Interesting Science

From materials@nature.com (part of the Nature publishing group): Simple pest control techniques may have given rise to the greatest violins ever made. Biochemists say the key to the instrument's sweet sounds come not only from their construction but also from chemicals used to treat wood.

For hundreds of years people have tried to duplicate the tone of Italian violins such as a Stradivari and a Guarneri. Now scientists say at least part of the secret is to boil the wood in minerals.

A team of scientists lead by Joseph Nagyvary* (homepage) of Texas A and M University, College Station, used nuclear magnetic resonance and infrared spectroscopy to analyse the chemical makeup of wood in antique and modern-day instruments.

Slivers of the wood used to make modern violins were compared with the shavings of five antique instruments from the 1700s. Included in the mix were a Stradivari violin and cello, a Guarneri violin, a Gand and Bernardel violin from Paris and a Henry Jay viola from London.

Continued at "The key to Stradivari's tone" (may require free registration)

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Based on the Brief Communication:

Wood used by Stradivari and Guarneri

Joseph Nagyvary, Joseph A. DiVerdi, Noel L. Owen and H. Dennis Tolley

Opening Paragraph

Whether or not the great Italian violin-makers used wood that had been chemically processed in order to preserve it and enhance the instrument's sound quality has long been a contentious issue. Here we use nuclear magnetic resonance and infrared spectroscopy to analyse organic matter in wood taken from antique instruments made by Stradivari and Guarneri del Gesu. Our results indicate that the wood used by the masters could indeed have been chemically treated, a technique that may inspire an approach to violin making that is more chemistry-based.

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*Joseph Nagyvary was the subject of a 2002 Discover article:

Stradivari's Secret - biochemist Jospeh Nagyvary's resarch on violin-making

...Is [Joseph Nagyvary] a genius or a crank?

He certainly bears some of the telltale marks of crankdom. For one thing, he's a monomaniac. Give him the slightest opening, and he'll talk for hours about his research, branching off into tributaries of arcana so narrow and obscure it seems he couldn't possibly find a rhetorical way out. Then, too, he's certain that jealous enemies are conspiring to keep his revolutionary discovery from gaining the respect it deserves. And as with most scientific cranks who claim to have solved a big problem - like discovering an unlimited source of cheap energy - Nagyvary is convinced he has solved an age-old riddle: Why are violins made by Antonio Stradivari, the legendary 18th-century Cremonese instrument maker, so dramatically better than anything built since?

Yet for all of Nagyvary's pretensions to crankdom, one fact counteracts all appearances: He does make extraordinary violins, violas, and cellos. Indeed, the instruments this biochemistry professor builds have been purchased for as much as $15,000 apiece and reviewed favorably by members of the Cleveland Quartet, Chicago Symphony, and New York Philharmonic. Yehudi Menuhin played one, on loan from Nagyvary, for 15 years. Still, no one has ever found a satisfactory explanation for the transcendently beautiful sounds that come from the violins made by Stradivari and his Cremonese contemporaries Nicolo Amati and Giuseppe Guarneri - and it isn't for want of trying. Instrument makers have patiently disassembled their violins, calibrated every dimension of the pieces to the hundredth of an inch, and replicated the measurements perfectly in new instruments, yet failed to duplicate the magic. Physicists have used lab equipment to analyze the vibrational patterns of Stradivari front and back plates, the big pieces of wood that generate most of a violin's sound, and had craftsmen carve new plates that faithfully reproduce the patterns, all to no avail. Chemists have cooked up elaborate recipes for the varnish that coats and colors a violin's raw maple and spruce, assuming it's the icing on the cake that counts. Again, no luck.

Yet Nagyvary's theories suggest the chemists were closest to the truth. It is the varnish, he says, along with the specially treated spruce used to craft the tops of the instruments, that makes Cremonese violins great...

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From the Navygary Violins website:

"Dr. Joseph Nagyvary has brought an unprecedented level of academic expertise to bear upon the age old violin puzzle. A native of Hungary, he majored in chemistry at the Eotvos Lorand University of Budapest (1952-1956); he became a student of the Swiss Nobel Laureate Paul Karrer in 1957, and received his PhD in the chemistry of natural products in 1962. While in Zurich, he had his first formal violin lessons on a violin which once belonged to Albert Einstein, a coincidence which helped turning his attention to the physical mysteries of the violin. He gained his first glimpses into the art of violin making from the Zurich luthier Amos Segesser. In 1963, he spent a postdoctoral year in Cambridge with Lord Alexander Todd, a British Nobel Laureate. He came to the United States in 1964, and settled down in Texas in 1968 where he has remained a professor of biochemistry and biophysics at Texas A and M University. Dr. Nagyvary was the recipient of a Career Development Grant,and numerous other research grants from the National Institutes of Health, the National Science Foundation, and the NASA. His discoveries concerning the classical violins were made public in over 120 lectures sponsored by the American Chemical Society. On such occasions, his claims were examined by professionals and comparisons were made between Professor Nagyvary's new recreations and the finest locally available antique Italian violins." [Stradivarius]

