Tag Archives: American Chemical Society (ACS)

Celebrate the 150th anniversary and International Year of the Periodic Table of Elements in 2019

The 150th anniversary of the Periodic Table of Elements has occasioned its own International Year as declared by the United Nations (UN) and, hopefully, a revival of the ‘elements cupcake’ craze which seems to have had its heyday in 2011/12. (I wrote about the cupcakes here in a March 21, 2012 posting ‘Periodic table of cupcakes, a new subculture?‘)

As for IYPT 2019, let’s get started with Mark Lorch’s (professor of Science, Communication, and Chemistry at the University of Hull) January 2, 2019 essay for The Conversation (h/t phys.org), Note: Links have been removed,

The periodic table stares down from the walls of just about every chemistry lab. The credit for its creation generally goes to Dimitri Mendeleev, a Russian chemist who in 1869 wrote out the known elements (of which there were 63 at the time) on cards and then arranged them in columns and rows according to their chemical and physical properties. To celebrate the 150th anniversary of this pivotal moment in science, the UN has proclaimed 2019 to be the International year of the Periodic Table

But the periodic table didn’t actually start with Mendeleev. Many had tinkered with arranging the elements. Decades before, chemist John Dalton tried to create a table as well as some rather interesting symbols for the elements (they didn’t catch on). And just a few years before Mendeleev sat down with his deck of homemade cards, John Newlands also created a table sorting the elements by their properties.

Mendeleev’s genius was in what he left out of his table. He recognised that certain elements were missing, yet to be discovered. So where Dalton, Newlands and others had laid out what was known, Mendeleev left space for the unknown. Even more amazingly, he accurately predicted the properties of the missing elements.

You can find the website for the International Year of the Periodic Table here and it’s still possible to attend the Opening Ceremony in Paris (from the Announcement for the Opening Ceremony Registration page),

November 14, 2018 | Today the registration opened for the launch of the 2019 International Year of the Periodic Table of Chemical Elements (IYPT2019). This Opening Ceremomy will take place on Tuesday the 29th of January 2019 from 10 a.m. till 7 p.m. in Paris, France at the UNESCO House. It promises to be an exciting day with inspiring speakers and exhibitions.

Some of the speakers will be Professor Ben Feringa (Nobel Laureate in Chemistry 2016), Professor Youri Oganessian (Author of the Element 118 – Oganesson) and sir Martyn Poliakoff (Lead presenter of the Periodic Table of Videos).

More information about the programme and a link for registration can be found here.

International Year of the Periodic Table
The United Nations General Assembly during its 74th Plenary Meeting proclaimed 2019 as the International Year of the Periodic Table of Chemical Elements. The IYPT2019 was adopted by the UNESCO General Conference at its 39th Session (39 C/decision 60) to highlight the contributions of chemistry and other basic sciences to the implementation of the 2030 Agenda for Sustainable Development.

The IYPT2019 is an IUPAC initiative and administered by a Management Committee consisting of representatives of the initiating organizations, UNESCO and a number of other supporting international organizations.

The founding partners of IYPT2019 are the International Union of Pure and Applied Chemistry, the European Chemical Society (EuChemS), the International Science Council (ISC), the International Astronomical Union (IAU), the International Union of Pure and Applied Physics (IUPAP) and the International Union of History and Philosophy of Science and Technology (IUHPST).

I checked and registration still seems to be open. Plus, they have listings for the events taking place all over the world.

On other fronts, the American Chemical Society (ACS) has a dedicated page for the IYPT 2019, which includes, amonst other things, a section on the Latest News,

Latest News
How far does the periodic table go?
First IYPT Event took place in India on January 2
Join the IUPAC periodic table challenge quiz! Which element will you choose?
Nature Chemistry‘s January 2019 issue celebrates the periodic table

As for what Canadians might be doing, I have contacted the Chemical Institute of Canada [CIC], (an umbrella organization representing the Canadian Society for Chemistry [CSC]; the Canadian Society for Chemical Engineering [CSChE]; and the Canadian Society for Chemical Technology [CSCT]) and they’re busily preparing to highlight the 2019 IYPT according to one of Peter Mirtchev, one of the organizers (Conference Technical Programs Officer) for the 102nd Canadian Chemistry conference,

… at the 2019 Canadian Chemistry Conference and Exhibition (CCCE2019), we will organize an event called Chemistry Across the Periodic Table, whereby we will highlight a single element from every abstract submitted. We’re printing the highlighted elements on the
name badges of our attendees in the hope of facilitating conversation and networking throughout the conference.

Since things can change, I suggest that you keep an eye on the CCCE 2019 website to track the progress of their plans. I’m sure they hope to organize more 2019 IYPT celebratory moments at the conference, which will be held in Québec City, Québec from Monday, June 3, 2019 to Friday, June 7, 2019. You might also want to keep an eye on the
Chemical Institute of Canada (CIC} and its affiliated organizations for other 2019 IYPT events in Canada.

