a little light chemistry

The chemistry of life fundamentally depends on light - without photosynthesis there wouldn't be much worth reporting. In contrast, chemistry as a discipline from fundamental research through to industrial applications doesn't use light all that often. The most common way of making things react is to heat them, add a catalyst, or even put pressure on. The science of light-induced reactions, aka photochemistry has remained a poor relation.

I am picking up signals that this may be about to change for a variety of reasons. We now have a much better understanding of how photochemistry works in natural systems so we could borrow an idea or two there. Also, in the quest to make chemistry more sustainable and "green", using light instead of high temperatures and pressures may often be a better solution.

I wrote a feature about various recent developments in photochemistry which is out now:

Let there be light

Chemistry & Industry 83, No. 10, pp 30-33.

access via:

Wiley Online Library (paywalled)

SCI (members)

Any access problems give me a shout and I can send a PDF.




Source: Wikipedia: By Masohe - Own work, CC BY-SA 4.0,


In the same issue, page 38, you can find my review of the book

Modern thermodynamics for chemists and biochemists


Oh, and it appears that I forgot to blog about my previous feature in C&I, which appeared in issue 8 and was about developing new kinds of magnets depending less on rare earth elements.

Mining for ideas

Chemistry & Industry 83, No. 8, pp 26-29.

access via:

Wiley Online Library (paywalled)

SCI (members)

bobtail squid in starring role

Open Archive Day


Starting its third year now, the Open Archive Day happens on the Mondays between those when new features come out. It highlights one feature that was published more than a year ago and is thus on permanent open access. From 2011 to 2017, there are 160 to choose from now, with two from 2018 joining every month, so I won't get bored soon.

Today's edition stars the Hawaiian bobtail squid, Euprymna scolopes whose genome sequence has just been reported in PNAS (also on open access, apparently). The transparent larvae of this cephalopod represent an important model system for studies of the symbiosis between higher organisms and bioluminescent bacteria. And these bacteria normally coordinate their light production by quorum sensing, which was the topic of my last feature of 2017, which is in the open archive now:

Shining new light on quorum sensing




The adult Hawaiian bobtail squid (Euprymna scolopes) with inset scale.

Image source: Margaret McFall-Ngai - Divining the Essence of Symbiosis: Insights from the Squid-Vibrio Model

twisted light

Lenses in your cameras, spectacles, or other optical devices are still exactly the same as those used by Galilei and van Leeuwenhoek, a surviving example of analogue technology in a digital world. Physicists have come up with various alternative technologies that can shape light in other ways, independent of the limitations of traditional optics.

In a rare excursion into the scary world of physics, I have written a short feature about these alternative approaches, which is out now in Chemistry & Industry:

Light without lenses

Chemistry & Industry Volume 82, Issue 01, pages 34-35


open access to full (HTML) text via SCI website

restricted access to full text and PDF file via Wiley Online Library

And my story also made the lovely cover:




Oh, and no page 42 of the same issue there is my long essay review of the book:


Astrochemistry
by Claire Vallance
World Scientific Press 2017

bacterial voting

Quorum sensing is the fascinating mechanism by which bacteria decide whether they are present in sufficient numbers to have an effect, eg to produce light for a symbiotic host organism, or to launch an infection in an unsuspecting victim. This field has a fan community among those interested in the resulting phenomena (eg bioluminescence, infection) or in bacterial communications more generally, but I don't think it has received nearly the attention it deserves. Part of the reason may be that some of the most important areas where QS occurs are also incredibly complex. However, bioluminescence offers very simple and elegant model systems, and on the basis of things learned there, science can eventually progress to the messy ones, like our guts.

I think I last wrote about quorum sensing around 10 years ago (and, definitely, in my book Light and Life), so it was about time to revisit the field, which is becoming more important as we are beginning to appreciate the importance of the bacterial symbionts in our bodies. My feature on is out now:


Shining new light on quorum sensing

Current Biology Volume 27, Issue 24, pR1293–R1296, 18 December 2017


FREE access to full text and PDF download




Embryos of the Hawaiian bobtail squid (Euprymna scolopes), which are colonised specifically by the luminescent symbiont Vibrio fischeri, are an ideal model system to study aspects of symbiosis and quorum sensing.

