What can you do to bring some of the Smithsonian’s 137 million objects to life? Put them in 3-D!

This is a full-time job for two of the Smithsonian’s very own “laser cowboys,” Vince Rossi and Adam Metallo, who work in the Smithsonian’s 3D Digitization Program Office. They work hard to document, in very high three-dimensional detail, many of the institution’s many priceless and important collections so that the objects are available for research, education and general interest.

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Recent spectroscopic analysis of macaroni penguin (Eudyptes chrysolophus) crest feathers and king penguin (Aptenodytes patagonicus) neck feathers have shown they contain a yellow pigment that is chemically distinct from all other molecules known to give color to feathers. “Penguins use the yellow pigment to attract mates and we strongly suspect that the yellow molecule is synthesized internally,” explains Daniel Thomas, a fellow at the Smithsonian’s National Museum of Natural History, and lead author of the study recently published in Journal of the Royal Society Interface.

The vibrant yellow pigments found in the crest feathers of the macaroni penguin are chemically distinct from the five known classes of avian plumage pigments. This feather is in the collection of the Smithsonian’s National Museum of Natural History. (Photo by Daniel Thomas)

Using Raman spectroscopy Thomas and colleagues identified part of the molecular structure of this new pigment and hope to completely describe it in the near future. “At its very essence” explains Thomas, “Raman spectroscopy is a study of the way light and matter interact, and very specific interactions tell us about the chemistry of a sample.” The penguin pigment “is distinct from any of the five known classes of avian plumage pigmentation and represents a new sixth class of feather pigment,” Thomas says. “As far as we are aware, the molecule is unlike any of the yellow pigments found in a penguin’s diet.”

In birds, most yellow, red and orange plumage colors are easily linked to diet, Thomas explains. “Canaries are yellow because they eat seeds, fruits and insects that contain yellow carotenoid pigments. Canaries that eat a carotenoid-free diet have white feathers.”

Macaroni penguins, Hannah Point, Livingston Island, Antarctic Peninsula (Photo by Jerzy Strzelecki)

Parrots however are an exception. The red, orange and yellow pigments in the feathers of parrots, are synthesized internally and are not dependent on diet, Thomas says. Penguins can now be added to the list with parrots of birds that internally synthesize yellow feather pigments.

Although the yellow penguin pigment has only recently been discovered to have unique properties, it is by no means new, Thomas points out. “Very likely it has been made by penguins for more than 13 million years, and was possibly displayed by the extinct South American penguin Madrynornis mirandus”.

Co-authors of the paper “Vibrational spectroscopic analysis of unique yellow feather pigments in penguins,” with Thomas, include Helen James of the Smithsonian’s National Museum of Natural History, Odile Madden of the Smithsonian Museum Conservation Institute; Cushla McGoverin of Temple University; and Kevin McGraw of Arizona State University. –John Barrat

Click here for 14 Fun Facts about Penguins!

For more than a half-century, a six-foot tall granite cube and obelisk with a 150 to 200 pound marble slab insert marked the grave of Thomas Jefferson at Monticello. Following damage to the original monument and a government campaign to replace it, the original tombstone, including the marble slab, was presented to the University of Missouri, located in Columbia, Mo.

Thomas Jefferson’s original grave marker. The marker, which has been stored at Missouri University for the past 130 years, will be restored by the Smithsonian Museum Conservation Institute.

Missouri University was the first public university in the Louisiana Purchase Territory that Jefferson had been instrumental in acquiring, and university officials supported a curriculum and concept of higher education similar to those of Jefferson. In fact, the University of Missouri was modeled from the University of Virginia.

The tombstone was officially dedicated at Missouri University on July 4, 1885, and the marble slab was stored in the university’s Academic Hall until the building burned in 1892. The marble slab has been in the current administrative building, Jesse Hall, since it opened in 1895.

Now, nearly 130 years after the university received the marker, university officials and officials at the Smithsonian Institution are transporting the marble slab, which contains the original epitaph written by Jefferson himself, to the Smithsonian for extensive restoration.

Jefferson wrote a detailed description of his grave marker as well as the inscription.

