Tag: Technical University of Munich

Detecting the unseen particles

[ad_1]

Newswise — How high are concentrations of microplastics in the environment, in our drinking water or in foods? Researchers at the Technical University of Munich (TUM) have developed an automated analysis method for the identification and quantification of particles.

Microplastics are everywhere in the environment. The tiny particles, with diameters of less than 5 millimeters, can also absorb and transport contaminants and toxins. “We urgently need analytical techniques to learn about the size, concentration and composition of these particles,” says Dr. Natalia Ivleva at the Chair of Analytical Chemistry and Water Chemistry at TUM. Together with her team, the scientist has developed a new process.

To be able to detect microplastic particles, the researchers had several hurdles to overcome: The first was the problem of low concentrations. River water, for example, contains massive amounts of suspended solids and fine sand, with plastic accounting for less than 1 percent of the particles. These particles must first be isolated before their concentrations and ultimately their chemical composition are determined. Previous methods have relied on the analysis of the residues that are released when the samples are heated. With that approach, however, it is not possible to determine the number, size and shape of the plastic particles.

Plastics can be identified through light scattering

“Our approach is fundamentally different,” says Dr. Ivleva: “It is particle-based. That means that instead of destroying the particles, we analyze them directly.” To do this, the researchers use a method known as Raman microspectroscopy. It works by shining a monochromatic laser source onto a sample and detecting the light scattered by the molecules. Comparing the scattered light against the laser source provides information on the substance under investigation. To analyze plastic particles with a diameter greater than 1 µm (micrometer), they must first be filtered out of the aqueous solution, detected under the microscope and then illuminated with laser light. Because plastics such as polyethylene, polystyrene and polyvinyl chloride scatter the photons in characteristic ways, they each generate signals as unique as a fingerprint.

Automation instead of manual measurements

It took years to develop the tracing process: “When we started, we still had to make manual measurements,” recalls the chemist. “It took us months to investigate a few thousand particles.” In the meantime the team has succeeded in automating the detection of microplastics. A single analysis no longer takes weeks, but only a matter of hours. Although the tiny particles still have to be filtered out of the aqueous solution, followed by placement of the filter under the Raman microspectroscope, all remaining steps are carried out by the software developed by the team. The plastic particles are first localized with a light microscope, photographed and measured, and the particles are distinguished from fibers. The software uses these data to compute the number of particles and fibers and to select the image sections needed for a statistically significant result in the subsequent Raman spectroscopy.

In the next step, the laser is directed onto the sample and the scattering is detected and analyzed. This allows quick and reliable analysis of the number, size, shape and composition of the microplastics. The open-source TUM-Particle Typer 2 software is now available to researchers around the world.

Nanoplastics require special detection processes

To investigate nanoparticles with diameters of less than 1 µm, however, Dr. Ivleva’s team is already working on a modified process. “Nanoparticles like these are difficult or even impossible to discern under a light microscope. To detect them, we first have to carry out size fractionation and then identify them,” explains the researcher.

For this purpose, a field flow fractionation (FFF) system is used. This creates a water flow that captures the particles – depending on their size – and separates them by transporting them at varying speeds. A specially developed device, combined with Raman spectroscopy, permits the chemical characterization of different types of nanoplastics.

“The new analytical processes permit rapid and precise investigation of concentration, size and composition of micro- and nanoplastics,” sums up Dr. Ivleva. “This will now make it possible to study the influence of these particles on the environment and human health.”

[ad_2]

Technical University of Munich

Source link

July 26, 2023
Dialysis exercise improves health, study says

[ad_1]

Newswise — Patients who engage in light exercise while undergoing dialysis are physically fitter and are admitted to hospital less frequently than those who do not. These are the findings of a large-scale study conducted by a consortium led by the Technical University of Munich (TUM). The researchers believe that exercise programs should be offered to dialysis patients as standard.

Around 558,000 people in the United States have such severely impaired kidney function that they require dialysis several times per week. In Germany, about 80,000 people regularly undergo dialysis. Many also suffer from additional health issues such as diabetes and heart disease. “The limitations imposed by these diseases, and the time required for dialysis, often mean that those affected engage in little physical exercise. We wanted to change that,” says Martin Halle, Professor of Preventive and Rehabilitative Sports Medicine at TUM, who headed up the study.

Personalized exercise plans

Approximately 1,000 patients at 21 dialysis centers in Germany took part in the study, which has been published in the New England Journal of Medicine – Evidence. “We mounted one of the world’s largest studies on physical activity in the context of specific diseases,” says Martin Halle. Data from health insurance providers was consulted to ensure that the participant pool was representative of dialysis patients in Germany in terms of aspects such as age, gender and overall health.

