David Bradley – Page 310

Are all snowflakes different?

Snowflake shape The short answer is no. Despite what you may have heard some snowflakes are exactly the same shape and size as other snowflakes, at least to the naked eye.

The long answer follows: Jon Nelson, a researcher with Ritsumeikan University in Japan, has studied snowflakes for fifteen years, and has some interesting insights into their delicate structures. He points out that the old adage that ‘no two snowflakes are alike’ might be true for larger snowflakes, but it does not hold true for smaller, simpler crystals that fall before they’ve had a chance to fully develop into the familiarly evocative hexagonal flakes. Regardless, the shape of snow crystals are incredibly diverse, this is partly due to their sensitivity to even the smallest temperature change as they fall through the clouds.

So, how do snowflakes form in the first place?

Put simply, at the heart of every snowflake is a minute grain of dust that was once floating in a cloud. Water vapor from the atmosphere condenses on this dust grain forming a droplet that freezes instantly (it’s a nucleation process to put it technically).

The ice crystals grow with hexagonal symmetry. The shape originates from the chemistry of the water molecule, which consists of two hydrogen atoms bonded to an oxygen atom, H-O-H. These atoms are not in a straight line though, they’re at an angle and this angle means that when several water molecules get hitched together through hydrogen-bonding in the frozen state the simplest way to do that (i.e. the lowest-energy arrangement) results in six-sided symmetry, hence six-sided snowflakes. By the way, you never get octagonal or pentagonal snowflakes, please report anyone who draws or makes snowy decorations with flakes showing that symmetry.

The growing flake eventually sprouts six tiny branches. Each of these branches grows to form side branches in a direction and shape that are influenced by the clustering of water molecules on the ice crystal surfaces.

The American Chemical Society has produced an excellent poster illustrating all this. You can download it as a PDF file here.

You may be wondering why scientists are so interested in snowflakes, after all in many parts of the world, you’re never going to get a chance to test your theories.

Well, snowflakes and ice crystals have an effect on the global climate because of the reflectivity, they are thought to help catalyze the break down of ozone in the upper atmosphere depletion, and they also play a critical role in the build up electric charges in clouds that leads to lightning.

The Scout Report recently highlighted another researcher with an interest in ice crystal growth and pattern formation in ice. Kenneth Libbrecht at Caltech University, the Report says, is “so interested in fact, he went
ahead and created this lovely website that documents the very wide, and very
interesting world, of ‘snowflakes, snow crystals, and other ice phenomena.’

But, that’s probably enough science for today. So, wherever you are let it snow, let it snow, let it snow…and compliments of the season from Sciencebase.com

Santa Claus’ address

A couple of years ago NASA released satellite images of Santa Claus’ summer hideaways, turns out there are two locations in the USA where old Father Christmas likes to spend the lazy summer months. Santa Claus, Georgia (left) and Santa Claus, Indiana (right), are typical of Santa’s summer retreats, says NASA, offering Santa and Mrs Claus, all the reindeer and elves the usual amenities and a nice warm respite from their chilly Polar home during the off season.

Of course, these satellite images are rather out of date now, so we should turn to Google Maps for the current view. As you can see from the image on the right, Santa Claus’ summer home in Georgia nestles among beautiful lakes that provide the reindeer with crystal clear drinking water and perfect grazing as well as great water skiing for Mrs Claus. If you put your nose close to the screen you can just about see Rudolph’s glowing red nose poking out from the water as he takes a pre-Christmas dip. Of course, FBI regulations prevent us from revealing Santa’s current whereabouts but what we can say is that he and his entourage are already now working hard somewhere at the North Pole, with a special envoy in Lapland to handle public relations.

Anyway, the official address to send your Letter to Santa is: Mr S Claus, North Pole, H0H OH 0, don’t worry if that zipcode looks a little odd, just try saying it out loud and you’ll feel okay.

Father Christmas Research

Drugs and addiction

Fly agaric Many people in the modern Western world delude themselves that their culture is generally free from the effects of intoxicating substances except in the criminal underworld, and that ‘nice people don’t take drugs’. But Richard Rudgley of the University of Oxford, a researcher of the oasis communities of Chinese Central Asia, shows that our culture and other cultures across the world have a rich tradition of using chemicals, mainly from plants, to produce altered states of consciousness. These range from the ritualistic use of the fly-agaric in Palaeolithic Europe to betel-nut chewing in Papua New Guinea, and from pretentious bone-china tea sets in Surbiton to the tragic inhaling of petrol fumes by Aboriginal Australians.

