An alternative approach to carbon nanotube sample preparation for TEM investigation.

A two-stage replication technique (positive replica) is shown to be suitable for transmission electron microscopy (TEM) examination of carbon nanotubes (CNTs) and other one-dimensional nanostructures in their longitudinal direction. This method enables handling the fragile nanostructures, is fast and simple and allows to study the growth mechanism of nanofeatures, including the early stages of their growth. CNTs may also be examined when the growth layers are very thin, and even when only a few nanotubes are on a substrate. Replicas can be taken from various substrate shapes covered with nanostructures and from minute or specifically selected areas of the substrates. CNTs extracted by the replica are not disturbed, and their nanostructures are preserved. It is demonstrated that using positive replicas, HRTEM images from the nanosized carbon forms can also be obtained.

Identification of the abiotic stress-related transcription in little Neptune grass Cymodocea nodosa with RNA-seq.

Seagrasses exhibit vital ecological roles in the marine environment. Nevertheless, the genomic resources available for seagrasses are still scarce. In the present study, the transcriptome of Cymodocea nodosa was sequenced with a view to study the molecular mechanisms underlying abiotic stress responses. The sequenced transcriptome for the species was near-complete and a high percentage of the transcripts was computationally annotated. An experimental simulation of marine plant exposure to extreme temperature (34°C), salinity (50psu) and their combination was conducted. A dynamic transcriptome 24h response (short-term) from stress initialization was recorded. The most noteworthy alteration in gene expression was observed in heat-stressed plants. Transcripts associated with development, photosynthesis, osmotic balance and stress-response were differentially expressed, under the set experimental conditions. Results indicate a potential negative interaction of heat and osmotic stress on seagrasses transcriptome.

Monitoring of pesticide residues in fresh peaches produced under conventional and integrated crop management cultivation.

The frequency and severity of crop protection product (pesticide) contamination of peaches grown conventionally were compared with those of peaches grown by integrated crop management (ICM). The peach samples (n = 150) were collected preharvest (June-August 2001) from both conventional (n = 55) and ICM (n = 95) cultivations from the Pella and Imathia districts of Macedonia, Northern Greece. The residue levels of selected insecticides, fungicides and acaricides in peach samples were determined by gas chromatography-mass spectrometry following solid-phase extraction. The concentrations of all detected pesticides were lower than the maximum residue limits (MRLs) in all peach samples grown with the ICM system (p<0.001). However, chlorpyrifos residues at levels higher than the MRLs were detected in four peach samples (i.e. 7% of the total samples) grown by the conventional system. Comparing the results for both cultivation methods with the reported average percentage (3.6%) of fruit samples with pesticide residues above the MRLs (European Union report for Greece in 2001), it was concluded that the initial implementation of the ICM in Greece was successful. The present study indicates that ICM cultivation has a higher efficiency in terms of product safety and quality. Furthermore, the results suggest that the application of conventional cultivation requires continuous monitoring of various crop protection product levels.