MRC Laboratory of Molecular Biology
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2D and 3D inkjet printing of biopharmaceuticals – A review of trends and future perspectives in research and manufacturing
No full textThere is an ongoing global shift in pharmaceutical business models from small molecule drugs to biologics. This increase in complexity is in response to advancements in our diagnoses and understanding of diseases. With the more targeted approach coupled with its inherently more costly development and manufacturing, 2D and 3D printing are being explored as suitable techniques to deliver more personalised and affordable routes to drug discovery and manufacturing. In this review, we explore first the business context underlying this shift to biopharmaceuticals and provide an update on the latest work exploring discovery and pharmaceutics. We then draw on multiple disciplines to help reveal the shared challenges facing researchers and firms aiming to develop biopharmaceuticals, specifically when using the most commonly explored manufacturing routes of drop-on-demand inkjet printing and pneumatic extrusion. This includes separating out how to consider mechanical and chemical influences during manufacturing, the role of the chosen hardware and the challenges of aqueous formulation based on similar challenges being faced by the printing industry. Together, this provides a review of existing work and guidance for researchers and industry to help with the de-risking and rapid development of future biopharmaceutical products
Global material flow analysis of glass: From raw materials to end of life
No full textGlobal glass production grew to 150 million tonnes (Mt) in 2014, equating to approximately 21 kg per person. Producing this glass is energy intensive and contributes annual CO2 emissions of some 86Mt. An accurate map of the global glass supply chain is needed to help identify emissions mitigation options from across the supply chain, including process energy efficiency and material efficiency options. This map does not yet exist, so we address this knowledge gap by tracing the production chain from raw materials to end of life and producing a global Sankey diagram of container and flat glass making for 2014. To understand future demand for flat glass we also model the stocks of glass in vehicles and buildings. The analysis shows the relative scale of glass flows and stocks worldwide and provides a baseline for future study of the emission mitigation potential of energy and material efficiency of manufacturing with glass
Self-supervised transfer learning of physiological representations from free-living wearable data.
No full textSeven principles of toolpath design in conventional metal spinning
No full textSpinning sheet metal parts successfully requires the design of a complex toolpath to avoid workpiece failure. Notwithstanding decades of research, industrial CNC spinning of new parts today still relies on trial and error, which results in considerable time waste and does not guarantee optimisation of the toolpath. Yet, hand spinning artisans in non-industrial settings can successfully spin new parts first time thanks to the skill accumulated in years of practice. So this paper asks: is there a way to capture and parameterise human skill to drive research into automation? What rules do hand spinners follow? A haptic spinning system is implemented to capture and parameterise the skill of six spinning artisans. Their speech and actions are recorded in a set of over 70 experimental trials and a database of toolpaths is created including information on the trajectory of the roller, applied forces and shape of the workpiece, alongside their speech. The database is analysed, and seven principles for toolpath design are formulated: 1. Take small bites, 2. Stay on the mandrel, 3. Use forward and backward passes, 4. Push in the right place, 5. Go at the right speed, 6. Keep the flange at the right angle, 7. Use a draft. Quantitative toolpath parameters are developed to parameterise the first six principles: the average plastic strain in each toolpass, the fraction of workpiece shape on the mandrel, the fraction of backward passes, the position of the force peak, the feed ratio and the concavity of the toolpass. In trials on thinner and larger blanks than previously investigated in the literature, these parameters appear to be a good predictor of success. This suggests that displacement control alone is not sufficient to automate toolpath design, and that new parameters relating to force and shape control must be employed
A thermoacoustic combined cooling, heating, and power (CCHP) system for waste heat and LNG cold energy recovery
No full textWaste energy recovery is crucial for reducing greenhouse gas emissions and alleviating the increasing demand for central power grids. In the paper, theoretical analyses have been carried out on a novel thermoacoustic combined cooling, heating, and power system for simultaneously recovering waste heat and liquefied natural gas cold energy. The system is designed based on acoustic impedance matching between the thermoacoustic and alternator units for maximizing the overall exergy efficiency. The efficiency, cost savings, and emission reductions of the optimal system are investigated. With cold and waste heat temperatures of 130 K and 500 K, the system achieves an overall exergy efficiency of 24.1%, allowing 78.4 MWh of primary fuel energy reduction, and correspondingly, 30.6 tons of CO2 emissions reduction per year. Investigations are further performed on the system parametric sensitivities. A method for adjusting the alternator external electric impedance is proposed to allow for matching piston displacement within design parameters. Besides, comparisons are made with alternative thermoacoustic cogeneration models. The results show that the proposed system can operate effectively for various supply modes, which is promising for adaptation in different applications. Finally, comparisons are drawn with similar existing technologies and future developments are discussed
