Data for the analysis of PolyHIPE scaffolds with tunable mechanical properties for bone tissue engineering

This article presents data related to the research article titled, 'Emulsion templated scaffolds with tunable mechanical properties for bone tissue engineering' (Owen et al., in press) [1]. This data article contains excel files with the results obtained during the mechanical characterisation of 20 acrylate-based PolyHIPE compositions, giving the Young's modulus, ultimate tensile stress and strain at failure for each specimen tested. Also included are the measurements taken to determine the degree of openness (DOO) of each composition, and the data for the cell viability and alkaline phosphatase (ALP) activity on the emulsion templated scaffolds

Incorporation of the natural marine multi-mineral dietary supplement Aquamin enhances osteogenesis and improves the mechanical properties of a collagen-based bone graft substitute

Aquamin is a commercially-available supplement derived from the algae species Lithothamnion, which has proven osteogenic potential. By harnessing this potential and combining Aquamin with a collagen scaffold, with architecture and composition optimised for bone repair, the aim of this study was to develop a natural osteo-stimulative bone graft substitute. A fabrication process was developed to incorporate Aquamin into scaffolds to produce collagen-Aquamin (CollAqua) scaffolds at two different Aquamin concentrations, 100F or 500F (equivalent weight% of collagen or five times the weight of collagen respectively). CollAqua constructs had improved mechanical properties which were achieved without reducing the scaffold׳s permeability or porosity below the minimum level required for successful bone tissue engineering. The fabrication process produced a homogenous Aquamin distribution throughout the scaffold. Release kinetics revealed that in the first 12h, the entire Aquamin content was released from the 100F however, less than half of Aquamin in the 500F was released with the remainder released approximately 21 days later giving an initial burst release followed by a delayed release. Osteoblasts cultured on the CollAqua scaffolds showed improved osteogenesis as measured by alkaline phosphatase, osteopontin and osteocalcin expression. This was confirmed by increased mineralisation as determined by von Kossa and Alizarin red staining. In conclusion, a cell and growth factor free collagen-based bone graft substitute with enhanced mechanical properties has been developed. The addition of Aquamin to the collagen biomaterial significantly improved mineralisation by osteoblasts and results in a new product which may be capable of enhancing osteogenesis to facilitate bone repair in vivo.</p

Photon-pair generation in photonic crystal fibre with a 1.5 GHz modelocked VECSEL

Four-wave mixing (FWM) in optical fibre is a leading technique for generating high-quality photon pairs. We report the generation of photon pairs by spontaneous FWM in photonic crystal fibre pumped by a 1.5 GHz repetition-rate vertical-external-cavity surface-emitting laser (VECSEL). The photon pairs exhibit high count rates and a coincidence-to-accidental ratio of over 80. The VECSEL's high repetition-rate, high average power, tunability, and small footprint make this an attractive source for quantum key distribution and photonic quantum-state engineering.Comment: 17 Pages, 5 Figure

A mixed methods study to explore women and clinician׳s response to pain associated with suturing second degree perineal tears and episiotomies [PRAISE]

Background: perineal suturing is a common event which affects women across a variety of international settings. Women have expressed pain related to perineal trauma in the postnatal period but little is known about pain during suturing. In addition, there is a lack of evidence to identify how professional decisions are made about pain management during the suturing process. Objective: to explore women and clinician׳s response to pain during the suturing of second degree tears and episiotomies. Design: mixed method feasibility study which included observation, questionnaires and interviews. Setting: a Hospital Trust in Northwest England. Participants: 40 women and 21 clinicians participated. Measurements and findings: mild, moderate and severe pain was measured via the McGill Pain Questionnaire-Short Form (MCPQ-SF). Psychological distress was identified via the Hospital Anxiety and Depression Scale (HADS). Semi-structured face to face interviews identified three themes, Psychological distress and future functioning; Variation in practice and Style of communication. Key conclusions: women who experienced psychological distress during previous or current childbirth scored higher on HADS and MCPQ-SF, and appeared to express more concerns about future functioning and healing. Variation in practice exists and style of communication had the potential to make the difference for women. Implications for practice and research: the process of suturing is complex and is not a standalone event for a woman. It is crucial that health professionals consider previous and subsequent experience of perineal suturing. Future research aims to develop a decision tree to support pain management during suturing

