David Bradley – Page 327

Chemical Structure of Avenacoside B

Polish student Marcin Mielecki emailed to ask where he might find a 3D, as opposed to 2D, structure for the compound Avenacoside B. A very quick Google brought me almost immediately to this page (by searching for “avenacoside b mol file”: http://www.genome.jp/dbget-bin/www_bget?cpd+C08888, which provides the flat molecular structure and a link to the MDL mol file for this molecule. If Marcin has Chime or another mol reader installed in his browser clicking that link will spawn the 3D structure he requires. It’s also in Pubchem of course.

Marcin’s research focuses on the biological role of the avenacosides, which are steroidal saponins from Avena sativa.

A hearty approach to female sexual dysfunction

Heart drugs are proving rather useful to pharma companies hoping to find lucrative treatments of another kind of disorder, that maybe involves the heart, but mostly involves the loins.

A heart drug that went into clinical trials in the 1990s has become the linchpin for efforts to develop a medication to treat female sexual arousal disorder (FSAD), researchers are reporting. An estimated 40 percent of women have FSAD or another form of female sexual dysfunction, the difficulty or inability to find satisfaction in sexual expression.

Compounds that sustain the activity of vasoactive intestinal peptide (VIP) are a major target of drug research efforts. VIP controls blood flow to the vagina, and decreased blood flow is believed to be one factor in female sexual dysfunction. VIP is degraded in the body by several enzymes, including an enzyme called NEP. Blocking NEP thus allows VIP to continue working.

David Pryde and colleagues at Pfizer in the UK (the company that brought us Viagra) began work with Candoxatril, a powerful NEP inhibitor tested in the 1990s for chronic heart failure. By re-engineering Candoxatril’s molecular structure, they developed a compound with the key actions needed for an FSAD drug.

The new compound blocks NEP, takes effect rapidly, and continues having an effect for a relatively short time. “The compound demonstrates excellent efficacy in a rabbit model of sexual arousal and was expected to be similarly efficacious in humans,” the researchers state in the Journal of Medicinal Chemistry. The compound is undergoing clinical evaluation as a potential treatment for FSAD.

Punched while drunk

It’s usually fairly easy to justify even the most esoteric of scientific research in terms of improving our fundamental understanding of the universe etc etc. But, when a press release pops up announcing that drinking [alcohol] can be dangerous and that “People who drink alcohol are up to four times more likely than non-drinkers to be hurt from physical injuries such as a fall or punch…” you begin to wonder about your convictions. Apparently, this astounding discovery was made by researchers at the University of Queensland, Australia, who found that, “any alcohol consumption quadrupled the risk of injury for the first six hours after drinking alcohol and this risk remained at 2.5 times that of a non drinker for the next 24 hours.”

Do you have to have had a drink to be punched, I guess the inhibition inhibiting effects of alcohol can make some people say more provocative things that might offend someone and land them in a fight, but what about someone having a few “tinnies” alone in an armchair watching Aussie soap opera Neighbours or listening to Kylie? Are they more likely to suffer an injury or more weirdly get punched.

Some people might say that if they’re really watching Neighbours or listening to Kylie they deserve all they get, but Kerianne Watt earned her PhD for also discovering that, “people who sustained serious injuries were more likely to have consumed beer and have been drinking in a licensed premises” and “Binge drinkers were more at risk of being injured than regular drinkers”.

“My findings suggest that it’s not a property of the beverage that increases aggression and risk of injury, it’s more a personality characteristic that is attracted to a certain type of alcohol,” Watt says.

I suppose the research can be justified in terms of understanding the nature of alcohol abuse and how it relates to injury rates and it probably is quite useful to know what kinds of drink are most associated with injury, but strewth this still feels like this should have been published in the Australian Journal of the Bleedin Obvious (Aus J Bleed Obv), don’t you think?

You can read the complete press release here.

No plaice like home

The slime that covers the flat-fish plaice contains an antimicrobial agent that kills Staphylococcus aureus, the bacteria causing concern in hospitals across the globe as its drug-resistant strains spread.

Chemical engineer Trude Tvete of Nord-Trondelag University College (HiNT) in Norway, has developed a technique for extracting the antimicrobial protein from plaice slime and has tested its biological activity against several types of bacteria. “Previous research has shown that plaice slime kills bacteria, but it didn’t show which substance breaks the bacteria,” says Tvete. “I found that there is a protein in the slime that has the greatest effect.”

Read on…

Pyridine joins the supersonic set

The pyridine chemical group, basically a benzene ring in which one of the six carbons and its attendant hydrogen atom have been swapped for a nitrogen atom, is one of the building blocks of a vast number of biological molecules and is a crucial component in the functionality of an almost as expansive selection of pharmaceuticals. As such, understanding its chemistry and physical properties are important in a fundamental way to the chemical and life sciences.
Now, chemists Yoshinori Nibu, Ryosuke Marui, and Hiroko Shimada of Fukuoka University, in Japan, have used infra-red spectroscopy to sniff out important new clues as to this aromatic compound’s behaviour.