“It’s irresistible. Thomas Jefferson himself wrote what he wanted written on the stone. Scholars find it interesting that he left out the fact that he was president, among other accomplishments,” said Carol Grissom, senior objects conservator at the Museum Conservation Institute, a conservation research laboratory that serves the entire Smithsonian. Grissom is leading the restoration project

“Could the dead feel any interest in Monuments (sic) or other remembrances of them,” Jefferson wrote. He continued, saying that he would prefer a “plain die or cube . . . surmounted by an Obelisk. (sic)”

Jefferson also dictated the words on the marble slab:

Here was buried

Thomas Jefferson

Author of the Declaration of American Independence

Of the Statute of Virginia for religious freedom

& Father of the University of Virginia

“Jefferson was a major proponent of public higher education,” said Kee Groshong, vice chancellor for administrative services emeritus. “The university made a case to his family that this would be an ideal place to display his original grave marker. We believe we should take care of it and display it for everyone to see and enjoy because it is a very interesting piece of history.”

Once at the Smithsonian Museum Conservation Institute, Grissom and her team will remove the plaque from a wooden box that it has been stored in since the 1890s. The restoration team will analyze the piece first to determine exactly why the stone is deteriorating. Grissom said that the top 1/8 inch of the plaque is separating in places and the corners seem to be disintegrating.

“We will examine some samples using the scanning electron microscope and conduct other analyses,” Grissom said. “We also know that the stone was previously broken, so we might try to take it apart first to get a better look at the internal damage. We’re also interested to identify where the stone came from — was it something that was imported, domestic or local? The information is historically significant, but it could also affect the treatment of the stone.”

It is anticipated that the project will take at least a year to complete. Following the restoration, the stone will be returned to Missouri University, where it will be displayed permanently.  –Christian Basi, Missouri University News Bureau

In the early 1880s, three inventors—Alexander Graham Bell, Chichester Bell and Charles Sumner Tainter, collectively making up the Volta Laboratory Associates—brought together their creativity and expertise in a laboratory on Connecticut Avenue in Washington, D.C., to record sound. In one experiment, Nov. 17, 1884, they recorded the word “barometer” on a glass disc with a beam of light. This disc and about 200 other experimental recordings from their laboratory were packed up for safekeeping, given to the Smithsonian and, with a few exceptions, never played again.

Image right: Alexander Graham Bell

In 2011, scholars from three institutions—National Museum of American History Curators Carlene Stephens and Shari Stout, Library of Congress Digital Conversion Specialist Peter Alyea and Lawrence Berkeley National Laboratory Scientists Carl Haber and Earl Cornell—came together in a newly designed preservation laboratory at the Library of Congress to recover sound from those recordings made more than 100 years ago. Using high-resolution digital scans made from the original Volta discs, they were able to hear the word “barometer.”

The museum’s collection has about 400 of the earliest audio recordings ever made, including the 200 from Bell’s Volta lab. A reflection of the intense competition between Bell, Thomas Edison and Emile Berliner for patents following the invention of the phonograph by Edison in 1877, these recordings, along with supporting documents, were offered to the Smithsonian by each inventor in his lifetime.

“These recordings were made using a variety of methods and materials such as rubber, beeswax, glass, tin foil and brass, as the inventors tried to find a material that would hold sound,” said Stephens. “We don’t know what is recorded, except for a few cryptic inscriptions on some of the discs and cylinders or vague notes on old catalog cards written by a Smithsonian curator decades ago.”

Image left: Volta Laboratory recording made by Alexander Graham Bell, #287654-11. (Photo by Carl Haber, Lawrence Berkeley National Laboratory)

Now, through a collaborative project with the Library of Congress and Lawrence Berkeley National Laboratory, the mystery of what is on these recordings is being unraveled. To date, the team has successfully submitted six discs—all experimental recordings made by the Volta Laboratory Associates between 1881 and 1885—to the sound recovery process.

The recordings in the museum’s collection are in fragile condition due to their age and experimental nature. Until now, the technology to listen to the recordings without damaging the discs and cylinders was not available. The noninvasive optical technique used in this project to scan and recover sounds was first studied by Berkeley Lab in 2002–2004 and installed at the Library of Congress in 2006 and 2009. The process creates a high-resolution digital map of the disc or cylinder. This map is then processed to remove evidence of wear or damage (e.g., scratches and skips). Finally, software calculates the motion of a stylus moving through the disc or cylinder’s grooves, reproducing the audio content and producing a standard digital sound file. For more information, visit www.irene.lbl.gov.