(Image: Tim Miyashiro and Andrew Cecere (Appl. Environ. Microbiol. (2016) 82, 3082–3091.)

the trouble with photosynthesis

If you look at plants from a technological point of view, there is a fascinating flaw in photosynthesis which is simply down to the fact that it evolved in an atmosphere with virtually no oxygen, and now it is having problems with its own waste product. Some tropical plants like maize and sugar cane have found a fix, but other crops like rice and wheat are massively inefficient at turning carbon dioxide into food, which is why various research groups are trying to improve them.

Read all about it in my feature:

Fixing photosynthesis
Chemistry & Industry April 2015, pp 42-45
Free access to the full text

In the same issue I also have a "long essay review" of the book Fracking by Hester and Harrison (from the series Issues in environmental science and technology)

Fracking - points of view
Chemistry & Industry April 2015, pp 50-51
limited access

light reading

In the round-up of German pieces published in January/February it's mostly about light, so we have photosynthesis, seasonal affective disorder, UNESCO's year of light. Along with that a bit of chemistry bang in the shape of Knallgas bacteria and a new synthesis approach:

Ein neuer Molekülbaukasten
Chemie in unserer Zeit Volume 49, Issue 1, page 12, Februar 2015
abstract and limited access to full text/pdf
related content in English

Jahr der Erleuchtung
Nachrichten aus der Chemie 63, Nr 1, pages 133–135
free access

Die Brennstoffzelle der Knallgasbakterien
Nachrichten aus der Chemie 63, Nr 2, pp 133–135 DOI: 10.1002/nadc.201590047

Chemische Heiterkeit
Nachrichten aus der Chemie 63, Nr 2, p 215

Fotosynthese mit Turbolader
Spektrum der Wissenschaft Nr 2, pp 17-19

Mehr Licht - die saisonale Depression
Trillium Diagnostik 2014, 12, Nr 4, pp 188-189

solar fuel

My latest feature in Current Biology discusses artificial photosynthesis and the quest to produce transport fuel from renewable energies:

Closing the carbon cycle

Current Biology Volume 24, Issue 13, pR583–R585, 7 July 2014

Free access to full text and PDF link

own photo

social jetlag

From a paper in the latest issue of Current Biology, I learned that the habit of many people to switch their sleeping hours between a later weekend time and an earlier work / school time is now referred to as social jetlag in the chronobiological literature. The latest research links this seemingly innocuous behaviour pattern to obesity.

The more extreme variant, the lifestyle of shift workers, has been studied in some detail before, and it is well known that it has serious health implications, as our metabolism works according to our inbuilt circadian rhythm, not by our alarm clock and work schedule. I believe that the investigations have led to some improvements and people who want to soften the blow can treat their jet lag with the clock hormone melatonin, but I’m not sure how widely the problem is appreciated among people working variable shifts and among their employers.

The more widespread version of just having your sleep two or three hours later on weekends than on weekdays (equivalent to a return trip across several timezones each weekend) hasn’t been appreciated as a health risk so far, but the authors of the new study describe it as “chronic social jetlag” and show that there is a statistically significant link with obesity, at least for some who are sensitive to weight gain.

Intriguingly, those in the normal range of body mass index (BMI), there was no significant correlation between the number of hours of social jetlag (up to 5 hours – that must be stressful!). For those in the overweight to obese range however, the BMI appears to correlate positively with social jetlag above 1h.

There are some very obvious measures that could reduce this problem instantaneously, for instance, adapting school hours to the (typically late) chronotype of teenagers, but will anybody pay attention? I doubt it. Personally I’m in the clear – my weekend timeshift is typically less than half an hour, and I’m not overweight anyway.

