The potential of pyrolysis/gas chromatography/mass spectrometry for determining the progress of lignification: An investigation of maturing asparagus sclerenchyma tissue

Sclerenchyma tissues from semi-mature and mature asparagus spears were analysed by pyrolysis/gas chromatography/mass spectrometry and by conventional chemical methods in order to determine the degree of lignification and compare analytical techniques. The pyrolysis data are similar to those obtained by a chemical method involving alkaline extraction at 70°C followed by spectrophotometric determination of phenolic content. The pyrolysis method was more rapid, sensitive and informative than the chemical technique and shows considerable potential for studying the chemical basis of the textural development of plant foods.     

A Novel Dimeric Eremophilane from Ligularia virgaurea spp. oligocephala

A novel dimeric eremophilane, ligulolide B, was isolated from the alcoholic extract of the whole plant of Ligularia virgaurea spp. oligocephala. The structure was elucidated by various spectroscopic methods including intensive 2D NMR techniques （^1H-^1H COSY, gHMQC, gHMBC and ^1H-^1H NOESY） and HR-ESI-MS.     

Numbers,scale and symbols: the public understanding of nanotechnology

Nanotechnology will be an increasing part of the everyday lives of most people in the world. There is a general recognition that few people understand the implications of the technology, the technology itself or even the definition of the word. This lack of understanding stems from a lack of knowledge about science in general but more specifically difficulty in grasping the size scale and symbolism of nanotechnology. A potential key to informing the general public is establishing the ability to comprehend the scale of nanotechnology. Transitioning from the macro to the nanoscale seems to require an ability to comprehend scales of one-billion. Scaling is a skill not common in most individuals and tests of their ability to extrapolate size based upon scaling a common object demonstrates that most individuals cannot scale to the extent needed to make the transition to nanoscale. Symbolism is another important vehicle to providing the general public with a basis to understand the concepts of nanotechnology. With increasing age, individuals are able to draw representations of atomic scale objects, but these tend to be iconic and the different representations not easily translated. Ball and stick models are most recognized by the public, which provides an opportunity to present not only useful symbolism but also a reference point for the atomic scale.     

On-line system for peptide mapping by capillary electrophoresis at sub-micromolar concentrations

Peptide mapping has been widely used for the identification of modified proteins involved in certain diseases. Despite the fact that capillary electrophoresis (CE) has been shown to be a powerful tool for the separation and detection of tryptic peptide fragments after protein digestion, this technique lacks sensitivity for mapping proteins isolated in very small quantities from biological samples. Consequently, it has been necessary to preconcentrate the protein before adding the proteolytic enzyme for digestion in solution. These experimental steps are quite long, labor intensive and require a lot of sample handling. In this paper, we describe an on-line system allowing digestion of the protein, followed by preconcentration, separation and detection of the tryptic fragments in 4 h. Up to an 800-fold preconcentration factor was achieved for cytochrome c, despite a loss of separation efficiency induced by the multiple-valve design of the system and dispersion of the 60-nl desorption plug. Moreover, our system showed good migration time reproducibility between peptide maps and could be reused for several samples.     

Hydrogen isotope analysis of natural abundance and deuterium-enriched waters by reduction over chromium on-line to a dynamic dual inlet isotope-ratio mass spectrometer

This paper describes the application of a simple chromium reduction furnace which can be interfaced with a dual inlet isotope-ratio mass spectrometer thus providing the capacity for cheap, fast, accurate and precise measurement of deltaD(V-SMOW) by dynamic mass spectrometry. Measurements are precise to the order of < or =0.5 per thousand. Mean 95% confidence intervals for the Vienna Standard Mean Ocean Water (V-SMOW) to Standard Light Antarctic Precipitation (SLAP) range are in the order of 2.5 per thousand and the system is linear over the range -428 to 23,000 per thousand. Memory effects do exist, but are small for natural abundance samples and can be minimised by careful planning of the analytical load.     

Development of an enzymatic microreactor based on microencapsulated laccase with off-line capillary electrophoresis for measurement of oxidation reactions

Microencapsulation is used here as a new technique to immobilize enzymes in a microreactor coupled off-line to capillary electrophoresis (CE), allowing the determination of enzymatic reaction products. The redox enzyme laccase was encapsulated using the method of interfacial cross-linking of poly(ethyleneimine) (PEI). The 50 μm diameter capsules were slurry packed from a suspension into a capillary-sized reactor made easily and quickly from a short length of 530 μm diameter fused-silica tubing. The volume of the bed of laccase microcapsules in the microreactor was in the order of 1.1 μL through which 50 μL of the substrate o-phenylenediamine (OPD) was flowed. The oxidation product 2,3-diaminophenazine (DAP) and the remaining OPD were quantified by CE in a pH 2.5 phosphate buffer. Peak migration time reproducibility was in the order of 0.4% RSD and peak area reproducibility was less than 1.7% RSD within the same day. Using the OPD peak area calibration curve, a conversion efficiency of 48% was achieved for a 2-min oxidation reaction in the microreactor.     

Capillary zone electrophoresis separation and laser-based detection of both fluorescein thiohydantoin and dimethylaminoazobenzene thiohydantoin derivatives of amino acids

Capillary zone electrophoresis is employed for the separation and analysis of both fluorescein thiohydantoin and dimethylaminoazobenzene thiohydantoin derivatives of amino acids. Detection of minute amounts of these amino acid derivatives is an important milestone in the development of a high sensitivity protein sequencer. Current detection limits for the fluorescein derivative is on the order of 10(-21) moles whereas detection limits for the dimethylaminoazobenzene derivative is on the order of 10(-16) moles.     

Determining the efficacy of a nanotechnology media product in enhancing children’s engagement with nanotechnology

Public engagement in nanotechnology media products can lead to a greater interest in understanding of nanotechnology. A study was undertaken to determine middle school student engagement in Nanooze, a magazine featuring nanotechnology research that has been developed for a young adult audience. Teachers at 116 Detroit middle schools distributed two issues of the magazine to their students, and surveys were collected from 870 students after reading the magazines. Results suggest that the majority of students liked reading the magazine and learned something about nanotechnology. Engagement in nanotechnology led to understanding of nanotechnology. The Nanooze magazine was an effective medium for engaging middle school students in learning about nanotechnology.