Nanoparticle Platform to Modulate Reaction Mechanism of Phenothiazine Photosensitizers

Herein, we report on the synthesis of photosensitizing nanoparticles in which the generation of different oxidizing species, i.e., singlet oxygen ((1)O(2)) or radicals, was modulated. Sol gel and surface chemistry were used to obtain nanoparticles with specific ratios of dimer to monomer species of phenothiazine photosensitizers (PSs). Due to competition between the reactions involving electron transfer within dimer species and energy transfer from monomer triplets to oxygen, the efficiency of (1)O(2) generation could be controlled. Nanoparticles with an excess of dimer have an (1)O(2) generation efficiency (S(Delta)) of 0.01 while those without dimer have a S, value of 0.4. Furthermore, we demonstrate that the PS properties of the nanoparticles are not subjected to interference from the external medium as is commonly the case for free PSs, i.e., PS ground and triplet states are not reduced by NADH and ascorbate, respectively, and singlet excited states are less suppressed by bromide. The modulated (1)O(2) generation and the PS protection from external interferences make this nanoparticle platform a promising tool to aid in performing mechanistic studies in biological systems. Also, it offers potential application in technological areas in which photo-induced processes take place.

Tryptophan photooxidation promoted by new hybrid materials prepared by condensation of naphthalene imides with silicate by the sol-gel process

Three novel hybrid organic/inorganic materials were synthesized from 4-substituted (NO(2), Br, H) 1,8-naphthalene imide-N-propyltriethoxysilane by the sol-gel process. These materials were obtained as a xerogel and partially characterized. The ability to photosensitize the oxidation and degradation of tryptophan indole ring by these materials was studied through photophysical and photochemical techniques. Although the derivatives containing Br and NO(2) as substituent do not cause efficient tryptophan photodamage, the hybrid material obtained from 1,8-naphthalic anhydride is very efficient to promote tryptophan photooxidation. By using laser flash photolysis it was possible to verify the presence of naphthalene imide transient radical species. The presence of oxygen causes an increase of the yield of radical formation. These results suggest that the mechanism of photodegradation of tryptophan occurs by type I, i.e. the transient radical (TrpH(center dot+)) formed by the direct reaction of the triplet state of the naphthalene imide moiety with tryptophan. Thus a inorganic-organic hybrid material that can be used to promote the oxidation of biomolecules was obtained. (C) 2009 Elsevier B.V. All rights reserved.

Use of copper and gold electrodes as sensitive elements for fabrication of an electronic tongue: Discrimination of wines and whiskies

A low-cost method is proposed to classify wine and whisky samples using a disposable voltammetric electronic tongue that was fabricated using gold and copper substrates and a pattern recognition technique (Principal Component Analysis). The proposed device was successfully used to discriminate between expensive and cheap whisky samples and to detect adulteration processes using only a copper electrode. For wines, the electronic tongue was composed of copper and gold working electrodes and was able to classify three different brands of wine and to make distinctions regarding the wine type, i.e., dry red, soft red, dry white and soft white brands. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.

Characterization of banana, sugarcane bagasse and sponge gourd fibers of Brazil

In recent times, increasing attention has been paid to the use of renewable resources particularly of plant origin keeping in view the ecological concerns, renewability and many governments passing laws for the use of such materials. On the other hand, despite abundant availability of lignocellulosic materials in Brazil, very few attempts have been made about their utilization, probably due to lack of sufficient structure/property data. Systematic studies to know their properties and morphology may bridge this gap while leading to value addition to these natural materials. Chemical composition, X-ray powder diffraction, and morphological studies and thermal behavior aspects in respect of banana, sugarcane bagasse sponge gourd fibers of Brazilian origin are presented. Chemical compositions of the three fibers are found to be different than those reported earlier. X-ray diffraction patterns of these three fibers exhibit mainly cellulose type I structure with the crystallinity indices of 39%, 48% and 50% respectively for these fibers. Morphological studies of the fibers revealed different sizes and arrangement of cells. Thermal stability of all the fibers is found to be around 200 degrees C. Decomposition of both cellulose and hemicelluloses in the fibers takes place at 300 degrees C and above, while the degradation of fibers takes place above 400 degrees C. These data may help finding new uses for these fibers. (C) 2009 Elsevier B.V. All rights reserved.

