All posts by Callum Tyndall

31 scientific societies remind US lawmakers that man-made climate change is real

Thirty one leading scientific societies have today written to United States policymakers reconfirming the reality of man-made climate change and urging them to take action

The letter is intended as a reaffirmation of the message conveyed in a 2009 letter, at the time signed by eighteen leading scientific organisations, in the hope of providing authoritative information to those who have the power to work towards solutions.

“Observations throughout the world make it clear that climate change is occurring, and rigorous scientific research concludes that the greenhouse gases emitted by human activities are the primary driver,” the collaboration said in its letter to Members of Congress. “This conclusion is based on multiple independent lines of evidence and the vast body of peer-reviewed science.”

The letter has been signed by the leaders of organisations including the American Association for the Advancement of Science, the American Meteorological Society, the American Institute of Biological Sciences and the American Statistical Association.

Image courtesy of Ocean Biology Processing Group at NASA's Goddard Space Flight Center. Above: image courtesy of ESA / NASA

Image courtesy of Ocean Biology Processing Group at NASA’s Goddard Space Flight Center. Above: image courtesy of ESA / NASA

The re-release of the letter, with its expanded consensus, is intended to drive home the dangers of greenhouse gas emissions from an objective perspective. With environmental issues often becoming politicised, the societies likely intend for their nonpartisan backgrounds to defuse accusations of political bias and enable them get straight to the science.

Citing the vast consensus of climate scientists and scientific organisations, including the US Global Change Research Program, the US National Academies and the Intergovernmental Panel on Climate Change, the organisations’ message focuses on the negative impact that greenhouse gas emissions could have on many aspects of life around the world.

“To reduce the risk of the most severe impacts of climate change, greenhouse gas emissions must be substantially reduced,” the group said, adding that adaptation is also necessary to “address unavoidable consequences for human health and safety, food security, water availability, and national security, among others.”

Image courtesy of NASA

Image courtesy of NASA

Already in the United States alone, the group reports that climate change has seen increased threats of extreme weather events, sea-level rise, water scarcity, heat waves, wildfires and disturbances to ecosystems and animals.

However, American politicians’ likely compliance with the suggestions of the intersociety group is uncertain, given their history with climate change.

We will have to wait to see whether the recent Paris Agreement will be ratified, but it would not be the first time the US has failed to ratify an ecological treaty; the Kyoto Protocol was notably never ratified under the Bush administration.

“Climate change is real and happening now, and the United States urgently needs to reduce greenhouse gas emissions,” said AAAS Chief Executive Officer Rush Holt, executive publisher of the Science family of journals.

“We must not delay, ignore the evidence, or be fearful of the challenge. America has provided global leadership to successfully confront many environmental problems, from acid rain to the ozone hole, and we can do it again. We owe no less to future generations.”

Bioink made from cow cells paves way for scaffold-free 3D printed replacement joints

A research team of engineers has developed a method to create artificial cartilage using 3D printing that may one day allow us to grow replacement patches for worn out joints.

“Our goal is to create tissue that can be used to replace large amounts of worn out tissue or design patches,” said Ibrahim T Ozbolat, associate professor of engineering science and mechanics. “Those who have osteoarthritis in their joints suffer a lot. We need a new alternative treatment for this.”

Cartilage represents a good target for bioprinting due to its simple structure, consisting of only one cell type and with no blood cells in the tissue. Additionally, its inability to repair itself means that the prospect of artificial patches represents an important medical opportunity.

Previous attempts to create cartilage did so by embedding cells in a hydrogel, a substance comprising of polymer chains and water that acts as a scaffold for the tissue’s growth. This method didn’t allow cells to grow as normal, however, meaning that the created tissues lacked sufficient mechanical integrity. Ozbolat’s team’s new method allows them to produce larger scale tissues without the need for a scaffold.

The multiarmed 3D bioprinter used to print the cartilage

The multiarmed 3D bioprinter used to print the cartilage

The method consists initially of creating a tiny tube from algae extract. Cartilage cells taken from cows are then injected into the tube and allowed to grow for about a week and adhere to each other. Because cells do not stick to alginate, the tube can be removed to leave a strand of printable cartilage.

This strand substitutes for ink in the 3D printing process. Using a specially designed prototype nozzle, the 3D printer lays down rows of cartilage strands in a pattern chosen by the researchers. After about half an hour, the cartilage patch self-adheres enough to move to a petri dish containing nutrient media. The nutrient media allows the patch to further integrate into a single piece of tissue.

“We can manufacture the strands in any length we want,” said Ozbolat. “Because there is no scaffolding, the process of printing the cartilage is scalable, so the patches can be made bigger as well. We can mimic real articular cartilage by printing strands vertically and then horizontally to mimic the natural architecture.”

A plug of 3D bioprinted cartilage sits in nutrient media. Images courtesy of Ozbolat, Penn State

A plug of 3D bioprinted cartilage sits in nutrient media. Images courtesy of Ozbolat, Penn State

The cartilage produced by the team is currently inferior to natural cartilage, but better than the cartilage made using hydrogel scaffolding. However, Ozbolat believes mechanical pressure on the artificial cartilage will improve its mechanical properties, mimicking the way in which natural cartilage forms with pressure from the joints.

Applying the process to human cartilage will likely involve each individual treated providing their own source material to avoid tissue rejection.

However, once successful, we will have proven the possibility of artificially repairing tissues, as opposed to our current limitation to replacement or support.

Other tissues are far more complex than cartilage but if we consider it a starting point, this developing method could potentially lead to the ability to create “patches” for a variety of tissues, enabling us to combat the degradation of cells that leads to a variety of medical problems.