Vitamin C Enhances Vitamin E Status and Reduces Oxidative Stress Indicators in Sea Bass Larvae Fed High DHA Microdiets

Docosahexaenoic acid (DHA) is an essential fatty acid necessary for many biochemical, cellular and physiological functions in fish. However, high dietary levels of DHA increase free radical injury in sea bass (Dicentrarchus labrax) larvae muscle, even when vitamin E (α-tocopherol, α-TOH) is increased. Therefore, the inclusion of other nutrients with complementary antioxidant functions, such as vitamin C (ascorbic acid, vitC), could further contribute to prevent these lesions. The objective of the present study was to determine the effect of vitC inclusion (3,600?mg/kg) in high DHA (5?% DW) and α-TOH (3,000?mg/kg) microdiets (diets 5/3,000 and 5/3,000?+?vitC) in comparison to a control diet (1?% DHA DW and 1,500?mg/kg of α-TOH; diet 1/1,500) on sea bass larvae growth, survival, whole body biochemical composition and thiobarbituric acid reactive substances (TBARS) content, muscle morphology, skeletal deformities and antioxidant enzymes, insulin-like growth factors (IGFs) and myosin expression (MyHC). Larvae fed diet 1/1,500 showed the best performance in terms of total length, incidence of muscular lesions and ossification degree. IGFs gene expression was elevated in 5/3,000 diet larvae, suggesting an increased muscle mitogenesis that was confirmed by the increase in the mRNA copies of MyHC. vitC effectively controlled oxidative damages in muscle, increased α-TOH larval contents and reduced TBARS content and the occurrence of skull deformities. The results of the present study showed the antioxidant synergism between vitamins E and C when high contents of DHA are included in sea bass larvae diets.     

Improvement of the compositional quality of monocot pectin extracts contaminated with glucuronic acid-containing components using a step-wise purification procedure

The analysis of the uronic acids within crude pectin extracts from banana peel and pineapple flesh, by a modified meta-hydroxydiphenyl assay in the presence and absence of sodium tetraborate, revealed a non-negligible amount of glucuronic acid (4.1–7.2 g/100 g) together with a much higher quantity of galacturonic acid (37.5–42.8 g/100 g). This suggested that fragments of glucuronic acid-containing heteroxylans, notably glucuronoarabinoxylans (GAXs), accompanied pectins extraction. A step-wise purification process was therefore developed to efficaciously remove, from pectin extracts, GAX contaminants including non-pectin-incorporated neutral sugar (NS) components. It primarily consisted in treating dialysed pectin extracts or not with 78–85% acidified methanol, which led to the precipitation of pectin-rich fractions while the bulk of GAX and free NS materials were solubilised in the aqueous acid–methanol mixture. Subsequently, advantage was taken of the multivalent ion-binding selectivity and ‘exclusivity’ of the pectin polymer anionic (carboxyl) groups to produce GAX and NS oligosaccharide contaminants-free final isolates, and hence greatly enriched in pectin components.     

Experience in eddy-current testing of mounting holes in aircraft components

Opportunities offered by the static and dynamic eddy-current techniques for testing mounting holes in aircraft components fabricated from nonmagnetic materials and features of these techniques are considered. Examples of applications of eddy-current techniques demonstrating considerable advantages of the dynamic technique in detection of cracks around holes are given.     

Determination of total cysteamine in human serum by a high-performance liquid chromatography with fluorescence detection

A convenient, reliable and rapid method for determination of total cysteamine in human plasma by high-performance liquid chromatography with fluorescence detection is reported. This assay involves reduction of samples with dithiothreitol, derivatization of total cysteamine by addition of monobromobimane and protein precipitation by perchloric acid. The calibration curve was linear in the range 2-150 nmol ml-1 and the detection limit was 0.5 nmol ml-1. This method was successfully applied for a pharmacokinetic study of three cysteamine derivatives in healthy volunteers without any interference from coexisting substances.     

