Tag Archives: magnets

Cotton that glows ‘naturally’

Interesting, non? This is causing a bit of excitement but before first, here’s more from the Sept. 14, 2017 American Association for the Advancement of Science (AAAS) news release on EurekAlert,

Cotton that’s grown with molecules that endow appealing properties – like fluorescence or magnetism – may one day eliminate the need for applying chemical treatments to fabrics to achieve such qualities, a new study suggests. Applying synthetic polymers to fabrics can result in a range of appealing properties, but anything added to a fabric can get washed or worn away. Furthermore, while many fibers used in fabrics are synthetic (e.g., polyester), some consumers prefer natural fibers to avoid issues related to sensation, skin irritation, smoothness, and weight. Here, Filipe Natalio and colleagues created cotton fibers that incorporate composites with fluorescent and magnetic properties. They synthesized glucose derivatives that deliver the desirable molecules into the growing ovules of the cotton plant, Gossypium hirsutum. Thus, the molecules are embedded into the cotton fibers themselves, rather than added in the form of a chemical treatment. The resulting fibers exhibited fluorescent or magnetic properties, respectively, although they were weaker than raw fibers lacking the embedded composites, the authors report. They propose that similar techniques could be expanded to other biological systems such as bacteria, bamboo, silk, and flax – essentially opening a new era of “material farming.”

Robert Service’s Sept. 14, 2017 article for Science explores the potential of growing cotton with new properties (Note: A link has been removed),

You may have heard about smartphones and smart homes. But scientists are also designing smart clothes, textiles that can harvest energy, light up, detect pollution, and even communicate with the internet. The problem? Even when they work, these often chemically treated fabrics wear out rapidly over time. Now, researchers have figured out a way to “grow” some of these functions directly into cotton fibers. If the work holds, it could lead to stronger, lighter, and brighter textiles that don’t wear out.

Yet, as the new paper went to press today in Science, editors at the journal were made aware of mistakes in a figure in the supplemental material that prompted them to issue an Editorial Expression of Concern, at least until they receive clarification from the authors. Filipe Natalio, lead author and chemist at the Weizmann Institute of Science in Rehovot, Israel, says the mistakes were errors in the names of pigments used in control experiments, which he is working with the editors to fix.

That hasn’t dampened enthusiasm for the work. “I like this paper a lot,” says Michael Strano, a chemical engineer at the Massachusetts Institute of Technology in Cambridge. The study, he says, lays out a new way to add new functions into plants without changing their genes through genetic engineering. Those approaches face steep regulatory hurdles for widespread use. “Assuming the methods claimed are correct, that’s a big advantage,” Strano says.

Sam Lemonick’s Sept. 14, 2017 article for forbes.com describes how the researchers introduced new properties (in this case, glowing colours) into the cotton plants,

His [Filipe Natalio] team of researchers in Israel, Germany, and Austria used sugar molecules to sneak new properties into cotton. Like a Trojan horse, Natalio says. They tested the method by tagging glucose with a fluorescent dye molecule that glows green when hit with the right kind of light.

They bathed cotton ovules—the part of the plant that makes the fibers—in the glucose. And just like flowers suck up dyed water in grade school experiments, the ovules absorbed the sugar solution and piped the tagged glucose molecules to their cells. As the fibers grew, they took on a yellowish tinge—and glowed bright green under ultraviolet light.

Glowing cotton wasn’t enough for Natalio. It took his group about six months to be sure they were actually delivering the fluorescent protein into the cotton cells and not just coating the fibers in it. Once they were certain, they decided to push the envelope with something very unnatural: magnets.

This time, Natalio’s team modified glucose with the rare earth metal dysprosium, making a molecule that acts like a magnet. And just like they did with the dye, the researchers fed it to cotton ovules and ended up with fibers with magnetic properties.

Both Service and Lemonwick note that the editor of the journal Science (where the research paper was published) Jeremy Berg has written an expression of editorial concern as of Sept. 14, 2017,

In the 15 September [2017] issue, Science published the Report “Biological fabrication of cellulose fibers with tailored properties” by F. Natalio et al. (1). After the issue went to press, we became aware of errors in the labeling and/or identification of the pigments used for the control experiments detailed in figs. S1 and S2 of the supplementary materials. Science is publishing this Editorial Expression of Concern to alert our readers to this information as we await full explanation and clarification from the authors.

The problem seems to be one of terminology (from the Lemonwick article),

… Filipe Natalio, lead author and chemist at the Weizmann Institute of Science in Rehovot, Israel, says the mistakes were errors in the names of pigments used in control experiments, which he is working with the editors to fix.

These things happen. Terminology and spelling aren’t always the same from one country to the next and it can result in confusion. I’m glad to see the discussion is being held openly.

Here’s a link to and a citation for the paper,

Biological fabrication of cellulose fibers with tailored properties by Filipe Natalio, Regina Fuchs, Sidney R. Cohen, Gregory Leitus, Gerhard Fritz-Popovski, Oskar Paris, Michael Kappl, Hans-Jürgen Butt. Science 15 Sep 2017: Vol. 357, Issue 6356, pp. 1118-1122 DOI: 10.1126/science.aan5830

This paper is behind a paywall.