Over a twelve-month period, half of the study participants completed accompanied exercise sessions at least once and ideally three times per week alongside their dialysis, while others were subject only to medical monitoring. These sessions included 30 minutes of endurance training with a bed-cycle ergometer and a further 30 minutes of exercises with weights, resistance bands and balls. The exercises were tailored to each patient’s ability.

Improvements in standardized testing

After a year, the health of the study’s active participants had improved significantly. This included completing more repetitions in a one-minute sit-to-stand test and walking further in six minutes than at the start of the study. In the control group, these values were even lower at the end of the study period than at the outset.

“This type of standardized testing may admittedly not appear to be particularly reflective of everyday life,” says Martin Halle. “However, the results demonstrate tangible improvements in quality of life and autonomy. For example, the participants were able to stand up from a chair at home without assistance, which was not always the case beforehand.” There are other signs of the training program’s positive effects: participants who completed regular training sessions spent an average of two days in hospital during the study, compared to an average of five days for the control group.

Low costs per training unit

“To my mind, the results speak for themselves,” says Martin Halle. “We were able to improve the participants’ health and also reduce the costs to the healthcare system with relatively little outlay.” The researchers’ figures suggest that the costs for personalized training would be around €25 per session per person.

The DiaTT (Dialysis Training Therapy) consortium submitted the final report to the Federal Joint Committee (Gemeinsamer Bundesausschuss – G-BA), which had financed the study through its Innovation Fund (Innovationsfonds). This committee will ultimately determine whether this training is offered to all dialysis patients with statutory health insurance. “I hope our exercise program will become standard in statutory health insurance in Germany,” says Martin Halle. “The benefits will likely also apply to patients in other countries. However, the best approach for a broad implementation has to be found for each society.”

The study participants will continue to be monitored in future to help researchers learn more about the effects of exercise over the long term. “Our study shows how important it is to adopt a holistic view of health, especially when it comes to elderly and infirm patients”, says Martin Halle. “While high-tech medicine is important, it can only achieve its full potential in combination with other fields, such as preventive medicine.”

Publication:

K. Anding-Rost, G. von Gersdorff, P. von Korn, G. Ihorst, A. Josef, M. Kaufmann, M. Huber, T. Bär, S. Zeißler, S. Höfling, C. Breuer, N. Gärtner, M.J. Haykowsky, S. Degenhardt, C. Wanner and M. Halle, for the DiaTT Study Group. “Exercise during Hemodialysis in Patients with Chronic Kidney Failure.” NEJM Evidence (2023). DOI: 10.1056/EVIDoa230005

[ad_2]

Technical University of Munich

Source link

July 14, 2023
Artificial photosynthesis could enable eco-friendly food production
[ad_1]
- Growing demand for food in the world
- Biotechnological process via methanol as intermediate product
- Less ground required than for plant cultivation
Newswise — Ensuring the supply of food to the constantly growing world population and protecting the environment at the same time are often conflicting objectives. Now researchers at the Technical University of Munich (TUM) have successfully developed a method for the synthetic manufacture of nutritional protein using a type of artificial photosynthesis. The animal feed industry is the primary driver of high demand for large volumes of nutritional protein, which is also suitable for use in meat substitute products.

A group led by Prof. Volker Sieber at the TUM Campus Straubing for Biotechnology and Sustainability (TUMCS) has succeeded in producing the amino acid L-alanine, an essential building block in proteins, from the environmentally harmful gas CO₂. Their indirect biotechnological process involves methanol as an intermediate. Until now, protein for animal feed has been typically produced in the southern hemisphere with large-scale agricultural space requirements and negative consequences for biodiversity.

The CO₂, which is removed from the atmosphere, is first turned into methanol using green electricity and hydrogen. The new method converts this intermediate into L-alanine in a multi-stage process using synthetic enzymes; the method is extremely effective and generates very high yields. L-alanine is one of the most important components of protein, which is essential to the nutrition of both humans and animals.

Prof. Sieber, of the TUM Professorship for Chemistry of Biogenic Resources, explains: “Compared to growing plants, this method requires far less space to create the same amount of L-alanine, when the energy used comes from solar or wind power sources. The more efficient use of space means a kind of artificial photosynthesis can be used to produce the same amount of foodstuffs on significantly fewer acres. This paves the way for a smaller ecological footprint in agriculture.”

Bioeconomy and hydrogen economy in combination

The manufacture of L-alanine is only the first step for the scientists. “We also want to produce other amino acids from CO₂ using renewable energy and to further increase efficiency in the realization process,” says co-author Vivian Willers, who developed the process as a doctoral candidate at the TUM Campus Straubing. The researchers add that the project is a good example of how bioeconomy and hydrogen economy in combination can make it possible to achieve more sustainability.

