Epitaxial Growth of La1/3_{1/3}Sr2/3_{2/3}FeO3_3 thin films by laser ablation

We report on the synthesis of high quality La$_{1/3}$Sr$_{2/3}$FeO$_3$ (LSFO) thin films using the pulsed laser deposition technique on both SrTiO$_3$ (STO) and LaAlO$_3$ (LAO) substrates (100)-oriented. From X-Ray diffraction (XRD) studies, we find that the films have an out-of-plane lattice parameter around 0.3865nm, almost independent of the substrate (i.e. the nature of the strains). The transport properties reveal that, while LSFO films deposited on STO exhibit an anomaly in the resistivity vs temperature at 180K (corresponding to the charge-ordered transition and associated with a transition from a paramagnetic to an antiferromagnetic state), the films grown on LAO display a very small magnetoresistance behavior and present an hysteresis around 270K under the application of a 4T magnetic field. The changes in transport properties between both substrates are discussed and compared with the corresponding single crystals.Comment: 9 pages, 4 figure

Corrections to the universal behavior of the Coulomb-blockade peak splitting for quantum dots separated by a finite barrier

Building upon earlier work on the relation between the dimensionless interdot channel conductance g and the fractional Coulomb-blockade peak splitting f for two electrostatically equivalent dots, we calculate the leading correction that results from an interdot tunneling barrier that is not a delta-function but, rather, has a finite height V and a nonzero width xi and can be approximated as parabolic near its peak. We develop a new treatment of the problem for g much less than 1 that starts from the single-particle eigenstates for the full coupled-dot system. The finiteness of the barrier leads to a small upward shift of the f-versus-g curve at small values of g. The shift is a consequence of the fact that the tunneling matrix elements vary exponentially with the energies of the states connected. Therefore, when g is small, it can pay to tunnel to intermediate states with single-particle energies above the barrier height V. The correction to the zero-width behavior does not affect agreement with recent experimental results but may be important in future experiments.Comment: Title changed from ``Non-universal...'' to ``Corrections to the universal...'' No other changes. 10 pages, 1 RevTeX file with 2 postscript figures included using eps

The challenges of optimising glycaemic control in children with type 1 diabetes: a qualitative study of parents’ experiences and views

Aims To explore the difficulties parents encounter in trying to achieve clinically recommended blood glucose levels and how they could be better supported to optimize their child's glycaemic control. Methods In-depth interviews were conducted with 54 parents of children with Type 1 diabetes (≤ 12 years). Data were analysed thematically. Results Parents described being reluctant and finding it difficult to keep their child's blood glucose levels consistently within clinically recommended ranges. As well as worrying about their child's ability to detect/report hypoglycaemia, parents highlighted a multitude of factors that had an impact on their child's blood glucose levels and over which they could exercise little control. These included: leaving their child with other caregivers who could not be trusted to detect hypoglycaemia; difficulties remotely monitoring and regulating their child's food consumption and activity; and physical and social changes accompanying childhood development. Most parents used two sets of blood glucose targets, with clinically recommended targets employed when their child was in their immediate care and higher targets when in the care of others. Parents described health professionals as lacking understanding of the difficulties they encountered keeping blood glucose within target ranges and needing more empathetic, tailored and realistic advice. Conclusion It is not parents' fear of hypoglycaemia in isolation that leads to decisions to raise their child's blood glucose but, rather, parental fear in conjunction with other factors and considerations. Hence, to improve diabetes management in children, these factors may need to be addressed; for instance, by training others in diabetes management and using new technologies. Changes to consultations are also recommended

Systematic review of the effectiveness and cost-effectiveness of Healozone for the treatment of occlusal pit/fissure caries and root caries.

