In recent years some attention has been focused on the low temperature storage of various protozoa. The purpose of this work was to confirm that Trichomonas vaginalis can be preserved for several months at a temperature of -196°C. in liquid nitrogen. Weinman and McAllister (1947), who successfully preserved a number of pathogenic protozoa, failed to preserve T. vaginalis, and only a proportion ...

Protein conformational changes, which regulate the activity of proteins, are induced by the alternation of intramolecular interactions. Therefore, the detection of the local environmental changes around the key amino acid residues is essential to understand the activation mechanisms of functional proteins. Here we developed the methods to scan the local environmental changes using the vibration...

Molecular contacts are generally poorly conducting because their energy levels tend to lie far from the Fermi energy of the metal contact, necessitating undesirably large gate and bias voltages in molecular electronics applications. Molecular radicals are an exception because their partly filled orbitals undergo Kondo screening, opening the way to electron passage even at zero bias. Whereas tha...

Flow cytometry is set to become the standard method for enumerating prokaryotes and viruses in marine samples. However, the samples need to be flash-frozen in liquid nitrogen directly after aldehyde fixation. Because liquid nitrogen may not always be available, we tested the potential of sodium azide as a preservative for prokaryotes and viruses in marine samples as a possible alternative. For ...

When He gas is injected from room temperature into boiling liquid N2, boiling is suppressed, leaving liquid surface flat like a mirror. Although the qualitative explanation for this phenomenon is known [Minkoff G J et al. Nature 1957;180(4599):14134.], it has not been studied quantitatively and comprehensively yet. In this report, we made careful simultaneous measurements of temperature and wei...

Human granulocytes (PMNL) were successfully cryopreserved for up to 14 months. The PMNL (1-2 X 10(7)/ml) were stored in 2-ml ampoules in the gas phase of liquid nitrogen at a temperature between -160 degrees C and -196 degrees C using dimethylsulphoxide (DMSO 10%) as cryoprotectant. Morphology and phagocytic and bactericidal capacity were best preserved by adding fetal calf serum to the freezin...

Received for publication 26 April 1963. is thawed immediately after freezing a precipitate of denatured protein can be seen in the solution. We have recently been investigating the storage of human red cells in liquid nitrogen for serological purposes (Huntsman, Hum, Ikin, Lehmann, and Liddell, 1962). We thought that this technique might be useful for the preservation of haemoglobin as well as ...

Gonococci suspended in 1% proteose peptone containing 8% glycerol can be snap frozen in liquid nitrogen without detectable loss on thawing. This recovery rate has allowed the use of frozen organisms as the starting inoculum for the bulk growth of gonococci and to preserve gonococci both in urethral pus and after primary subculture for use in studies on gonococcal virulence. The method described...

The purpose of this study was to determine the negative effects (cryodamage) on human spermatozoa after freeze-thawing and to determine whether freeze-thawing of spermatozoa with a programmed slow freezer is better than freezing with liquid nitrogen vapour (rapid freezing) with regard to alterations in sperm chromatin and morphology in semen from fertile (donor) and subfertile, IVF/ICSI, patien...