Publication:

The article “Cell-free enzymatic L-alanine synthesis from green methanol” recently appeared in the journal Chem Catalysis from Cell Press.
Vivian Pascal Willers, Manuel Döring, Barbara Beer, Volker Sieber. Cell-free enzymatic L-alanine synthesis from green methanol. Chem Catalysis, Volume 3, Issue 3, 2023, 100502.
https://doi.org/10.1016/j.checat.2022.100502
[ad_2]

Technical University of Munich

Source link
April 28, 2023
Autonomous driving: New algorithm distributes risk fairly

[ad_1]

Newswise — Technical realization is not the only obstacle to be mastered before autonomously driving vehicles can be allowed on the street on a large scale. Ethical questions play an important role in the development of the corresponding algorithms: Software has to be able to handle unforeseeable situations and make the necessary decisions in case of an impending accident. Researchers at TUM have now developed the first ethical algorithm to fairly distribute the levels of risk rather than operating on an either/or principle. Approximately 2,000 scenarios involving critical situations were tested, distributed across various types of streets and regions such as Europe, the USA and China. The research work published in the journal “Nature Machine Intelligence” is the joint result of a partnership between the TUM Chair of Automotive Technology and the Chair of Business Ethics at the TUM Institute for Ethics in Artificial Intelligence (IEAI).

Maximilian Geisslinger, a scientist at the TUM Chair of Automotive Technology, explains the approach: “Until now, autonomous vehicles were always faced with an either/or choice when encountering an ethical decision. But street traffic can’t necessarily be divided into clear-cut, black and white situations; much more, the countless gray shades in between have to be considered as well. Our algorithm weighs various risks and makes an ethical choice from among thousands of possible behaviors – and does so in a matter of only a fraction of a second.”

More options in critical situations

The basic ethical parameters on which the software’s risk evaluation is oriented were defined by an expert panel as a written recommendation on behalf of the EU Commission in 2020. The recommendation includes basic principles such as priority for the worst-off and the fair distribution of risk among all road users. In order to translate these rules into mathematical calculations, the research team classified vehicles and persons moving in street traffic based on the risk they present to others and on the respective willingness to take risks. A truck for example can cause serious damage to other traffic participants, while in many scenarios the truck itself will only experience minor damage. The opposite is the case for a bicycle. In the next step the algorithm was told not to exceed a maximum acceptable risk in the various respective street situations. In addition, the research team added variables to the calculation which account for responsibility on the part of the traffic participants, for example the responsibility to obey traffic regulations.

Previous approaches treated critical situations on the street with only a small number of possible maneuvers; in unclear cases the vehicle simply stopped. The risk assessment now integrated in the researchers’ code results in more possible degrees of freedom with less risk for all. An example will illustrate the approach: An autonomous vehicle wants to overtake a bicycle, while a truck is approaching in the oncoming lane. All the existing data on the surroundings and the individual participants are now utilized. Can the bicycle be overtaken without driving in the oncoming traffic lane and at the same time maintaining a safe distance to the bicycle? What is the risk posed to each respective vehicle, and what risk do these vehicles constitute to the autonomous vehicle itself? In unclear cases the autonomous vehicle with the new software always waits until the risk to all participants is acceptable. Aggressive maneuvers are avoided, while at the same time the autonomous vehicle doesn’t simply freeze up and abruptly jam on the brakes. Yes and No are irrelevant, replaced by an evaluation containing a large number of options.

“The sole consideration of traditional ethical theories resulted in a dead end”

“Until now, often traditional ethical theories were contemplated to derive morally permissible decisions made by autonomous vehicles. This ultimately led to a dead end, since in many traffic situations there was no other alternative than to violate one ethical principle,” says Franziska Poszler, scientist at the TUM Chair of Business Ethics. “In contrast, our framework puts the ethics of risk at the center. This allows us to take into account probabilities to make more differentiated assessments.”

The researchers emphasized the fact that even algorithms that are based on risk ethics – although they can make decisions based on the underlying ethical principles in every possible traffic situation – they still cannot guarantee accident-free street traffic. In the future it will additionally be necessary to consider further differentiations such as cultural differences in ethical decision-making.

Software now to be tested in street traffic

Until now the algorithm developed at TUM has been validated in simulations. In the future the software will be tested on the street using the research vehicle EDGAR. The code embodying the findings of the research activities is available as Open Source software. TUM is thus contributing to the development of viable and safe autonomous vehicles.

[ad_2]

Technical University of Munich

Source link

February 3, 2023