A review on recent advances in numerical modelling of bone cutting

[EN] Common practice of surgical treatments in orthopaedics and traumatology involves cutting processes of bone. These operations introduce risk of thermo-mechanical damage, since the threshold of critical temperature producing thermal osteonecrosis is very low. Therefore, it is important to develop predictive tools capable of simulating accurately the increase of temperature during bone cutting, being the modelling of these processes still a challenge. In addition, the prediction of cutting forces and mechanical damage is also important during machining operations. As the accuracy of simulations depends greatly on the proper choice of the thermo-mechanical properties, an essential part of the numerical model is the constitutive behaviour of the bone tissue, which is considered in different ways in the literature. This paper focuses on the review of the main contributions in modelling of bone cutting with special attention to the bone mechanical behaviour. The aim is to give the reader a complete vision of the approaches commonly presented in the literature in order to help in the development of accurate models for bone cutting.The authors acknowledge to the Ministry of Economy and Competitiveness of Spain the financial support for this work received through the projects DPI2011-25999 and DPI2013-46641-R.Marco, M.; Rodríguez Millán, M.; Santiuste, C.; Giner Maravilla, E.; Henar Miguélez, M. (2015). A review on recent advances in numerical modelling of bone cutting. Journal of the Mechanical Behavior of Biomedical Materials. 44:179-201. https://doi.org/10.1016/j.jmbbm.2014.12.006S1792014

Emulsion Templated Scaffolds with Tunable Mechanical Properties for Bone Tissue Engineering

Polymerised High Internal Phase Emulsions (PolyHIPEs) are manufactured via emulsion templating and exhibit a highly interconnected microporosity. These materials are commonly used as thin membranes for 3D cell culture. This study uses emulsion templating in combination with microstereolithography to fabricate PolyHIPE scaffolds with a tightly controlled and reproducible architecture. This combination of methods produces hierarchical structures, where the microstructural properties can be independently controlled from the scaffold macrostructure. PolyHIPEs were fabricated with varying ratios of two acrylate monomers (2-ethylhexyl acrylate (EHA) and isobornyl acrylate (IBOA)) and varying nominal porosity to tune mechanical properties. Young's modulus, ultimate tensile stress (UTS) and elongation at failure were determined for twenty EHA/IBOA compositions. Moduli ranged from 63.01±9.13 to 0.36±0.04MPa, UTS from 2.03±0.33 to 0.11±0.01MPa and failure strain from 21.86±2.87% to 2.60±0.61%. Selected compositions were fabricated into macro-porous woodpile structures, plasma treated with air or acrylic acid and seeded with human embryonic stem-cell derived mesenchymal progenitor cells (hES-MPs). Confocal and two-photon microscopy confirmed cell proliferation and penetration into the micro- and macro-porous architecture. The scaffolds supported osteogenic differentiation of mesenchymal cells and interestingly, the stiffest IBOA-based scaffolds that were plasma treated with acrylic acid promoted osteogenesis more strongly than the other scaffolds

Influence of elevated radiative lifetime on efficiency of CdSe/CdTe Type II colloidal quantum dot based solar cells

Colloidal quantum dots (CQDs) are promising materials for solar cells because their optoelectronic properties are easily adjusted by control of their size, structure and composition. We present calculations of the band gap and radiative lifetime for varying core diameter and shell thickness of CdSe/CdTe core/shell Type II CQDs using a combination of single particle (2,6)-band k·pk·p and many-electron configuration interaction (CI) Hamiltonians. These calculations are validated by comparison with experimental absorption spectra and photoluminescence decay data. The results are then incorporated into a model of photovoltaic efficiency which demonstrates how the overall performance of a solar cell based on Type II CQDs is affected by changes in the core/shell geometry. The largest effect on photovoltaic efficiency is found to be due to the longer radiative lifetime produced by increasing the shell thickness