You can read the full story in the first August edition of my science news round-up for spectroscopyNOW.com

Light Harvest for the World

In order to trap the energy from sunlight antenna plants construct chlorophyll groups through chemical self-assembly in a highly ordered manner. Emulating this system would not only improve our understanding of how plants function so effectively but could also lead to new materials for harvesting solar energy as an alternative to silicon-based photovoltaic devices.

Researchers have exploited long-range chemical order to creating aggregate compounds that can either trap light or transfer energy. Now, Tsutomu Ishi-i and Shuntaro Mataka of the Kurume National College of Technology and their colleagues have synthesised a new type of light harvester and by incorporating different materials into the aggregate structure they can induce energy transfer too. UV-Vis spectroscopy and other techniques were used to reveal the details of this novel group of artificial self-assembling light-harvesting compounds that will help us understand plant photosynthesis and may eventually lead to an alternative to semiconductor-based solar panels.

I offer a light report via SpectroscopyNOW

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Water waste

Water is commonly known as the universal solvent because it dissolves more substances than other compounds. But, water is commonly known as an enigmatic substance too, with many properties that seem at first glance paradoxical and others that chemists are yet to explain. Researchers at Argonne National Laboratory hoped to learn more about how ions interact with mineral surfaces in water and have used X-ray studies to open the door on understanding how contaminants travel in the environment.

Ions, ranging from nutrients such as calcium to contaminants such as lead, are present in natural waters across the globe. Their transportation through the environment is often controlled by the degree of adsorption to mineral surfaces. Understanding the adsorption and desorption processes involved could lead to new ways of controlling water quality.

Get the full story here.

The Art of ET

Extraterrestrial Art After centuries of speculation concerning the existence or otherwise of extraterrestrial intelligence, it has been discovered that a radio signal detected by the Arecibo Observatory in Puerto Rico contains artwork broadcast from deep space.

Initially dismissed by scientists as meaningless, the transmission – which originated between the constellations Aries and Pisces thousands of years ago – is now claimed to be the most significant addition to the artistic canon since the Mona Lisa, or even the Venus of Willendorf.

The artistic signal has been painstakingly decoded and transferred onto canvas by conceptual artist Jonathon Keats and is unveiled today at the Magnes Museum in Berkeley California. “This is the ultimate outsider art,” notes Keats, “Historically, our culture has ignored extraterrestrial artistic expression. Exhibited at the Magnes, the art becomes accessible to everyone.”

The discovery of artwork from beyond the solar system did not come as a surprise to Keats, who has frequently collaborated with scientists across multiple disciplines. “It’s a familiar story,” he says, “Researchers expect intelligent life elsewhere in the universe to behave just like them. Since scientists are mathematical, they expect extraterrestrials to broadcast the digits of pi or the Pythagorean theorem.”

The discovery augments earlier findings here on earth of artifacts dating back to a prehistoric alien landing, the so-called Shao-Shan object, they too are very aesthetically pleasing!

South African shards

Raman analysis of South African pottery (shards) dating from the 13th and 14th centuries reveals that the potters used a variety of clays and fired their wares at less than 800 Celsius using open fires rather than kilns. Such details could only be unearthed without damaging the artefacts using this powerful spectroscopic technique.

Chemists Malebogo Legodi and Danita de Waal of the University of Pretoria in South Africa examined samples from four archaeological sites – Rooiwal, Lydenburg, Makahane, and Graskop using normal dispersive Raman spectroscopy. They complemented this technique with X-ray fluorescence, X-ray diffraction and Fourier transform infrared spectroscopy.

Read the complete story in the latest online issue of SpectroscopyNOW.com

Moon Orbit Earth How Long

not the full moon photo by David Bradley It might seem like a trivial question, and most people would probably say 28 days. But, it isn’t so simple.

On average it takes 27.322 days (that’s a sidereal month, and a nice number of significant figures for something astronomical, especially when defining the day is not so clear cut) for the Moon to complete one orbit around Earth. However, the number of days between Full Moons is about 29.5306 days as the Moon has to “catch up with the sun” as it were. So, the actual number of days may differ from the average number by more than a half day. From one Full Moon to the next, the number of days in one lunation can vary between 29.272 and 29.833 days (another nice clutch of significant figures).

The age and apparent size of the Full Moon vary in a cycle of just under 14 synodic months, which is called the Full moon cycle.

The true Full Moon may differ from the calculated peak by up to about 14.5 hours, due to the normal irregularity in the Moon’s Keplerian orbit, and due to the periodic perturbations in that orbit caused by the Sun, the equatorial bulge of the Earth, and the proximity of other planets.

Anyway, I hope this little snippet answer the search query a recent visitor plugged into the sciencebase search box – “moon orbit earth how long”