̽��ֱ�� of Cambridge - gold

̽��ֱ��Fitzwilliam Museum reveals how the Saka people made history and great art

ta385 — Thu, 14 Oct 2021 06:30:00 +0000

A new exhibition of Iron Age treasures recently discovered in East Kazakhstan transforms our understanding of an extraordinary civilisation rooted in one of the world’s most powerful landscapes.

“Trojan horse” treatment could beat brain tumours

tdk25 — Wed, 13 Aug 2014 07:00:12 +0000

A “Trojan horse” treatment for an aggressive form of brain cancer, which involves using tiny nanoparticles of gold to kill tumour cells, has been successfully tested by scientists.

̽��ֱ��ground-breaking technique could eventually be used to treat glioblastoma multiforme, which is the most common and aggressive brain tumour in adults, and notoriously difficult to treat. Many sufferers die within a few months of diagnosis, and just six in every 100 patients with the condition are alive after five years.

̽��ֱ��research involved engineering nanostructures containing both gold and cisplatin, a conventional chemotherapy drug. These were released into tumour cells that had been taken from glioblastoma patients and grown in the lab.

Once inside, these “nanospheres” were exposed to radiotherapy. This caused the gold to release electrons which damaged the cancer cell’s DNA and its overall structure, thereby enhancing the impact of the chemotherapy drug.

̽��ֱ��process was so effective that 20 days later, the cell culture showed no evidence of any revival, suggesting that the tumour cells had been destroyed.

While further work needs to be done before the same technology can be used to treat people with glioblastoma, the results offer a highly promising foundation for future therapies. Importantly, the research was carried out on cell lines derived directly from glioblastoma patients, enabling the team to test the approach on evolving, drug-resistant tumours.

̽��ֱ��study was led by Mark Welland, Professor of Nanotechnology at the Department of Engineering and a Fellow of St John’s College, ̽��ֱ�� of Cambridge, and Dr Colin Watts, a clinician scientist and honorary consultant neurosurgeon at the Department of Clinical Neurosciences. Their work is reported in the Royal Society of Chemistry journal, Nanoscale.

“ ̽��ֱ��combined therapy that we have devised appears to be incredibly effective in the live cell culture,” Professor Welland said. “This is not a cure, but it does demonstrate what nanotechnology can achieve in fighting these aggressive cancers. By combining this strategy with cancer cell-targeting materials, we should be able to develop a therapy for glioblastoma and other challenging cancers in the future.”

To date, glioblastoma multiforme (GBM) has proven very resistant to treatments. One reason for this is that the tumour cells invade surrounding, healthy brain tissue, which makes the surgical removal of the tumour virtually impossible.

Used on their own, chemotherapy drugs can cause a dip in the rate at which the tumour spreads. In many cases, however, this is temporary, as the cell population then recovers.

“We need to be able to hit the cancer cells directly with more than one treatment at the same time” Dr Watts said. “This is important because some cancer cells are more resistant to one type of treatment than another. Nanotechnology provides the opportunity to give the cancer cells this ‘double whammy’ and open up new treatment options in the future.”

In an effort to beat tumours more comprehensively, scientists have been researching ways in which gold nanoparticles might be used in treatments for some time. Gold is a benign material which in itself poses no threat to the patient, and the size and shape of the particles can be controlled very accurately.

When exposed to radiotherapy, the particles emit a type of low energy electron, known as Auger electrons, capable of damaging the diseased cell’s DNA and other intracellular molecules. This low energy emission means that they only have an impact at short range, so they do not cause any serious damage to healthy cells that are nearby.

In the new study, the researchers first wrapped gold nanoparticles inside a positively charged polymer, polyethylenimine. This interacted with proteins on the cell surface called proteoglycans which led to the nanoparticles being ingested by the cell.

Once there, it was possible to excite it using standard radiotherapy, which many GBM patients undergo as a matter of course. This released the electrons to attack the cell DNA.

While gold nanospheres, without any accompanying drug, were found to cause significant cell damage, treatment-resistant cell populations did eventually recover several days after the radiotherapy. As a result, the researchers then engineered a second nanostructure which was suffused with cisplatin.

̽��ֱ��chemotherapeutic effect of cisplatin combined with the radiosensitizing effect of gold nanoparticles resulted in enhanced synergy enabling a more effective cellular damage. Subsequent tests revealed that the treatment had reduced the visible cell population by a factor of 100 thousand, compared with an untreated cell culture, within the space of just 20 days. No population renewal was detected.