Objectives: To assess the effectiveness and cost-effectiveness of HealOzone® (CurOzone USA Inc., Ontario, Canada) for the management of pit and fissure caries, and root caries. The complete HealOzone procedure involves the direct application of ozone gas to the caries lesion on the tooth surface, the use of a remineralising solution immediately after application of ozone and the supply of a ‘patient kit’, which consists of toothpaste, oral rinse and oral spray all containing fluoride. Data sources: Electronic databases up to May 2004 (except Conference Papers Index, which were searched up to May 2002). Review methods: A systematic review of the effectiveness of HealOzone for the management of tooth decay was carried out. A systematic review of existing economic evaluations of ozone for dental caries was also planned but no suitable studies were identified. The economic evaluation included in the industry submission was critically appraised and summarised. A Markov model was constructed to explore possible cost-effectiveness aspects of HealOzone in addition to current management of dental caries. Results: Five full-text reports and five studies published as abstracts met the inclusion criteria. The five full-text reports consisted of two randomised controlled trials (RCTs) assessing the use of HealOzone for the management of primary root caries and two doctoral theses of three unpublished randomised trials assessing the use of HealOzone for the management of occlusal caries. Of the abstracts, four assessed the effects of HealOzone for the management of occlusal caries and one the effects of HealOzone for the management of root caries. Overall, the quality of the studies was modest, with many important methodological aspects not reported (e.g. concealment of allocation, blinding procedures, compliance of patients with home treatment). In particular, there were some concerns about the choice of statistical analyses. In most of the full-text studies analyses were undertaken at lesion level, ignoring the clustering of lesions within patients. The nature of the methodological concerns was sufficient to raise doubts about the validity of the included studies’ findings. A quantitative synthesis of results was deemed inappropriate. On the whole, there is not enough evidence from published RCTs on which to judge the effectiveness of ozone for the management of both occlusal and root caries. The perspective adopted for the study was that of the NHS and Personal Social Services. The analysis, carried out over a 5-year period, indicated that treatment using current management plus HealOzone cost more than current management alone for non-cavitated pit and fissure caries (£40.49 versus £24.78), but cost less for non-cavitated root caries (£14.63 versus £21.45). Given the limitations of the calculations these figures should be regarded as illustrative, not definitive. It was not possible to measure health benefits in terms of quality-adjusted life-years, due to uncertainties around the evidence of clinical effectiveness, and to the fact that the adverse events avoided are transient (e.g. pain from injection of local anaesthetic, fear of the drill). One-way sensitivity analysis was applied to the model. However, owing to the limitations of the economic analysis, this should be regarded as merely speculative. For non-cavitated pit and fissure caries, the HealOzone option was always more expensive than current management when the probability of cure using the HealOzone option was 70% or lower. For non-cavitated root caries the costs of the HealOzone comparator were lower than those of current management only when cure rates from HealOzone were at least 80%. The costs of current management were higher than those of the HealOzone option when the cure rate for current management was 40% or lower. One-way sensitivity analysis was also performed using similar NHS Statement of Dental Remuneration codes to those that are used in the industry submission. This did not alter the results for non-cavitated pit fissure caries as the discounted net present value of current management remained lower than that of the HealOzone comparator (£22.65 versus £33.39). Conclusions: Any treatment that preserves teeth and avoids fillings is welcome. However, the current evidence base for HealOzone is insufficient to conclude that it is a cost-effective addition to the management and treatment of occlusal and root caries. To make a decision on whether HealOzone is a cost-effective alternative to current preventive methods for the management of dental caries, further research into its clinical effectiveness is required. Independent RCTs of the effectiveness and cost-effectiveness of HealOzone for the management of occlusal caries and root caries need to be properly conducted with adequate design, outcome measures and methods for statistical analyses

Correlation induced switching of local spatial charge distribution in two-level system

We present theoretical investigation of spatial charge distribution in the two-level system with strong Coulomb correlations by means of Heisenberg equations analysis for localized states total electron filling numbers taking into account pair correlations of local electron density. It was found that tunneling current through nanometer scale structure with strongly coupled localized states causes Coulomb correlations induced spatial redistribution of localized charges. Conditions for inverse occupation of two-level system in particular range of applied bias caused by Coulomb correlations have been revealed. We also discuss possibility of charge manipulation in the proposed system.Comment: 6 pages, 4 figures Submitted to JETP Letter

Force balance and membrane shedding at the Red Blood Cell surface

During the aging of the red-blood cell, or under conditions of extreme echinocytosis, membrane is shed from the cell plasma membrane in the form of nano-vesicles. We propose that this process is the result of the self-adaptation of the membrane surface area to the elastic stress imposed by the spectrin cytoskeleton, via the local buckling of membrane under increasing cytoskeleton stiffness. This model introduces the concept of force balance as a regulatory process at the cell membrane, and quantitatively reproduces the rate of area loss in aging red-blood cells.Comment: 4 pages, 3 figure

Quantum Computation with Quantum Dots

We propose a new implementation of a universal set of one- and two-qubit gates for quantum computation using the spin states of coupled single-electron quantum dots. Desired operations are effected by the gating of the tunneling barrier between neighboring dots. Several measures of the gate quality are computed within a newly derived spin master equation incorporating decoherence caused by a prototypical magnetic environment. Dot-array experiments which would provide an initial demonstration of the desired non-equilibrium spin dynamics are proposed.Comment: 12 pages, Latex, 2 ps figures. v2: 20 pages (very minor corrections, substantial expansion), submitted to Phys. Rev.