An effective three-dimensional ordered mesoporous CuCo2O4 as electrocatalyst for Li-O2 batteries

Three-dimensional ordered mesoporous (3DOM) CuCo₂O₄ materials have been synthesized via a hard template and used as bifunctional electrocatalysts for rechargeable Li-O₂ batteries. The characterization of the catalyst by X-ray diffractometry and transmission electron microscopy confirms the formation of a single-phase, 3-dimensional, ordered mesoporous CuCo₂O₄ structure. The as-prepared CuCo₂O₄ nanoparticles possess a high specific surface area of 97.1 m² g^{- 1} and a spinel crystalline structure. Cyclic voltammetry demonstrates that mesoporous CuCo₂O₄ catalyst enhances the kinetics for either oxygen reduction reaction (ORR) or oxygen evolution reaction (OER). The Li-O₂ battery utilizing 3DOM CuCo₂O₄ shows a higher specific capacity of 7456 mAh g^{- 1} than that with pure Ketjen black (KB). Moreover, the CuCo₂O₄-based electrode enables much enhanced cyclability with a 610 mV smaller discharge-recharge voltage gap than that of the carbon-only cathode at a current rate of 100 mA g^{- 1}. Such excellent catalytic performance of CuCo₂O₄ could be associated with its larger surface area and 3D ordered mesoporous structure. The excellent electrochemical performances coupled with its facile and cost-effective way will render the 3D mesoporous CuCo₂O₄ nanostructures as attractive electrode materials for promising application in Li-O₂ batteries.

Three-dimensional cultures of normal human osteoblasts: proliferation and differentiation potential in vitro and upon ectopic implantation in nude mice.

This paper is novel andreports on the in vitro establishment of 3-D cultures of human osteoblasts. These were evaluated for protein markers of bone cells. Sequentially alkaline phosphatase, calcium incorporation for matrix mineralisation and then finally osteocalcin expression were detected in cultures. The extracellular matrix was composed of type 1 collagen and as it mineralised, needle shaped crystals were often associated with matrix vesicles initiating mineralisation. In vivo implantation in nude mice showed progression of mineralisation from the inner region outward with peripheral cells in a non-mineralised matrix. Host vessels invaded the implanted cell area. The research has relevance to musculoskeletal tissue engineering.

Three-dimensional macroporous silicon photonic crystal with large photonic band gap

Three-dimensional photonic crystals based on macroporous silicon are fabricated by photoelectrochemical etching and subsequent focused-ion-beam drilling. Reflection measurements show a high reflection in the range of the stopgap and indicate the spectral position of the complete photonic band gap. The onset of diffraction which might influence the measurement is discussed.

Optimisation of radiotherapy for carcinoma of the parotid gland: a comparison of conventional, three-dimensional conformal, and intensity-modulated techniques

Background and purpose: To compare external beam radiotherapy techniques for parotid gland tumours using conventional radiotherapy (RT), three-dimensional conformal radiotherapy (3DCRT), and intensity-modulated radiotherapy (IMRT). To optimise the IMRT techniques, and to produce an IMRT class solution.Materials and methods: The planning target volume (PTV), contra-lateral parotid gland, oral cavity, brain-stem, brain and cochlea were outlined on CT planning scans of six patients with parotid gland tumours. Optimised conventional RT and 3DCRT plans were created and compared with inverse-planned IMRT dose distributions using dose-volume histograms. The aim was to reduce the radiation dose to organs at risk and improve the PTV dose distribution. A beam-direction optimisation algorithm was used to improve the dose distribution of the IMRT plans, and a class solution for parotid gland IMRT was investigated.Results: 3DCRT plans produced an equivalent PTV irradiation and reduced the dose to the cochlea, oral cavity, brain, and other normal tissues compared with conventional RT. IMRT further reduced the radiation dose to the cochlea and oral cavity compared with 3DCRT. For nine- and seven-field IMRT techniques, there was an increase in low-dose radiation to non-target tissue and the contra-lateral parotid gland. IMRT plans produced using three to five optimised intensity-modulated beam directions maintained the advantages of the more complex IMRT plans, and reduced the contra-lateral parotid gland dose to acceptable levels. Three- and four-field non-coplanar beam arrangements increased the volume of brain irradiated, and increased PTV dose inhomogeneity. A four-field class solution consisting of paired ipsilateral coplanar anterior and posterior oblique beams (15, 45, 145 and 170o from the anterior plane) was developed which maintained the benefits without the complexity of individual patient optimisation.Conclusions: For patients with parotid gland tumours, reduction in the radiation dose to critical normal tissues was demonstrated with 3DCRT compared with conventional RT. IMRT produced a further reduction in the dose to the cochlea and oral cavity. With nine and seven fields, the dose to the contra-lateral parotid gland was increased, but this was avoided by optimisation of the beam directions. The benefits of IMRT were maintained with three or four fields when the beam angles were optimised, but were also achieved using a four-field class solution. Clinical trials are required to confirm the clinical benefits of these improved dose distributions.

Domains in three-dimensional ferroelectric nanostructures

We report the experimental measurement of domains in single- crystal nanocolumns of ferroelectric BaTiO3, together with a theory of domain size scaling in three- dimensional structures which explains the observations.

Stochastic protein folding simulation in the three-dimensional HP-model

We present results from three-dimensional protein folding simulations in the HP-model on ten benchmark problems. The simulations are executed by a simulated annealing-based algorithm with a time-dependent cooling schedule. The neighbourhood relation is determined by the pull-move set. The results provide experimental evidence that the maximum depth D of local minima of the underlying energy landscape can be upper bounded by D < n(2/3). The local search procedure employs the stopping criterion (In/delta)(D/gamma) where m is an estimation of the average number of neighbouring conformations, gamma relates to the mean of non-zero differences of the objective function for neighbouring conformations, and 1-delta is the confidence that a minimum conformation has been found. The bound complies with the results obtained for the ten benchmark problems. (c) 2008 Elsevier Ltd. All rights reserved.