Category: Science

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Black Cohosh and Hot Flashes

black cohosh menopause remedyAccording to news just in from the American Chemical Society, millions of women use the herb black cohosh (Cimicifuga racemosa) as a dietary supplement to help treat hot flashes and other menopausal symptoms. However, there are no definitive clinical trials to say whether they are wasting their money or not. Some studies report that black cohosh helps relieve menopausal symptoms such as hot flashes, while others do not.

A new study to be published May 17 in the Journal of Agricultural & Food Chemistry reveals that many of the black cohosh supplements sold across the US actually do not contain any of this plant at all. Rather, they are formulated with a related plant species that has none of the same chemical compounds or clinical applications as the native North American plant.

Edward Kennelly, Fredi Kronenberg and colleagues report that a new analytical technique, allowed them to quickly test 11 products on the market claiming to contain black cohosh. Three contained an inactive adulterant, and one contained both genuine black cohosh and an Asian imitator. Products containing only black cohosh varied significantly in the amounts of the compounds believed to relieve menopausal symptoms.

“In the US, botanical dietary supplements are regulated as foods, rather than drugs,” noted Kennelly, “The manufacturers are required to follow good manufacturing practices, so this misbranding should not occur. Unfortunately, our study shows that at least in the case of black cohosh, many manufacturers are not following the regulations.”

In other words, caveat emptor applies as always, adds Kennedy: “Consumers should be aware of this situation in order to make proper choices for their health care.”

Natural Spinoffs

Writing on the CHMINF-l discussion group, Buffalo U librarian A. Ben Wagner explains how he has come to an agreement with faculty to draw a line under subscribing to new spinoff publications of the journal Nature. “no sooner had reluctantly subscribed to Nature Physics partly under the justification that at least this time they had picked a major discipline,” he says, “only to find
out in a few months they are bringing out Nature Nanotechnology and Nature Photonics within months of Nature Physics.”

Here’s the list of spinoffs Wagner cites together with first publication date (Nature Biotechnology was a new incarnation of the journal Bio/Technology)

Nature 1869, Nature Biotechnology 1983, Nature Genetics 1992, Nature Structural & Mol. Biology 1994, Nature Medicine 1995, Nature, Neuroscience 1998, Nature Cell Biology 1999, Nature Immunology 2000, Nature Reviews. Genetics 2000, Nature Reviews. Molecular Cell Biology 2000, Nature Reviews., Neuroscience 2000, Nature Reviews. Cancer 2001, Nature Reviews. Immunology 2001, Nature Materials 2002, Nature Reviews. Drug Disc. 2002, Nature Reviews. Microbiology 2003, Nature Clinical Practice Cardiovascular Medicine 2004, Nature Clinical Practice Gastroenterology & Hepatology 2004, Nature Clinical Practice Oncology 2004, Nature Clinical Practice Urology 2004, Nature Methods 2004, Nature Chemical Biology 2005, Nature Physics 2005, Nature Clinical Practice Endocrinology & Metabolism 2006, Nature Clinical Practice, Nephrology 2006, Nature Clinical Practice, Neurology 2006, Nature Clinical Practice Rheumatology 2006, Nature, Nanotechnology Oct. 2006, Nature Photonics Jan. 2007

“Even the Rocky movies only went to 5!” Wagner said. But, isn’t this just what every other academic publisher is doing, new journals seem to appear one after the other regardless of whether it’s a commercial, learned society, or open access publisher? Robert Michaelson of Northwestern U added that “Libraries and universities – especially faculty – need to stand up to “The New Elsevier”, which is displaying the avarice of the original model.” Dana Roth of Caltech also pointed out that Nature Protocols (putatively online only) is also on the horizon as is Nature Chemistry.

Michaelson also asks, “Is there really a need for Nature Physics, or Nature Nanotechnology? Certainly there isn’t a need in the scholarly community – all of the papers published in these titles could easily be published, at far less cost, in existing well-established journals.”

Presumably, Nature Publishing Group has a different spin on this and is addressing what it sees as a market need as increasingly multidisciplinary endeavour requires new outlets as the traditional boundaries between old disciplines become increasingly blurred.

That said, a follow up posting from UCR’s Chris Reed provocatively suggested that librarians and faculty should be proactive in stamping out this proliferation of journals, singling out not just NPG but citing Bentham as particularly aggressive in this area. “I have also recommended that the best way to change faculty habits is to pay them,” he said on the list, “Overpriced journals should be cancelled and some of the saved money given to Departments whose faculty agree not to submit to, referee for, accept editorial board appointments on journals they decide are too exploitive.”