Gold at the nanoscale in medieval textiles

It takes a while (i.e., you have to read the abstract for the paper) to get to the nanoscale part of the story. In the meantime, here are the broad brushstrokes (as it were) from a group of researchers in Hungary, from an Oct. 11, 2017 American Chemical Society (ACS) news release (also on EurekAlert),

Gold has long been valued for its luxurious glitter and hue, and threads of the gleaming metal have graced clothing and tapestries for centuries. Determining how artisans accomplished these adornments in the distant past can help scientists restore, preserve and date artifacts, but solutions to these puzzles have been elusive. Now scientists, reporting in ACS’ journal Analytical Chemistry, have revealed that medieval artisans used a gilding technology that has endured for centuries.

Researchers can learn a lot about vanished cultures from objects left behind. But one detail that has escaped understanding has been the manufacturing method of gold-coated silver threads found in textiles from the Middle Ages. Four decades of intensive research yielded some clues, but the findings have been very limited. Study of the materials has been hindered by their extremely small size: A single metal thread is sometimes only as thick as a human hair, and the thickness of its gold coating is a hundredth of that. Tamás G. Weiszburg, Katalin Gherdán and colleagues set out to fill this gap.

Using a suite of lab techniques, the researchers examined medieval gilded silver threads, and silver and gold strips produced during and after the Middle Ages. The items come from European cultures spanning the 13th to 17th centuries. The researchers characterized the chemistry of the silver thread, its gold coating, the interactions between the two and the shape of metal strips’ edges. To characterize the threads and strips, the researchers combined high-resolution scanning electron microscopy, electron back-scattered diffraction with energy-dispersive electron probe microanalysis and other analytical methods. Though previous studies indicated that these tiny objects were manufactured by a mercury-based method in fashion at that time, the new results suggest that the threads were gilded exclusively by using an ancient method that survived for a millennium. The goldsmiths simply heated and hammered the silver sheets and the gold foil together, and then cut them into strips. It was also possible to determine whether scissor- or knife-like tools were used for cutting. The results also show that this process was used widely in the region well into the 17th century.

The authors acknowledge funding from the European Social Fund.

Here’s an image of medieval bling,

Caption: A new study unravels how medieval artisans embellished textiles with gold. Credit: The American Chemical Society

Finally, here’s the abstract with the information about the nanoscale elements (link to paper follows abstract),

Although gilt silver threads were widely used for decorating historical textiles, their manufacturing techniques have been elusive for centuries. Contemporary written sources give only limited, sometimes ambiguous information, and detailed cross-sectional study of the microscale soft noble metal objects has been hindered by sample preparation. In this work, to give a thorough characterization of historical gilt silver threads, nano- and microscale textural, chemical, and structural data on cross sections, prepared by focused ion beam milling, were collected, using various electron-optical methods (high-resolution scanning electron microscopy (SEM), wavelength-dispersive electron probe microanalysis (EPMA), electron backscattered diffraction (EBSD) combined with energy-dispersive electron probe microanalysis (EDX), transmission electron microscopy (TEM) combined with EDX, and micro-Raman spectroscopy. The thickness of the gold coating varied between 70–400 nm [emphasis mine]. Data reveal nano- and microscale metallurgy-related, gilding-related and corrosion-related inhomogeneities in the silver base. These inhomogeneities account for the limitations of surface analysis when tracking gilding methods of historical metal threads, and explain why chemical information has to be connected to 3D texture on submicrometre scale. The geometry and chemical composition (lack of mercury, copper) of the gold/silver interface prove that the ancient gilding technology was diffusion bonding. The observed differences in the copper content of the silver base of the different thread types suggest intentional technological choice. Among the examined textiles of different ages (13th–17th centuries) and provenances narrow technological variation has been found.

Here’s a link to the paper,

Medieval Gilding Technology of Historical Metal Threads Revealed by Electron Optical and Micro-Raman Spectroscopic Study of Focused Ion Beam-Milled Cross Sections by Tamás G. Weiszburg, Katalin Gherdán, Kitti Ratter, Norbert Zajzon, Zsolt Bendő, György Radnóczi, Ágnes Takács, Tamás Váczi, Gábor Varga and György Szakmány. Anal. Chem., Article ASAP DOI: 10.1021/acs.analchem.7b01917 Publication Date (Web): September 19, 2017

Copyright © 2017 American Chemical Society

This paper is behind a paywall.

One final comment, if you read the abstract, you’ll see how many technologies the researchers needed to use to examine the textiles. How did medieval artisans create nanoscale and microscale gilding when they couldn’t see it? I realize there are now some optical microscopes that can provide a view of the nanoscale but presumably those artisans of the Middle Ages did not have access to that kind of equipment. So, how did they create those textiles with the technology of the day?

The science in Star Wars according to the American Chemical Society

The American Chemical Society (ACS) has produced a video in its Reactions series, which focuses on Stars Wars science from the middle part of the series (episodes 4, 5, & 6) or what some might consider the classic, ‘first’ episodes. From a Dec. 15, 2015 news ACS news release on EurekAlert,

Star Wars VII: The Force Awakens hits movie screens this week with its intense plot, edge-of-your-seat action scenes and, of course, lots of lightsabers. But is it actually possible to create a real-life lightsaber or build a functioning Death Star laser? To answer these questions and more, Reactions explores the science behind the Star Wars franchise.