Recovering sound from the six Volta discs is the first step in an ongoing project to preserve and catalog the museum’s early recording collection and to provide increased access to the collection and its contents for both the academic community and the public. The content of the recordings, studied in conjunction with the innovative nature of the physical discs and cylinders, provides insight into a variety of topics—from the invention process of these well-known 19th-century labs to speech patterns of the late 19th century.

Image right: Electrotyped copper negative disc of a sound recording, deposited at the Smithsonian in October 1881 and sealed in a tin box. Content: Tone; male voice saying: “One, two, three, four, five, six”; two more tones. Click this LINK to listen. (Photo by Brian Ireley)

This project has been made possible with funding from a variety of sources. The National Museum of American History received a special preservation grant from the Grammy Foundation and support from the museum’s Jackson Fund. The museum is looking for additional funding to continue the examination of other recordings in its exceptional collection. The Institute of Museum and Library Services provided funding to Berkeley Lab through a grant to further develop the optical scanning technology and bring it into use in support of collections and special projects around the world.

The Library of Congress, the nation’s oldest federal cultural institution and the largest library in the world, holds nearly 147 million items in various languages, disciplines and formats. The Library serves the U.S. Congress and the nation both on-site in its reading rooms on Capitol Hill and through its award-winning website at www.loc.gov.

Lawrence Berkeley National Laboratory addresses the world’s most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy’s Office of Science. For more, visit www.lbl.gov.

The Smithsonian’s National Museum of Natural History has pioneered the use of CT scanning technology in noninvasive scientific research. Now, with the gift of a Siemens SOMATOM Emotion 6 CT scanner from Siemens Healthcare, Smithsonian researchers are acquiring information about museum objects that is fundamentally changing the way scientists examine specimens.

Image right: A color-enhanced image from a CT scan of a violin from the collection of the National Museum of American History that reveals the thickness of the wood  of the violin’s front as well as past repairs.

“For more than a century scientists have pursued the mysteries of the natural world through the study of specimens in Smithsonian collections,” said Cristián Samper, director of the National Museum of Natural History. “The presence of the Siemens CT scanner in our anthropology department has revolutionized the way we look at everything from mummies and dinosaur fossils to the Smithsonian’s priceless collection of Stradivarius violins. This donation and its importance to Smithsonian research are significant.”

Image left: Bruno Frohlich, right, and Smithsonian anthropologist Dave Hunt prepare a mummy from Mongolia for entry into the the Natural History Museum’s CT scanner. (Photo by Don Hurlbert)

The National Museum of Natural History is one of the world’s preeminent research institutions in the field of the natural sciences. With more than 126 million specimens in its collections—the largest in the world—the museum is a repository for examples of the diversity of life on Earth and humanity’s common heritage. Under the leadership of anthropologist Bruno Frohlich, Smithsonian scientists and curators use the CT scanner on a daily basis to enrich understanding of the natural world and people’s place in it.

Research in the Smithsonian CT laboratory focuses on employing the CT scanner with the objective of understanding and studying objects, secure in the knowledge that they can be used and studied again in the future. “Most often scientific analytical research is associated with destructive methods,” said Bruno Frohlich. “Normally we have to destroy objects in order to study them. Nondestructive and noninvasive methods, such as CT scanning, not only enable us to study objects with greater attention to detail, but also ensure the preservation of the object and leaving it intact for future generations to study.”

This 53-second video consists of a series of images taken with a Siemens Somotom CT scanner of a mummy at the Department of Anthropology in the Smithsonian’s National Museum of Natural History, Washington, D.C. The individual shown here is a male who died at about 40 years of age; a relatively mature age by ancient Egyptian standards. He is believed to have lived in Lower Egypt sometime between the 25-26th Greco-Roman periods, which is between 600 B.C. and about 150 A.D., or roughly 2,500 to 1,900 years ago.

While the CT scanner belongs to the National Museum of Natural History and has been used extensively to study the mummy collections, it is also available for use with other Smithsonian collections. “We use CT equipment to study valuable and precious objects such as the musical instruments in Smithsonian collections,” Frohlich said. “Happily, after a study is completed, musicians can still play the instrument. This is a remarkable breakthrough for science and museum conservation.”