Although each intoxicant has its own effects on the mind – there is some overlap – but researchers have classed them as belonging to four types. Hallucinogens – compounds such as mescaline – are often found in ‘poisonous’ varieties of mushroom or South American weeds. Inebriants consist of generally simpler organic compounds such as alcohol, and the constituents of organic solvents and other volatile chemicals. Hypnotics are compounds that induce states of sleep, stupor or calm and include tranquilizers and narcotics. Stimulants increase mental activity and include caffeine, tobacco and the more potent cocaine and amphetamines.

Rudgley has scoured the scientific literature for examples and evidence from the European Stone Age to modern day Australia to improve our understanding of how these broad classes of intoxicants have affected society and religion. Beginning with evidence from the earliest days of hallucinogen use in Palaeolithic cave art, Rudgley describes in fascinating detail intoxicants and their cultural effects over the past few thousand years.

For example, peyote, the mescaline-containing cactus of Texas and Northern Mexico, apparently played an important role in the cultural development of indigenous peoples of that area, although the plant is now threatened with extinction because of increasing use by modern hedonists. On the Steppes biochemical evidence shows that Cannabis sativa and ethanol have been commonly used for many thousands of years.

Rudgley even has an explanation for the supposed flight of witches and the symbolism of the witch’s broom. A witch wanting to ‘fly’ to a witches’ sabbat, or orgiastic ceremony, would anoint a staff with specially prepared oils containing psychoactive plant matter, as well as rather gruesome ingredients such as baby fat and human blood. The potion could then be administered to areas of the body that could absorb the active components most rapidly. Rudgley quotes one researcher: ‘The use of a staff or broom was undoubtedly more than a symbolic Freudian act, serving as an application for the atropine-containing plant to the sensitive vaginal membranes. . .’ So now you know.

There is little spiritualism attached to the modern Western use of intoxicants such as caffeine and nicotine, and society more than frowns on the use of mind-altering drugs. The modern view is perhaps distorted to some extent by the development of highly addictive stimulants such as ‘crack’, with its potentially devastating effects.

Rudgley hopes that a deeper knowledge of intoxicants’ use in other cultures will result in a better understanding of our own culture of cafes and bars, and this in turn might help us understand the ‘importance of altered states of consciousness in both our collective and our personal lives’.

I wrote the original version of this item as a book review that was published in New Scientist magazine (The Alchemy of Culture by Richard Rudgley, British Museum Press, reviewed issue 1909, p43).

The professional staff at an addiction treatment facility knows how to help a drug addict, so you can rest assured your loved one is in good hands.

How does Santa do it

Santa Claus Technology An advanced knowledge of electromagnetic waves, the space-time continuum, nanotechnology, genetic engineering, and computer science easily explains Santa’s abilities to deliver presents to millions of homes and children in just one night, according to professor of mechanical and aerospace engineering, Larry Silverberg, at North Carolina State University.

Silverberg explains that Santa has a personal wireless connection to children’s thoughts — via a listening antenna that combines technologies currently used in cell phones and EKGs — which informs him that Mary in Miami hopes for a surfboard, while Michael from Minneapolis wants a snowboard. Sophisticated signal-processing technology maps out who wants what, where children live, and especially flags red or green children who’ve been bad or good.

Santinformatics software processese all the data and programs the onboard sleigh guidance system (OSG) to calculate the most efficient delivery route. Down on earth this is known as the “traveling salesman problem”, but it’s the TSantaP at the North Pole.

Silverberg is not so silly as to think that Santa and his reindeer can cover approximately 200 million square miles — making stops in some 80 million homes — in one night. Instead, he reckons that Santa uses his knowledge of the space-time continuum to form what Silverberg calls “relativity clouds.” “Based on his advanced knowledge of the theory of relativity, Santa recognizes that time can be stretched like a rubber band, that space can be squeezed like an orange and that light can be bent,’ Silverberg says. ‘Relativity clouds are controllable domains — rips in time — that allow him months to deliver presents while only a few minutes pass on Earth. The presents are truly delivered in a wink of an eye.’

