We studied the effect of freezing and thawing of serum on the determination of lipoprotein(a) [Lp(a)] with a commercial enzyme-linked immunosorbent assay (ELISA) and an immunoturbidimetric assay (ITA). Portions of sera from 11 apparently healthy persons and pooled sera, from an additional 10 subjects were frozen at either -20 or -70 degrees C and thawed at room temperature. Cycles of freezing a...

Poly(viny1 alcohol) (PVA) hydrogels were prepared by treating 15 or 20% aqueous PVA solutions to repeated cycles of freezing for 6 or 12 h at 20°C and thawing for 2 h at 25°C. The resulting gels did not contain any leachable toxic crosslinking agents or other residues. Their adhesive characteristics were examined using tensile experiments in contact with bovine submaxillary mucin. As the number...

The aim of this study was to determine whether more than once freezing and thawing of serum affects different patterns of anti-nuclear antibodies (ANA) and anti-neutrophil cytoplasmic antibodies (ANCA) as also to determine for how many days can serum samples be reliably refrigerated (2-8oC) for these tests. A total of 20 ANA (6 homogenous, 3 speckled, 3 centromere, 2 nucleolar, 2 cytoplasmic an...

In this study, we compared the effects of repeated freezing/thawing of human sperm by our in-house method of rapid freezing with slow programmable freezing. Sperm samples from 11 normozoospermic subjects were processed through density gradients and divided into three aliquots: non-frozen, rapid freezing and slow programmable freezing. Sperm in the rapid freezing group had better motility and vi...

In this paper, rapid freezing and thawing test of air-entrained fly–ash concrete was carried out. Gas adsorption of concrete pores, mass loss, dynamic elastic modulus, and chloride diffusion coefficient of concrete after different freezing and thawing cycles was tested; scanning electron image was used to study the microscopic pore structure of the specimens. Results show that after certain fre...

Soil freezing-thawing cycle may substantially influence soil physical properties, microbial activity, and the rates of carbon and nitrogen cycling in soils. In this study, the soil water soluble organic C, N (WSOC, WSON) as well as microbial biomass C, N (MBC, MBN) of two alpine grassland types, alpine meadow and alpine steppe, were investigated after freezing-thawing cycles in a grassland land...

OBJECTIVES The stability of circulating proteins can be affected by repeated freezing and thawing. The aim of our study was to identify the effect of repeated freezing and thawing on the plasma and serum concentrations of eight proteins [interferon-γ, interleukin (IL)-8, IL-15, IL-17A, matrix metalloproteinase (MMP)-7, tumor necrosis factor-α, vascular endothelial growth factor (VEGF), and VEGF...

The response of excised stem segments of several tree species to freezing and thawing cycles was studied. All species studied (Thuja occidentalis, Fagus grandifolia, and Betula papyrifera) except maple (Acer spp.) exuded sap while freezing and absorbed on thawing. Maple stems absorbed sap while freezing and exuded sap during the thaw only when sucrose was present in the vessel solution. Increas...

The ability to probe fresh tissue is a key feature to biomedical Raman spectroscopy. However, it is unclear how Raman spectra of calcified tissues are affected by freezing. In this study, six transverse sections of femoral cortical bone were subjected to multiple freeze∕thaw cycles and probed using a custom Raman microscope. Significant decreases were observed in the amide I and amide III bands...

This paper reviews new developments in methods of freezing (high-pressure freezing, dehydrofreezing and applications of antifreeze protein and ice nucleation protein) and thawing (high-pressure and microwave thawing, ohmic thawing and acoustic thawing) for foods. With a good understanding of the solid–liquid phase diagram of water, the effects of pressure on food freezing– thawing cycles are hi...