Natural Born Painkillers

According to a press release I only just spotted from the journal “The Cochrane Library, a randomised controlled trials has demonstrated that extracts of Devils Claw (Harpagophytum procumbens), White Willow Bark (Salix alba) and Cayenne (Capsicum frutescens) all reduce low-back pain better than placebo. Devils’ Claw and White Willow Bark also compare well with conventional medicines, claim researchers in a a systematic review published in Issue 2 of the journal this week.

Devils’ Claw is apparently well known for its anti-inflammatory and analgesic qualities and purportedly can reduce pain to the same degree Vioxx (well anything can beat Vioxx these days, surely, seeing as it’s a banned medication). But, that aside, it’s the seeming surprise in finding that S. alba can relieve pain. An extract of cricket bat willow was the very product that kick-started the pharmaceutical industry when German manufacturer Bayer branded a modified version of the active component, acetylsalicylic acid, as aspirin.

There is no mention of this in the press release, but it’s unlikely that the papers authors were totally unaware of the natural evolution of this compound.

Surely.

Russian Chemical Bulletin

Several Sciencebase visitors have been trying to locate the Bulletin of the Academy of Sciences of the USSR, Division of Chemical Science, a chemistry journal coming out of, you guessed it, Russia. Well, according to the Springer Publishers website this journal is now known as Russian Chemical Bulletin and can be found here.

The journal is edited by well-known Russian chemist O.M. Nefedov and publishes some 500 original, peer reviewed papers a year in the fields of General and Inorganic Chemistry, Physical Chemistry, Organic Chemistry, Organometallic Chemistry, Chemistry of Natural Compounds and Bioorganic Chemistry. So, now you know.

Carbon Nanosheets

carbon graphene sheet

Andre Geim of the University of Manchester and his colleagues reckon graphite, the slippery soft allotrope of carbon, could lead to a new generation of microelectronic devices. Geim and colleagues laid out graphite sheets one layer at a time to allow them to study the properties of these graphene sheets.

A graphene sheet is electrically conducting, behaving essentially like a two-dimensional metal. But it is a strange kind of metal, with properties dictated by quantum mechanics. For example, even if there are no mobile electrons to carry an electrical current, the electrical conductivity can never fall below a certain minimum value: it is like an electron gate that can never be fully closed.

The Manchester team has shown that graphene can be fashioned into a device called a spin valve, which discriminates between mobile electrons according to their spin. Spin is a quantum-mechanical property of electrons, and can take either of two values — somewhat akin to magnets that can orient their poles in either of two opposed directions. Conventional electronics takes no account of electron spin; but it has been suggested that a spin-dependent form of electronics, called spintronics, could provide new and powerful ways to process information. A graphene spin valve could act rather like a spintronic filter that lets a current pass only if the electrons have the correct spin.

Geim and colleagues announced their findings today at the Institute of Physics’ Condensed Matter and Materials Physics conference at the University of Exeter.

Cellular Barcodes

Fluorescent “barcodes” created by labelling pools of cells with different combinations of dyes could be a boon to researchers interested in performing large-scale cell-based studies for drug discovery and other applications, according to Gary Nolan and colleagues at Stanford.

Protein phosphorylation has a major role in a wide variety of essential cellular functions, and several years ago Nolan and colleagues developed “phospho flow”, an approach for simultaneously characterizing the phosphorylation status of multiple proteins in different groups of cells. However, phospho flow can become impractical when scaled up for the analysis of multiple protein targets in response to a large variety of different compounds.

Now, Nolan and Peter Krutzik have found a new solution to this problem. They have demonstrated that cells labelled with different concentrations of a fluorophore can be readily distinguished, and that combinations of fluorophores – each present at a different concentration – can generate cell-specific “barcodes”. Thanks to these barcodes, researchers can subject large numbers of cell populations to different treatments, then pool the cells for simultaneous phospho flow sorting and analysis, resulting in a considerable savings in efficiency and reagent consumption.

The team shows that with just three barcoding fluorophores, one can easily sort out the phospho flow data for differentially treated cells from a 96-well assay plate – and larger assays should prove equally feasible.

More information in the journal Nature Methods. You can get a free subscription to the print edition of Nature Methods here.