Technorati: nature, violins, chemicals, wood, stradivari, guarneri, secret, minerals, joseph, nagyvary, nuclear, magnetic, resonance, infrared, spectroscopy, chemical, antique, instruments, violin, viola, gand, bernardel, yehudi, menuhin, albert, einstein, stradivarius

Permanent Link posted by John Latter @ 10:00 AM 0 comments

The Tang dynasty*, seen by many historians as a glittering peak in China's history, was brought to its knees by shifts in the monsoon cycle, according to a study.

Famed for a flowering of art and literature and for prosperity brought by trade with India and the Middle East, the dynasty spanned nearly three centuries, from AD 618 to 907, before it was overwhelmed by revolt.

Scientists led by Gerald Haug of the Geoforschungszentrum (GFZ) in Potsdam, eastern Germany, looked at sedimentary cores taken from a lake at Zhanjiang in coastal southeastern China, opposite the tropical island of Hainan.

The magnetic properties and content of titanium in these deposits are an indicator of the strength of the winter cycle in the East Asian monsoon system, they believe.

They found that over the past 15,000 years, there had been three periods in which the winter monsoon was strong but the summer monsoon was weak.

The first two periods occurred at key moments during the last Ice Age, while the last ran from around 700 to 900. Each of these monsoon shifts coincided with what was, relative to the climate epoch, unusually cold weather.

The twilight of the Tang began in 751, when the imperial army was defeated by Arabs.

But what eventually destroyed the dynasty were prolonged droughts and poor summer rains, which caused crop failure and stoked peasants' uprisings.

Continued at "Climate shift helped destroy China's Tang dynasty" [Change]

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Based on the journal Nature letter:

Influence of the intertropical convergence zone on the East Asian monsoon

Gergana Yancheva, Norbert R. Nowaczyk, Jens Mingram, Peter Dulski, Georg Schettler, Jorg F. W. Negendank, Jiaqi Liu, Daniel M. Sigman, Larry C. Peterson and Gerald H. Haug

Nature 445, 74-77 (4 January 2007) | doi:10.1038/nature05431; Received 27 January 2006; Accepted 6 November 2006

Opening Paragraph

The Asian-Australian monsoon is an important component of the Earth's climate system that influences the societal and economic activity of roughly half the world's population. The past strength of the rain-bearing East Asian summer monsoon can be reconstructed with archives such as cave deposits but the winter monsoon has no such signature in the hydrological cycle and has thus proved difficult to reconstruct. Here we present high-resolution records of the magnetic properties and the titanium content of the sediments of Lake Huguang Maar in coastal southeast China over the past 16,000 years, which we use as proxies for the strength of the winter monsoon winds. We find evidence for stronger winter monsoon winds before the Bolling-Allerod warming, during the Younger Dryas episode and during the middle and late Holocene, when cave stalagmites suggest weaker summer monsoons. We conclude that this anticorrelation is best explained by migrations in the intertropical convergence zone. Similar migrations of the intertropical convergence zone have been observed in Central America for the period ad 700 to 900 suggesting global climatic changes at that time. From the coincidence in timing, we suggest that these migrations in the tropical rain belt could have contributed to the declines of both the Tang dynasty in China and the Classic Maya in Central America.

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*Info on the Tang Dynasty:

...Near the end of the Tang Dynasty, regional military governors took advantage of their increasing power and began to function more like independent regimes on their own right. At the same time, natural causes such as droughts and famine due to internal corruptions and incompetent emperors contributed to the rise of a series of rebellions. The Huang Chao rebellion of the 9th century, which resulted in the sacking of both Chang'an and Luoyang was the most destructive and took over 10 years to suppress. Although the rebellion was defeated by the Tang, it never really recovered from that crucial blow, weakening it for the future military powers to take over. In 907, after almost 300 years in power, the dynasty was ended when one of the military governors, Zhu Wen, deposed the last emperor and took the throne for himself which thereby inaugurated the Five Dynasties and Ten Kingdoms Period...

Technorati: tang, dynasty, china, history, monsoon, cycle, study, art, literature, trade, revolt, winter, summer, ice age, shifts, climate, epoch, cold, weather, droughts, rains, shift, system, maya, winds, change

Permanent Link posted by John Latter @ 10:07 PM 0 comments

Scientists at the National Institute of Arthritis and Musculoskeletal and Skin Diseases** (NIAMS), part of the National Institutes of Health in Bethesda, Md., and colleagues at the University of Virginia in Charlottesville have succeeded in imaging, in unprecedented detail, the virus that causes influenza.