Magnetically cleaning up oil spills

Researchers at the Massachusetts Institute of Technology (MIT) have developed a promising technique for cleaning up oil spills, using magnets, which is more efficient and more environmentally friendly.

ETA Sept. 14, 2012: For some reason the embedded video keeps disappearing, so here’s the link: http://youtu.be/ZaP7XOjsCHQ

The Sept. 12, 2012 news item on Nanowerk notes,

The researchers will present their work at the International Conference on Magnetic Fluids in January. Shahriar Khushrushahi, a postdoc in MIT’s Department of Electrical Engineering and Computer Science, is lead author on the paper, joined by Markus Zahn, the Thomas and Gerd Perkins Professor of Electrical Engineering, and T. Alan Hatton, the Ralph Landau Professor of Chemical Engineering. The team has also filed two patents on its work.

In the MIT researchers’ scheme, water-repellent ferrous nanoparticles would be mixed with the oil, which could then be separated from the water using magnets. The researchers envision that the process would take place aboard an oil-recovery vessel, to prevent the nanoparticles from contaminating the environment. Afterward, the nanoparticles could be magnetically removed from the oil and reused.

Larry Hardesty’s Sept. 12, 2012 MIT news release , which originated the news item, provides detail about the standard technique for  using magnetic nanoparticles and the new technique,

According to Zahn, there’s a good deal of previous research on separating water and so-called ferrofluids — fluids with magnetic nanoparticles suspended in them. Typically, these involve pumping a water-and-ferrofluid mixture through a channel, while magnets outside the channel direct the flow of the ferrofluid, perhaps diverting it down a side channel or pulling it through a perforated wall.

This approach can work if the concentration of the ferrofluid is known in advance and remains constant. But in water contaminated by an oil spill, the concentration can vary widely. Suppose that the separation system consists of a branching channel with magnets along one side. If the oil concentration were zero, the water would naturally flow down both branches. By the same token, if the oil concentration is low, a lot of the water will end up flowing down the branch intended for the oil; if the oil concentration is high, a lot of the oil will end up flowing down the branch intended for the water.

The MIT researchers vary the conventional approach in two major ways: They orient their magnets perpendicularly to the flow of the stream, not parallel to it; and they immerse the magnets in the stream, rather than positioning them outside of it.

The magnets are permanent magnets, and they’re cylindrical. Because a magnet’s magnetic field is strongest at its edges, the tips of each cylinder attract the oil much more powerfully than its sides do. In experiments the MIT researchers conducted in the lab, the bottoms of the magnets were embedded in the base of a reservoir that contained a mixture of water and magnetic oil; consequently, oil couldn’t collect around them. The tops of the magnets were above water level, and the oil shot up the sides of the magnets, forming beaded spheres around the magnets’ ends.

The design is simple, but it provides excellent separation between oil and water. Moreover, Khushrushahi says, simplicity is an advantage in a system that needs to be manufactured on a large scale and deployed at sea for days or weeks, where electrical power is scarce and maintenance facilities limited

. …

In their experiments, the MIT researchers used a special configuration of magnets, called a Halbach array, to extract the oil from the tops of the cylindrical magnets. When attached to the cylinders, the Halbach array looks kind of like a model-train boxcar mounted on pilings. The magnets in a Halbach array are arranged so that on one side of the array, the magnetic field is close to zero, but on the other side, it’s roughly doubled. In the researchers’ experiments, the oil in the reservoir wasn’t attracted to the bottom of the array, but the top of the array pulled the oil off of the cylindrical magnets.

While this work is promising, there are still a lot of issues to be addressed including how water will be removed from the recovered oil (oil and water can mix to some degree depending on their relative densities).

Buckyball legal suit: all about toys, rare earths, and magnets

The July 27, 2012 news item by Gary Thomas on Azonano highlights a legal suit involving Maxfield & Obertontoys that happen to be called Buckyballs and Buckycubes. From the news item,

The United States Consumer Product Safety Commission (CPSC) has filed a complaint against New York based Maxfield & Oberton Holdings LLC over their Buckyballs and Buckycube desk toys subsequent to a 3-1 Commission vote approving the filing of complaint.

The complaint seeks an order on the firm to prohibit sale of Buckyballs and Buckycubes, to inform the public about the defect and also refund the consumers in full for purchases made. …

Despite cooperative efforts by CPSC and Maxfield & Oberton to educate buyers that the products are meant for adults, reports of swallowing incidents and injuries kept coming in.

Before I go further, here’s what the toy looks like,

downloaded from Maxfield & Oberton’s http://www.getbuckyballs.com/ home page

The problem is that the small spherical magnets contain rare earths and are being swallowed by children and teenagers resulting in serious injury. I found more details about the situation in the July 25, 2012 news release issued by the CPSC (Note: I have removed some links) ,

In May 2010, CPSC and Maxfield & Oberton announced a cooperative recall of about 175,000 Buckyball high powered magnets sets, because they were labeled “Ages 13+” and did not meet the federal mandatory toy standard, F963-08. The standard requires that such powerful loose as received magnets not be sold for children younger than 14.

