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what's the buzz...

Why insects aren’t as big as humans

When news of Ant-Man - a comic superhero who can shrink to the size of an ant – being cast in a movie emerged, scientists wondered why ants couldn’t balloon to man size.
Director Edgar Wright, known for movies such as ‘Shaun of the Dead,’ announced earlier this week he would be making a movie about Ant-Man, according to the news site Grantland.

If it’s anything like the comic, it will also feature ants as big as humans, which got researchers thinking: Could ants be as big as people? And why aren’t insects bigger than they are?

Researchers don’t know exactly, although there are several hypotheses as to why insects and other arthropods don’t get bigger, insect physiologist Jon Harrison, at Arizona StateUniversity in Tempe said.

The first hypothesis is that insects’ exoskeletons may not be strong enough to allow them to get much bigger — that they’d have to become impossibly thick.
Harrison learned this theory as an established fact during his training, but little experimental evidence to support the idea exists, he said.

The only study to look at this question found that larger arthropods don’t have thicker exoskeletons, he said. “So there’s no direct evidence for this,” he added. Because exoskeletons are rigid, insects need to molt as they grow, shedding the old skin and growing a new one.

Why brain tumours are so difficult to treat

Researchers including one of an Indian origin have found that the most common and aggressive brain tumour grows by turning normal brain cells into stem cells, which can continuously replicate and regrow a tumour with only a handful of cells left behind.

The findings help explain why the tumours, called glioblastomas, are so difficult to treat, said study researcher Inder Verma, a molecular biologist at The Salk Institute in California.

Even the surgical removal of a tumour may not be able to extract every single cancerous cell, Verma told LiveScience.

Glioblastomas “reoccur because every cell that is left behind has the ability to start all over again,” Verma said.  Glioblastoma multiforme tumours make up the majority of brain tumour cases and have a very poor prognosis. According to a 2010 study in CA: A Cancer Journal for Clinicians, the average survival rate after a glioblastoma diagnosis is 14 months (though improving surgical techniques had boosted that number from 10 months in only five years prior to the study).

Engineered organs may soon be reality

A new research has shed light on the mechanics of cell, tissue and organ formation.
It revealed basic mechanisms about how a group of bacterial cells can form large three-dimensional structures.

Systems biologists teamed up with mechanical engineers from the University of Texas atDallas to conduct the cell research that provides information that may one day be used to engineer organs.

“If you want to create an organism, the geometry of how a group of cells self-organizes is crucial. We found that cell death leads to wrinkles, and the stiffer the cell the fewer wrinkles,” said Dr. Hongbing Lu, professor of mechanical engineering and holder of the Louis Beecherl Jr. Chair at UT Dallas and an author of the study.

Organ formation is the result of individual cells teaming with others.  The aggregate of the cells and their environment form a thin layer of what is known as a biofilm. These biofilms form 3-D wrinkled patterns.

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