A model for bound-water transport in wood

Summary A model for the isothermal transport of bound water through the cell wall of wood is developed, based on the assumption that the driving force for moisture movement is the gradient of spreading pressure , as first proposed by Babbitt (1950). This pressure is a surface phenomenon, derivable from the surface sorption theory of Dent (1977), a modification of the BET sorption theory. The force resisting moisture transport is assumed to be inversely proportional to moisture content and directly proportional to the equivalent viscosity of the sorbed water, calculated to be orders of magnitude larger than that of free water. The coefficients normally used to describe isothermal moisture transport in wood are derived from the model, and their predicted behavior as functions of the relative vapor pressure h of the cell wall are described graphically. An attempt is made to calculate a quantitative magnitude for the diffusion coefficient D, based on an assumed relationship between viscosity and the activation energy for water diffusion.     

Spotted wolffish (Anarhichas minor) sperm cryopreservation in 5-mL cryovials

Fish Physiology and Biochemistry - In spotted wolffish Anarhichas minor aquaculture, cryopreservation is used to secure sperm availability throughout the entire spawning season. Under current...     

Seminal plasma proteins of Atlantic halibut (Hippoglossus hippoglossus L.)

Protein content and properties in the seminal plasma of Atlantic halibut (Hippoglossus hippoglossus) were assayed using spectrophotometric and electrophoretic methods. The protein concentration ranged from 6.4 ± 3.1 to 19.4 ± 3.4 mg ml⁻¹ and anti-proteolytic activity from 585.2 ± 104.6 to 2912.4 ± 367.4 U l^−l. A high correlation between anti-proteolytic activity and protein concentration (r = 0.95), and between sperm concentration and osmolality was found (r = 0.92). There was a significant decrease in anti-proteolytic activity from the first to the second sampling, but not in protein concentration. Anti-proteolytic activity and protein concentration were significantly affected by variations in individual males. Electrophoresis revealed four anti-proteolytic bands and individual differences in bands of proteolytic activity, which were subsequently characterized as metalloproteases and serine proteases.     

Effects of Cryopreservation on Morphology and Viability of Sperm and Larvae of Atlantic Cod,Gadus morhua L.

The effects of cryopreservation on the viability, morphology and capability of spermatozoa in Atlantic cod, Gadus morhua L., were studied. The sperm was cryopreserved in straws using Hanks' balanced salt solution, hens' egg yolks and glycerol in the vapor of liquid nitrogen. Straws of cryopreserved sperm were stored in liquid nitrogen and thawed in seawater (35 C) for 8 sec before use. The motility of cryopreserved sperm was low (range 8–19%) compared to motility before freezing (range 69–76%). The fertilization rate (range 94–95%) in control groups using fresh sperm was significantly higher (P < 0.05) than in test groups (range 48–72%). In cryopreserved sperm, a relatively high percentage (range 82–93%) of the spermatozoa had changes in morphology. Many spermatozoa had no mitochondria; when mitochondria were present, the observed number varied from one and five in cryopreserved spermatozoa, and from two and seven in noncryopreserved spermatozoa. In groups where cryopreserved sperm was used, the hatching rate was lower (range 18–38%) than in control groups (range 41–63%), indicating higher mortality during embryonic development. Paternal effects on progeny performance were noted in the proportion of abnormalities but no negative effects were identified in newly hatched larvae produced using cryopreserved sperm.     

Fractional factorial design of screening experiments on cryopreservation of fish sperm

Milt of grass carp Ctenopharyngodon idella (Val.) and goldfish Carassius auratus auratus (L.) was cryopreserved in experiments following &Hf;1 2 and &Hf;1 4 fractional factorial designs. The efficiency of a graphical method and manova was tested, as well as the informative strength of both designs. Fractional factorial design was very suitable for screening experiments, and it allowed separation of important and unimportant effects. A graphical method showed the same efficiency and reliability as manova . The &Hf;1 4 fractional factorial design was less informative than the &Hf;1 2 fractional factorial design, because it did not allow an estimation of the interactions. The application of fractional factorial designs for multifactorial screening experiments on cryopreservation of fish sperm has been implemented in this study.     