THERMAL BEHAVIOR OF IN VITRO MINERALIZED ANIONIC COLLAGEN MATRICES

In the present study porcine skin and bovine pericardium were used as a source of type I collagen. Both were submitted to an alkaline treatment and mineralized by the alternate soaking method. Thermal stability and extent of mineralization have been investigated using DSC and TG. After alkaline hydrolysis there is a decrease in thermal stability but mineralization stabilizes collagen structure. Thermogravimetric data have shown that the amount of hydroxyapatite present in bovine pericardium matrix (45%) was greater than on porcine skin matrix (20%). Presence of hydroxyapatite was confirmed by EDX.

Dietary regulation of fat oxidative gene expression in different skeletal musle fiber types

Objective: To determine the effect of a high-fat diet on the expression of genes important for fat oxidation, the protein abundance of the transcription factors peroxisome proliferator-activated receptor (PPAR) isoforms α and γ, and selected enzyme activities in type I and II skeletal muscle. Research Methods and Procedures: Sprague-Dawley rats consumed either a high-fat (HF: 78% energy, <i>ni> = 8) or high-carbohydrate (64% energy, <i>ni> = 8) diet for 8 weeks while remaining sedentary. Results: The expression of genes important for fat oxidation tended to increase in both type I (soleus) and type II (extensor digitorum longus) fiber types after an HF dietary intervention. However, the expression of muscle type carnitine palmitoyltransferase I was not increased in extensor digitorum longus. Analysis of the gene expression of both peroxisome proliferator-activated receptor-γ coactivator and forkhead transcription factor O1 demonstrated no alteration in response to the HF diet. Similarly, PPARα and PPARγ protein levels were also not altered by the HF diet. Discussion: An HF diet increased the expression of an array of genes involved in lipid metabolism, with only subtle differences evident in the response within differing skeletal muscle fiber types. Despite changes in gene expression, there were no effects of diet on peroxisome proliferator-activated receptor-gamma coactivator and forkhead transcription factor O1 mRNA and the protein abundance of PPARα and PPARγ.

PGC-1α and exercise: important partners in combating insulin resistance

Diabetes and obesity are characterised by an impairment in mitochondrial function resulting in a decrease in glucose and fatty acid oxidation, respiration and an increase in intramuscular triglycerides (IMTG's) and insulin resistance. Peroxisome proliferator-activated receptor (PPAR)-ggr coactivator 1agr (PGC-1agr) is a nuclear transcriptional coactivator which regulates several important metabolic processes including, mitochondrial biogenesis, adaptive thermogenesis, respiration, insulin secretion and gluconeogenesis. In addition, PGC-1agr has been shown to increase the percentage of oxidative type I muscle fibres, with the latter responsible for the majority of insulin stimulated glucose uptake. PGC-1agr also co-activates PPAR's agr, bgr/dgr and ggr which are important transcription factors of genes regulating lipid and glucose metabolism. Exercise causes mitochondrial biogenesis, improves skeletal muscle fatty acid oxidation capacity and insulin sensitivity, therefore making it an important intervention for the treatment of insulin resistance. The expression of PGC-1agr mRNA is reduced in diabetic subjects, however, it is rapidly induced in response to interventions which signal alterations in metabolic requirements, such as exercise. Because of the important role of PGC-1agr in the control of energy metabolism and insulin sensitivity, it is seen as a candidate factor in the etiology of type 2 diabetes and a drug target for its therapeutic treatment.

Differential encoding technique for multi-antenna systems with correlated Rayleigh fading channels

Differential space-time modulation (DSTM) techniques developed for multi-antenna systems allow the receiver to detect the transmitted signal without the knowledge of the fading channels. It can be viewed as an extension of differential phase-shift keying (DPSK) in single antenna systems. In this paper, we derived the pairwise error probability upper bound of differential space-time coded systems with spatially correlated Rayleigh fading channels. Based on the performance analysis, we develop a novel DSTM scheme which can exploit the spatial correlation in the fading channels. It is found that by carefully designing the initial transmitted signal matrix, the performance of the differential space-time coded systems can be significantly improved.

