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We show that small quantities of 1,3:2,4-di(4- chlorobenzylidene) sorbitol dispersed in poly(ε- caprolactone) provide a very effective self-assembling nanoscale framework which, with a flow field, yields extremely high levels of polymer crystal orientation. We have used the small-angle X-ray scattering beamline I22 at Diamond to follow in a time resolving manner the formation of the particles and the subsequent crystallisation of the polymer. During modest shear flow of the polymer melt, the ...
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Why do some fossils preserve soft tissue in very fine detail while others most of the detail is lost? After death there is a race against time between soft tissue destruction and mineralisation of the carcass. In some cases soft tissue becomes mineralised in a state similar to the living animal; in others, only bone survives. One theory is that if the body is allowed to dehydrate, for example during a period of drought, and later rehydrated, for example during a flood, the soft tissue may be ...
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Better understanding of the distribution of elastic and plastic strains in deformed polycrystalline, multiphase materials is important for structural engineering. The deformation response depends upon the interaction of grains of different orientations, and the anisotropy associated with each phase. Strain partitioning and tensile-compressive hardening asymmetry arises due to mismatches in modulus and ductility between grains and phases in alloys such as Ti-6Al-4V, or Ni-base superalloys ...
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Chirality, the property of an object to exist as distinguishable mirror image forms (known as enantiomers), is ubiquitous. Intriguingly, the chemistry of life is intrinsically homochiral, as biological molecules such as sugars, amino acids and DNA exist almost exclusively as only one enantiomer. Identifying potential mechanisms for such asymmetry is therefore of tremendous interest, not least because those mechanisms may also allow more efficient asymmetric synthesis of pharmaceuticals. In a ...
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Electronic devices are getting smaller all the time, and the challenge is to make the individual components as small as possible without affecting how they function. This includes the need for nanometre scale wires to be placed on electrically insulating substrates. We used a technique called metal vapour deposition to grow palladium nanostructures on a dielectric support. We then used Scanning Tunnelling Microscopy (STM) to identify two distinct structures: roughly hexagonal islands and ...
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We have demonstrated the use of a new technique for determining absolute crystal chirality by resonant X-ray diffraction of circularly polarized X-rays from a crystal of tellurium. The new approach is based on studies of ‘forbidden’ reflections, which, as the name implies, are normally considered not to exist. With the high-intensity X-ray beam available on Diamond beamline I16 such signals gain considerable intensity and are exceptionally sensitive to the chirality (handedness) of the ...
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Diamond Light Source has been used to profile a new zeolitic microporous solid, created via a process that had previously been thought impossible. Using beam line I15 researchers were able to perform high-pressure synchrotron X-ray diffraction analysis of a material known as a zeolite ITQ-29, and were able to study how it transitioned into a new zeolite. The research also showed that the daughter zeolite is a more efficient adsorber for carrying out the separation of propene from mixtures ...
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In 2006 the Stardust mission returned to Earth with the first bona fide samples of a short period comet 81P/Wild2. Micron – sized dust samples were collected from the coma of the comet at a closing velocity of 6 km/s. The Stardust sample analyses including the work carried out by us at Diamond has shown that the traditional ideas of all comets being predominantly a mixture of low temperature material with a high proportion of interstellar grains and secondly of a rigid distinction between ...
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The vast majority of the electronic devices today are based on silicon technology and their performance and operation depend on the movement and mobility of electronic charge. This mode of operation sets the limits on power consumption, operation speed and results in potential device overheating, particularly at fast switching speeds. At the same time, it is well-known that electrons also possess a spin and the idea of manipulating this property led to a relatively new field of
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Great Britain is an island nation, with over 11,000 miles of coastline*. But the coastline is continually changing, due to the process of coastal erosion. A group of scientists have been using Diamond Light Source to study the weathering of shale cliffs in North Yorkshire to understand physical and chemical interactions on the molecular scale that could cause weakening of the cliffs , including the intriguing possibility that a novel microbial community might be responsible.
