in order to investigate the flexural behaviors of rc beams after freeze-thaw cycles, compressive strength test of concrete cubes after 0, 50, 100, 125 freeze-thaw cycles were made, and static flexural experiment of 48 rc beams after 0, 50, 100, 125 freeze-thaw cycles were made. the relationships of relative compressive strength, mass loss rate, relative dynamic elastic modulus and numbers of fr...

Possibilities to account for the mechanism of freeze-thaw injury to isolated protoplasts of Spinacia oleracea L. cv. Winter Bloomsdale were investigated. A freeze-thaw cycle to -3.9 C resulted in 80% lysis of the protoplasts. At -3.9 C, protoplasts are exposed to the equivalent of a 2.1 osmolal solution. Isolated protoplasts behave as ideal osmometers in the range of concentrations tested (0.35...

The effects of storage temperatures, repeated freeze-thaw cycles, or delays in separating plasma or serum from blood samples are largely unknown for heat shock protein 27 (HSP27). We evaluated (1) the imprecision of the HSP27 assay used in this study; (2) the in vitro stability of HSP27 in blood samples stored at 4°C for up to 6 hr with immediate and delayed serum/plasma separation from cells; ...

BACKGROUND Best practice when performing culture-independent microbiological analysis of sputum samples involves their rapid freezing and storage at -80°C. However, accessing biobanked collections can mean that material has been passed through repeated freeze-thaw cycles. The aim of this study was to determine the impact of these cycles on microbial community profiles. METHODS Sputum was coll...

Background: Reported concentrations of amyloid(1– 42) (A 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 42 and tau in CSF. Methods: Stability of samples stored at 80 °C was determined by use of an accelerated stability testing protocol according to the A...

As crucial terrestrial ecosystems, temperate forests play an important role in global soil carbon dioxide flux, and this process can be sensitive to atmospheric nitrogen deposition. It is often reported that the nitrogen addition induces a change in soil carbon dioxide emission in growing season. However, the important effects of interactions between nitrogen deposition and the freeze-thaw-cycl...

Complete closure of retinal neovascularisation due to proliferative sickle cell retinopathy was achieved in 28 'sea fans' (areas of neovascularisation) in 9 eyes of 9 patients by means of a triple freeze-thaw technique. However, 2 eyes developed subsequent rhegmatogenous retinal detachments, presumably related to vitreous traction on necrotic retina. We therefore recommend photocoagulation as...

OBJECTIVES Progastrin-releasing peptide (proGRP) is a promising biomarker for small cell lung cancer. However, not much is known about how sample processing and storage conditions affect the stability of proGRP. Here, we examined the effects of repeated freeze-thaw cycles on the stability of proGRP in plasma and serum. METHODS Concentrations of proGRP were measured in plasma and serum samples...

Meniscus allografting has provided relief of meniscal injuries that were previously thought irreparable. However, meniscus allograft tissue remains limited and a significant problem. To improve allograft tissue yield, decrease processing costs, and increase graft availability, this study investigated the biomechanical changes of meniscal allograft tissue frozen and thawed multiple times. Specif...

A freeze-thaw cycle to -12 degrees C induced several physical and compositional changes in the microsomal membranes isolated from crown tissue of winter wheat (Triticum aestivum L. cv Frederick). Exposing 7-day-old, nonacclimated seedlings to a single freeze-thaw cycle prevented regrowth of the crown and resulted in increased membrane semipermeability. The phospholipid and protein content of mi...