Superheavy elements: a crossroads

The failure to synthesize superheavy elements by using complete fusion reactions is most likely understandable in terms of the low survival probabilities of the superheavy precursors formed in these reactions or (in some cases) the failure to achieve complete fusion. Further attempts to synthesize these elements by using complete fusion or deep inelastic transfer reactions, or both, are discussed in light of these results.     

Interactions between different media and follicle‐stimulating hormone supplementation on in vitro culture of preantral follicles enclosed in ovarian tissue derived from collared peccaries (Pecari tajacu Linneaus, 1758)

The aim was to verify the effect of follicle‐stimulating hormone (FSH) supplementation to α‐MEM+ or TCM199+ media on the in vitro development of ovarian preantral follicles (PFs) derived from collared peccaries. Ovaries (n = 5 pairs) were collected and divided into fragments destined to control group (non‐cultured) or treatments that were cultured for 7 days. The PFs morphology, growth and activation were evaluated by classical histology. The immunohistochemistry markers Ag‐NOR and PCNA were used for nuclear proliferation analysis, and the picrosirius red labelling was used for ovarian extracellular matrix (ECM) evaluation. After 7‐day culture, only the TCM199+ treatment maintained the proportion of intact PFs similar to day 1 (63.2%), but no differences were found among treatments (p > .05). In addition, a significant increase in the growing follicles proportion was verified for all the treatments, indicating follicular activation (p > .05). By the Ag‐NOR analysis, only the TCM199+/FSH maintained the nuclear proliferation similar to the first day (p > .05). The picrosirius red staining revealed that the ECM remained intact in all the treatments (p > .05). We suggest the use of TCM199+ medium supplemented of FSH for the in vitro development of peccaries PFs under 7‐day culturing conditions.     

Chitinase production by an Arthrobacter sp. lysing cells of Fusarium roseum

An Arthrobacter sp. which actively lysed Fusarium roseum was found to liberate chitinase (E.C. 3.2-1.14, chitin glycanohydrolase), an enzyme essential for the hydrolysis of chitin, a major component of fusarial hyphal walls. Factors involved in the production of chitinase were investigated by modifying culture conditions and assaying for enzyme activity. Production occurred on colloidal chitin as well as on native chitin supplemented with yeast extract or peptone. Enzyme production paralleled growth; liberation of enzyme took place during the log phase with the maximum yield being obtained at the stationary phase. Addition of the non-ionic surfactant, polyoxyethylene sorbitan monooleate (Tween 80) increased enzyme yield. An inverse relationship was found between the amount of enzyme produced and the quantity of n-acetyl-glucosamine liberated. The enzyme was generally not produced when grown on various other carbohydrates. These findings suggest that chitinase is inducible and that chitin breakdown is regulated by a repressor-inducer mechanism.Initial hydrolysis rates of colloidal chitin were proportional to the concentration of chitinase used. Optimal pH and temperature for enzyme activity were 4.9 and 50°C, respectively. Purification of the chitinase was obtained by (NH₄)₂SO₄ precipitation followed by DEAE-cellulose and Sephadex chromatography, achieving a 12-fold increase in specific activity.     

Influence of dietary alpha-tocopherol on tocopherol concentrations in chick tissues

1. The effect of feeding alpha-tocopherol (5 to 180 micrograms/g diet) for 24 days on the concentrations of alpha-tocopherol in various chicken tissues was investigated. 2. Tissue alpha-tocopherol concentrations responded to dietary intake in the order: heart congruent to lung greater than liver greater than thigh muscle greater than brain, and in all cases the relationship between the concentrations of dietary and tissue alpha-tocopherol was highly significant (0.997 less than or equal to r less than or equal to 1). 3. Plasma alpha-tocopherol concentration appears to be a good index (r greater than or equal to 0.910, P less than 0.001) of alpha-tocopherol status of lung, liver and heart.     

Recognition by human V gamma 9/V delta 2 T cells of a GroEL homolog on Daudi Burkitt's lymphoma cells

All human gamma delta T cells coexpressing the products of the variable (V) region T cell receptor (TCR) gene segments V gamma 9 and V delta 2 recognize antigens from mycobacterial extracts and Daudi cells. Exogenous and endogenous ligands on the cell surface, homologous to the groEL heat shock family, induced reactivities that resembled superantigen responses in this major subset of human peripheral blood gamma delta T cells. Stimulation of human V gamma 9/V delta 2 T cells is not restricted by human leukocyte antigens (HLA), including nonpolymorphic beta 2-microglobulin (beta 2M)-associated class Ib molecules. These data may be important for understanding the role of gamma delta T cells in autoimmunity and in responses to microorganisms and tumors.     

Direct measurement of the current-phase relation of a superfluid 3He-B weak link

Direct measurements of the current-phase relation, I versus Deltaphi, for a weak link coupling two reservoirs of B-phase superfluid helium-3 (3He-B) were made over a wide range of temperatures. The weak link consists of a square array of 100-nanometer-diameter apertures. For temperatures T such that T/Tc >/= 0.6 (where Tc is the superfluid transition temperature), I approximately sin(Deltaphi). At lower temperatures, I(Deltaphi) approaches a straight line. Several remarkable phenomena heretofore inaccessible to superconducting Josephson junctions, including direct observation of quantum oscillations and continuous knowledge of Deltaphi, were also observed.     

