نتایج جستجو برای: freeze thaw cycles
تعداد نتایج: 107248 فیلتر نتایج به سال:
We investigated the effect of multiple freeze-thaw cycles on mumps, measles, and rubella virus serum antibody levels with whole-virus immunoglobulin G enzyme-linked immunoassays. Fresh serum samples from nine healthy adult volunteers were divided into six sets of five aliquots each. Samples were taken through a total of 10 freeze-thaw cycles and stored at 4 degrees C until assayed. Each assay m...
the cold climate is a favorable parameter for the development of tension cracks and decrease of rock brittleness. therefore, this paper attempts to investigate the hamekasi porous limestone in order to predict the brittleness indices during freeze-thaw cycles. the freeze–thaw test was executed for one cycle including 16 h of freezing, and 8 h of thawing. the geo mechanical properties and brittl...
an experimental program was carried out to investigate the behavior of steel, fiber reinforced concrete (sfrc) under abrasion and cycles of freeze and them. compression and flexural tests were also performed in order to reach a comprehensive conclusion of the response. in total, over 200 specimens were tested the test variables included two concrete strength., (i. e., 28 mpa as normal strength ...
The effect of bacterial cellulose (BC) on the freeze-thaw stability of rice starch gels during 5 freeze-thaw cycles were investigated, using scanning electron microscopy (SEM), rapid visco analyzer (RVA), X-ray diffractometry (XRD), differential scanning calorimetry (DSC) and textural analyzer (TA). SEM micrographs of freeze-thaw gels showed that smaller pore size and a thicker surrounding matr...
Polyphenoloxidase (PPO), protease activities, melanosis and exudate loss of pre-cooked Pacific white shrimp (Litopenaeus vannamei) subjected to multiple freeze-thaw cycles (1, 3 and 5 cycles) using different thawing methods were studied. PPO and protease activities increased as freeze-thaw cycles increased (p < 0.05). Thawing using running tap water resulted in the higher increases in both PPO ...
The effects of freeze-thaw events on the inactivation of Cryptosporidium parvum oocysts in soil were examined. Oocysts were inoculated into distilled water in microcentrifuge tubes or into chambers containing soil the water content of which was maintained at 3%, 43%, or 78% of the container capacity. The chambers and tubes were then embedded in 3 soil samples from different aspects of a hillsid...
Mortar samples were saturated with NaCl solutions of various concentrations and subjected to freeze– thaw cycles. Passive and active acoustic emission (AE) testing was conducted. The freezing temperature of the NaCl solutions in mortar corresponded with the sudden observation of passive AE events. The acoustic energy and damage parameter were calculated to evaluate the extent of freeze–thaw dam...
BACKGROUND Reported concentrations of amyloid beta (1-42) (A beta 42) and tau in cerebrospinal fluid (CSF) differ among reports. We investigated the effects of storage temperature, repeated freeze/thaw cycles, and centrifugation on the concentrations of A beta 42 and tau in CSF. METHODS Stability of samples stored at -80 degrees C was determined by use of an accelerated stability testing prot...
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...
Cytokines are a group of peptides which form a sophisticated network to modulate multiple cellular events. Within such a network, and through complex feedback mechanisms, cytokine functions are largely interdependent and closely associated with a number of pathological processes. In the present study, the EVIDENCE 180 system was used to study the ...
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