A team of researchers led by NIAMS' Alasdair Steven, Ph.D., working with a version of the seasonal H3N2 strain of influenza A virus, has been able to distinguish five different kinds of influenza virus particles in the same isolate (sample) and map the distribution of molecules in each of them. This breakthrough has the potential to identify particular features of highly virulent strains, and to provide insight into how antibodies inactivate the virus, and how viruses recognize susceptible cells and enter them in the act of infection.

"Being able to visualize influenza virus particles should boost our efforts to prepare for a possible pandemic flu attack," says NIAMS Director Stephen I. Katz, M.D., Ph.D. "This work will allow us to 'know our enemy' much better."

One of the difficulties that has hampered structural studies of influenza virus is that no two virus particles are the same. In this fundamental respect, it differs from other viruses; poliovirus, for example, has a coat that is identical in each virus particle, allowing it to be studied by crystallography.

The research team used electron tomography* (ET) to make its discovery. ET is a novel, three-dimensional imaging method based on the same principle as the well-known clinical imaging technique called computerized axial tomography, but it is performed in an electron microscope on a microminiaturized scale.

Original news release available via this link (Molecular Anatomy of Influenza Virus Detailed, December 29, 2006)

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Based on the Proceedings of the National Academy of Sciences (PNAS) paper:

Influenza virus pleiomorphy characterized by cryoelectron tomography

Audray Harris, Giovanni Cardone, Dennis C. Winkler, J. Bernard Heyman, Matthew Brecher, Judith M. White, and Alasdair C. Steven

PNAS | December 12, 2006 | vol. 103 | no. 50 | 19123-19127

Abstract

Influenza virus remains a global health threat, with millions of infections annually and the impending threat that a strain of avian influenza may develop into a human pandemic. Despite its importance as a pathogen, little is known about the virus structure, in part because of its intrinsic structural variability (pleiomorphy): the primary distinction is between spherical and elongated particles, but both vary in size. Pleiomorphy has thwarted structural analysis by image reconstruction of electron micrographs based on averaging many identical particles. In this study, we used cryoelectron tomography to visualize the 3D structures of 110 individual virions of the X-31 (H3N2) strain of influenza A. The tomograms distinguish two kinds of glycoprotein spikes [hemagglutinin (HA) and neuraminidase (NA)] in the viral envelope, resolve the matrix protein layer lining the envelope, and depict internal configurations of ribonucleoprotein (RNP) complexes. They also reveal the stems that link the glycoprotein ectodomains to the membrane and interactions among the glycoproteins, the matrix, and the RNPs that presumably control the budding of nascent virions from host cells. Five classes of virions, four spherical and one elongated, are distinguished by features of their matrix layer and RNP organization. Some virions have substantial gaps in their matrix layer ("molecular fontanels"), and others appear to lack a matrix layer entirely, suggesting the existence of an alternative budding pathway in which matrix protein is minimally involved.

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*A 2001 open access review from the Journal of Histochemistry and Cytochemistry:

The Emergence of Electron Tomography as an Important Tool for Investigating Cellular Ultrastructure

By Bruce F. McEwena and Michael Markoa

Journal of Histochemistry and Cytochemistry, Vol. 49, 553-564, May 2001

Abstract

Electron tomography has emerged as the leading method for the study of three-dimensional (3D) ultrastructure in the 5-20-nm resolution range. It is ideally suited for studying cell organelles, subcellular assemblies and, in some cases, whole cells. Tomography occupies a place in 3D biological electron microscopy between the work now being done at near-atomic resolution on isolated macromolecules or 2D protein arrays and traditional serial-section reconstructions of whole cells and tissue specimens. Tomography complements serial-section reconstruction by providing higher resolution in the depth dimension, whereas serial-section reconstruction is better able to trace continuity over long distances throughout the depth of a cell. The two techniques can be combined with good results for favorable specimens. Tomography also complements 3D macromolecular studies by offering sufficient resolution to locate the macromolecular complexes in their cellular context. The technology has matured to the point at which application of electron tomography to specimens in plastic sections is routine, and new developments to overcome limitations due to beam exposure and specimen geometry promise to further improve its capabilities. In this review we give a brief description of the methodology and a summary of the new insights gained in a few representative applications.

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** "The mission of the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a part of the Department of Health and Human Services’ National Institutes of Health, is to support research into the causes, treatment and prevention of arthritis and musculoskeletal and skin diseases; the training of basic and clinical scientists to carry out this research; and the dissemination of information on research progress in these diseases."

Technorati: national, institute, arthritis, skin, diseases, niams, imaging, influenza, virus, strain, a, cells, infection, pandemic, flu, research, electron, tomography, et, discovery, pnas, global, health, threat, human, 3-d, 2-d, technology, review, insights

Permanent Link posted by John Latter @ 9:24 AM 0 comments