Interlaboratory evaluation of a real-time multiplex polymerase chain reaction method for identification of salmon and trout species in commercial products

This interlaboratory study evaluated a real-time multiplex polymerase chain reaction (PCR) method for identification of salmon and trout species in a range of commercial products in North America. Eighty salmon and trout products were tested with this method by three independent laboratories. Samples were collected in the United States and Canada, and only the collecting institution was aware of the species declaration. Following analysis with real-time PCR, all three laboratories were able to identify species in 79 of the 80 products, with 100% agreement on species assignment. A low level of fraud was detected, with only four products (5%) found to be substituted or mixtures of two species. The results for two of the fraudulent products were confirmed with alternate methods, but the other two products were heavily processed and could not be verified with methods other than real-time PCR. Overall, the results of this study show the usefulness and versatility of this real-time PCR method for the identification of commercial salmon and trout species.     

Long-term phosphorus fertilisation increased the diversity of the total bacterial community and the phoD phosphorus mineraliser group in pasture soils

Fertilisers, especially nitrogen (N) and phosphorus (P) supplies, are frequently used in agricultural soil management to attain high crop yields. However, the intensive application of these chemical inputs can decrease the quality of agricultural soils and increase the probability of environmental pollution. In this study, the impact of P fertilisation on the diversity of the soil bacterial community was assessed. For this, a culture-independent approach targeting 16 rRNA and phoD genes was used on DNA extracted from pasture soils subjected to three different P fertilisation regimes for a long-term (42 years). As alkaline phosphomonoesterase (ALP) is necessary for mineralisation of organic P, an inverse relationship between the level of potential ALP activity and soil available P was expected. Indeed, a lower ALP activity was observed in soil subjected to higher chemical P fertiliser input. Analysis of the prevalence of three divergent families of ALP (PhoA, PhoD and PhoX) in metagenomic datasets revealed that PhoD is the most frequent ALP in soil samples and was selected as the most representative ALP possessed by the soil bacterial communities. Diversity of the phoD phosphorus mineraliser group, as well as the total bacterial community, was both increased in response to long-term P fertilisation. Specifically, phosphorus fertilisation decreased the relative abundance of certain taxa, including Acidobacteria and Pseudomonas fluorescens. In conclusion, this study shows that P fertilisation affects the microbial diversity of soil ecosystems, which might potentially modulate the soil biogeochemical cycle.     

Effects of alpha-tocopheryl acetate supplementation and salt addition on the oxidative stability (TBARS) and warmed-over flavour (WOF) of cooked turkey meat.

1. Day-old turkey poults (n = 14) were randomly divided into 2 groups (n = 7) and fed diets containing 20 (E20) and 600 (E600) mg all-rac-alpha-tocopheryl acetate/kg food for 21 weeks prior to slaughter. Following slaughter, breast and leg meat was removed and 4 batches of patties were produced from each. Two of the batches were formed from E20 meat (E20) and E20 plus 1% salt (E20S). Two similar batches were formed from E600 meat (E600) and E600 plus 1% salt (E600S). 2. Patties were fried, cooled and overwrapped with high oxygen-permeable film. Overwrapped patties were displayed in a 4 microC cabinet under fluorescent light (616 lux). Lipid oxidation (TBARS numbers) was determined on d 0, 2, 4, 6, 8 and 10, while taste panels to assess warmed-over flavour (WOF) were carried out on d 0, 2 and 4 of refrigerated (4 degrees C) display. 3. In the case of both leg and breast meat, E600 patties were the least susceptible of the 4 treatment batches to lipid oxidation. Salt had the effect of promoting lipid oxidation, with E20S and E600S patties having higher TBARS numbers than the corresponding patty batches where salt was absent. 4. Taste panel results showed that leg and breast patties formed from the meat of turkeys given alpha-tocopheryl acetate enriched diets developed significantly (P < 0.05) less WOF than those formed from control turkey meat on d 2 and 4 of refrigerated (4 degrees C) display. Patties containing 1% salt generally exhibited a greater degree of WOF than patties without salt. 5. A linear relationship was observed between TBARS numbers and WOF percentages for all batches of leg and breast patties.     

Measurements of the equation of state of deuterium at the fluid insulator-metal transition

A high-intensity laser was used to shock-compress liquid deuterium to pressures from 22 to 340 gigapascals. In this regime deuterium is predicted to transform from an insulating molecular fluid to an atomic metallic fluid. Shock densities and pressures, determined by radiography, revealed an increase in compressibility near 100 gigapascals indicative of such a transition. Velocity interferometry measurements, obtained by reflecting a laser probe directly off the shock front in flight, demonstrated that deuterium shocked above 55 gigapascals has an electrical conductivity characteristic of a liquid metal and independently confirmed the radiography.