Seeded Synthesis of CdSe/CdS Rod and Tetrapod Nanocrystals

We demonstrate a method for the synthesis of multicomponent nanostructures consisting of CdS and CdSe with rod and tetrapod morphologies. A seeded synthesis strategy is used in which spherical seeds of CdSe are prepared first using a hot-injection technique. By controlling the crystal structure of the seed to be either wurtzite or zinc-blende, the subsequent hot-injection growth of CdS off of the seed results in either a rod-shaped or tetrapod-shaped nanocrystal, respectively. The phase and morphology of the synthesized nanocrystals are confirmed using X-ray diffraction and transmission electron microscopy, demonstrating that the nanocrystals are phase-pure and have a consistent morphology. The extinction coefficient and quantum yield of the synthesized nanocrystals are calculated using UV-Vis absorption spectroscopy and photoluminescence spectroscopy. The rods and tetrapods exhibit extinction coefficients and quantum yields that are higher than that of the bare seeds. This synthesis demonstrates the precise arrangement of materials that can be achieved at the nanoscale by using a seeded synthetic approach.     

A multiple chemostat system for consortia studies on microbially influenced corrosion

A multiple chemostat system has been developed in which metal specimens can be exposed to a consortium of bacteria. The system comprises a single test chemostat containing the test specimen operated at a high dilution rate to facilitate the wash out of planktonic bacteria, selecting for attached or biofilm growth. This chemostat is fed at a steady low rate by a number of separate chemostats each of which contains a pure axenic culture of one member of the consortium being tested. This system has the advantage of providing a continual inoculum of the test species to the test specimen allowing both aerobic and anaerobic bacteria to be grown in the same system. Constant levels of three bacterial types were maintained in the system: Pseudomonas aeruginosa, Thiobacillus ferrooxidans and Desulfovibrio vulgaris. Exposure of 316L stainless steel electrodes to this system resulted in increased corrosion of coupons exposed biotically, as compared to those exposed abiotically. A current monitoring technique and electrochemical impedance spectroscopy were used to evaluate effects of bacteria on metallic corrosion.     

The Maleny ‘Fire Event’: Rehearsals Toward Neo-liminality

Although the anthropological literature on ritual is extensive, little theoretical attention has been paid to recent attempts to (re)create rituals among mainstream groups in post-industrial, secularised societies. The authors address this issue by examiuning the annual Fire Event, which is constructed as a ritual climax to the Maleny Folk Festival in southern Queensland, Australia. Using the work of Victor Turner and John MacAloon as a point of departure, we argue that at best such celebrations constitute a neo-liminal framework within which participants can achieve a consensus of belief and action. By showing that some Fire Events have been more successful ‘rituals’ than others, we also highlight the factors which tend to impede participation and ‘con-subjectivity’ in such settings. In the process we identify some of the cultural divisions at Maleny, such as those between artists and ‘folk’, feral hippies and ‘hoons’, Aboriginals and Anglos, and begin to reflect on how these may relate to more general patterns of interaction in Australian society at large.     

Fluorescence Lifetime Imaging of Alterations to Cellular Metabolism by Domain 2 of the Hepatitis C Virus Core Protein

Hepatitis C virus (HCV) co-opts hepatic lipid pathways to facilitate its pathogenesis. The virus alters cellular lipid biosynthesis and trafficking, and causes an accumulation of lipid droplets (LDs) that gives rise to hepatic steatosis. Little is known about how these changes are controlled at the molecular level, and how they are related to the underlying metabolic states of the infected cell. The HCV core protein has previously been shown to independently induce alterations in hepatic lipid homeostasis. Herein, we demonstrate, using coherent anti-Stokes Raman scattering (CARS) microscopy, that expression of domain 2 of the HCV core protein (D2) fused to GFP is sufficient to induce an accumulation of larger lipid droplets (LDs) in the perinuclear region. Additionally, we performed fluorescence lifetime imaging of endogenous reduced nicotinamide adenine dinucleotides [NAD(P)H], a key coenzyme in cellular metabolic processes, to monitor changes in the cofactor’s abundance and conformational state in D2-GFP transfected cells. When expressed in Huh-7 human hepatoma cells, we observed that the D2-GFP induced accumulation of LDs correlated with an increase in total NAD(P)H fluorescence and an increase in the ratio of free to bound NAD(P)H. This is consistent with an approximate 10 fold increase in cellular NAD(P)H levels. Furthermore, the lifetimes of bound and free NAD(P)H were both significantly reduced – indicating viral protein-induced alterations in the cofactors’ binding and microenvironment. Interestingly, the D2-expressing cells showed a more diffuse localization of NAD(P)H fluorescence signal, consistent with an accumulation of the co-factor outside the mitochondria. These observations suggest that HCV causes a shift of metabolic control away from the use of the coenzyme in mitochondrial electron transport and towards glycolysis, lipid biosynthesis, and building of new biomass. Overall, our findings demonstrate that HCV induced alterations in hepatic metabolism is tightly linked to alterations in NAD(P)H functional states.     

Topical minoxidil in the treatment of alopecia areata.

A modified double blind crossover study was performed to assess the effect of 1% topical minoxidil as compared with placebo in 30 patients with alopecia areata and alopecia totalis. The active preparation produced a highly significant incidence of hair regrowth. A cosmetically acceptable response was noted in 16 patients. No side effects were seen. The study confirmed that topical minoxidil will induce new hair growth in alopecia areata but that it is less likely to do so in more severe and extensive disease. Furthermore, patients with alopecia universalis and totalis may not respond at all. Nevertheless, as compared with other drugs minoxidil applied topically is relatively non-toxic, is easy to use, and has no systemic or local side effects.     

A Rapid Method for Preparing High Quality Alizarin Stained Skeletons of Adult Mice

A simple three-day technique is described for preparing completely cleared and high quality alizarin stained total skeletons of adult mice. Unfixed specimens are partially macerated during staining. Older specimens are heated for 15 min in 1% KOH. A heated solution of benzyl and ethyl alcohol, glycerin, and water is used for final clearing and hardening. This procedure requires about 10 min work per specimen and greatly simplifies preparation of stained and cleared skeletons of adult mice. Another technique, giving slightly better preparations, but requiring 11-14 days, is also described.