Key scientific method terms are poorly understood

The Department of Basic Education, in its report on the matric Life Sciences NSC exams of 2014, commented on how poorly several key terms in the scientific method are understood. In efforts to remedy this, they have spelled out how they want these terms understood and applied. What follows is an extract from that document.

DBE comments on hypothesis reliability and validity from 2014 NSC exams

While it’s lovely to see the DBE making things plain and obvious for all teachers, it is saddening to realise that many teachers probably need this help and assistance, because they don’t understand it, so are not teaching it correctly to their students. Hopefully all Science students (not just in Life Sciences) will take note of this and use this information to their good.

Brain barrier opened for first time to treat cancer

For the first time, doctors have opened and closed the brain’s protector – the blood-brain barrier – on demand. The breakthrough will allow drugs to reach diseased areas of the brain that are otherwise out of bounds. Ultimately, it could make it easier to treat conditions such as Alzheimer’s and brain cancer.

The blood-brain barrier (BBB) is a sheath of cells that wraps around blood vessels (in black) throughout the brain. It protects precious brain tissue from toxins in the bloodstream, but it is a major obstacle for treating brain disorders because it also blocks the passage of drugs.

Several teams have opened the barrier in animals to sneak drugs through. Now Michael Canney at Paris-based medical start-up CarThera, and his colleagues have managed it in people using an ultrasound brain implant and an injection of microbubbles.

When ultrasound waves meet microbubbles in the blood, they make the bubbles vibrate. This pushes apart the cells of the BBB.

With surgeon Alexandre Carpentier at Pitié-Salpêtrière Hospital in Paris, Canney tested the approach in people with a recurrence of glioblastoma, the most aggressive type of brain tumour. People with this cancer have surgery to remove the tumours and then chemotherapy drugs, such as Carboplatin, are used to try to kill any remaining tumour cells. Tumours make the BBB leaky, allowing in a tiny amount of chemo drugs: if more could get through, their impact would be greater, says Canney.

The team tested the idea on four patients by implanting an ultrasound transducer through a hole already made in their skulls during tumour-removal surgery. They were then given an injection of microbubbles and had the transducer switched on for 2 minutes. This sent low-intensity pulses of ultrasound into a region of the brain just 10 millimetres by 4 mm. Canney reckons this makes the BBB in this region more permeable for about 6 hours. In this time window, each person received normal chemotherapy.


What an amazing advance! This could open doors for all sorts of things. However, there is so much about the functioning of the brain that we don’t understand, that we will need to watch the long term effects carefully.

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