An explicit dissipative model for isotropic hard magnetorheological elastomers
No full textHard magnetorheological elastomers (h-MREs) are essentially two phase composites comprising permanently magnetizable metallic inclusions suspended in a soft elastomeric matrix. This work provides a thermodynamically consistent, microstructurally-guided modeling framework for isotropic, incompressible h-MREs. Energy dissipates in such hard-magnetic composites primarily via ferromagnetic hysteresis in the underlying hard-magnetic particles. The proposed constitutive model is thus developed following the generalized standard materials framework, which necessitates suitable definitions of the energy density and the dissipation potential. Moreover, the proposed model is designed to recover several well-known homogenization results (and bounds) in the purely mechanical and purely magnetic limiting cases. The magneto–mechanical coupling response of the model, in turn, is calibrated with the aid of numerical homogenization estimates under symmetric cyclic loading. The performance of the model is then probed against several other numerical homogenization estimates considering various magneto–mechanical loading paths other than the calibration loading path. Very good agreement between the macroscopic model and the numerical homogenization estimates is observed, especially for stiff to moderately-soft matrix materials. An important outcome of the numerical simulations is the independence of the current magnetization to the stretch part of the deformation gradient. This is taken into account in the model by considering an only rotation-dependent remanent magnetic field as an internal variable. We further show that there is no need for an additional mechanical internal variable. Finally, the model is employed to solve macroscopic boundary value problems involving slender h-MRE structures and the results match excellently with experimental data from literature. Crucial differences are found between uniformly and non-uniformly pre-magnetized h-MREs in terms of their pre-magnetization and the associated self-fields
Electronics with shape actuation for minimally invasive spinal cord stimulation
No full textSpinal cord stimulation is one of the oldest and most established neuromodulation therapies. However, today, clinicians need to choose between bulky paddle-Type devices, requiring invasive surgery under general anesthetic, and percutaneous lead-type devices, which can be implanted via simple needle puncture under local anesthetic but offer clinical drawbacks when compared with paddle devices. By applying photo-and soft lithography fabrication, we have developed a device that features thin, flexible electronics and integrated fluidic channels. This device can be rolled up into the shape of a standard percutaneous needle then implanted on the site of interest before being expanded in situ, unfurling into its paddle-Type conformation. The device and implantation procedure have been validated in vitro and on human cadaver models. This device paves the way for shape-changing bioelectronic devices that offer a large footprint for sensing or stimulation but are implanted in patients percutaneously in a minimally invasive fashion
Versatile Solution-Processed Organic–Inorganic Hybrid Superlattices for Ultraflexible and Transparent High-Performance Optoelectronic Devices
No full textCrystalline or amorphous metal oxides are widely used in various optoelectronic devices as key components, such as transparent conductive electrodes, dielectrics or semiconducting active layers for thin-film transistor (TFT) backplanes in large-area displays, photovoltaics, and light-emitting diodes. Although crystalline inorganic materials demonstrate outstanding optoelectronic performance, owing to their wide bandgaps, large conductivities, and high carrier mobilities, their inherent brittleness makes them vulnerable to mechanical stress, thereby limiting the use of metal-oxide films in emerging flexible electronic applications. In this study, stress-diffusive organic–inorganic hybrid superlattice nanostructures are developed to overcome the mechanical limitation of crystalline oxides and to provide high mechanical stability to metal-oxide semiconductors. In particular, hybrid transparent superlattice electrodes based on crystalline indium–tin oxide exhibit high electrical conductivities of up to 555 S cm–1 (resistance variation < 3%) and effectively reduce the mechanical stress on the inorganic layer (up to 10 000 bending cycles with a radius of 1 mm). Furthermore, to ensure the viability of the hybrid superlattice flexible electronics, all solution-processed superlattice crystalline indium–gallium-oxide TFTs are implemented on a thin (≈5 µm) polyimide substrate, providing highly robust and excellent electrical performance (average mobility of 7.6 cm2 V–1 s–1)