Reference:

Till Roennebergsend, Karla V. Allebrandt, Martha Merrow, Céline Vetter: Social jetlag and obesity

Current Biology, Volume 22, Issue 10, 939-943, 10 May 2012 10.1016/j.cub.2012.03.038

abstract, video abstract

who's who in Ancient Egypt's New Kingdom

very excited to hear that for the first time DNA sequences have been analysed to sort out the family relations between various mummies of Egyptian pharaohs. According to this report in National Geographic, Egyptian researchers using DNA from Tutankhamun and ten other members of his family have been able to establish a detailed family tree of Tutankhamun, demonstrate that the sun-worshipping inventor of monotheism, Akhenaten, was his father, and identify Akhenaten's mummy, previously known only as KV55. King Tut's mother appears to be one of Akhenaten's sisters, but her identity remains unclear. This rules out the previously popular hypothesis that his mother might have been Akhenaten's most famous wife, Nefertiti. Oh, and they also found evidence of various health problems, including malaria, allowing them to speculate on the likely causes of Tut's premature death at age 19.

Haven't read the paper yet, which is out today in the Journal of the American Medical Association:

Zahi Hawass et al., JAMA. 2010;303(7):638-647:
Ancestry and Pathology in King Tutankhamun's Family

blind as a bat ?

Thanks to a tweet from Peter (@PD_Smith) I was reminded of the issue of echolocation in blind humans, which appears to be so unknown in the UK that the BBC ran a news story on a child using the technique.

Goes to show that we live on an island – elsewhere it is quite common for blind people to tap their sticks very loudly and use the echo for orientation. I lived in Marburg for two years, where Germany’s national school for blind people is located, and the first thing to learn when you move to that city is to jump into the next ditch when you hear loud tapping sounds approaching. Well I’m only exaggerating slightly. Truth is, many blind people there walk around so fast and confidently that they are almost a danger to others.

I had considered this the normal state of affairs until a few years ago I came across the issue again when editing entries for a UK based encyclopaedia, where the entries for echolocation and blindness seemed to lack this piece of information. Doing a bit of research I found a text by Jim Blackshear, apparently written as teaching material. Apart from various interesting bits of history (apparently human echolocation was first observed by Diderot in 1749, so well done to the BBC for trying to sell it as news!), the text also contained the crucial information as to why the technique is unknown in some countries and common in others. Apparently, many people, especially when they are blind from an early age, develop the technique naturally, but in some places it is actively discouraged by education professionals.

Blackshear cites Robert Feinstein who writes in Bent Voices:

Sadly, echolocation is not talked about, nor is it taught. It's only learned intuitively or by example. I read about it only once, in a book called Follow My Leader, which claimed that an eleven-year-old boy, blinded by a firecracker explosion, had developed the skill. From all that I can tell, however, those blinded later in life almost never learn how to do it. I know a girl, blind at fourteen, who will walk smack into a wall, even though she has been blind for twenty-eight years. Once she walked straight into the closed door of my lobby. "Didn't you hear that door?" I asked incredulously. "Don't be a retard!" she countered, "you don't hear doors!" "I do!" I said, in my most condescending voice. "Yeah, right!" she said, and I supposed you hear traffic lights!" "I hate you damn sighted blind people!" I remonstrated, and changed the subject before we got into a fight.

As we grow older and learn to use canes or dogs we grow to rely less on the information gained from echolocation. The skill is there, but it can go dormant. Mobility instructors discourage echolocation, especially clicking. While training with my first dog, I forgot myself and clicked to determine if I was near a pole. The instructor told me that my dog would be taken from me if I continued to make "those sounds," that they served no purpose, that they made blind people objects of ridicule. And furthermore, I'd confuse the dog. I stopped clicking—until I returned home!

Now that really drove me up the wall when I read that he was discouraged from clicking. If you have the choice between not perceiving your environment at all, and perceiving it through echolocation while looking a bit silly, I think it is perfectly obvious what everybody would and should do. Discouraging people from using echolocation is to me like robbing them of their eyesight all over again.