̽��ֱ��researchers believe that similar models could eventually be used to treat other types of challenging cancers. First, however, the method itself needs to be turned into an applicable treatment for GBM patients. This process, which will be the focus of much of the group’s forthcoming research, will necessarily involve extensive trials. Further work needs to be done, too, in determining how best to deliver the treatment and in other areas, such as modifying the size and surface chemistry of the nanomedicine so that the body can accommodate it safely.

Sonali Setua, a PhD student who worked on the project, said: “It was hugely satisfying to chase such a challenging goal and to be able to target and destroy these aggressive cancer cells. This finding has enormous potential to be tested in a clinical trial in the near future and developed into a novel treatment to overcome therapeutic resistance of glioblastoma.”

Welland added that the significance of the group’s results to date was partly due to the direct collaboration between nanoscientists and clinicians. “It made a huge difference, as by working with surgeons we were able to ensure that the nanoscience was clinically relevant,” he said. “That optimises our chances of taking this beyond the lab stage, and actually having a clinical impact.”

̽��ֱ��full research paper can be found at: http://dx.doi.org/10.1039/c4nr03693j

A smart technology which involves smuggling gold nanoparticles into brain cancer cells has proven highly effective in lab-based tests.

By combining this strategy with cancer cell-targeting materials, we should be able to develop a therapy for glioblastoma and other challenging cancers in the future

Mark Welland

M Welland

A cancer cell containing the nanoparticles. ̽��ֱ��nanoparticles are coloured green, and have entered the nucleus, which is the area in blue

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Mystery of Anglo-Saxon teen buried in bed with gold cross

bjb42 — Fri, 16 Mar 2012 09:08:45 +0000

One of the earliest Anglo-Saxon Christian burial sites in Britain has been discovered in a village outside Cambridge. ̽��ֱ��grave of a teenage girl from the mid 7^th century AD has an extraordinary combination of two extremely rare finds: a ‘bed burial’ and an early Christian artefact in the form of a stunning gold and garnet cross.

̽��ֱ��girl, aged around 16, was buried on an ornamental bed - a very limited Anglo-Saxon practice of the mid to later 7^th century - with a pectoral Christian cross on her chest, that had probably been sewn onto her clothing. Fashioned from gold and intricately set with cut garnets, only the fifth of its kind ever to be found, the artefact dates this grave to the very early years of the English Church, probably between 650 and 680 AD.

In 597 AD, the pope dispatched St Augustine to England on a mission to convert the pagan Anglo-Saxon kings; a process that was not completed for many decades. Using the latest scientific techniques to analyse this exceptional find could result in a greater understanding of this pivotal period in British history, and the spread of Christianity in eastern England in the Anglo-Saxon period.

Was this teenage girl an early Christian convert, a standard-bearer for the new God? “Christian conversion began at the top and percolated down,” says Dr Sam Lucy, a specialist in Anglo-Saxon burial from Newnham College, Cambridge.

“To be buried in this elaborate way with such a valuable artefact tells us that this girl was undoubtedly high status, probably nobility or even royalty. This cross is the kind of material culture that was in circulation at the highest level of society. ̽��ֱ��best known example of the pectoral cross was that found in the coffin of St Cuthbert now in Durham Cathedral.”

“That this is a bed burial is remarkable in itself - the fifteenth ever uncovered in the UK, and only the fourth in the last twenty years - add to that a beautifully made Christian cross and you have a truly astonishing discovery,” says Alison Dickens, who led the excavation for the ̽��ֱ��’s Archaeological Unit.

“We think there’s only been one other bed burial combined with a Christian pectoral cross ever found - at Ixworth nearby in Suffolk in the 19^th century; the records of this find are unclear, however. ̽��ֱ��fact that we will be able to apply modern techniques to thoroughly investigate the site is a thrilling prospect.”

̽��ֱ��bed consisted of a wooden frame held together by metal brackets, with further pieces of looped metal fixing the cross-slats to create a suspended bed base, similar to modern beds, but with a straw mattress. ̽��ֱ��body was then placed on the bed, probably when it was already in the grave.