Green decisions : demographics and consumer understanding of environmental labels

This research examined the demographic profiles of Australian green consumers in relation to their satisfaction of environmental labelling. It examined consumers’ understanding of labelling and empirically investigated the association of demographic profile of consumers with their attitudes towards such labels. The results indicated that some of the demographic variables were significant, which is largely consistent with earlier findings by other researchers in this area. Label dissatisfaction was higher in the older and middle age respondents. However, some respondents disagreed that labels were accurate while commenting that labels were easy to understand. The key issue arising from the findings is that in order to provide perception of accuracy in labels, it is an option to use Type I or Type III labelling on products. These labels are, arguably, more credible because they are endorsed by third party labelling experts. This would come at a cost and for green products that use third party labelling, they will also have to bear in mind to keep the prices competitive.

Effect of dietary omega-3 fatty acid deficiency on heart rate variability in hooded rats

Introduction: Recent reports in adult humans suggest that heart rate variability is modulated by the concentration of omega-3 polyunsaturated fatty acids (PUFA) contained in blood cell membranes. Material and methods: Hurst analysis of ECG data was conducted on 12 male adult hooded (Long-Evans) rats, representing the 3rd generation to be fed diets that were either deficient in, or supplemented with, omega-3 PUFA. ECG data were obtained from surface electrodes and 4000 beats were analyzed for each animal. Results: Dietary manipulation, despite leading to large changes in tissue omega- 3 PUFA levels, did not significantly affect the complexity of heart rate dynamics, with Hurst exponent (H) values of 0.15±0.02 and 0.12±0.03, for animals fed omega- 3 fatty acid-adequate and -deficient diets, respectively. Mean heart rate was also unaffected by the diets. A power calculation revealed that about one hundred animals per group would have been required to avoid a type II error. Conclusions: According to this model of dietary PUFA manipulation, omega-3 fatty acids are unlikely to exert a large effect on the autonomic functions that control heart rate variability. Prospective studies into the effect of omega-3 fatty acids on HRV should consider the need for large sample size as estimated by the results contained in this report.

Habitat use by five sympatric Australian freshwater crayfish species (Parastacidae)

1. The Grampians National Park in Victoria is a 'hot spot' for freshwater crayfish diversity, with seven species from six genera occurring in sympatry. Few studies have examined how multiple species of freshwater crayfish co-exist across landscapes consisting of a mosaic of perennial and seasonal habitats. Despite their endemicity and likely key role in freshwaters, the ecology and biology of these crayfish remains unknown.

2. This study determined the distribution and habitat use of five crayfish species (<i>Euastacus bispinosus, Cherax destructor, Geocharax falcata, Gramastacus insolitus i>and<i> Engaeus lyellii>). Seasonal sampling surveys ascertained whether crayfish distribution was related to habitat type, environmental or physicochemical variables, catchment or season.

3. Distribution was directly related to habitat type and the environmental and physicochemical variables that characterised habitats. <i>Engaeus lyelli, G. falcata i>and<i> G. insolitusi> occurred predominantly in floodplain wetlands and flooded vegetation habitats, <i>E. bispinosusi> occurred only in flowing soft-sediment channels and <i>C. destructori> was found in all catchments and habitat types studied. <i>Gramastacus insolitusi> co-occurred with <i>G. falcatai> at all sites except two, so no distinct habitat separations were apparent for these two species.

4. A high percentage cover of boulders was the best indicator of crayfish absence, and discriminated between habitat types and crayfish species: it was probably a surrogate for a larger range of environmental and physicochemical variables. Catchment and season did not affect crayfish distribution.

5. These crayfish species varied in their degree of habitat specialisation from strongly generalist (<i>C. destructori>) to occupying only a specific habitat type (<i>E. bispinosusi>). Some species appeared specialised for seasonal wetlands (<i>G. insolitus i>and <i>G. falcatai>). Overlap in site occupancy also varied: <i>G. insolitus i>and<i> G. falcatai> distributions were strongly associated, whereas <i>C. destructori> appeared to occur opportunistically across habitats, both alone and co-occurring with all the other species.

6. Management strategies to conserve multiple species of crayfish co-existing within landscapes will need to incorporate a range of perennial and seasonal habitat types to ensure sufficient space is available for species to maintain different occupancy patterns. Given that water resources are under increasing pressure and are strongly regulated within the Grampians National Park, this may present a conservation challenge to water managers in this location.