Rational screening low-cost counter electrodes for dye-sensitized solar cells

Dye-sensitized solar cells have attracted intense research attention owing to their ease of fabrication, cost-effectiveness and high efficiency in converting solar energy. Noble platinum is generally used as catalytic counter electrode for redox mediators in electrolyte solution. Unfortunately, platinum is expensive and non-sustainable for long-term applications. Therefore, researchers are facing with the challenge of developing low-cost and earth-abundant alternatives. So far, rational screening of non-platinum counter electrodes has been hamstrung by the lack of understanding about the electrocatalytic process of redox mediators on various counter electrodes. Here, using first-principle quantum chemical calculations, we studied the electrocatalytic process of redox mediators and predicted electrocatalytic activity of potential semiconductor counter electrodes. On the basis of theoretical predictions, we successfully used rust (alpha-Fe2O3) as a new counter electrode catalyst, which demonstrates promising electrocatalytic activity towards triiodide reduction at a rate comparable to platinum.

A cleavable network based on crosslinked star polymers containing acid-labile diacetal crosslinks: Synthesis, characterization and hydrolysis

A hydrolyzable model network comprising interconnected star polymers was prepared by the sequential group transfer polymerization of methyl methacrylate and the acid-labile diacetal-based dimethacrylate crosslinker bis[(2-methacryloyloxy)ethoxymethyl] ether. in contrast to other polymer networks previously synthesized by our group, all the branching points of this polymer network were found to hydrolyze under mildly acidic conditions, giving a linear copolymer with the theoretically expected molecular weight and composition. The ease of hydrolysis of this polymer network renders it a good candidate for use in the biomedical field. The characterization of the synthesized network, its linear and star polymer precursors and the hydrolysis products of the network and its precursors, by a variety of techniques, established the successful synthesis and hydrolysis of this well-defined polymer nanostructure.

Covariance Averaging for Improved Estimation and Portfolio Allocation

We propose a new method for estimating the covariance matrix of a multivariate time series of nancial returns. The method is based on estimating sample covariances from overlapping windows of observations which are then appropriately weighted to obtain the nal covariance estimate. We extend the idea of (model) covariance averaging o ered in the covariance shrinkage approach by means of greater ease of use, exibility and robustness in averaging information over different data segments. The suggested approach does not su er from the curse of dimensionality and can be used without problems of either approximation or any demand for numerical optimization.

Photosensitisers - the progression from photodynamic therapy to anti-infective surfaces

Introduction: The application of light as a stimulus in pharmaceutical systems and the associated ability to provide precise spatiotemporal control over location, wavelength and intensity, allowing ease of external control independent of environmental conditionals, has led to its increased use. Of particular note is the use of light with photosensitisers.

Areas covered: Photosensitisers are widely used in photodynamic therapy to cause a cidal effect towards cells on irradiation due to the generation of reactive oxygen species. These cidal effects have also been used to treat infectious diseases. The effects and benefits of photosensitisers in the treatment of such conditions are still being developed and further realised, with the design of novel delivery strategies. This review provides an overview of the realisation of the pharmaceutically relevant uses of photosensitisers, both in the context of current research and in terms of current clinical application, and looks to the future direction of research.

Expert opinion: Substantial advances have been and are being made in the use of photosensitisers. Of particular note are their antimicrobial applications, due to absence of resistance that is so frequently associated with conventional treatments. Their potency of action and the ability to immobilise to polymeric supports is opening a wide range of possibilities with great potential for use in healthcare infection prevention strategies.

Difference equation approach to two-thermocouple sensor characterization in constant velocity flow environments

Thermocouples are one of the most popular devices for temperature measurement due to their robustness, ease of manufacture and installation, and low cost. However, when used in certain harsh environments, for example, in combustion systems and engine exhausts, large wire diameters are required, and consequently the measurement bandwidth is reduced. This article discusses a software compensation technique to address the loss of high frequency fluctuations based on measurements from two thermocouples. In particular, a difference equation (DE) approach is proposed and compared with existing methods both in simulation and on experimental test rig data with constant flow velocity. It is found that the DE algorithm, combined with the use of generalized total least squares for parameter identification, provides better performance in terms of time constant estimation without any a priori assumption on the time constant ratios of the thermocouples.

Zinc selenide nano- and microspheres via microwave-assisted ionothermal synthesis

Zinc selenide nanospheres were prepared from a diphenyl diselenide precursor and a range of chloro- and bromozincate(II) ionic liquids via a microwave-assisted ionothermal route; this is the first report on the use of microwave irradiation in combination with ionic liquids to prepare this material. The method is a time-efficient and a facile one-pot reaction to produce zinc(II) selenide nanomaterials. The product formation in the ionic liquids has been monitored using Raman spectroscopy. The products have been characterised using PXRD, SEM, EDX, photoluminescence and UV-VIS spectroscopy. Advantages of this new route, such as ease of solubilisation of all reactants into one phase at high concentration, the negligible vapour pressure irrespective of the reaction temperature, very fast reaction times, ease of potential scale-up and reproducibility are discussed.

Care Planning in Children and Young Peoples Nursing

Care Planning in Children and Young People's Nursing addresses a selection of the most common concerns that arise when planning care for infants, children and young people within the hospital and community setting. Clear and detailed, this text reflects both the uniqueness and diversity of contemporary children's nursing and utilizes images and case studies to provide a holistic insight into the practice of care planning through the reporting of best available evidence and current research, policy and education.

Divided into sections for ease of reference, Care Planning in Children and Young People’s Nursing explores both the theory and practice of care planning. Chapters on the principles of care planning include issues such as managing risk, safeguarding children, ethical and legal implications, integrated care pathways, interprofessional assessment, and invaluable parent perspectives. Additional chapters on the application of planning care examine the practical aspects of a wide range of specific conditions including cystic fibrosis, obesity, cardiac/renal failure and HIV/AIDS. Each chapter is interactive, with questions, learning activities and points for discussion creating an engaging and enquiry-based learning approach.

Care Planning in Children and Young People’s Nursing is a definitive resource, reflecting innovative practice which is suitable for undergraduate and postgraduate nurse education.

Stout: Cloudy's Atomic and Molecular Database

We describe a new atomic and molecular database we developed for use in the spectral synthesis code Cloudy. The design of Stout is driven by the data needs of Cloudy, which simulates molecular, atomic, and ionized gas with kinetic temperatures and densities spanning the low-to high-density limits. The radiation field between photon energies 10−8 Ry and 100 MeV is considered, along with all atoms and ions of the lightest 30 elements, and ~102 molecules. For ease of maintenance, the data are stored in a format as close as possible to the original data sources. Few data sources include the full range of data we need. We describe how we fill in the gaps in the data or extrapolate rates beyond their tabulated range. We tabulate data sources both for the atomic spectroscopic parameters and for collision data for the next release of Cloudy. This is not intended as a review of the current status of atomic data, but rather a description of the features of the database which we will build upon.