John M. Bell

Temperature, field and grain size dependence of flux pinning in high Tc superconductors

Abstract Three models of flux pinning are discussed in terms of their basic geometric characteristics. The models are distinguished by their predictions of the field, temperature and sample size dependence of resistivity in an applied magnetic field below T c . Field dependent resistance data below T c from several good quality thin film samples and a single crystal are examined to extract activation energies and the resistivity pre-factor. A universal correlation between the latter two quantities and evidence that activation energies scale with sample thickness point strongly to a model involving flux pinning along a line as the most appropriate to describe thermally activated flux creep behaviour. These data also indicate that vortex lines are straight and the vortex lattice ordered for fields along the c -axis and for sample thickness up to at least ∽ 20 μm provided one is not too close to T c .

Prescriber and Patient Responsibilities in Treatment of Acute Respiratory Tract Infections — Essential for Conservation of Antibiotics.

Inappropriate antibiotic use in normally self-limiting acute respiratory tract infections (RTIs), such as sore throat and the common cold, is a global problem and an important factor for increasing levels of antibiotic resistance. A new group of international experts—the Global Respiratory Infection Partnership (GRIP)—is committed to addressing this issue, with the interface between primary care practitioners and their patients as their core focus. To combat the overuse of antibiotics in the community, and facilitate a change from prescribing empiric antibiotic treatment towards cautious deferment combined with symptomatic relief, there is a need to introduce and enhance evidence-based dialogue between primary care practitioners and their patients. Communication with patients should focus on the de-medicalisation of self-limiting viral infections, which can be achieved via a coherent globally endorsed framework outlining the rationale for appropriate antibiotic use in acute RTIs in the context of antibiotic stewardship and conservancy. The planned framework is intended to be adaptable at a country level to reflect local behaviours, cultures and healthcare systems, and has the potential to serve as a model for change in other therapeutic areas.

Precision ultra-microhardness measurements of sol-gel-derived zirconia thin films

Reports of measurements of the hardness of sol-gel deposited zirconia coatings on stainless steel substrates. Hardness tests were carried out on three multiply coated samples, each having a total film thickness of 0.6μm. These films do have mechanical properties similar to bulk zirconia, so they could be useful as wear-resistant coatings

Electrochromism in sol-gel deposited TiO2 films

Electrochromism is sol-gel deposited TiO2 films and films containing TiO2 and WO3 has been observed. The films are deposited by dip-coating from a precursor containing titanium isopropoxide in ethanol or titanium propoxide in ethanol, and after deposition the films are heat treated to between 250 degree(s)C and 300 degree(s)C. The films do not show any signs of crystallinity. However substantial coloration is observed using Li+ ions in a non-aqueous electrolyte, both in pure TiO2 films and in mixed metal oxide films (WO3:TiO2), although the voltage required to produce coloration is different in the two cases. Results will be presented detailing the optical switching and charge transport properties of the films during cyclic voltammetry. These results will be used to compare the performance of the TiO2 films with other electrochromics. The TiO2 and mixed metal films all color cathodically, and the colored state is a neutral greyish color for TiO2, while the bleached state is transparent and colorless, Results on coloration efficiency and the stability under repeated electrochemical cycling will also be presented. The neutral color of the TiO2 films and mixed-metal films means that electrochromic windows based on TiO2 may have significant advantages over WO3-based windows. A detailed analysis of the optical properties of the colored state of the films will be presented. The dynamics of coloration for these films is also under investigation, and preliminary results will be presented.

Sore throat: effective communication delivers improved diagnosis, enhanced self-care and more rational use of antibiotics

The majority of throat infections are of viral origin and resolve without antibiotic treatment. Despite this, antibiotic use for sore throat infections remains high, partly because it is difficult to determine when antibiotics may be useful, on the basis of physical findings alone. Antibiotics may be beneficial in bacterial throat infections under certain clinical and epidemiological circumstances; however, even many of those infections in which bacteria play a role do resolve just as quickly without antibiotics. Furthermore, non‐medical factors such as patient expectations and patient pressure are also important drivers of antibiotic use. To address these issues, a behavioural change is required that can be facilitated by improved communication between primary healthcare providers and patients. In this article, we provide doctors, nurses and pharmacy staff, working in primary care or in the community, with a structured approach to sore throat management, with the aim of educating and empowering patients to self‐manage their condition. The first component of this approach involves identifying and addressing patients’ expectations and concerns with regard to their sore throat and eliciting their opinion on antibiotics. The second part is dedicated to a pragmatic assessment of the severity of the condition, with attention to red‐flag symptoms and risk factors for serious complications. Rather than just focusing on the cause (bacterial or viral) of the upper respiratory tract infections as a rationale for antibiotic use, healthcare providers should instead consider the severity of the patients condition and whether they are at high risk of complications. The third part involves counselling patients on effective self‐management options and providing information on the expected clinical course. Such a structured approach to sore throat management, using empathetic, non‐paternalistic language, combined with written patient information, will help to drive patient confidence in self‐care and encourage them to accept the self‐limiting character of the illness – important steps towards improving antibiotic stewardship in acute throat infections.

