Acceleration of pH variation in cloudy apple juice using electrodialysis with bipolar membranes

The purpose of this study was to accelerate pH variation in cloudy apple juice using electrodialysis (ED). The testing was conducted using two ED configurations. The bipolar and cationic membrane configuration showed that reducing the spacing from 8 to 0.75 mm had little effect on treatment time, whereas stacking eight bipolar membranes reduced acidification time by 30%, although the treatment still took too long (21 min). Furthermore, it was not possible to acidify apple juice to a pH of 2.0 to completely inhibit enzymatic browning. The bipolar and anionic membrane configuration helped to accelerate the acidification step by a factor of 3, increasing the yield from 3.3 to 10 L of juice/m(2) membrane/min. Moreover, treatment time was inversely proportional to the size of the membrane stack. The speed at which the pH of acidified juice returned to its initial value was, however, 4 times slower than the speed of acidification, giving a yield of 2.5 L of juice/m(2) membrane/min. By accelerating the acidification step, ED treatment with bipolar and anionic membranes results in more effective polyphenol oxidase activity and more rapid control of juice browning at pH 2.0. Also, the treatment has very little effect on the chemical composition and organoleptic quality of apple juice.     

NUCLEATION,POLYMERIZATION, AND PRECIPITATION OF FeOOH1

Fresh Fe(ClO₄)₃ solutions, 0.01 M or 0.001 M in iron (III), were seeded with iron (III) hydroxide brown sols and the reaction processes were investigated. In two experiments, HC1O₄ was added to fresh Fe(ClO₄)₃ solutions to lower their degrees of super saturation with respect to iron (III) hydroxide. Depending upon the quantity of seeding solution added, it was found that samples differed greatly in appearance and in the stability during ageing. With a small amount of seeding solution added and following a relatively long induction period, the sample rapidly developed to a dense, cloudy yellow suspension with FeOOH precipitate settled shortly afterwards. With an increased amount of seeding solution added, the sample gradually became more brownish and less turbid and eventually a clear brown sol was observed. Although α-FeOOH was the major hydrolysed species in all samples, a yellow precipitate which settled under gravity was found only in those containing a small quantity of seeding solution. The above results provide experimental evidence supporting the hypothesis (Hsu and Ragone, 1972) that the initial number of nuclei relative to the concentration of mono-meric species is the key factor governing the appearance and the stability of an hydrolysed iron (III) solution. In another experiment, varying amounts of a seeding solution were added to a fresh, pure 0.001 M Fe(ClO₄)₃ solution to which no HC1O₄ was added. All samples rapidly hydrolysed to clear brown sols in less than 6 hours and no noticeable seeding effect was observed. It is suggested that a pure 0.001 M Fe(ClO₄)₃ solution is highly supersaturated with respect to iron (III) hydroxide and a large number of nuclei spontaneously form in situ shortly after preparation.     

MAGNETIC RESONANCE IMAGING FEATURES OF OBLIQUE AND STRAIGHT DISTAL SESAMOIDEAN DESMITIS IN 27 HORSES

Injury to the oblique and straight distal sesamoidean ligaments is becoming recognized as a more common cause of lameness in horses than was previously thought. The purpose of this study was to review the magnetic resonance (MR) imaging findings of 27 horses affected with desmitis of the oblique and/or straight distal sesamoidean ligament and determine long-term prognosis for horses with this diagnosis. Imaging was performed with horses in right lateral recumbency in a high-field 1 T magnet. All horses had lameness localized to the digit or metacarpophalangeal/metatarsophalangeal joint region with diagnostic local anesthetic blocks. Ten horses had forelimb lameness and 17 horses had hind limb lameness. MR imaging revealed abnormalities in the oblique distal sesamoidean ligaments in 18 horses, in the straight distal sesamoidean ligament in three horses, and in both the oblique and straight distal sesamoidean ligament in six horses. Treatment consisted of a 6-month rest and rehabilitation program in all horses. The digital flexor tendon sheath was injected with methylprednisolone acetate and hyaluronic acid in 22 horses to decrease inflammation in the injured ligaments before starting the rest and rehabilitation program. Two horses had ligament splitting performed, one in the oblique distal sesamoidean ligament and one in the straight distal sesamoidean ligament. MR imaging is an effective method for diagnosing injury to the oblique and straight distal sesamoidean ligaments in horses. Treatment, primarily a 6-month rest and rehabilitation program, allowed 76% of the horses to successfully resume performance.     

