Tag Archives: KCL

Nanoparticles and strange forces

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An April 10, 2017 news item on Nanowerk announces work from the University of New Mexico (UNM), Note: A link has been removed,

A new scientific paper published, in part, by a University of New Mexico physicist is shedding light on a strange force impacting particles at the smallest level of the material world.

The discovery, published in Physical Review Letters (“Lateral Casimir Force on a Rotating Particle near a Planar Surface”), was made by an international team of researchers lead by UNM Assistant Professor Alejandro Manjavacas in the Department of Physics & Astronomy. Collaborators on the project include Francisco Rodríguez-Fortuño (King’s College London, U.K.), F. Javier García de Abajo (The Institute of Photonic Sciences, Spain) and Anatoly Zayats (King’s College London, U.K.).

An April 7,2017 UNM news release by Aaron Hill, which originated the news item, expands on the theme,

The findings relate to an area of theoretical nanophotonics and quantum theory known as the Casimir Effect, a measurable force that exists between objects inside a vacuum caused by the fluctuations of electromagnetic waves. When studied using classical physics, the vacuum would not produce any force on the objects. However, when looked at using quantum field theory, the vacuum is filled with photons, creating a small but potentially significant force on the objects.

“These studies are important because we are developing nanotechnologies where we’re getting into distances and sizes that are so small that these types of forces can dominate everything else,” said Manjavacas. “We know these Casimir forces exist, so, what we’re trying to do is figure out the overall impact they have very small particles.”

Manjavacas’ research expands on the Casimir effect by developing an analytical expression for the lateral Casimir force experienced by nanoparticles rotating near a flat surface.

Imagine a tiny sphere (nanoparticle) rotating over a surface. While the sphere slows down due to photons colliding with it, that rotation also causes the sphere to move in a lateral direction. In our physical world, friction between the sphere and the surface would be needed to achieve lateral movement. However, the nano-world does not follow the same set of rules, eliminating the need for contact between the sphere and the surface for movement to occur.

“The nanoparticle experiences a lateral force as if it were in contact with the surface, even though is actually separated from it,” said Manjavacas. “It’s a strange reaction but one that may prove to have significant impact for engineers.”

While the discovery may seem somewhat obscure, it is also extremely useful for researchers working in the always evolving nanotechnology industry. As part of their work, Manjavacas says they’ve also learned the direction of the force can be controlled by changing the distance between the particle and surface, an understanding that may help nanotech engineers develop better nanoscale objects for healthcare, computing or a variety of other areas.

For Manjavacas, the project and this latest publication are just another step forward in his research into these Casimir forces, which he has been studying throughout his scientific career. After receiving his Ph.D. from Complutense University of Madrid (UCM) in 2013, Manjavacas worked as a postdoctoral research fellow at Rice University before coming to UNM in 2015.

Currently, Manjavacas heads UNM’s Theoretical Nanophotonics research group, collaborating with scientists around the world and locally in New Mexico. In fact, Manjavacas credits Los Alamos National Laboratory Researcher Diego Dalvit, a leading expert on Casimir forces, for helping much of his work progress.

“If I had to name the person who knows the most about Casimir forces, I’d say it was him,” said Manjavacas. “He published a book that’s considered one of the big references on the topic. So, having him nearby and being able to collaborate with other UNM faculty is a big advantage for our research.”

Here’s a link to and a citation for the paper,

Lateral Casimir Force on a Rotating Particle near a Planar Surface by Alejandro Manjavacas, Francisco J. Rodríguez-Fortuño, F. Javier García de Abajo, and Anatoly V. Zayats. Phys. Rev. Lett. (Vol. 118, Iss. 13 — 31 March 2017) 118, 133605 DOI:https://doi.org/10.1103/PhysRevLett.118.133605 Published 31 March 2017

This paper is behind a paywall.

Growing a tooth—as an adult

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These days it seems that teeth are the most erogenous zone of all. Actors on screens of all types flash pearly whites that are increasingly blinding while the rest of us are enjoined to buy teeth whiteners in toothpastes, mouthwashes, whitening strips, and/or find dental professionals to assist us in our quest for the brightest and whitest teeth. It would all be so much easier if we could just grow new teeth and discard the old ones.

Coincidentally or not, it seems researchers at King’s College London have also been thinking about how we might grow new teeth. Ben Schiller in a Mar. 14, 2013 article for Fast Company highlights the work,

Researchers from the U.K. have successfully bioengineered teeth from gum tissue and cells taken from mice. By combining and transplanting two groups of cells, they were able to grow full teeth, complete with roots, dentine, and enamel.

This King’s College London Mar. 11, 2013 news release provides more details,

New research published in the Journal of Dental Research describes an advance in efforts to develop a method to replace missing teeth with new bioengineered teeth generated from a person’s own gum cells. …

Current implant-based methods of whole tooth replacement fail to reproduce a natural root structure and as a consequence of the friction from eating and other jaw movement, loss of jaw bone can occur around the implant.