Research findings made possible through the use of the new CT scanner were announced at an Oct. 27 presentation to Washington, D.C., public school elementary students at the National Museum of Natural History’s public hands-on Forensic Anthropology Lab. Four high school students from the museum’s youth internship program, “Youth Engagement Through Science,” visited Frohlich’s lab to observe the CT scanner on the mummy collection. The program included remarks by Samper, Hemani, Frohlich and Spiegel.

Strand for strand no fabric can compare to the luxurious feel, luminosity and sheen of pure silk. Since millennia, the Chinese have been unraveling the cocoons of the silk worm (Bombyx mori) and weaving the fibers into sumptuous garments, hangings, carpets, tapestries and even artworks of painted silk.

Now, for the first time scientists at the Smithsonian’s Museum Conservation Institute have developed a fast and reliable method to date silk. This new technique, which is based on capillary electrophoresis mass spectrometry, has great potential to improve the authentication and dating of the priceless silk artifacts held in museum and other collections around the world.

Chinese silk textile from the Warring States period (475-221 B.C.) (Metropolitan Museum of Art, www.metmuseum.org)

The new method uses the natural deterioration of the silk’s amino acids, a process known as racemization, to determine its age. As time goes by the abundance of the L-amino acids used in the creation of the silk protein decreases while the abundance of D-amino acids associated with the silk’s deterioration, increases. Measuring this ever changing ratio between the two types of amino acids can reveal the age of a silk sample. Archaeologists and forensic anthropologists have used this process for decades to date bone, shells and teeth, but the techniques used required sizeable samples, which for precious silk objects are almost impossible to obtain.

This Japanese artwork, “Pair of Cranes on Branch,” was made from ink and color painted on silk. It is one of hundreds of artworks containing silk fibers in the collections of the Smithsonian’s Freer and Sackler Galleries.

“Many things an animal makes are protein based, such as skin and hair. Proteins are made of amino acids,” explains Smithsonian research scientist Mehdi Moini, chief author of a recent paper in the journal Analytical Chemistry announcing the new dating method. “Living creatures build protein by using specific amino acids known commonly as left-handed [L] amino acids. Once an animal dies it can no longer replace the tissues containing left-handed amino acids and the clock starts. As L- changes to D-amino acids [right handed], the protein begins to degrade,” Moini explains. Measuring this ever-changing ratio between left-handed and right-handed (D) amino acids can be used as a scientific clock by which a silk’s age can be estimated. In controlled environments such as museum storage, the decomposition process of silk is relatively uniform, rendering D/L measurement more reliable.

This Order of the World War medal with its colorful ribbon is one of many artifacts in the collections of the Smithsonian’s National Air and Space Museum that contain silk.

The Smithsonian Museum Conservation Institute team used fiber samples taken from a series of well-dated silk artifacts to create a chart of left-hand and right-handed amino-acid calibration ratios against which other silks fabrics can be dated. Those items included new silk fibers; a silk textile from the Warring States Period, China (475-221 B.C.) from the Metropolitan Museum of Art in New York City; a silk tapestry (1540s) from the Fontainebleau Series, Kunsthistorisches Museum, Vienna, Austria; a silk textile from Istanbul (1551-1599) from the Textile Museum, Washington, D.C.; a man’s suit coat (1740) from the Museum of the City of New York; and  a silk Mexican War flag (1845-1846) from the Smithsonian’s National Museum of American History.

Previously, the scientists write, dating silk has been largely been a speculative endeavor that has mostly relied on the historical knowledge of a silk piece, as well as its physical and chemical characteristics.” The new technique takes about 20 minutes, and requires the destruction of about 100 microgram of silk fiber, making it preferable over C14 (carbon 14) dating, which requires the destruction of so much material that it is prohibitive for most fine silk items.

The article “Dating Silk by Capillary Electrophoresis Mass Spectrometry,” appared in the scientific journal Analytical Chemistry, and was authored by Mehdi Moini; Mary Ballard, Smithsonian senior textile conservator; and Museum Conservation Institute intern Kathryn Klauenberg.

The Freer Gallery of Art and the Arthur M. Sackler Gallery Archives announces a new 3-D digital resource that will enable scholars and the public to learn more about the ancient Near East through a unique group of pressed-paper molds called squeezes. This resource provides unparalleled access to the archives’ collection of squeezes from ancient Near Eastern archaeological sites.