Dr Richard Dance, an expert on Old English at the ̽��ֱ��, has pointed out that the Anglo-Saxon word ‘leger’ can mean either ‘bed’ or ‘grave’. “Etymologically, the word means 'place where one lies', but there are examples of this meaning both bed and grave in literature of the time,” says Dr Dance. A clue to the possible symbolism of bed burials perhaps? But why only a chosen few were buried in their beds remains a mystery.

“Bed burials were never widespread, but there is a little cluster around the Cambridge area and another in Wessex, with a solitary very high status example in Teeside” says Dr Lucy. “Where we do find them they seem to be predominantly burials of females, and date to the mid to later 7^th century; most have indications of high status such as fine jewellery or burial under a barrow.

̽��ֱ��gold and garnet construction of the Trumpington cross also tends to be used for female associated items, although the recently discovered Staffordshire Hoard, as well as the slightly earlier famous ship burial at Sutton Hoo, show that such material was also used in high status weapon fittings throughout the 7^th century. It is interesting that the same decorative techniques are seen both in overtly pagan and overtly Christian settings.”

̽��ֱ��cross itself - 3 and a half centimetres in diameter - is only the fifth pectoral cross to be discovered in the UK. As well as the examples from Ixworth and Durham, one example was picked up as a stray find in Holderness, East Yorkshire, and another was a 19^th-century find from Wilton in Norfolk. These other crosses are pendants designed to hang suspended on a necklace, whereas the Trumpington cross has a loop on the reverse of each arm, so that it could be stitched directly onto clothing.

“You can tell from the shiny look of three of these loops, where they have rubbed against fabric, that this item was worn in daily life, most likely as a symbol of social status as well as religious affiliation,” says Dickens.

̽��ֱ��excavations at Trumpington Meadows on the southern city limits of Cambridge, funded by the property developers Grosvenor, have unearthed significant findings from the Neolithic and Iron Ages, as well as material from a contemporary Anglo-Saxon settlement. ̽��ֱ��Christian girl was in one of a very small group of four graves, along with an unsexed individual in his or her twenties and two other slightly younger women.

̽��ֱ��graves are thought to be broadly contemporary with each other, although the team are only at the very beginning of the investigative process. This will include radiocarbon dating of each of the bodies (to establish their date of burial) and isotopic analysis of their bones and teeth, to help determine both their diet and hopefully to establish where they had lived in childhood.

Detailed study of their skeletons will be able to tell, in addition to their sex and age, their stature, health and any visible medical conditions. Analysis of the gold and garnets in the cross will also reveal further details about its place of manufacture; garnets in this period were probably imported from the Black Sea or even further afield, from Asia.

̽��ֱ��teenager’s grave also contained other items. An iron knife and a chatelaine (a chain that would have hung from the waist) were found in the girl’s grave, along with some glass beads which seemed to have been kept in a purse on the end of the chain. Preserved textile on the iron knife and chain offers the possibility of reconstructing her burial costume.

“ ̽��ֱ��custom of grave goods was long-established in the pagan period, but it doesn’t mean that the burials at Trumpington weren’t Christian” states Dr Lucy. “ ̽��ֱ��church never issued any edicts against the use of grave goods, but it’s something that does seem to fade away by the 8^th century, just at the point where Christianity was becoming the dominant religion. There is, though, a time through the second half of the 7^th century, where clearly Christian people were still making use of a limited range of goods within their burials, and these often carried explicitly Christian symbolism, such as the cross here.

“ ̽��ֱ��Trumpington bed burial does seem to belong at that transition between the two religions. Did she have a formal role in the church? ̽��ֱ��site is just behind the village church, which is first documented over 400 years later. Perhaps there was a monastery – even a nunnery - there before that we don’t know about. This is certainly something worth looking into.”

A small number of structures associated with the burials seem to represent part of a settlement that was in use at the same time. Analysis of the finds from these will help to determine the nature and function of that settlement; initial assessment of the pottery has suggested the presence of some high status imports, of a type usually only associated with high status ecclesiastical centres.

There may even be a possible link to the founding of the first monastery in Ely at around the same time. St Æthelthryth (or Etheldreda), daughter of King Anna of East Anglia, established the female-headed house at Ely in 673 AD. A cemetery found in Ely by the CAU in 2006 also contained a later 7^th-century burial of a 10-12 year-old with a delicate gold cross pendant, who was thought to have been associated with the monastery. ̽��ֱ��parallels between this site and Trumpington are intriguing, and suggest a more interesting origin for the village than has previously been thought.