Survey of incidence of Clostridium difficile infection in Canadian hospitals and diagnostic approaches

A questionnaire relating to Clostridium difficile disease incidence and diagnostic practices was sent to 380 Canadian hospitals (all with > 50 beds). The national questionnaire response rate was 63%. In-house testing was performed in 17.6, 61.5, and 74.2% of the hospitals with < 300, 300 to 500, and > 500 beds, respectively. The average test positivity rates were 17.2, 15.3, and 13.2% for hospitals with < 300, 300 to 500, and > 500 beds, respectively. The average disease incidences were 23.5, 30.8, and 40.3 cases per 100,000 patient days in the hospitals with < 300, 300 to 500, and > 500 beds, respectively. In the 81 hospitals where in-house testing was performed, cytotoxin testing utilizing tissue culture was most common (44.4%), followed by enzyme-linked immunosorbent assay (38.3%), culture for toxigenic C. difficile (32.1%), and latex agglutination (13.6%). The clinical criteria for C. difficile testing were variable, with 85% of hospitals indicating that a test was done automatically if ordered by a doctor. Our results show that C. difficile-associated diarrhea is a major problem in hospitals with > or = 200 beds. Despite a lower disease incidence in smaller hospitals, there was a higher diagnostic test positivity rate. This may reflect the preference of smaller hospitals for culture and latex agglutination tests.     

Pectin quantity,composition and physicochemical behaviour as influenced by the purification process

To examine the purification procedure effect on the pectin amount, purity, macromolecular characteristics, and gelling ability, three pectin isolates, namely, alcohol (APP)-, dialysis (DPP)-, and metal ion (MPP)-purified pectins are obtained from acid extracts of yellow passion fruit rind using alcohol-precipitation, dialysis, or ion-binding precipitation. The results show that the amount of MPP (4.1 g/100 g) is significantly (p < 0.05) lower than the amount of the two other pectins (6.8–7.5 g/100 g). In contrast, MPP has a higher galacturonic acid (78.9 g/100 g) and lower neutral sugar (9.7 g/100 g), ash (0.9 g/100 g), and protein (1.4 g/100 g) contents than the remainder (62.4–70.1, 16.0–17.8, 2.7–5.8, 3.1–3.2 g/100 g, respectively). Molecular-weight distribution patterns suggest that MPP is free of neutral sugar oligosaccharide contaminants unlike the others, especially APP. Therefore, the term of ‘the galacturonic acid yield’ is introduced to complement the conventional term of ‘the pectin yield’. Furthermore, MPP gel preparation is likely to set more rapidly, with the gel formed achieving a much higher strength. It is concluded that the pectin amount, composition, and physicochemical properties can be considerably affected by the purification mode.     

Design and characterization of porous mullite based semi-vitrified ceramics

Three porous ceramic composites were prepared from readily available raw materials (kaolin, bauxite, feldspar and kyanite). The porous ceramic formulations were sintered at different temperatures ranging from 1200 to 1400°C. The fired specimens were characterized by determining their porosity, bulk density, flexural strength, thermochemical stability, microstructure, water and mercury permeability. Apparent porosity and bulk density in the range 15.57 ± 1.56–42.73 ± 2.28?vol% and 2.23 ± 0.31–2.68 ± 0.41?g?cm^?3 respectively were obtained after firing. The flexural strength was in the range of 32.31 ± 2.1–74.88 ± 2.57?MPa and the thermal expansion coefficient of 5–9 × 10^?6 C^?1. The values of water permeability were 745.4, 641.45 and 525.91?L/m² h?kPa respectively for PK3, PK4 and PK5. It was found that at high temperature (1400?°C), kyanite particles enhanced the porosity and thermal stability by reducing glass formation and improving crystallization. The presence of the interconnected pores with size between 0.03 and 4.50?µm, the high total volume of pores together with the high flexural strength and thermal stability make the synthesized porous ceramics suitable for high-pressure filtering applications.