[1] Arctic warming is expected to increase thermokarst erosion in thaw lakes, thus inducing large emissions of CH4 to the atmosphere. To reduce uncertainties about the mechanisms, magnitude and timing of methane emissions, we conducted an in-situ experiment to simulate lake expansion following thermokarst erosion. Three tundra horizons were excavated, incubated at the bottom of a thaw lake and ...

The terrestrial cryosphere comprises cold areas of Earth’s land surface where water is either permanently or seasonally frozen. This includes most regions north of 40 degrees North latitude and most mountainous regions where elevation is greater than 1000m [1]. Permafrost is ground that perennially at or below 0 throughout the year. Above the permafrost is the active layer, which experiences su...

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 effects of reduced doses of OvaprimTM (GnRHa + domperidone) on sperm release of Brycon orbignyanus and Prochilodus lineatus were evaluated. Furthermore, sperm quality was compared among fresh, equilibrated and postthaw samples. Males received a single and reduced dose of OvaprimTM (0.125 or 0.25 ml/kg); control males received pituitary extract (cPE; 3 mg/kg). Fresh sperm was evaluated for v...

BACKGROUND Variability among stallions in terms of semen cryopreservation quality renders it difficult to arrive at a standardized cryopreservation method. Different extenders and processing techniques (such us colloidal centrifugation) are used in order to optimize post-thaw sperm quality. Sperm chromatin integrity analysis is an effective tool for assessing such quality. The aim of the presen...

Ice formation in the xylem sap produces air bubbles that under negative xylem pressures may expand and cause embolism in the xylem conduits. We used the centrifuge method to evaluate the relationship between freeze-thaw embolism and conduit diameter across a range of xylem pressures (Px) in the conifers Pinus contorta and Juniperus scopulorum. Vulnerability curves showing loss of conductivity (...

Recent fire activity throughout Alaska has increased the need to understand postfire impacts on soils and permafrost vulnerability. Our study utilized data and modeling from a permafrost and ecosystem gradient to develop a mechanistic understanding of the shortand long-term impacts of tundra and boreal forest fires on soil thermal dynamics. Fires influenced a variety of factors that altered the...

Permafrost soils store over half of global soil carbon (C), and northern frozen peatlands store about 10% of global permafrost C. With thaw, inundation of high latitude lowland peatlands typically increases the surface-atmosphere flux of methane (CH4), a potent greenhouse gas. To examine the effects of lowland permafrost thaw over millennial timescales, we measured carbon dioxide (CO2) and CH4 ...

In the present study, motility, ultrastructure and fertilization capacity of fresh and cryopreserved striped bass spermatozoa were investigated in order to evaluate semen dilution ratio, freezing rate and cryomedia. Four dilution ratios (semen/cryomedia), and four freezing rates were evaluated on the basis of post-thaw sperm motility. The dilution ratio of 1:3 yielded the highest (P < 0.05) pos...

The mucoadhesive hydrogel film was prepared and optimized for the purpose of local drug delivery to oral cavity for the treatment of oral Candidiasis. The mucoadhesive hydrogel film was prepared with the poly(vinyl alcohol) by freeze/thaw crosslinking technique. 3(2) full factorial design was employed to optimize the formulation. Number of freeze/thaw cycles (4, 6, and 8 cycles) and the concent...