We report on the preparation of both porous and non-porous poly(vinyl alcohol) (PVA) hydrogels that can be used as carriers to release proteins. Non-porous gels were prepared by freezing and thawing of aqueous PVA solutions, while porous gels were formed by adding porosigens such as NaCl or ammonium carbamate into aqueous PVA solutions. Bovine serum albumin, a model protein, was loaded into non...

The stability of asphalt concrete under the effects of freezing and thawing was studied experimentally, and the experimental test results were modelled using fuzzy logic and statistical methods. The stability was investigated experimentally using the Marshall and ultrasound methods. Asphalt core samples 10 cm in diameter were alternately frozen (–20°C for 16 hr) and thawed (16°C for 8 hr) for 5...

BACKGROUND: Freezing is a common way and one of the best methods of seafood preservation for long periods of time; however, the freeze thawing process may influence the quality of food. OBJECTIVES: Oxidation and denaturation of proteins, sublimation and recrystallization of ice crystals can cause changes in the quality of the frozen products. This study was aimed to evaluate the effect of three...

background: freezing is a common way and one of the best methods of seafood preservation for long periods of time; however, the freeze thawing process may influence the quality of food. objectives: oxidation and denaturation of proteins, sublimation and recrystallization of ice crystals can cause changes in the quality of the frozen products. this study was aimed to evaluate the effect of three...

Abstract—A number of studies have been conducted recently to investigate the influence of randomly oriented fibers on some engineering properties of cohesive and cohesionless soils. However, few studies have been carried out on freezing-thawing behavior of fine-grained soils modified with discrete fiber inclusions and additive materials. This experimental study was performed to investigate the ...

The incorporation of a model protein, bovine serum albumin (BSA), into poly(vinyl alcohol) (PVA) hydrogel films during the freezing and thawing process and its subsequent release behavior were investigated. The effect of the number of freezing and thawing cycles as well as the stability of BSA were examined. BSA release profiles were not significantly different from gels prepared after 3 or 5 c...

Concern over nonpoint source P losses from agricultural lands to surface waters in frigid climates has focused attention on the role of freezing and thawing on P loss from catch crops (cover crops). This study evaluated the effect of freezing and thawing on the fate of P in bare soils, soils mixed with dairy manure, and soils with an established catch crop of annual ryegrass (Lolium multiflorum...

AIMS Clostridium difficile is a common nosocomial pathogen and as such diagnostic and research methods may necessitate storage of faecal specimens for long periods, followed by subsequent re-examination. This study investigated the effects of storage conditions upon the viability of this organism and its toxin. METHODS Three genotypically distinct strains of C difficile (two clinical isolates...

*The 'thaw-expansion hypothesis' postulates that xylem embolism is caused by the formation of gas bubbles on freezing and their expansion on thawing. We evaluated the hypothesis using centrifuge experiments and ultrasonic emission monitoring in Pinus contorta. *Stem samples were exposed to freeze-thaw cycles at varying xylem pressure (P) in a centrifuge before the percentage loss of hydraulic c...

BACKGROUND A number of factors influence the success of oocyte cryopreservation and subsequent ICSI. The aim of the present study is to establish the ideal time, after oocyte retrieval, for human oocyte cryopreservation via slow freezing/rapid thawing protocol with 0.3 M sucrose concentration in cryoprotectant solution (SF/RT 0.3 M). METHODS Retrospective study with 75 patients on the clinica...