Residues of nortestosterone esters at injection sites. Part 2. Behavioural effects.

Anecdotal evidence in man suggests that abuse of anabolic androgenic steroids (AAS) is linked with increased aggression. In order to test the hypothesis that administration of nortestosterone (beta-NT) esters may increase aggression, behavioural effects following beta-NT phenylpropionate (NTPP) administration were assessed in male mice using the isolation-induced aggression paradigm. Mice (n = 80) were individually caged and randomly assigned to 'resident' or 'intruder' status. Residents received one of four treatments: subcutaneous (s/c) injection of oil of arachis (OILINJ), s/c injection of NTPP in oil of arachis (NTINJ), oil of arachis per os (OILOS) and NTPP in oil of arachis per os (NTOS). After treatment, weight-matched intruders were introduced into each resident's cage and the encounter was videotaped to allow the frequency (f) and duration (d) of social, non-social, offensive and defensive behaviours displayed by residents and intruders to be measured. The latency of bite attack for residents was significantly shorter in NTOS compared to OILOS. There was no difference in either f or d of aggressive behaviours between NTINJ and OILINJ. Because OILINJ residents demonstrated similar levels of aggression to NTOS, it is possible that the aggression in NTOS mice may be mediated by a different biochemical pathway. Extrapolation of these results indicate that ingestion of beta-NT esters may have a role in the induction of aggression in consumers.     

Occurrence and prevention of photodissolution at the phase junction of magnetite and titanium dioxide

A stable magnetic photocatalyst was prepared by coating a magnetic core with a layer of photoactive titanium dioxide. A direct deposition of titanium dioxide onto the surface of magnetic iron oxide particles proved ineffective in producing a stable magnetic photocatalyst, with high levels of photodissolution being observed with these samples. This observed photodissolution is believed to be due to the dissolution of the iron oxide phase, induced by the photoactive the titanium dioxide layer due to electronic interactions at the phase junction in these magnetic photocatalysts. The introduction of an intermediate passive SiO₂ layer between the titanium dioxide phase and the iron oxide phase inhibited the direct electrical contact and hence prevented the photodissolution of the iron oxide phase. The magnetic photocatalyst is for use in slurry-type reactors from which the catalyst can be easily recovered by the application of an external magnetic field.     

Application of matrix-assisted laser desorption/ionization to on-line aerosol time-of-flight mass spectrometry

Matrix-assisted laser desorption/ionization (MALDI) mass spectra were obtained from single biological aerosol particles using an aerosol time-of-flight mass spectrometer (ATOFMS). The inlet to the ATOFMS was coupled with an evaporation/condensation flow cell that allowed the aerosol to be coated with matrix material as the sampled stream entered the spectrometer. Mass spectra were generated from aerosol composed either of gramicidin-S or erythromycin, two small biological molecules, or from aerosolised spores of Bacillus subtilis var niger. Three different matrices were used: 3-nitrobenzyl alcohol, picolinic acid and sinapinic acid. A spectrum of gramicidin-S was generated from approximately 250 attomoles of material using a molar ratio of 3-nitrobenzyl alcohol to analyte of approximately 20:1. A single peak, located at 1224 Da, was obtained from the bacterial spores. The washing liquid and extract solution from the spores were analyzed using electrospray mass spectrometry and subsequent MS/MS product ion experiments. This independent analysis suggests that the measured species represents part of the B. subtilis peptidoglycan. The on-line addition of matrix allows quasi-real-time chemical analysis of individual, aerodynamically sized particles, with an overall system residence time of less than 5 seconds. These results suggest that a MALDI-ATOFMS can provide nearly real-time identification of biological aerosols. Copyright 2000 John Wiley & Sons, Ltd.     

Spatially resolved measurement of inhomogeneous electrocoloration/insertion in polycrystalline molybdenum oxide thin films via chronoabsorptometric imaging

A new integrated electrochemical and transmission optical microscopy approach is presented which allows for elucidation of inhomogeneous ion/charge-transfer behavior in polycrystalline electrochromic/insertion materials. Spatially resolved Li+ diffusion coefficients and ionic conductivities are determined from the time-lapsed optical density imaging response monitored during electrochemical potential-step perturbation. Non-uniform coloration changes and dispersed insertion kinetics are observed and associated with domain specific reactivity of polymorphous materials comprising alpha-MoO3 and beta-MoO3.     

(∈, ∈∨q)-fuzzy subnear-rings and (∈, ∈∨q)-fuzzy ideals of near-rings

In this paper, we introduce the notions of (∈, ∈∨q)-fuzzy subnear-ring, (∈, ∈∨q)-fuzzy ideal and (∈, ∈∨q)-fuzzy quasi-ideal of near-rings and find more generalized concepts than those introduced by others. The characterization of such (∈, ∈ ∨q)-fuzzy ideals are also obtained.     