Phase slippage in a magnetic field at intra- and intergranular Josephson junctions in high-Tc superconductors

Abstract The intra- and intergranular components of resistance in high- T c superconductors are modelled, after configurational averaging, as due to a single resistively shunted Josephson junction in each case. They are combined in series. A voltage develops across each junction due to thermally activated phase slippage. In the presence of a magnetic field slippage occurs at a faster rate and is accompanied by motion of the entire flux bundle in the junction. Data on thin films is fitted well by the model over a wide temperature range. The model predicts that in a flux density B the critical currents and activation energies at higher fields fall off as (o 0 /B) 1 2 /[D+(o 0 /B) 1 2 ] with D the junction width. Experimental data on thin films of YBa 2 Cu 3 O 7 agrees with this prediction for both types of junction. It also shows that neither the intra- nor the intergranular components of resistance are sensitive to the relative direction of macroscopic current and field down to low temperatures. Differences between the roles of the Lorentz force in flux creep and phase slippage models are discussed.

Structure and properties of electrochromic WO3 produced by sol-gel methods

Electrochromic tungsten oxide thin films produced by dip-coating from a sol-gel solution are of interest for large area electrochromic window applications. The influence of the sol-gel formulation and the subsequent processing of the film required to produce uniform WO3 films are discussed together with the effects of the dipping and processing parameters on the structure, optical properties, and electrochemical behavior of the films. The electrochemical behavior of the films has been studied using cyclic voltammetry. Electrolyte solutions, with different cations for insertion into the WO3 layers, have been used in this work, and the resultant coloration of the films studied using spectrophotometry. Both colored and uncolored films have been studied using Rutherford backscattering spectrometry (RBS) and scanning electron microscopy (SEM). The sol-gel processing steps are shown to have a significant influence on the film microstructure and therefore the electrochemical coloration behavior of the films, as well as the lifetime of the film under repeated cycling. Results are shown illustrating the coloration behavior of the films, and the transmittance of the films over the visible and near-infrared spectra. WO3 films approximately 0.15 micrometers thick are highly transparent and color quite uniformly, although the process is not completely reversible. There is evidence from the auger electron spectroscopy (AES) and RBS data that there is residual carbon in the films after conventional processing. Some progress has been made toward examination of the effect of this carbon on both coloration efficiency and long-term switching life of prototype devices.

Self-Care in the Twenty First Century: A Vital Role for the Pharmacist

AbstractIn order for the global healthcare system to remain sustainable, healthcare spending needs to be reduced, and self-treating certain conditions under the guidance of a pharmacist provides a means of accomplishing this goal. This article was developed to describe global healthcare trends affecting self-care with a specific focus on the role of the pharmacist in facilitating over-the-counter (OTC) medication management. Potential healthcare-related economic benefits associated with the self-care model are outlined. The importance of the collaboration between healthcare providers (HCPs), including specialists, primary care providers, and pharmacists, is also discussed. The evolving role of the pharmacist is examined and recommendations are provided for ways to successfully engage with other HCPs and consumers to optimize the pharmacist’s unique qualifications and accessibility in the community. Using the management of frequent heartburn with an OTC proton-pump inhibitor as a model, the critical role of the pharmacist in patient self-treatment of certain symptoms will be discussed based on the World Gastroenterology Organization’s recently published guidelines for the community-based management of common gastrointestinal symptoms. As the global healthcare system continues to evolve, self-care is expected to have an increasing role in treating certain minor ailments, and pharmacists are at the forefront of these changes. Pharmacists can guide individuals in making healthy lifestyle choices, recommend appropriate OTC medications, and educate consumers about when they should consult a physician. Funding: Pfizer Inc.

Ferroelectric electrode interactions in BaTiO3 and PZT thin films

Abstract We have studied ferroelectric thin films deposited by sol-gel processing onto non-noble metal substrates. The results obtained indicate that by careful control of processing conditions, ferroelectric materials can be deposited onto these substrates, although interdiffusion between the metal and the ferroelectric can significantly degrade the ferroelectric properties of the materials. The effects of this interdiffusion are demonstrated and possible implications of ferroelectric-electrode interactions for fatigue in ferroelectric materials are discussed.

Simple computer‐controlled potentiostat for the characterization of electrochromic films

We describe a simple and inexpensive potentiostat, incorporating current boosting and filtering circuitry for use in the study of coloration and bleaching in electrochromic thin films. The system is sufficiently flexible to permit utilization in other electrochemical applications.