Organic electronics are on the rise as a complement and, in some cases, a replacement to traditional silicon-based electronics. Thanks to simple manufacturing, high flexibility, and low weight combined with the electrical properties typically associated with traditional semiconductors, it can be useful for applications such as digital displays, energy storage, solar cells, sensors, and soft implants.

Organic electronics are built from semiconducting plastics, known as conjugated polymers. However, processing conjugated polymers often requires environmentally hazardous, toxic, and flammable solvents. This is a major obstacle to the wide commercial and sustainable use of organic electronics.

Now, researchers at Linköping University have developed a new sustainable method for processing these polymers from water. In addition to being more sustainable, the new inks are also highly conductive.

“Our research introduces a new approach to processing conjugated polymers using benign solvents such as water. With this method, called ground-state electron transfer, we not only get around the problem of using hazardous chemicals, but we can also demonstrate improvements in material properties and device performance,” says Simone Fabiano, senior associate professor at the Laboratory of Organic Electronics.

When researchers tested the new conductive ink as a transport layer in organic solar cells, they found that both stability and efficiency were higher than with traditional materials. They also tested the ink to create electrochemical transistors and artificial neurons, demonstrating operating frequencies similar to biological neurons.

“I believe that these results can have a transformative impact on the field of organic electronics. By enabling the processing of organic semiconductors from green and sustainable solvents like water, we can mass-produce electronic devices with minimal impact on the environment,” says Simone Fabiano, a Wallenberg Academy Fellow.

“The good news is that most episodes of back pain recover, and this is the case even if you have already had back pain for a couple of months,” University of South Australia Professor Lorimer Moseley says.

“The bad news is that once you have had back pain for more than a few months, the chance of recovery is much lower. This reminds us that although nearly everyone experiences back pain, some people do better than others, but we don’t completely understand why.”

The systematic review and meta-analysis, conducted by an international team of researchers, included 95 studies with the goal of understanding the clinical course of acute (< 6 weeks), subacute (6 to less than 12 weeks) and persistent (12 to less than 52 weeks) low back pain.

For people with new back pain, pain and mobility problems lessened significantly in the first 6 weeks, but then recovery slowed.

This study filled a gap in a 2012 paper from the same research team, with new findings showing that many people with persistent low back pain (more than 12 weeks) continue to have moderate-to-high levels of pain and disability.

“These findings make it clear that back pain can persist even when the initial injury has healed,” Prof Moseley says.

“In these situations, back pain is associated with pain system hypersensitivity, not ongoing back injury. This means that if you have chronic back pain — back pain on most days for more than a few months — then it’s time to take a new approach to getting better.”

He notes that there are new treatments based on training both the brain and body that “focus on first understanding that chronic back pain is not a simple problem, which is why it does not have a simple solution, and then on slowly reducing pain system sensitivity while increasing your function and participation in meaningful activities.”

The authors state that identifying slowed recovery in people with subacute low back pain is important so that care can be escalated and the likelihood of persistent pain reduced.

Further research into treatments is needed to help address this common and debilitating condition, and to better understand it in people younger than 18 and older than 60 years.

There are four main chemical approaches that are commonly used to create sulfoximines, sulfonimidoyl fluorides and sulfonimidamides. Recently an additional approach called sulfur fluorine exchange (SuFEx) chemistry has gained attention. But the approach has several limitations to its widespread use, such as the requirement for the use of high pressures.

The Moffitt research team wanted to develop a more efficient process to create sulfoximines, sulfonimidoyl fluorides and sulfonimidamides. Through a variety of chemical experiments and processes, they developed a reagent called t-BuSF that serves as a hub in the SuFEx chemical process to synthesize these sulfur-containing compounds. The use of t-BuSF decreased the number of steps required to make these compounds and improved the reaction times and stability of their chemical precursors. The researchers further demonstrated the potential utility of t-BuSF in medicinal chemistry in over 70 examples and by preparing five therapeutical targets and intermediates. They showed that t-BuSF was able to create these products in high yields with fewer synthesis steps.

“Given the cost-effectiveness and the chemical space accessible from this reagent platform, it is expected to have positive impacts on the discovery sciences from the development of new medicines and agrochemicals to the discovery of new ligands, organocatalysts and materials,” said Justin Lopchuk, Ph.D., associate member of the Department of Drug Discovery at Moffitt.

This study was supported by the National Institutes of Health (R35-GM142577, P30-CA076292) and the University of South Florida’s Chemical Purification, Analysis, and Screening Core Facility.