Research towards achieving the aim of producing bioengineered teeth (bioteeth) has largely focused on the generation of immature teeth (teeth primordia) that mimic those in the embryo that can be transplanted as small cell ‘pellets’ into the adult jaw to develop into functional teeth. Remarkably, despite the very different environments, embryonic teeth primordia can develop normally in the adult mouth and thus if suitable cells can be identified that can be combined in such a way to produce an immature tooth, there is a realistic prospect bioteeth can become a clinical reality. Subsequent studies have largely focussed on the use of embryonic cells and although it is clear that embryonic tooth primordia cells can readily form immature teeth following dissociation into single cell populations and subsequent recombination, such cell sources are impractical to use in a general therapy.

Professor Sharpe [Paul Sharpe, an expert in craniofacial development and stem cell biology at King’s College London’s Dental Institute] said: ‘What is required is the identification of adult sources of human epithelial and mesenchymal cells that can be obtained in sufficient numbers to make biotooth formation a viable alternative to dental implants.’

In this new work, the researchers isolated adult human gum (gingival) tissue from patients at the Dental Institute at King’s College London, grew more of it in the lab, and then combined it with the cells of mice that form teeth (mesenchyme cells). By transplanting this combination of cells into mice the researchers were able to grow hybrid human/mouse teeth containing dentine and enamel, as well as viable roots.

Professor Sharpe concluded: ‘Epithelial cells derived from adult human gum tissue are capable of responding to tooth inducing signals from embryonic tooth mesenchyme in an appropriate way to contribute to tooth crown and root formation and give rise to relevant differentiated cell types, following in vitro culture. These easily accessible epithelial cells are thus a realistic source for consideration in human biotooth formation. The next major challenge is to identify a way to culture adult human mesenchymal cells to be tooth-inducing, as at the moment we can only make embryonic mesenchymal cells do this.’

If I read this rightly, researchers are several years away from actually growing a new tooth in an adult human mouth but this work suggests they might be on the right research track.

Sunscreen from coral

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It’s a fascinating project they’re working on at King’s College London (KCL), converting an amino acid found in coral into a sunscreen for humans. The researchers have just signed an agreement to work with skincare company, Aethic but the  research was first discussed when it was still at the laboratory stage in an Aug. 2011 video produced by KCL,

The Sept. 12, 2012 news item on physorg.com makes the latest announcement about the project,

King’s College London has entered into an agreement with skincare company Aethic to develop the first sunscreen based on MAA’s (mycosporine-like amino acids), produced by coral.

It was last year that a team led by Dr Paul Long at King’s discovered how the naturally-occurring MAA’s were produced. Algae living within coral make a compound that is transported to the coral, which then modifies it into a sunscreen for the benefit of both the coral and the algae. Not only does this protect them both from UV damage, but fish that feed on the coral also benefit from this sunscreen protection.

The KCL Sept. 11, 2012 news release (which originated the new item) notes,

The next phase of development is for the researchers to work with Professor Antony Young and colleagues at the St John’s Institute of Dermatology at King’s, to test the efficacy of the compounds using human skin models.

Aethic’s Sôvée sunscreen was selected as the best ‘host’ product for the compound because of its existing broad-spectrum UVA/UVB and photo-stability characteristics and scientifically proven ecocompatibility credentials.

Dr Paul Long, Reader in Pharmacognosy at King’s Institute of Pharmaceutical Science, said: “While MAA’s have a number of other potential applications, human sunscreen is certainly a good place to begin proving the compound’s features. If our further studies confirm the results we are expecting, we hope that we will be able to develop a sunscreen with the broadest spectrum of protection.  Aethic has the best product and philosophy with which to proceed this exciting project.” [emphasis mine]

I went to the Aethic website and found this on the Be Aethic page,

Being Aethic means you are one with nature through our products. It means your skin lives better, feels better and looks better.

It means you do too.

…

Your skin is your largest organ. It’s worth looking after from within, with a good diet, and from the outside by protecting it from daily life and the sun’s harmful rays, by keeping it nourished.

Aethic Sôvée has the most photostable sun filters – anywhere. It has organic moisturisers. It contains a skin anti-oxidant. We developed this formula to treat your skin like royalty. And nature will love you for it as well.

People have been telling us that doing less damage to your skin and the ocean are amazing things to do together

Be loved by nature even more – share this with your friends. The more people you tell, the bigger the difference you make. Here’s why.

Deep down, most people probably suspected that the many ingredients they put on their skin from other sunscreens, must do some harm somewhere. Sure enough, in 2008 it was proven by Prof Roberto Danovaro, from Marche Polytechnic University in Italy, that these products can seriously damage coral. He has since discovered they do damage to clams too.