Recent advances in the development and application of microemulsion EKC

Microemulsion EKC (MEEKC) is an electrodriven separation technique. Separations are typically achieved using oil-in-water microemulsions, which are composed of nanometre-sized oil droplets suspended in an aqueous buffer. The droplets are stabilised by a surfactant and a cosurfactant. The novel use of water-in-oil microemulsions has also been investigated. This review summarises the advances in the development of MEEKC separations and also the different areas of application including determination of log P values, pharmaceutical applications, chiral analysis, natural products and bioanalytical separations and the use of new methods such as multiplexed MEEKC and high speed MEEKC. Recent applications (2004-2006) are tabulated for each area with microemulsion composition details.     

1,3,4-Oxadiazole-containing hybrids as potential anticancer agents: Recent developments,mechanism of action and structure-activity relationships

Chemotherapy is an important therapeutic approach for the treatment of cancer. Currently, many anticancer drugs are available in the market that plays an important role in cancer treatment, but concerns such as, drug resistance and side effects create an urgent need for the development of new anti-tumor drugs with high potency and less side effects. Heterocycles are of great interest due to their fascinating anticancer activity. Among them, 1,3,4-oxadiazoles showed attracting anti-tumor activity and its derivatives are under clinical trials for the treatment of cancer. Hybridization of 1,3,4-oxadiazole moiety with other heterocyclic pharmacophoresis a promising approach to overcome various disadvantages of current anticancer drugs such as drug resistance, toxicity, and other side effects. Thus, 1,3,4-oxadiazole-heterocycle hybrids occupy a significant position in the discovery of anti-tumor drugs. Among the reported oxadiazole-based hybrids reviewed here, compounds 45i, 59j, and 62x showed the highest anticancer activity with IC₅₀ values in the nanomolar range. This review summarizes the recent developments in the anticancer potential, structure–activity relationships, and mechanisms of actions of 1,3,4-oxadiazole-heterocycle hybrids.     

The effects of high energy electron beam irradiation on the thermal and structural properties of low density polyethylene

Radiation is currently being exploited to modify polyethylene in order to improve properties for various applications such as hip replacements. This paper thoroughly examines the effects of high energy electron beam irradiation (10 MeV) on low density polyethylene (LDPE) material. ASTM (American Society for Testing and Materials) testing specimens were manufactured from LDPE and subjected to a broad range of doses ranging between 25 and 400 kGy at room temperature in an air atmosphere. Extensive characterisation techniques such as modulated differential scanning calorimetry (MDSC) and the Fourier transform infrared spectroscopy (FTIR) were conducted on the non-irradiated and irradiated samples. While considering the semicrystalline nature of LDPE during the MDSC experiment, the melting temperature (T_m) and the temperature crystallinity (T_c) were calculated. This revealed that the T_m and the T_c decreased in temperature as the irradiation dose increased. The FTIR analysis was implemented to evaluate the presence of polar species such as carbonyl groups and trans-vinylene double bond groups. The IR spectra illustrated that the concentration of characteristic bands for trans-vinylene bonds increased with increasing radiation dose indicating the formation of carbonyl bond groups. Furthermore, the results demonstrated an occurrence of oxidative degradation due to the formation of carbonyl groups at 1718 cm^?1.     

The substrate-bound crystal structure of a Baeyer-Villiger monooxygenase exhibits a Criegee-like conformation

The Baeyer-Villiger monooxygenases (BVMOs) are a family of bacterial flavoproteins that catalyze the synthetically useful Baeyer-Villiger oxidation reaction. This involves the conversion of ketones into esters or cyclic ketones into lactones by introducing an oxygen atom adjacent to the carbonyl group. The BVMOs offer exquisite regio- and enantiospecificity while acting on a wide range of substrates. They use only NADPH and oxygen as cosubstrates, and produce only NADP(+) and water as byproducts, making them environmentally attractive for industrial purposes. Here, we report the first crystal structure of a BVMO, cyclohexanone monooxygenase (CHMO) from Rhodococcus sp. HI-31 in complex with its substrate, cyclohexanone, as well as NADP(+) and FAD, to 2.4 ? resolution. This structure shows a drastic rotation of the NADP(+) cofactor in comparison to previously reported NADP(+)-bound structures, as the nicotinamide moiety is no longer positioned above the flavin ring. Instead, the substrate, cyclohexanone, is found at this location, in an appropriate position for the formation of the Criegee intermediate. The rotation of NADP(+) permits the substrate to gain access to the reactive flavin peroxyanion intermediate while preventing it from diffusing out of the active site. The structure thus reveals the conformation of the enzyme during the key catalytic step. CHMO is proposed to undergo a series of conformational changes to gradually move the substrate from the solvent, via binding in a solvent excluded pocket that dictates the enzyme's chemospecificity, to a location above the flavin-peroxide adduct where catalysis occurs.