Stabilisation with dorsal and ventral fixation of a traumatic cervical instability in a dog

This case study reports the outcome of dorsal and ventral stabilisation of a traumatic cervical instability in a dog. A 2-year-old, male Pointer was admitted following a motor vehicle accident. Clinical examination revealed non-ambulatory tetraparesis, severe neck pain and upper motor neuron changes in all limbs. Deep pain response was present. Subluxation of C2/3 and fractures of the dorsal spinous process and lamina of C2 were observed on radiographs. Ventral stabilisation was performed with screws and bone cement (polymethylmethacrylate). For dorsal fixation of the fractures, screws and cerclage wire were used. The dog stood up independently after 1 month, was able to walk 1.5 months postoperatively and had recovered completely at 1 year following surgery. We conclude that combined stabilisation techniques are effective for this type of cervical fracture in which the dorsal, middle and ventral structures of the vertebra are severely disrupted.     

Preliminary Studies on Stocking Density and Production of Hamoor Epinephelus tauvina in PVC-Lined Raceways

The results of two stocking density trials on the nursery and grow-out stages of Epinephelus tauvina (Family: Serranidae), in PVC-lined raceways are presented.
At the nursery stage, fry of 17.1 g initial mean weight showed no significant differences in growth rate, survival rate and condition factor when stocked at densities of 200 and 400 fish/m³ over a period of 52 days. Fish grew to mean weights of 61.7 and 63.7 g, giving growth rates of 0.86 and 0.90 g/fish/day and final biomasses of 12.1 and 2S.2 kg/m³ for densities of 200 and 400 fish/m³, respectively. Survival rates were excellent for both treatments at 98percnt; or greater. Food conversion efficiency was slightly improved at the higher density.
At the grow-out stage, E. tauvina of mean weights ranging from 150-170 g cultured for a period of 215 days grew better at a density of 5 fish/m³ than at densities of 20 and 60 fish/m³ (final size: 770, 560 and 450 g with growth rates of 2.8, 1.8 and 1.4 g/fish/day, respectively). Survival rates were higher at the two lower densities. Overall, total biomass increased with stocking density (3.9, 11.1 and 23.4 kg/m³, for 5, 20 and 60 fish/m³, respectively). These results indicate that hamoor has potential to be successfully cultured in raceways.     

Optical chlorophyll measurements as predictors of total nitrogen,nitrogen fractions and in vitro ruminal nitrogen degradability in tropical grass forages

This study evaluated whether the FieldScout CM 1000 NDVI and Yara N–Tester models can produce accurate and reliable estimates of nitrogen (N), buffer-soluble nitrogen (BSN), buffer-insoluble nitrogen (BISN), non-protein nitrogen (NPN) and in vitro ruminal nitrogen degradability after 3, 12 and 24?h incubation (ND3, ND12 and ND24) in three tropical grasses: Brachiaria hybrid, Megathyrsus maximus and Paspalum atratum. Correlation between the Yara N-Tester and N, BISN and in vitro ruminal N degradability of the Brachiaria hybrid and M. maximus were high (r 0.67–0.83). The Yara N-Tester accounted for 81% and 86% (p 0.000) of N variability in the Brachiaria hybrid and M. maximus, respectively. The Yara N-Tester prediction models explained 72% and 70% (p 0.000) BISN variability in the Brachiaria hybrid and M. maximus, respectively. In vitro ND24 of the Brachiaria hybrid (R?2 0.75) and M. maximus (R?2 0.75) was also best predicted with the Yara N-Tester. Model validation showed generally low (≤0.90) concordance correlation coefficients except for Yara N-Tester N and ND24 in M. maximus. Random error was the main source of error. We conclude that the accuracy of the Yara N-Tester prediction models was superior to that of the FieldScout CM 1000 NDVI models, and that the Yara N-Tester can produce accurate and reliable estimates of Brachiaria hybrid and M. maximus N and M. maximus ND24.     

BIOECONOMICS OF COBIA,RACHYCENTRON CANADUM,CULTURE IN VIETNAM

This article presents an analysis of the profitability and intensity of cobia culture by small-scale farmers in Vietnam, especially focusing on current feeding practices and perceptions regarding adoption of manufactured diets. Bioeconomic modelling is used so the interactions between biological and economic processes can be analyzed. Overall, it is found that cobia farming is moderately to highly profitable when compared to other aquaculture species in Vietnam. Culture practices and the level of intensity of cobia farming differ significantly across Vietnam. Initial stocking density, total number of fish stocked, number and size of cages, and quantity of feed used are all higher in southern Vietnam than the north. The higher level of intensification in the south leads to significantly higher total costs, productivity and profitability. The dominant cost source is feed, which is predominantly low-value fish. To capture the environmental and potential economic benefits of adopting pelleted diets, then negative farmer perceptions regarding relatively slow growth rates, and lack of availability compared with low-value fish need to be overcome.