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Porcupine quills for painless needles

Inspired by the structure of porcupine quills, researchers are working on less painful hypodermic needles that can penetrate the skin more easily and resist buckling.

The North American porcupine carries an intimidating array of around 30,000 defencive quills on its back which it can bury in the flesh of predators.

The spiky rodents can then shed them before scurrying away. But once lodged in the flesh of their assailants, they are difficult to remove, the Daily Mail reported.

Researchers are working to harness porcupine quill’s unique properties to develop surgical super glues, needles and other medical devices as well.

Each quill has a conical tip studded with microscopic backward-facing barbs. These act like serrated blades, providing a cleaner cut through tissue by localising forces at the teeth tips.
As well as anchoring the quill into the flesh, the barbs minimise the amount of penetration pressure needed.

“We were most surprised to find that the barbs on quills serve a dual function,” said study leader Dr Jeffrey Karp, from Brigham and Women’s Hospital in Boston, US.

“Namely, the barbs reduce the penetration force for easy insertion into tissue and maximise the holding force to make the quills incredibly difficult to remove,” he said.

Studying porcupine quills is expected to lead to improvements in the design of needles and medical adhesives, said the researchers.

“Towards medical applications we developed plastic replicas that remarkably mimicked the reduced penetration force and increased pullout.

“This should be useful to develop next generation medical adhesives and potentially design needles with reduced pain,” Karp added.

How fins evolved into limbs

A new study has suggested that the development of hands and feet occurred through the gain of new DNA elements that activate particular genes.

“First, and foremost, this finding helps us to understand the power that the modification of gene expression has on shaping our bodies,” said Dr. Jose Luis Gomez-Skarmeta of the CSIC-Universidad Pablo de Olavide-Junta de Andalucia, in Seville, Spain.

“Second, many genetic diseases are associated with a ‘misshaping’ of our organs during development. In the case of genes involved in limb formation, their abnormal function is associated with diseases such as synpolydactyly and hand-foot-genital syndrome,” he noted.

In order to understand how fins may have evolved into limbs, researchers led by Dr. Gomez-Skarmeta and his colleague Dr. Fernando Casares at the same institute introduced extra Hoxd13, a gene known to play a role in distinguishing body parts, at the tip of a zebrafish embryo’s fin. Surprisingly, this led to the generation of new cartilage tissue and the reduction of fin tissue—changes that strikingly recapitulate key aspects of land-animal limb development.

The researchers wondered whether novel Hoxd13 control elements may have increased Hoxd13 gene expression in the past to cause similar effects during limb evolution. They turned to a DNA control element that is known to regulate the activation of Hoxd13 in mouse embryonic limbs and that is absent in fish.

“We found that in the zebrafish, the mouse Hoxd13 control element was capable of driving gene expression in the distal fin rudiment. This result indicates that molecular machinery capable of activating this control element was also present in the last common ancestor of finned and legged animals and is proven by its remnants in zebrafish,” asserted Dr. Casares.
Saliva test can reveal decision-making skills

University of Granada researchers have found that cortisol levels in saliva are associated with a person’s ability to make good decisions in stressful situations.  In a study, researchers at the University of Granada Group of Neuropsychology exposed the participants (all women) to a stressful situation by using sophisticated virtual reality technology. They found that people who are not skilled in decision-making have lower baseline cortisol levels in saliva as compared to skilled people.

Cortisol –known as the stress hormone– is a steroid hormone segregated at the adrenal cortex and stimulated by the adrenocorticotropic (ACTH) hormone, which is produced at the pituitary gland. Cortisol is involved in a number of body systems and plays a relevant role in the muscle-skeletal system, blood circulation, the immune system, the metabolism of fats, carbohydrates and proteins and the nervous system. Recent studies have demonstrated that stress can influence decision making in people. This cognitive component might be considered one of the human resources for coping with stress.

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