When you use Aethic Sôvée, you know that you’re leaving nothing behind to harm the ocean. In fact, with your contribution to The Going Blue Foundation’s coral nursery fund, you are going positive. Marine Positive – the certification Aethic Sôvée has received.

Unfortunately this copy is a bit of heavy on the sanctimonious side but the possibility of minimizing one’s negative impact on the  world’s oceans while preventing damage to skin can’t be ignored.

In any event, I found the information about the sunscreen making its way up the food chain and benefitting predators amused me when I considered the possibility of a bear or cougar benefitting should they happen to eat me while I’m using this new sunscreen. Given that this solution is not based on metal oxides perhaps it will find more favour with the ‘anti-nanosunscreen’ crowd.

Science attitude kicks in by 10 years old

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There’s a lot of talk these days about STEM (Science, Technology, Engineering, and Mathematics) in the field of education. It seems that every country that has produced materials about innovation, economic well being, etc.  in English and I’m guessing all the other countries too (I just can’t read their materia]s) want more children/young people studying STEM subjects.

One of the research efforts in the UK is the ASPIRES research project at King’s College London (KCL), which is examining children’s attitudes to science and future careers. Their latest report, Ten Science Facts and Fictions: the case for early education about STEM careers (PDF), is profiled in a Jan. 11, 2012 news item on physorg.com (from the news item),

Professor Archer [Louise Archer, Professor of Sociology of Education at King’s] said: “Children and their parents hold quite complex views of science and scientists and at age 10 or 11 these views are largely positive. The vast majority of children at this age enjoy science at school, have parents who are supportive of them studying science and even undertake science-related activities in their spare time. They associate scientists with important work, such as finding medical cures, and with work that is well paid.

“Nevertheless, less than 17 per cent aspire to a career in science. These positive impressions seem to lead to the perception that science offers only a very limited range of careers, for example doctor, scientist or science teacher. It appears that this positive stereotype is also problematic in that it can lead people to view science as out of reach for many, only for exceptional or clever people, and ‘not for me’.

Professor Archer says the findings indicate that engaging young people in science is not therefore simply a case of making it more interesting or more fun. She said: “There is a disconnect between interest and aspirations. Our research shows that young people’s ambitions are strongly influenced by their social backgrounds – ethnicity, social class and gender – and by family contexts. [emphases mine]

I was particularly struck by the fact that attitudes are positive but, by age 10, researchers are already observing that children are concluding ‘it’s not for me’.

Here’s a little more about the ASPIRES project,

The ASPIRES research team, led by Louise Archer, Professor of Sociology of Education at King’s, is tracking children’s science and career aspirations over five years, from ages 10 to 14. To date they have surveyed over 9000 primary school children and carried out more than 170 interviews of parents and children. After the age of 10 or 11 children’s attitudes towards science often start to decline, suggesting that there is a critical period in which schools and parents can do much to educate the next generation of the options available to them. [emphasis mine]

As for the report ‘Ten Science Facts and Fictions’, you may be in for a surprise if you’re expecting a standard academic study. It’s very colourful and illustrated with cartoons; each fact/fiction has its own page and only one; it summarizes and aggregates other research; and the whole report is 16 pp.  It’s easy reading and the reference notes mean you can follow up and read the research studies yourself.

On a note related to the conclusions made the ASPIRES researchers, I came across a Jan. 27, 2012 news item on Medical Xpress about a US study where researchers attempted an intervention designed to encourage more teens to study science,

In a different intervention study aimed at changing teen behavior in math and science, researchers did not target the students themselves but rather their parents. The goal was to increase students’ interest in taking courses in science, technology, engineering, and mathematics (STEM). “We focus on the potential role of parents in motivating their teens to take more STEM courses, because we feel that they have been an untapped resource,” says Judith Harackiewicz of the University of Wisconsin, Madison. [emphasis mine]

The participants consisted of 188 U.S. high school students and their parents from the longitudinal Wisconsin Study of Families and Work. Harackiewicz and her colleague Janet Hyde found that a relatively simple intervention aimed at parents – two brochures mailed to parents and a website that all highlight the usefulness of STEM courses – led their children to take on average nearly one semester more of science and mathematics in the last two years of high school, compared with the control group. “Our indirect intervention,” funded by the National Science Foundation, “changed the way that parents interacted with their teens, leading to a significant and important change in their teens’ course-taking behavior,” Harackiewicz says.

Given Dr. David Kent’s panel at the 2011 Canadian Science Policy Conference (David’s interview about the panel is in my Oct. 24, 2011 posting) where he noted we have too many science graduates and not enough jobs, I’m wondering if we’re going to see a Canadian effort to encourage more study in STEM subjects. It wouldn’t surprise me; I have seen policy disconnects before. For example, there’s a big effort to get more children and teens to study science while graduate students from the universities have difficulty finding employment because the policy didn’t take the end result (the sector [e.g. universities] that needed people [science professors] when the policy was instituted had already started to shrink and 10 years later no one needs these graduates) into account.