Electron tomography is currently the only method that allows the direct three-dimensional visualization of macromolecules in an unperturbed cellular context. In principle, tomography should enable the identification and localization of the major macromolecular complexes within intact bacteria, embedded in amorphous ice. In an effort to optimize conditions for recording data that would bring us ...

Freeze fixation of cells and tissues provides a method of avoiding chemical fixation artifacts (9), and it often improves immunolocalization (1,4,9). Various devices and techniques have been devised for freeze fixation of different microbial, plant and animal materials (2,5,6,9,10). One of the simplest methods is plunge freezing, in which samples for microscopy are quickly plunged into a suitab...

Genomic DNA extraction with a high quantity and quality is a basic requirement in molecular biology. The DNA obtained was free of any contamination proteins, polysaccharide, polyphenols and colored pigments. These compounds would interfere with the genomic isolation procedures and downstream reactions such as restriction enzyme analysis and gene amplification. The isolated genomic DNA was fo...

Acquisition of freezing tolerance during the seed development of Pisum sativum L. cv. Akabana was studied in relation to changes in growth, dry matter accumulation, and water content. Seeds were cooled down rapidly by direct plunging into liquid nitrogen, so that below a determined water content, tissues could vitrify with the consequent survival of seeds. The proportion of seeds that were able...

The site of protonation in a molecule can greatly affect the fragments observed in product ion MS/MS spectra. In electrospray positive ionization mass spectra, protonation usually occurs predominantly on the most basic site on the molecule to produce the thermodynamically favored protonated species. However, the literature is unclear whether liquid phase or gas phase thermodynamics has the grea...

We evaluated the possible induction of a systemic immune response to increase anti-tumour activity by the re-implantation of destructive tumour tissue treated by liquid nitrogen in a murine osteosarcoma (LM8) model. The tumours were randomised to treatment by excision alone or by cryotreatment after excision. Tissue from the tumour was frozen in liquid nitrogen, thawed in distilled water and th...

We studied the effects of liquid nitrogen storage of maize, common bean and soybean seeds on their germination, electrolyte leakage, levels of chlorophylls, phenolics, aldehydes, proteins and peroxidase activity. After storage for 28 days, seeds were retrieved from liquid nitrogen, some were set to germinate and others were analyzed biochemically. No phenotypic modifications were observed visua...

Title of Document: FLOW AND ATOMIZATION CHARACTERISTICS OF CRYOGENIC FLUID FROM A COAXIAL ROCKET INJECTOR Vivek Gautam, Ph.D., 2007 Directed By: Professor, Ashwani K. Gupta, Department of Mechanical Engineering High thrust-to-weight ratio and consistent performance over a range of operating conditions make cryogenic rocket engines one of the best options for space propulsion. However, future sp...