Santa’s reindeer are genetically engineered, of course, allowing them to fly, balance on rooftops and see in the dark. And, just in case you’ve forgotten, here are their names: Donner, Blitzen, Dasher, Dancer, Prancer, Vixen, Comet, Cupid, Rudolph, and Olive! Olive, you say? Yes, as in: “Olive the other reindeer, used to laugh and call him names…” These latter two were recruited to the team many years after the original poem naming the reindeer – A Visit from St Nicholas.

Finally, many people wonder how Santa and the reindeer can eat all the food left out for them. Silverberg says they take just a nibble at each house. The remainder is either left in the house or placed in the sleigh’s built-in food dehydrator, where it is preserved for future consumption. It takes a long time to deliver all those presents, after all.

Silverberg says “Children shouldn’t put too much credence in the opinions of those who say it’s not possible to deliver presents all over the world in one night. It is possible, and it’s based on plausible science.”

Christmas rose and hellebrigenin

Members of the plant family Ranunculaceae are ever-popular at this time of year, especially in Europe, where the Christmas rose, Helleborus niger, is wheeled out as a natural decoration for countless households. Interesting then, that extracts of this plant have been used as a heart tonic in herbal medicine alongside the likes of digitalin (from foxglove) and strophanthin from the West African plant Strophanthus gratus.

H. niger contains various potent toxins in addition to cardiac glycosides helleborin, hellebrin and helleborein and saponosides and the ranunculoside derivative, protoanemonine. It was searching for information on the compound hellebrigenin (3-acetate) that brought one Sciencebase reader to this site, so here’s the structure of the molecule. This biologically active compound, which also goes by the name (3beta,5beta,14beta)-3,5,14-trihydroxy-19-oxobufa-20,22-dienolide, is a cardioactive steroid compound as well as having been demonstrated (in the 1960s) to have activity against tumour growth.

Latest chemical discoveries

The latest bumper Xmas issue of Reactive Reports, actually the 61st issue I’ve produced for the site is now online. In this issue we cover:

Molecular Light Switch – According to Nobel laureate Roald Hoffmann, “Nanotechnology is the result of the marriage of the synthetic talent of Chemists with a device-driven ingenuity.”

Blood, Light, and Water – Two molecules that occur naturally in blood have been engineered by scientists from the UK and Japan to use sunlight to split water into hydrogen and oxygen.

Plastic Shape Shifter – Temperature-controlled “triple-shaped plastics” that can change shape from one form to another, then another, have been developed by researchers in Germany and the US.

Top Chemical Discoveries of 2006

My good friend Stu Borman and his colleagues at Chemical & Engineering News (C&EN) have come up with a fascinating mash up of the most important chemical discoveries of 2006.

First up, is the total synthesis of UCS1025A, this esoteric-sounding compound is actually a potential inhibitor of the enzyme telomerase, and the incredibly compact synthesis was achieved by Tristan Lambert and Samuel Danishefsky of the Sloan-Kettering Institute for Cancer Research and Columbia University (J. Am. Chem. Soc. 2006, 128, 426). Inhibiting this enzyme could retard the growth of tumours.

Another synthesis published in JACS is second in Stu’s list. The scheme comes from Elias J. Corey’s group at Harvard University and represents a cheaper and faster way to construct the flu drug oseltamivir phosphate, better known as Roche’s antiviral Tamiflu (J. Am. Chem. Soc. 2006, 128, 6310).

Another synthetic achievement this year is the construction of the compound 2-quinuclidone by Brian Stoltz and Kousuke Tani at California Institute of Technology (Nature 2006, 441, 731). A quick glance at this simple-seeming structure might have you reaching for your Merck Index thinking that surely it must have been synthesised decades ago. But, no, this is the first synthesis of this bicyclic. Their synthetic scheme may provide new insights into biological amide hydrolysis as well as representing a rather aesthetically pleasing synthesis.

You can read about the other syntheses picked out by Borman and his colleagues in C&EN.

