نتایج جستجو برای: freeze

تعداد نتایج: 16891  

Today, sperm cryopreservation is a routine practice in infertility clinics. One of the alternative methods to preserve sperm is freeze-drying. This process consists of three steps. The first step is sample freezing, during which the solvent is separated from the solvent. Water forms ice crystals and the solute is placed between the ice crystals. Freezing may be done in a separate device or in a...

Journal: :iranian journal of science and technology (sciences) 2015
m. r. nikudel

freeze-thaw is one of the most powerful weathering agents that may cause a rapid change in the initial engineering properties of stones, and limit their durability. freeze-thaw induces stress over the pores’ surface of stones. consequently, stone durability is closely related to its engineering and physical properties. the purpose of this study is estimating the engineering properties of deteri...

2015
Ronald Angoff Jillian Wood Maria C. Chernock Diane Tipping

BACKGROUND The aim of this study was to determine whether the use of visual freeze indicators on vaccines would assist health care providers in identifying vaccines that may have been exposed to potentially damaging temperatures. METHODS Twenty-seven sites in Connecticut involved in the Vaccine for Children Program participated. In addition to standard procedures, visual freeze indicators (FR...

2001
Todor Donev Irena Savova Anna Kujumdzieva

The growth curves of strains belonging to genera Candida and Saccharomyces grown through surfaced and submerged cultivation and their survival after lyophilization have been studied. Conclusions of practical importance have been drawn. It was found out that three-day-old cultures cultivated in solid medium possessed maximal resistance to freeze-drying. Nevertheless the cultures obtained by subm...

Journal: :Proceedings. Biological sciences 2004
C L Brown J S Bale K F A Walters

Cold-hardy insects overwinter by one of two main strategies: freeze tolerance and freeze avoidance by supercooling. As a general model, many freeze-tolerant species overwinter in extreme climates, freeze above -10 degrees C via induction by ice-nucleating agents, and once frozen, can survive at temperatures of up to 40 degrees C or more below the initial freezing temperature or supercooling poi...

Journal: :The Journal of Cell Biology 1972
Helmut Plattner Walter M. Fischer Werner W. Schmitt Luis Bachmann

The technique of spray-freeze etching was applied to unicellular organisms. The superior freezing rates obtainable with this method gave excellent cryofixation on Chlorella, Euglena, and spermatozoa without the use of antifreeze agents, and cell damage due to ice crystal formation was never observed. In many instances the resultant morphology differed significantly from that obtained from glyce...

Journal: :iranian journal of public health 0
zahra kakooei 1. dept. of medical parasitology and mycology, school of public health, tehran university of medical sciences , tehran, iran. mehdi mohebali 1. dept. of medical parasitology and mycology, school of public health, tehran university of medical sciences , tehran, iran ; 2. center for research of endemic parasites of iran(crepi), tehran university of medical sciences , tehran, iran. behnaz akhoundi 1. dept. of medical parasitology and mycology, school of public health, tehran university of medical sciences , tehran, iran. abbas rahimi foroshani 3. dept. of biostatistics and epidemiology, school of public health, tehran university of medical sciences , tehran, iran.

this study aimed to evaluate freeze-dried sera as an alternative to non-freeze dried for detection of anti-leishmania infantum antibodies over the course of 11 months using the direct agglutination test (dat).altogether, 60 serum samples (30 from humans and 30 from dogs) were collected from various geographical locations in iran. all the collected sera were pooled and each pooled serum sample c...

1958
C. S. THOM H. SHAW

A set of freeze thresholds is defined which replaces the loosely defined element “killing frost.” Freeze series are tested and found to be random. This makes it possible to fit frequency distributions. It is hypothesized that these distributions are normal and a test of significance verifies this. A hypothesis that the variance parameter is constant over Iowa is tested and found to be true. It ...

2001
Kenneth Storey

Table of contents 1. Strategies of winter survival in animals 2. Freeze-induced gene expression 2.1. Freeze-induced gene expression in wood frogs 2.2. Freeze-induced gene expression in hatchling turtles and mitochondrial gene expression 3. Freeze tolerance, glucose metabolism and signal transduction 3.1. Unique glucose metabolism of freeze tolerant frogs 3.2. Structural modification of insulin ...

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