Effect of a standardised dietary restriction protocol on multiple laboratory strains of Drosophila melanogaster

Background: Outcomes of lifespan studies in model organisms are particularly susceptible to variations in technical procedures. This is especially true of dietary restriction, which is implemented in many different ways among laboratories. Principal Findings: In this study, we have examined the effect of laboratory stock maintenance, genotype differences and microbial infection on the ability of dietary restriction (DR) to extend life in the fruit fly Drosophila melanogaster. None of these factors block the DR effect. Conclusions: These data lend support to the idea that nutrient restriction genuinely extends lifespan in flies, and that any mechanistic discoveries made with this model are of potential relevance to the determinants of lifespan in other organisms

Quantum state preparation in semiconductor dots by adiabatic rapid passage

Preparation of a specific quantum state is a required step for a variety of proposed practical uses of quantum dynamics. We report an experimental demonstration of optical quantum state preparation in a semiconductor quantum dot with electrical readout, which contrasts with earlier work based on Rabi flopping in that the method is robust with respect to variation in the optical coupling. We use adiabatic rapid passage, which is capable of inverting single dots to a specified upper level. We demonstrate that when the pulse power exceeds a threshold for inversion, the final state is independent of power. This provides a new tool for preparing quantum states in semiconductor dots and has a wide range of potential uses.Comment: 4 pages, 4 figure

Microcavity quantum-dot systems for non-equilibrium Bose-Einstein condensation

We review the practical conditions required to achieve a non-equilibrium BEC driven by quantum dynamics in a system comprising a microcavity field mode and a distribution of localised two-level systems driven to a step-like population inversion profile. A candidate system based on eight 3.8nm layers of In(0.23)Ga(0.77)As in GaAs shows promising characteristics with regard to the total dipole strength which can be coupled to the field mode.Comment: 4 pages, 4 figures, to be published in J. Phys. Conf. Ser. for QD201

Legal aspects of open disclosure II: Attitudes of health professionals - Findings from a national survey

Objective: To assess the attitudes of health care professionals engaged in open disclosure (OD) to the legal risks and protections that surround this activity. Design and participants: National cross-sectional survey of 51 experienced OD practitioners conducted in mid 2009. Main outcome measures: Perceived barriers to OD; awareness of and attitudes towards medicolegal protections; recommendations for reform. Results: The vast majority of participants rated fears about the medicolegal risks (45/51) and inadequate education and training in OD skills (43/51) as major or moderate barriers to OD. A majority (30/51) of participants viewed qualified privilege laws as having limited or no effect on health professionals' willingness to conduct OD, whereas opinion was divided about the effect of apology laws (state laws protecting expressions of regret from subsequent use in legal proceedings). In four states and territories (Western Australia, South Australia, Tasmania and the Northern Territory), a majority of participants were unaware that their own jurisdiction had apology laws that applied to OD. The most frequent recommendations for legal reform to improve OD were strengthening existing protections (23), improving education and awareness of applicable laws (11), fundamental reform of the medical negligence system (8), and better alignment of the activities of certain legal actors (eg, coroners) with OD practice (6). Conclusions: Concerns about both the medicolegal implications of OD and the skills needed to conduct it effectively are prevalent among health professionals at the leading edge of the OD movement in Australia. The ability of current laws to protect against use of this information in legal proceedings is perceived as inadequate

Neutrophil gelatinase-associated lipocalin: its response to hypoxia and association with acute mountain sickness.

Acute Mountain Sickness (AMS) is a common clinical challenge at high altitude (HA). A point-of-care biochemical marker for AMS could have widespread utility. Neutrophil gelatinase-associated lipocalin (NGAL) rises in response to renal injury, inflammation and oxidative stress. We investigated whether NGAL rises with HA and if this rise was related to AMS, hypoxia or exercise. NGAL was assayed in a cohort (n = 22) undertaking 6 hours exercise at near sea-level (SL); a cohort (n = 14) during 3 hours of normobaric hypoxia (FiO2 11.6%) and on two trekking expeditions (n = 52) to over 5000 m. NGAL did not change with exercise at SL or following normobaric hypoxia. During the trekking expeditions NGAL levels (ng/ml, mean ± sd, range) rose significantly (P < 0.001) from 68 ± 14 (60-102) at 1300 m to 183 ± 107 (65-519); 143 ± 66 (60-315) and 150 ± 71 (60-357) at 3400 m, 4270 m and 5150 m respectively. At 5150 m there was a significant difference in NGAL between those with severe AMS (n = 7), mild AMS (n = 16) or no AMS (n = 23): 201 ± 34 versus 171 ± 19 versus 124 ± 12 respectively (P = 0.009 for severe versus no AMS; P = 0.026 for mild versus no AMS). In summary, NGAL rises in response to prolonged hypobaric hypoxia and demonstrates a relationship to the presence and severity of AMS

Measuring antibody coatings on gold nanoparticles by optical spectroscopy

The adsorption of antibodies onto gold nanoparticles to make gold–antibody conjugates is finding application in multiple areas. Gold–antibody conjugates for use in malaria diagnostics were prepared and a method of characterisation that can be applied to any gold–protein conjugate was developed. When protein adsorbs onto a gold nanoparticle, it changes the local refractive index and so changes the surface plasmon resonance of the gold particle. Changes to the surface plasmon resonance manifest in the absorbance spectrum of the conjugates. This was measured by optical spectroscopy and relatively simple equations to convert spectral shifts to predictions of the protein layer thickness and mass coverage are presented. As with most protein adsorption reported in the literature, the results showed the protein adsorption to depend on antibody concentration, reaching a plateau at around 1 μg ml−1. The coverage was estimated to be approximately 2–3 mg m−2 and the coating thickness estimates were approximately 10 nm, which is consistent with active antibody. The results suggested more antibody was used in conjugate preparation than was necessary for complete coverage of the gold. This excess antibody could bind to the target antigen to reduce malaria test sensitivity. A key advantage of this characterisation method is that it is sufficiently simple to be used for quality control of conjugate production and the equations presented can be applied to other coatings on gold nanoparticles