Extraordinary 7th century discovery on outskirts of Cambridge offers unique insights into the origins of English Christianity.

To be buried in this elaborate way with such a valuable artefact tells us that this girl was undoubtedly high status, probably nobility or even royalty.

Dr Sam Lucy

Cambridge Archaeological Unit

Anglo-Saxon bed burial with gold cross

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Golden touch makes low-temperature graphene production a reality

ns480 — Wed, 12 Oct 2011 10:25:09 +0000

̽��ֱ��technique opens up new opportunities for the use of graphene, which is widely regarded as a potential “wonder substance” for the 21^st century.

̽��ֱ��researchers from the ̽��ֱ�� of Cambridge’s Department of Engineering added a very small amount of gold to the surface of a nickel film, on which the graphene was then grown. ̽��ֱ��resulting alloy meant that they were able to grow graphene at 450ºC as opposed to the 1,000ºC that is normally required.

̽��ֱ��team, which was led by Robert Weatherup and Bernhard Bayer in the Department’s Hofmann research group, was also able to find out more about how graphene forms during this process.

“Only once we’d developed a detailed picture of how the graphene was growing were we able to start tuning that growth and rationally engineering the catalyst – the nickel – to improve it,” Weatherup said. “Understanding this is interesting from a scientific point of view, but using this knowledge to improve the growth process has been the really useful outcome of our work.”

Graphene is a microscopically thin substance – essentially existing in only two dimensions. It consists of a single, atom-thick sheet of carbon atoms, arranged in a hexagonal lattice.

What makes it exciting for scientists is its remarkable range of properties. Graphene is very strong, transparent and highly conductive. This means that it could be used for a whole range of applications, including flexible electronics that can be worn by the user, fast broadband, high-performance computing and lightweight components for planes and other machines.

For any of these possibilities to be realised, a reliable method for producing high-quality graphene is needed. ̽��ֱ��best option to date has involved scientists using chemical vapour deposition. In this process, a catalyst film – in some cases nickel, in others copper – is exposed to a carbon-containing gas at very high temperatures. Graphene then assembles on the surface of the film.

Until now, temperatures of about 1,000ºC were needed for the graphene to form. This poses a problem, because the high-growth temperatures would severely damage many of the materials that are used in common manufacturing electronics, which means that the graphene cannot be directly integrated into the circuits that would then be used in electronic products.

Weatherup and Bayer’s use of nickel films with a small amount of gold (less than 1%) opens up this possibility by reducing the growth temperature to 450º. ̽��ֱ��alloy also reduces the number of places where graphene grows on the film, because the gold blocks graphene growth.

This means that as each graphene flake emerges it grows larger and for longer before it joins with another flake. Because electrons travelling through the graphene are therefore not disturbed by joins between flakes as often, the conductivity of the graphene is improved. ̽��ֱ��result is graphene that can be produced at a drastically reduced temperature, but is still of the very high quality that would be needed for future applications.

Specialist techniques were also employed during the process to “sense” the atom-thick layer of graphene as it grew. ̽��ֱ��researchers were able to show definitively that graphene growth does not just occur when the substance cools down (as some academics had previously thought), and that its growth is not just affected by the surface of the catalyst film, but by a region of the film underneath.

Researchers widely predict that it is only a matter of time before graphene moves from the domain of scientific research and into industry. For now, however, commercial development is still some way off.

“We would ideally like to produce graphene directly on to an insulating substrate, as at present the alloy has to be removed after growth for graphene to be used in applications,” Weatherup said. “ ̽��ֱ��problem is that insulators tend to be less good at converting carbon-containing gases into high-quality graphene.”

“Graphene growth is still a very young field, but it’s moving incredibly fast. Using alloying of the catalyst, as we have here, is a brand new approach in improving the process and we expect further investigation of this will likely lead to improved graphene production, and perhaps at even lower temperatures.”

̽��ֱ��findings are reported in the new issue of the academic journal, Nano-letters.

A method which more than halves the temperature at which high-quality graphene can be produced has been pioneered by researchers.

Graphene growth is still a very young field, but it’s moving incredibly fast.

Robert Weatherup

Graphene growing on Au Ni

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