"best" sellers

March/April is a very important time of year for authors, because we receive royalty statements from our various publishers. If we're lucky, we even receive a small amount of royalties, though the more likely version is that the statement will inform us that we still owe money.

This year, I have finally managed to create a spreadsheet of all my book sales, which is endlessly fascinating, as I can now get the sheet to calculate all kinds of statistics for me. For instance, the best year (so far) for sales of my books was 2001.

I've also taken this opportunity to update my personal "best" sellers list (note that none of my books ever came close to troubling any real bestsellers lists!). Maybe I should call it the leastpoorsellers list. Anyhow, to avoid confusion I have now combined different editions of identical title (e.g. hardback and paperback ed. of Life on the Edge) and come to the following top 5:

1. Travels to the Nanoworld
2. Life on the Edge
3. Light and Life
4. Exzentriker des Lebens
5. Astrobiology

Note that Astrobiology may still rise in the charts as it is still selling. Amazingly, if I listed the books by the sales in the first year of publication of a given edition, I would arrive at exactly the same top 5. So their fate is sealed by the end of the first Christmas sale period!

Also, congratulations are due to Ken Derham of Plenum Publishing (now part of Kluwer, which has probably been swallowed up by some even bigger fish), as he commissioned the top 2 titles of this list.

German pieces in August

This month, the German publications are all driven by light, it seems, as we have the light-driven molecular motor and photodynamic therapy:

Groß M:
Chemie in unserer Zeit 42, Nr 4, 254
Energieumwandlung: Lichtgetriebener Molekülmotor
PDF

Groß M:
Spektrum der Wissenschaft Nr 8, 16-17
Laserskalpell mit Tiefenwirkung


Oops, I nearly forgot, we also have conservation issues in Africa:

Michael Groß
Biologie in unserer Zeit Nr 4, 221
Neue Wege für den Artenschutz in Afrika
Published Online: Aug 4 2008 5:35AM
DOI: 10.1002/biuz.200890063

PDF

(Both pdf links have restricted access, but they do work within Oxford University, even though these are German magazines!)

And finally, the magazine of Austrian pharmacists has reprinted my story on bacterial hairs, or pili:
Bakterien am Schopf gepackt
Österreichische Apotheker-Zeitung 62, Nr 15, 778-9 (21.7.2008)

light therapy

Photodynamic therapy is a rather clever way of activating drugs by laser light, such that they only become effective at the precise location where you want them to act. It is routinely used in treatment of age-dependent macular degeneration and some cancers, but there could be additional benefits in cancer therapy, if only the light could penetrate deeper into tissues.

Oxford chemist Harry Anderson and his team have now demonstrated a new approach that promises to improve the method significantly and broaden the range of its applications. Read my story here.

dusting down the book shelves

I'm at the moment cleaning up the book pages of my web site. Using the slightly improved design of the new pages created for The birds, the bees and the platypuses, I've now blown the cobwebs off the pages for Astrobiology, Light and life, Lust and love as well and may keep working my way down the list, unless I get too bored with that.

I shouldn't click around on my own website, really, I always discover lots of things that need fixing ...

(solar) power to the people

Way back when in the eighties, when I was young and green, Germany's Green Party, untainted by real government responsibility, had lots of nice policies in their programs, including the one that people who produce renewable energy small scale, e.g. with a solar panel on their roof, should be entitled to sell any spare electricity back to the providers. Very simple, very obvious, though we never really believed we'd get through with this in a capitalist world.

When the red-green coalition came to power, it very sneakily introduced this idea into a new law governing energy provision (living abroad by then, I actually missed it when it happened), without creating the storm I would have expected.

These so-called feed-in tariffs have since then become a major success story, as they have made private photovoltaic cells economically attractive, plus the idea has been copied by legislators in many other countries -- as I found out to my surprise when I researched a news feature for Current Biology.

Read my story here:

Current Biology 17, No 16 (21.08.), R616
Germany goes for solar