Ab Initio Thermodynamics Calculation of Beta Decay Rates

Beta‐decay half‐lives for the free neutron, for ⁶He and ⁸He, and for ⁸Li are calculated ab initio from geometrical thermodynamics arguments, independently of any quantum mechanics. Half‐lives for the decay of ⁸Be to two alphas and for the disintegration of the tetraneutron are also calculated. The calculated values are close to those experimentally observed

Modifying Polyester Surfaces with Incompatible Polymer Additives

Surface modification of amorphous PET in incompatible blends is demonstrated using fluorocarbon end-functional polystyrenes. Contact angles with water and decane were consistent with high levels of surface fluorocarbon, even for spin-cast films with no further processing required. Hydrophobicity and lipophobicity were further increased by annealing above the glass transition temperature. High resolution depth profiling using complementary ion beam analysis and specular neutron reflectometry has enabled accurate characterisation of the composition profile of the additive including the minimum in additive concentration found just below the surface enriched layer. This analysis quantified the very low compatibility between the modifying polymer and the amorphous PET and was consistent with the highly segregated nature of the adsorbing species and its sharp interface with the subphase. For these incompatible polymer blends, surfaces enriched with the surface active polymer could coexist at equilibrium with extremely low (∼0.4%) bulk loadings of the additive. This suggests that for thicker films at even lower additive concentrations than the minimum 1% that we studied, it may be possible to achieve efficient surface modification. However, at this concentration, the efficiency of surface modification is limited by the processing conditions. Finally we note that in higher loadings of surface active additive there is clear evidence for lateral phase separation into patterned domains of differing composition. The enhancement in surface properties is due to local reorganisation rather than bulk redistribution of the components within the film, as the composition versus depth distributions of the polymer blend components was observed to be relatively unaffected by annealing

Psalms: the Prayerbook of the Church

The biblical book of Psalms is discussed from an historical point of view. Who were the original poets, when did they write and what did they intend by their poetry? The short answer to these questions is: "we don't know for sure", but the long answer is considerably more interesting. This poetry from three millennia ago has changed the world, and has the potential to continue changing it

Science and Creation

This is an abridgement of S.L.Jaki, "Science and Creation, from eternal cycles to an oscillating universe" (Scottish Academic Press, Edinburgh, 1974: 367pp, 14 chapters). Why is it that in all recorded history, modern science with all its technical success and mastery has arisen only in Europe? Science was stillborn in civilisations that thought of time as infinite in extent and cyclic in effect. Only in Europe, under the strong philosophical influence of Christianity, was time thought of as finite in extent and progressive in effect. The primary requirement for a scientific attitude to take hold is for there to be underlying presumptions that God is rational and that people matter. This essay attempts a summary of Stanley Jaki’s book, mostly in Jaki’s own words

Ion beam analysis for cultural heritage

Beams of ions from electrostatic accelerators have long been used by curators, conservators, and archaeologists for deep analysis of the near-surface of cultural heritage samples after simpler methods have been exhausted. Ion beam analysis is a versatile and powerful method with many different imaging and analysis modalities which can be done without sample preparation and which is essentially nondestructive. This introduction is aimed at making users aware of the facilities available at national laboratories and how to use them, including a survey of characteristic and novel cultural heritage applications. The spectrometry modalities include particle-induced luminescence (both X-rays and optical photons), particle elastic and inelastic scattering, and combinations of these. Imaging at high spatial resolution is easy with modern equipment for all the spectrometries. These energetic particle beams are penetrating, allowing fully featured in-air analysis

Psalms: the Prayerbook of the Church

The biblical book of Psalms is discussed from an historical point of view. Who were the original poets, when did they write and what did they intend by their poetry? The short answer to these questions is: "we don't know for sure", but the long answer is considerably more interesting. This poetry from three millennia ago has changed the world, and has the potential to continue changing it

Science and Creation

This is an abridgement of S.L.Jaki, "Science and Creation, from eternal cycles to an oscillating universe" (Scottish Academic Press, Edinburgh, 1974: 367pp, 14 chapters). Why is it that in all recorded history, modern science with all its technical success and mastery has arisen only in Europe? Science was stillborn in civilisations that thought of time as infinite in extent and cyclic in effect. Only in Europe, under the strong philosophical influence of Christianity, was time thought of as finite in extent and progressive in effect. The primary requirement for a scientific attitude to take hold is for there to be underlying presumptions that God is rational and that people matter. This essay attempts a summary of Stanley Jaki’s book, mostly in Jaki’s own words

Direct quantification of rare earth doped titania nanoparticles in individual human cells

There are many possible biomedical applications for titania nanoparticles (NPs) doped with rare earth elements (REEs), from dose enhancement and diagnostic imaging in radiotherapy, to biosensing. However, there are concerns that the NPs could disintegrate in the body thus releasing toxic REE ions to undesired locations. As a first step, we investigate how accurately the Ti/REE ratio from the NPs can be measured inside human cells. A quantitative analysis of whole, unsectioned, individual human cells was performed using proton microprobe elemental microscopy. This method is unique in being able to quantitatively analyse all the elements in an unsectioned individual cell with micron resolution, while also scanning large fields of view. We compared the Ti/REE signal inside cells to NPs that were outside the cells, non-specifically absorbed onto the polypropylene substrate. We show that the REE signal in individual cells co-localises with the titanium signal, indicating that the NPs have remained intact. Within the uncertainty of the measurement, there is no difference between the Ti/REE ratio inside and outside the cells. Interestingly, we also show that there is considerable variation in the uptake of the NPs from cell-to-cell, by a factor of more than 10. We conclude that the NPs enter the cells and remain intact. The large heterogeneity in NP concentrations from cell-to-cell should be considered if they are to be used therapeutically