Also on their list is research at the frontiers of carbohydrate chemistry, where researchers have developed a high-throughput technique for screening mutant glycosyltransferases (GTs) for biomedical activity. The work could lead to a new generation of designer sugars for a range of medical conditions. Advances in structural biology (chemistry by any other name) achieved Nobel status this year, and crystallography also produced some amazing results in revealing the structure of Dicer, an enzyme that initiates RNA interference (RNAi). Also in this field a new NMR technique, SAIL, on which I reported for SpectroscopyNOW earlier in the year, could revolutionize solution structure determination of proteins.

Molecular biology (also chemistry by another name) features in Borman’s round-up with researchers gaining important insights into the molecular mechanisms of cellular protein production, Alzheimer’s disease, and RNA interference.

In the field of analytical chemistry, a new approach to nanoscale secondary ion mass spectrometry (nanoSIMS) was developed for imaging lipid bilayers at below 100 nm resolution and computational chemistry produced a 3000-member family of artificial cytochrome P450 enzymes for studying how these enzymes metabolize drugs and toxins.

In inorganic chemistry, says Borman, researchers produced previously elusive molecules and atoms, such as P₂. Nuclear, polymer, and space chemistry also feature in this year’s round-up as does nanotechnology, not surprisingly.

But, one highlight of the chemical year not mentioned in C&EN, but certainly on my list was the culmination of work at a small laboratory in Northern Ireland that has led to the maturation of work I first wrote about for New Scientist back in the early 1990s and that has now, in its teens, reached a level of application its detractors said could never be – AP de Silva’s research on molecular logic.

Bird flu non-news

Over on foreignpolicy.com they’re reporting the Top Ten non-News Stories of 2006. Among their picks is the non-story of bird flu, or avian influenza as it’s more correctly known. In case you missed it, we didn’t all die of bird flu again this year. However, there were a few people who, having got so scared of the tiny risk that they might catch the H5N1 strain of the disease began taking Tamiflu prophalactically. More fool them, it turned out. Here’s what the site had to say:

“In November, the Canadian health ministry issued a warning on Tamiflu after 10 Canadians taking the drug had died suspiciously. And the US Food and Drug Administration received more than 100 reports of injury and delirium among Tamiflu takers for a 10-month period in 2005 and 2006. That’s nearly as many cases as were logged over the drug’s five-year trial period. For now, the cure seems worse than the disease.”

Highly ironic that a drug taken for its protective effects against a disease that doesn’t really yet exist should have claimed so many victims. Unless we see a sudden spate of bird flu infections in the developed world, 2006 will remain another year in which none of the scaremongerees actually died of bird flu.

Marrying up lost chemistry and chemists

British-born Dick Lewin Wife followed a traditional educational path, receiving his chemistry first degree from the University of Leeds in 1969 and staying on to do an organic PhD with David W. Jones. Research fellowships then took him to London, New York, and finally California, after which he returned to a job in the UK with Shell in 1976, moving to The Netherlands with the company in 1979. He stayed with Shell until 1987 at which point he founded SPECS and BioSPECS BV, in The Netherlands. In 2005, he co-founded a new company, SORD, which aims to find “lost chemistry” and make it accessible to the scientific world.

Read the full story in the latest issue of Reactive Reports online now.

Sniffing out our sense of smell

How we smell Our sense of smell is much better than we give it credit for. A report in Nature Neuroscience puts paid to the notion that the human reputation for having a poor sense of smell compared to other animals.

Noam Sobel and colleagues laid down scent trails in a grassy field, and asked human subjects to find the trail and track it to the end. Subjects were blindfolded and wore thick gloves and earplugs to force them to rely exclusively on smell. Contrary to expectations, the volunteers exhibited some of the same tracking strategies used by dogs and were certainly capable of following the trail.

In follow-up experiments, the authors also demonstrated that this ability partially depends on comparisons of odour information in each nostril, it’s almost like smelling in stereo.

When subjects had one nostril plugged their tracking performance was much worse.

Admittedly, the volunteers were much slower than dogs at following the scent trail, but with practice they got quicker.

the findings raise the intriguing possibility that our sense of smell is far better than we think and that using it more effectively is simply a skill we don’t teach our children so it gives us the impression that we don’t have it.

For more on a provocative theory of how we smell check out this page from the Sciencebase archives.