The Buckyballs and Buckycubes sets contain up to 216 powerful rare earth magnets.

In November 2011, CPSC and Maxfield & Oberton worked cooperatively to inform and educate consumers that Buckyballs were intended for adult use only, and although the risk scenarios differ by age group, the danger when multiple rare earth magnets are ingested is the same. However, even after the safety alert, ingestions and injuries continued to occur.

Here’s more about the number of injuries associated with the Maxfield & Oberton toys and more about how children and why teenagers accidentally swallow the magnets (from the CPSC news release),

Since 2009, CPSC staff has learned of more than two dozen ingestion incidents, with at least one dozen involving Buckyballs. Surgery was required in many of incidents. The Commission staff alleges in its complaint that it has concluded that despite the attempts to warn purchasers, warnings and education are ineffective and cannot prevent injuries and incidents with these rare earth magnets.

CPSC has received reports of toddlers finding loose magnets left within reach and placing them in their mouths. It can be extremely difficult for a parent to tell if any of the tiny magnets are missing from a set. In some of the reported incidents, toddlers have accessed loose magnets left on a refrigerator and other parts of the home.

Use of the product by tweens and teenagers to mimic piercings of the tongue, lip or cheek has resulted in incidents where the product is unintentionally inhaled and swallowed. These ingestion incidents occur when children receive it as a gift or gain access to the product in their homes or from friends.

When two or more magnets are swallowed, they can attract to one another through the stomach and intestinal walls, resulting in serious injuries, such as holes in the stomach and intestines, intestinal blockage, blood poisoning and possibly death. Medical professionals may not diagnose the need for immediate medical intervention in such cases, resulting in worsening of the injuries.

Here’s how the CPSC explains the reason for filing suit (from the CPSC news release),

The Commission staff filed the administrative complaint against Maxfield & Oberton after discussions with the company and its representatives failed to result in a voluntary recall plan that CPSC staff considered to be adequate. This type of legal action against a company is rare, as this is only the second administrative complaint filed by CPSC in the past 11 years.

Michelle Castillo’s July 26, 2012 news item for CBS News provides more background,

Currently marketed to adults, the CPSC reported that more than 2 million Buckyballs have been sold in the U.S., as well as 200,000 Buckycubes. Each container has anywhere from between 10 to 216 small magnets.

CPSC spokesperson Alex Filip told CBSNews.com that there were 22 cases of swallowing these magnets from 2009 to October 2011. One of the most high-profile cases was that of a 3-year-old from Portland, Ore., who swallowed 37 magnets. The girl needed surgery after the balls ripped three holes through her intestines.

The American Academy of Pediatrics (AAP)said in a statement that they agreed with the CSPS complaint, adding that the minute size of the magnets made it hard for caregivers to see if one is missing. A survey of North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition members found that there have been more than 60 magnet ingestion cases over the last two years, which necessitated 26 surgeries and involved 23 bowel perforations. It wasn’t stated how many of these cases were related to Buckyball or Buckycube magnets. [emphasis mine]

According to the CPSC information, there were a dozen or more  incidents associated with the Buckyball/Buckycube magnets. I’m unclear as to how many incidents that is per year since 2009 – 2011 could be considered either two years (e.g. July 2009 – July 2011) or three years (Jan. – Dec. of 2009, 2010, and 2011). Regardless,  either four or six incidents per year in the US have been attributed to these Maxfield & Oberton toys (or, seven to eleven incidents based on the total number [22] of accidents involving the ingestion of these kinds of magnets).

Maxfield & Oberton’s response covers a number of points,

“We are deeply disappointed that the CPSC has decided to go after our firm – and magnets in general. Magnets have been around for centuries and are used for all sorts of purposes. Our products are marketed to those 14 and above and out of over half a billion magnets in the market place CPSC has received reports of less than two-dozen cases of misuse. We worked with the Commission in order to do an education video less than 9 months ago, so we are shocked they are taking this action. We find it unfair, unjust and un-American,” added Zucker [Craig Zucker, founder and Chief Executive Officer]. “We will vigorously fight this action taken by President Obama’s hand picked agency.”

Maxfield believes the CPSC is now taking the absurd position that warnings can never work. By doing so, CPSC has called into question the efficacy of all of the warnings the agency relies upon including its recently announced program to warn about the risk of strangulation posed by cords on baby monitors, cords that have been involved in 7 deaths.

What will CPSC do about drowning for which its remedy is warnings?

For balloons involved in several deaths each year, the Commission warns about the risk of suffocation from uninflated or broken balloons and says “Adult supervision required.” But for some reason when it comes to an American company that sells Buckyballs® exclusively to adults, the CPSC takes a different approach and decides that warnings don’t work. The Company believes the CPSC can’t have it both ways.

While this isn’t a nanotechnology story as such, despite what the toys are named, it  does illustrate issues around risk s, hazards, and regulations. What are the benefits? What risks are we prepared to tolerate? What are the hazards and how do we mitigate against them? How much regulation do we need? What are the impacts economically and socially?