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Metal-on-metal hip replacement is a treatment for “wear and tear” arthritis (osteoarthritis) – one of the commonest diseases in the world. These hip replacements use cobalt chrome alloy for both bearing surfaces and are the only type that can be made thin enough to enable resurfacing of both sides of the worn hip joint, called a hip resurfacing. The most common type was developed 13 years ago in the UK and has been adopted world wide. One million people now have a metal-on-metal hip ...
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Battlefield use of depleted uranium (DU) weapons has generated considerable controversy because of the potential long-term effects on the environment and on the health of people exposed to it. DU projectiles have been used as armour-piercing weapons by both the British and American militaries and deployed in the Balkans and both Gulf wars. Upon impact the metal combusts and a fraction is dispersed as uranium oxide particulates. Inhalation of these particulates constitutes the main long-term ...
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Framework structures are molecular cages which are capable of selectively trapping atoms, ions and molecules within the cage. Materials that adopt framework structures have attracted significant attention recently as they have potential applications in a wide range of areas, including catalysis and the pharmaceutical industry. Currently almost all existing framework structures are neutral or negatively charged, but a group led by researchers from the University of Liverpool in collaboration ...
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Peptoids are analogues of α-peptides where the backbone is achiral due to the proteinogenic side chains being relocated from the α-C to the amide nitrogen. In the peptoids discussed here, chiral centres are present in the side chains thus making them suitable for chiroptical analysis. The presence of tertiary amides complicates NMR interpretation which means that circular dichroism (CD) becomes an invaluable tool for the study of peptoid conformation. Understanding of the spatial orientation ...
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The two prototypical members of the Fibroblast growth factors (FGF) family, FGF-1 and-2, have fundamentally distinct binding requirements and the secondary structures induced by binding of polysaccharides are also distinct. Analogues of HS, which are active with FGF-1 act in essentially the same way as the natural ligand, but not in the case of FGF-2. This improves our understanding of the structural basis of the signalling complexes and is vital for the design of analogues, which can be ...
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Metal organic frameworks (MOFs) are molecular structures, constructed from metal cations linked by organic molecules. They have recently shown considerable promise in a wide range of applications, including hydrogen storage, catalysis and drug delivery. MOFs can be built systematically for desired applications, including particular configurations that are stable and porous and which can be used to trap other molecules in a cage-like structure.
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Cancer comes in many forms, but it is characterised by cells rapidly dividing out of control. Chemotherapy refers to a group of drugs which use a range of mechanisms to try and block the cells from dividing. One group of chemotherapy drugs, commonly used to treat chronic and acute leukemia, lymphoma and Hodgkin disease among others, works by targeting the genetic material inside cancer cells linking together the DNA strands, thereby stopping the cell copying its genetic material so the cell ...
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Extending our knowledge of how magnetic materials behave on an atomic scale has led to considerable technological advances, particularly in the area of information storage. University of Leeds scientists have been working with the Nanoscience beamline team at Diamond to study the properties of magnetic domain walls, which are areas where the sample magnetisation rapidly changes direction. The ability to manipulate domain walls using an electric current has recently generated a great deal of ...
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Researchers into from Imperial College London and Harvard University have used Diamond to solve a 20-year-old puzzle about how HIV establishes itself in the human body. They have used the synchrotron to determine the structure of an enzyme called integrase, used by the HIV and similar viruses to copy their genetic information into the DNA of their hosts. Antiretroviral drugs have already been developed which work by blocking integrase, but the mechanism behind this was not fully understood ...
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MX beamlines are extremely powerful instruments for solving the structure of proteins. There are nearly 100 operational Macromolecular Crystallography (MX) beamlines around the world, and being able to accurately calibrate them is vital to ensuring the accuracy of the data they collect. Scientists from Diamond have shown that an unusual calibration standard – beeswax – may be able to help this happen. This work has been published in the Journal of Synchrotron Radiation.