Cryopreservation of sperm of common carp, Cyprinus carpio L.

Milt of common carp, Cyprinus carpio L. was cryopreserved in pellet form with the use of 12 extenders. Most efficient were: BE2 original extender (containing 85 mM NaCl, 50 mM KCl, 3 mm CaCl₂, 1 mm MgCl₂ with 10% dimethyl-acetamide (DMA) and 10% addition of hen's egg yolk) and Kurokura et al.'s extender with 15% DMA and 10% yolk (about 73% and 69% of eyed eggs, about 61% and 52% of swim-up larvae, respectively). Within the most effective treatments, survival from the eyed-egg stage to the swim-up stage was similar to that observed in the control group. Survival from the eyed-egg stage to the swim-up stage (percentage of eyed eggs was considered as 100%) was highly significantly and positively correlated with the actual rate of swim-up larvae.     

A contribution to the definition of the fiber saturation point

Summary There is hardly any term in wood science literature that has been defined so many times as the term fiber saturation point (FSP). In spite of this fact the discussion is still going on how to define and how to measure it. The aim of the paper is to evaluate some of the known definitions and propose a method of experimental measurement of FSP. The term cell wall saturation, in contrast with FSP, is clearly defined quantity that can be easily measured.The authors are grateful to the Slovak Grant Agency for Science for partial support of this work     

Suitable methods for cryopreservation of semen from Atlantic halibut, Hippoglossus hippoglossus L.

Decrease in the quality and quantity of Atlantic halibut, Hippoglossus hippoglossus L., semen towards the end of the reproductive season hampers production of good-quality embryos. Therefore, cryopreservation of spermatozoa is a method showing potential to facilitate controlled reproduction in Atlantic halibut. The present study aimed at establishing the appropriate cryopreservation procedure. We tested 20 extenders composed of four various diluents and five cryoprotectants (DMSO, DMA, methanol, propylene glycol, and glycerol) to determine the best extender. Then, we examined cryopreservation quality using various methods of loading and various volumes of cryopreserved samples. In most of the tested variants, sperm diluted with an extender showed high motility after 24-h incubation despite the high osmotic pressure of the extender. Modified turbot extender (MTE) was the best of the tested diluents, securing the highest post-thaw motility (P < 0.05), and DMSO, DMA, and methanol were the best cryoprotectants (P < 0.05). There was no significant effect of 15-min equilibration of semen in MTE-based extenders prior to freezing on post-thaw motility (P > 0.05). MTE-based extender was chosen as the most suitable. Semen cryopreserved in straws, Eppendorfs or Ziploc bags in volumes ranging from 0.25 to 20 ml showed similar high fertilization ability. Survival of larvae produced with the cryopreserved sperm did not differ from controls produced with freshly collected sperm. Motility 3 h after thawing was high but depended on the type of cryoprotectant and the volume of cryopreserved sperm (P < 0.05). The developed cryopreservation procedure has been applied at our Atlantic halibut breeding station for seed production.     

Effect of individual male variability on cryopreservation of northern pike, Esox lucius L., sperm

Milt from individual males of northern pike, Esox lucius L., was separately cryopreserved. Concentration of spermatozoa in fresh milt and spermatozoa motility before freezing and after thawing was evaluated. Activity of aspartate aminotransferase (AspAT, E.C. 2.6.1.1.) and acid phosphatase (AcP, E.C. 3.1.2.2.) in fresh and thawed sperm were determined. In comparison with the control group, egg fertilization with cryopreserved milt varied from 6.6% to 96.0%, depending on the donor male. Fertilization success with cryopreserved pooled milt was 71.8%. Freezing and thawing procedure caused loss of proteins from injured spermatozoa, resulting in significantly lower enzymatic activity in spermatozoa. Intensity of enzyme leakage in thawed milt correlated negatively with fertilization success. Concentration of spermatozoa could be a possible accessory quality indication, useful when selecting sperm samples appropriate for cryopreservation.