profile of Nonverbal Sensitivity. Interviewer behavior was rated subjectively by the client as well as objectively by 2 trained observers who counted the occurrences of certain verbal and nonverbal behaviors. Comparison of good and poor decoders revealed no significant differences between groups on the 2 multivariate sets of ratings for clients and observers. (7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Standard vapour mixtures by means of a multi-capillary flow-proportioner

A dynamic method is described for the preparation of standard gaseous mixtures of condensable vapours such as water vapour, gas odorants or hydrocarbons with an accuracy of better than ·5%. The possible concentration range is from a few parts per miliion to saturation level. The method is also suitable for the preparation of multi-vapour mixtures.