Here’s the video,

You’ll notice the ‘parsec’ situation is not explained. In Star Wars they reference the term parsec as a unit of time (in the first episode produced which is now no. 4, Star Wars: A New Hope). But, a ‘parsec’ is a unit of distance. Here’s Kyle Hill writing about the ‘parsec’ situation in a Feb. 12, 2013 article for Wired (Note: A link has been removed),

You’ll hear any reputable Star Wars fan point it out eventually: Han Solo’s famous boast that the Millennium Falcon “made the Kessel Run in less than 12 parsecs” may have sounded impressive, but from an astronomical perspective, it made no sense. A parsec is a unit of distance, not time, so why would Solo use it to explain how quickly his ship could travel?

There are two stories going on here. The first is that Solo’s famous line of dialog was simply a mistake of terminology. The second — the one I choose believe [sic] — is far more interesting, because it means that when Obi-Wan sat down across from the wryly smiling Han Solo in that cramped cantina, he met a time-traveling smuggler born at least 40 years before the events of The Phantom Menace [episode 1, which was produced after the classic episodes, effectively the ‘first’ episode is a prequel] ever took place.

I understand the new movie, episode 7 is quite good but haven’t had a chance to see it yet. If you get there before I do, please let me know if it’s as good as the reviews suggest and what you think of the science.

Anatase and rutile titanium dioxide and nanosunscreens

The American Chemical Society (ACS) features some research into nanoscreens and the anatase form of titanium dioxide in a Sept. 25, 2013 news release,,

Using a particular type of titanium dioxide — a common ingredient in cosmetics, food products, toothpaste and sunscreen — could reduce the potential health risks associated with the widely used compound. The report on the substance, produced by the millions of tons every year for the global market, appears in the ACS journal Chemical Research in Toxicology.
Francesco Turci and colleagues explain that titanium dioxide (TiO2) is generally considered a safe ingredient in commercially available skin products because it doesn’t penetrate healthy skin. But there’s a catch. Research has shown that TiO2 can cause potentially toxic effects when exposed to ultraviolet light, which is in the sun’s rays and is the same kind of light that the compound is supposed to offer protection against. To design a safer TiO2 for human use, the researchers set out to test different forms of the compound, each with its own architecture.

They tested titanium dioxide powders on pig skin (which often substitutes for human skin in these kinds of tests) with indoor lighting, which has very little ultraviolet light in it. They discovered that one of the two most commonly used crystalline forms of TiO2, called rutile, easily washes off and has little effect on skin. Anatase, the other commonly used form, however, was difficult to wash off and damaged the outermost layer of skin — even in low ultraviolet light. It appears to do so via “free radicals,” which are associated with skin aging. “The present findings strongly encourage the use of the less reactive, negatively charged rutile to produce safer TiO2-based cosmetic and pharmaceutical products,” the researchers conclude.

It should be noted that the researchers used pig skin, i.e., the skin was not on a pig and, therefore, not part of a living organism with its various biological systems coming into play. As well, the testing was done indoors not under direct sunlight which is the condition under which most of us use sunscreen. This research points to problems  with using anatase nanoscale titanium dioxide in sunscreens but it doesn’t provide unequivocal proof.

The Danish Environmental Protection Agency report (this Oct. 3, 2013 posting of mine) on the state of the art of research into nanomateial dermal absorption does refer to research in this area, although it does not include Turci’s work (Note: The numbers n the excerpted text are reference numbers for the bibliography)),

When looking at bulk composition and the level of dermal penetration noted in studies using a specific material type, there appears to be very little pattern between bulk composition and penetration depth. Taking for example TiO2 as one of the most widely studied nanoparticles, we see reports of penetration no further than the SC [subcutaneous skin layer] 78, 86, 91 but also several studies suggesting deeper penetration (basal cell layer) and even penetration into the dermis 63, 84 although this is often reported as being a very small fraction/infrequent. Another compositional issue in relation to nanoparticles and in particular TiO2 is the crystalline structure. TiO2 is often used in either its anatase or rutile form or as mixture of both. Within the literature, there are studies using both the anatase form 86, 94, the rutile form 91, 114 or a mixture 84, 114 although we were unable to find any studies which appear to systematically evaluate the role of crystal form in TiO2 absorption into the skin. [emphasis mine] (p. 44 of this report: Dermal Absorption of Nanomaterials Part of the ”Better control of nano” initiative 2012 – 2015 Environmental Project No. 1504, 2013).

For those who would like to read Turci’s research for themselves,

Crystalline Phase Modulates the Potency of Nanometric TiO2 to Adhere to and Perturb the Stratum Corneum of Porcine Skin under Indoor Light by Francesco Turci, Elena Peira, Ingrid Corazzari, Ivana Fenoglio, Michele Trotta, and Bice Fubini. Chem. Res. Toxicol., Article ASAP DOI: 10.1021/tx400285j Publication Date (Web): September 12, 2013
Copyright © 2013 American Chemical Society

This research is behind a paywall.