Clearer View of Teary Role

Peter Petrov of the University of Exeter and colleagues have found that tears are a much more complex fluid than previously thought. Their surfaces are, they say, highly structured, almost like cell membranes with a protective coating just two molecules thick.

The tear film that covers and moistens our eyes must keep debris and microorganisms out as well as holding water in and keeping the eye lubricated. Petrov’s team has investigated how this two-molecule coating, made up of a mixture of many different biological molecules, is ordered with the aim of getting a clearer view of its role.

Some of the molecular components of the tear film’s “skin” are soap-like lipid molecules. These are similar to the key constituents of cell membranes, and have a water-soluble ‘head’ and an insoluble ‘tail’. At the surface of water, these molecules tend to sit in layers one molecule thick, with their water-loving heads immersed and their insoluble tails poking up out of the water. But some other constituents of tear films are wholly ‘water-fearing’ (hydrophobic) — they will dissolve readily in fats, but very poorly in water. On their own, such molecules tend to clump together in droplets on the water surface, like droplets of oil or fat.

Petrov and colleagues have attempted to explain how this mixture organize itself in a tear film by bouncing X-rays off the surface of both natural tear films (taken from cows) and artificial analogues composed of a comparable mixture of lipids and oily compounds. Their results show that, in both the real and the synthetic films, the molecules seem to line up at the water surface in regular, orderly arrays, rather like two-dimensional crystals.

When the researchers added fluorescent molecules to synthetic tear films containing just the lipid components, they saw that the lipids separated into two different states: a relatively disorderly state, like a two-dimensional liquid, interspersed with blobs of a more closely packed, crystal-like state. These lipid crystals grew into remarkable patterns shaped rather like flower heads. When the fat-like components were added to these artificial films, they seemed to form a separate later on top of the lipids, which enabled them to remain out of the water. Petrov and colleagues think that this arrangement enables the tear film to keep a relatively constant structure even when it is severely squeezed and stretched, as is likely to happen for example when we blink: squeeze the film and the lipid crystals grow a bit bigger; stretch it out and they become smaller again.

Petrov and colleagues describe their findings at the Condensed Matter and Materials Physics conference in Exeter today.

Rejected Elements

A perennial point of contention among chemists is the issue of naming the chemical elements. At least at the top end of the periodic table. However, the periodic table of rejected elements provides some light relief while concentrating on this crucial chemical conundrum. Where else can you find delirium, sin, and crouton?

I’m sure they meant element 15 (Bs) to be Bosphorus, but somehow missed the s, although Boss Porous would be a great name for a Dukes of Hazard revival set in a lab…

Crystallized Ink

I haven’t mentioned search terms for a while, but one that drew in the punters to the sciencebase site stood out in my recent trawl of the site logs – “crystallized ink”. Now, what’s all that about? I wondered.

At first, I assumed it was someone worrying about their little pot of Indian blue going all glacial on them (as is the wont of certain types of honey and concentrated acetic acid solutions). But, then I thought maybe the pen manufacturers, in a bid to recapture a dwindling market for handwriting implements, had come up with a way to add a glittery appearance to the extruded product of their implements…

A quick Google, however, revealed that crystallized ink, at least on the basis of the page one SERP is a product of science fiction – an ink that can oscillate between two states: visible and invisible. This product could thus be used to create animations on the page without the need for a conventional computer screen. The main citation is on this page http://lattice.mysteryandmagic.com/reference.a.html. Pull back to the top-level and you will a sci-fi game called The Lattice (semantically the name is reminiscent of another sci-fi genre, I’d say). So, that was an intriguing find.

But.

Trawling the logs a bit deeper revealed the keyphrase “clogged printer head”. A quick cross-check revealed that the search had come from the same IP within a couple of minutes. So, I suspect our inkvestigator was actually just looking for information on how to unblock their printer rather than either anything as archaic as Quink or as futuristic as animated ink.

Shame.

Science Projects Demonstrations Guides Ideas

mad-professor

We’ve got a stack of information available to science students including science homework and chemistry assignment help, science fair projects and science class demonstration guides. The free stuff is fine, but we also offer science project resources in partnership with 24 Hour Science Projects, which you or your parent will have to pay for. We recommend these project packs very highly though as they’re almost guaranteed to help you make the grade in science class as well as improve your understanding of some important scientific principles.

The following pages in the Sciencebase archives will help you find the science project inspiration you need:

Apologies for those typos in some of the file names, they can’t be corrected now, but rest assured we do know how to spell science