Highly interesting work and research are currently underway in defining and standardizing various nanostructures. To enable effective research, reliable and standardized measuring instruments and methods are required. At the RISE Magnetic Sensor Systems Lab, we have successfully developed and standardized measurement instruments and methodology for dynamic magnetic measurement and analysis, which are part of standardized measurement systems for MNPs.

Christer Johansson, senior expert at the Sensor Systems unit at RISE, explains that in dynamic magnetic measurements, an alternating (AC) magnetic field with a specific frequency and amplitude is used on the sample. The resulting dynamic magnetic response, also called AC-susceptometry (ACS), is measured contactless through coils and sensitive magnetic measurement technology.

“The DynoMag system, developed and manufactured at the RISE Magnetic Sensor Systems Lab in Gothenburg, has been central in over 160 scientific articles, particularly in the magnetic analysis of MNP systems. The goal has always been to create a sensitive and user-friendly measurement system with integrated electronics and software, along with associated magnetic models for accurate analysis of measurement data”, says Christer.

The development of DynoMag and other similar ACS systems has been conducted in both internal projects and several EU projects, as well as nationally funded projects. Through the EU projects NanoMag and MagNaStand, the DynoMag system and the measurement methodology have been further developed, resulting in an approved ISO standard for ACS measurement methodology for MNPs. 

“By sweeping the frequency and measuring the sample response, the DynoMag system, with its magnetic models, can identify magnetic relaxations and determine the particle size distribution for MNP systems in colloidal solution”, Christer continues.

Another application is monitoring the stability of MNP systems over time under external influences, or as a quality assurance method in the manufacturing of MNP systems to maintain optimal properties or develop new applications. The ACS response in the frequency domain varies depending on the MNP configuration and the presence of particle aggregates.

Through ACS measurement technology and optimal MNP systems, rheological properties can be determined for different substances, from simple Newtonian fluids, like water and glycerol solutions, to complex non-Newtonian substances like gelatin and Xanthan solutions used in the food industry. In a successful project funded by Formas, RISE, together with Chalmers University of Technology, utilized ACS measurement methodology and optimal MNP systems to measure viscoelastic properties in food research. 

The DynoMag ACS system also enables sensitive detection of biological markers by measuring and analyzing the response from functionalized MNP systems. A successful project in collaboration with Chalmers University of Technology, Karolinska Institute, Uppsala University, and Stockholm University, funded by SSF, resulted in an integrated measurement system for influenza. 

“In summary, the DynoMag system is a key component for the characterization of magnetic nanostructures, rheological studies, and biomedical research, with its applications spanning across various disciplines and fields”, Christer concludes.

Is Swedish demand for Norwegian salmon linked to the move from small-scale to large-scale fishing in the Baltic Sea, where the catch is used as feed?

"Salmon is the most consumed fish in Sweden, so it is very important for us to understand how we can eat it with a clear conscience. If there are problems, we need to understand them so that we can act together with the relevant stakeholders," says Krishan Kent, Chairman of the Swedish Fish Industry Association.  

Independent review of research 

The industry organisation represents more than 165 companies from sea to table, with a combined turnover of almost SEK 18 billion and 5,000 employees. The Swedish Fish Industry Association works for a sustainable "blue" food chain. This includes ensuring that there are functioning regulations, guidelines and trade policy instruments that make the supply of raw materials to Swedish companies qualitatively and quantitatively secure. Answering questions from the industry is also an important part of the work.  

"I believe that all industries would benefit from moving from discussions based on opinions to a common platform based on facts. When I look at our industry, I feel that the fact base on seafood is generally quite weak and the dialogue is fragmented with many stakeholders in different channels," says Krishan Kent.

"In this case, there had been discussions about whether Norwegian salmon farming was having a negative impact on the ecosystem in the Baltic Sea, and we wanted to understand more about it."

Taking ownership of the problem

RISE has twice compiled and analysed available data, industry data and public reports. This has resulted in reports that the Swedish Fish Industry Association now uses as a knowledge base. These include reports on the nutritional content, undesirable substances and climate footprint of farmed salmon, and on whether Swedish consumption of farmed salmon is driving Swedish industrial fishing in the Baltic Sea.

"We chose RISE because we believe they are the strongest independent actor linking industry and research," says Krishan Kent.

Friederike Ziegler, researcher and project manager for sustainable seafood at RISE:

"Seafood is quite complex, involving many different production systems and many actors with different perspectives. It can be difficult to navigate. The Swedish Fish Industry Association cannot be familiar with all the technical details. That is why they wanted an independent review of what the research says about the claims being made."

"I think it's impressive that a trade organisation like the Swedish Seafood Federation wants to find out what the situation is without preconditions and put the cards on the table."

Krishan Kent:

"We choose to be transparent in order to take responsibility for any problems, so that the issues come to us rather than floating around on social media. We want to show that we are following, seeing and taking the issue of farmed salmon seriously."

"The latest report shows that there is a very small link between the consumption of Norwegian salmon and the industrial fishing of herring in the Baltic Sea, but it is still the case that there are things we need to work on to ensure a sustainable Swedish market in the long term."

Want to be more proactive

In the debate about fishing and seafood, new issues are constantly emerging. The Swedish Fish Industry Association has therefore asked RISE to help it plan which questions the organisation should answer in the future. The idea is to move away from being reactive to things that flare up in the media, to thinking about what knowledge is needed to provide clear and robust information, thereby creating the factual platform that is currently lacking.

"At our Seafood Forums, where we meet with stakeholders, we highlight the big issues and the bubbles that have not yet burst. We want to develop this approach further. Our members and stakeholders should be confident that we as an industry association have a factual basis and credibility, not just opinions," says Krishan Kent.