The squeezes were created in the early 20th century by the German archaeologist Ernst Herzfeld (1879-1948), a prominent scholar on the ancient Near East, as a way to record intricate inscriptions on monuments and other stone buildings. They were formed by pressing layered, wet, moldable paper into an inscription and leaving it to dry, creating a 3-D mirror-image representation of the original. Created to serve as temporary reference materials, the squeezes have become vital to continued research for archaeological sites that are no longer accessible.

Image right: Detail of cuneiform squeeze from the Ernst Herzfeld papers, Freer Gallery of Art and Arthur M. Sackler Gallery Archives.

The squeezes contain Arabic script, Middle Persian and Cuneiform impressions from archaeological sites such as Pasargadae, Persepolis, Naqsh-i Rustam and Paikuli. The captured inscriptions were often carved on commissioned temples, civic buildings and statues to record battles won, titles acquired or the lineage of kings. Scholars have used the squeezes to chronicle the reigns of local rulers and discover the nature of otherwise unidentifiable structures. More recently, scholars have used microscopic traces of pigments retained from the original surface to provide a unique and exceptional journal of the color and decoration used at the time of the monument’s creation.

“These digital images offer extraordinary access to inscriptions from the cradle of civilization,” said Alex Nagel, assistant curator of Near East art. “By making them available to scholars and enthusiasts worldwide, we’re ensuring that new discoveries can come from these remarkable artifacts.”

The archives hold almost 400 paper squeezes that belong to its larger collection of Ernst Herzfeld papers.

In 2010, the archives received a grant from the Smithsonian’s Collections Care and Preservation Fund to aid in the preservation of the squeezes. The Archives, in collaboration with the Smithsonian’s Museum Conservation Institute, created a digital version of each squeeze using a new imaging technique called Reflectance Transformation Imaging. RTI allows users to manipulate the image and enhance a squeeze’s readability, while protecting the fragile original objects from further damage.

For more information on the squeeze digitization project, the Herzfeld papers, and the process of making squeezes, visit www.asia.si.edu/research/squeezeproject/.

Recent analysis using DNA sequencing of ancient Roman pills found aboard a ship that sank in Italy’s Gulf of Baratti between 140 -120 B.C, has revealed that the medicines consist of material from simple garden plants, namely carrot, radish, parsley, celery, wild onion and cabbage. The presence of yarrow and hibiscus also were detected in the pills.

Alain Touwaide and Robert Fleischer examine a phial recovered from the wreckage. (Photo: Emanuela Appetiti)

The pills were found aboard the shipwreck, which was first located in 1974, inside a tin container. Other medical implements also were found aboard the ship including a surgical hook, a mortar, a copper bleeding cup and a tin pitcher. The implements were all located close together, leading researchers to believe they were originally packed in a chest belonging to a physician.

A wide phial and its lid, recovered from the wreckage. (Photo: Emanuela Appetiti)

Alain Touwaide, historian of sciences in the Department of Botany at the Smithsonian’s National Museum of Natural History and scientific director of the Institute for Preservation of Medical Traditions, collaborated in the discovery. In 2004, he received fragments of the pills from the Italian Department of Antiquities. DNA sequencing was done by Robert Fleischer, head of the genetics program at the Natural History Museum.

A recovered phial, still in its original setting. (Photo: Emanuela Appetiti)

The identification of the plant components in the Roman pills is a first,” Touwaide says. “The pills are the only know archaeological remains of ancient medicines, and their analysis is the first ever performed.”

The Gulf of Baratti in Italy (Photo: Emanuela Appetiti)

References to all of the components identified in the medicines can be found in ancient medical texts. Not only does this new discovery validate these ancient texts, but it opens promising avenues for new scientific research and innovative thinking in drug discovery.

A library of ancient medicinal texts is maintained by the Institute for the Preservation of Medical Traditions, which specializes in recovering the medical heritage of the ancient Mediterranean world.

More information about this project can be found on the Institute for the Preservation of Medical Traditions Web site at http://medicaltraditions.org/

The National Science Resources Center, a joint program of the Smithsonian Institution and the National Academies, will receive a $25.5 million Investing in Innovation (i3) grant from the U.S. Department of Education to support its work in transforming science education for grades one through eight. The NSRC is one of only 49 applicants chosen from a pool of 1,700 to receive an i3 grant. The grant is contingent on a 20 percent match from private-sector donors.

