A new paper by Iacob, Kuncser, and Ladislau Vekas et al. carefully investigated, both theoretically and experimentally, the behavior of different concentrations of superparamagnetic nanoparticles in an alternating AC magnetic field ranging from 14-35 kA/m. They found that magnetic interactions, that increase with increasing volume fraction, can result in a decrease in SAR, whereas some authors claim that interactions can cause an increase in SAR.
See for yourself and read the paper here.
The U.S. Food and Drug Administration (FDA) is strengthening an existing warning that serious, potentially fatal allergic reactions can occur with the anemia drug Feraheme (ferumoxytol). We have changed the prescribing instructions and approved a Boxed Warning, FDA’s strongest type of warning, regarding these serious risks. Also added is a new Contraindication, a strong recommendation against use of Feraheme in patients who have had an allergic reaction to any intravenous (IV) iron replacement product. Health care professionals should follow the new recommendations in the drug label.
Check out this pamphlet here to read about it.
The effects were very serious, as you can learn from the last paragraph of the FDA warning: Since the approval of Feraheme on June 30, 2009, cases of serious hypersensitivity reactions, including death, have occurred. A search of the FDA Adverse Event Reporting System database identified 79 cases of anaphylactic reactions associated with Feraheme administration, reported from the time of approval to June 30, 2014. Of the 79 cases, 18 were fatal, despite immediate medical intervention and emergency resuscitation attempts. The 79 patients ranged in age from 19 to 96 years. Nearly half of all cases reported that the anaphylactic reactions occurred with the first dose of Feraheme. Approximately 75 percent (60/79) of the cases reported that the reaction began during the infusion or within 5 minutes after administration completion. Frequently reported symptoms included cardiac arrest, hypotension, dyspnea, nausea, vomiting, and flushing. Of the 79 cases, 43 percent (34/79) of the patients had a medical history of drug allergy, and 24 percent had a history of multiple drug allergies.
For more information, check out this website: http://www.fda.gov/Drugs/DrugSafety/ucm440138.htm
All of you probably know Bernhard Gleich, Jürgen Weizenecker and team who invented the Magnetic Particle Imaging (MPI) technique. We now have a chance of helping them to win the European Inventor Award 2017 in the industry section. Please go to
and vote for them. Would be great if we can help them to win this prestigious award!
And by the way, the video that they made about MPI and the possibilities of this technique in the future is very impressive, well worth the 6 minutes it takes to watch it!
EPFL researchers together with the University Hospital in Geneva have developed a shoe sole with valves that electronically control the pressure applied to the arch of the foot, aiming at preventing foot ulcers commonly caused by diabetes. The sole has around 50 small electromagnetic valves filled with magnetorheological material. The viscosity of the material, which is made up of suspended iron microparticles, can be controlled by applying a magnetic field. The particles react immediately and align themselves with the field, causing the material to change from liquid to solid state in a fraction of a second. The system should not only help the wounds heal quickly but also prevent the onset of new ulcers. Every year, 250'000 diabetics have a leg amputated in Europe alone, mainly because of foot ulcers.
This fiery ring is actually a layer of iron oxide on a 500-nm-wide silicate particle. Researchers at the University of Texas, Dallas, created this image while using transmission electron microscopy to look at the distribution of iron oxide inside the nanoshell; brighter colors in the image represent higher concentrations. The nanoshells are being developed as a contrast agent for real-time Doppler imaging of tumors during surgery (Adv. Funct. Mater. 2015, DOI: 10.1002/adfm.201500610). This image won a 2015 scientific image contest put on by JEOL, an imaging and spectroscopic instrument maker.
Computers perform complex calculations using billions of tiny electronic switches called transistors, which are organized into circuits and memory. Replacing these transistors with magnetic switches could enable more energy-efficient computers. Magnets have shown their worth in energy-efficient memory technologies, but they haven’t been used for processing. Researchers have now demonstrated that this is possible, combining low-power magnetic switches to perform a simple information processing step (Nano Lett. 2016, DOI: 10.1021/acs.nanolett.5b04205).
On a computer chip, each transistor can be switched between an on and off state, encoding a 0 or a 1—known as a bit. Nanomagnets can be switched between two states, too. One way to do this is to apply an electric field to flip the magnetic field’s orientation, but that takes 1,000 times as much energy as switching an electronic transistor, says Jayasimha Atulasimha, a mechanical engineer at Virginia Commonwealth University.
But another approach to switching the nanomagnet’s field is to apply a mechanical stress. This has been used to demonstrate magnet-based computer memory. Putting the magnets under strain to do the switching requires just one-hundredth the energy of a conventional transistor.
Atulasimha’s group wanted to demonstrate that these low-power, strain-gated nanomagnets could be used for information processing, not just memory. So Atulasimha and colleagues made a device that uses multiple nanomagnets to carry out a simple information processing problem. They deposited cobalt disks about 200 nm across onto a 0.5-cm-thick layer of a piezoelectric material called PMN-PT. A small electric field causes the piezoelectric layer to expand or contract, depending on the design. This pulls on or compresses the nanomagnet, changing its shape slightly, and flips the orientation of the magnetic field. Turning off the field flips it back.
The group used a chain of three nanomagnets to make a basic logic device called a NOT gate, one of the essential elements for doing digital computation. It’s nowhere near the full complement of logic operations needed to make a computer, but an important first step. Their magnetic logic device uses about 450 attojoules per operation. The researchers calculate that future systems using smaller nanomagnets and a thinner piezoelectric layer would use only 1 attojoule per operation.
A technique that combines gene therapy and magnets could someday provide a new tool for treating cardiovascular disease, which puts millions of lives at risk every year. Prof. Daniela Wenzel et al. at the University of Bonn have produced cells that carry magnetic nanoparticles linked to a therapeutic gene. With an external magnet to direct the cells, the researchers used them to repair damaged arteries in mice (ACS Nano 2015, DOI: 10.1021/acsnano.5b04996).
The researchers packaged genes coding for a green fluorescent protein and a nitric oxide-synthesizing enzyme within a viral vector, commonly used to deliver genetic material into cells. They linked the vectors to magnetic, silica-iron oxide nanoparticles, and loaded the vector-nanoparticle combo into endothelial cells. The researchers then injected these engineered cells into the carotid arteries of mice where the endothelial cells within those vessels had been removed. In half of the animals, they placed a magnet over the treatment site for 30 minutes. Two days later, the arteries of animals exposed to magnets showed green fluorescing cells attached to their inner surfaces, covering at least half of the circumference. In the other animals, blood flow had swept the introduced cells out of the arteries and deposited them in the brain.
Isometric force measurements on removed carotid arteries showed that the magnetically treated arteries were able to contract and expand, while the untreated arteries could not, showing that the grafted cells were doing their job producing nitric oxide.
For more information, check out our Archives.