The funding will allow the NSRC to validate its LASER (Leadership Assistance for Science Education Reform) Model. LASER, a systemic approach to reform, is a set of processes and strategies designed to help state, district and school leadership teams effectively implement and sustain high-quality science education for elementary, middle and secondary school students. More than 1,500 leadership teams from states and school districts throughout the United States—representing an estimated 30 percent of the U.S. student population—have already participated in LASER activities to improve science education in their states and communities.

The grant enables the NSRC to improve the learning and teaching of science for a total of 75,000 students in grades one through eight and 3,000 teachers in rural schools in Indiana, North Carolina and the urban district of Houston. The NSRC and its partners will work with these sites to execute a comprehensive, research-based science education program and simultaneously build the infrastructure to sustain ongoing science-education reform.

The University of Memphis in Tennessee and its partners will serve as outside evaluators of the project, conducting a large-scale, rigorous, cross-state randomized controlled study to test the LASER Model in high-poverty urban and rural schools. This validation study of the effectiveness of the model will support the scale-up of LASER throughout the United States.

Scientists from the Smithsonian Museum Conservation Institute, the University of Valencia in Spain and the University of Minnesota, recently made an important observation regarding charcoals from wood fires excavated at ancient archaeological sites. They verified that the remains of fungi that had been living in the wood before it was burned could clearly be seen with a scanning electron microscope. Scientists have long known that the carbonization process preserves the anatomical structure of a wood well enough to identify its tree species. Now, new evidence shows that even the fine hyphae, mycelia and other structures of fungi living in the wood often survive the burning process and are clearly evident in wood charcoal. They are preserved well enough that scientists can sometimes distinguish between different fungi groups.

Charcoal analysis, a science known as anthracology, is an area of archaeology that can reveal important information about the wood used by ancient civilizations and, in turn, the users themselves, says Melvin Wachowiak, a senior furniture conservator at the Smithsonian. Knowing what type of fungus infested a wood before it was burned can reveal where the wood came from and why and how it was gathered, say for firewood, a funeral pyre, building a house or other purpose. Dry wood gathered from a forest floor for cooking often has a different fungi content than fresh wood cut and dried for fires or construction. Archaeologists can use this information to better understand wood management strategies of long vanished civilizations and the environment in which they may have lived.

Images: The scanning electron microscope image above shows living brown-rot fungi growing on a fragment of wood. The image at left shows the same fragment with its fungi still visible after the wood has been turned to charcoal. (All images by Magdalena Moskal-del Hoyo)

To confirm their findings Wachowiak and Magdalena Moskal-del Hoyo of the Department of Prehistory and Archaeology at the University of Valencia, burned hardwood and conifer wood samples infested with three primary wood fungi—brown rot, white rot and soft rot—in a laboratory, turning them into charcoal. The fungi were identified prior to burning by plant pathologist Robert Blanchette of the University of Minnesota, a co-author of the study. Then, using a scanning electron microscope, Wachowiak and Moskal-del Hoyo examined the charcoal for visual evidence of the carbonized remains of each fungus. Evidence of all three fungi was visible in the carbonized samples.

Image right: Wood mircostructure and its accompanying white-rot fungi can clearly be seen in this scanning electron microscope image of a charcoal fragment.

The scientists then compared these samples with charcoal taken from ancient archaeological sites: two Neolithic settlements in eastern Hungary, one of the Körös culture and one of the Tisza culture of Polgár-Csőszhalom, and wood from the Bronze Age necropolis of Kokótow in what is now Kraków, Poland. In their research, the scientists were careful to verify that the fungus structures they observed in the ancient charcoal samples had attacked the wood before it was burned and not after.

Other scientists have observed this phenomenon before, Moskal-del Hoyo points out. But this is the first time it has been verified “in a systematic manner,” she says, by using known fungi-infested wood samples, burning them, and then verifying that the same ultrastructure of the wood and fungi are still visible.

A paper on this research “Preservation of Fungi in Archaeological Charcoal” was published recently in the Journal of Archaeological Science.  –John Barrat