Neutrino’s mass nailed down

A group of scientists in Germany have constrained the mass of the neutrino, calculating that it cannot weigh more than one-millionth the mass of an electron. Neutrinos are the lightest of all the Standard Model particles with mass. They are electrically neutral and interact incredibly weakly with other particles via the weak force, making them almost impossible to detect. Initially, they were thought to be massless, but later experiments proved that they must have a tiny mass.

The team at the Karlsruhe Tritium Neutrino (KATRIN) experiment calculated the neutrino’s mass using a clever trick that avoided having to isolate the elusive particle. Instead, they studied the radioactive decay of an isotope of hydrogen with two neutrons and one proton, tritium. When tritium decays, it releases an electron and an antineutrino (the neutrino’s antiparticle, which has the same mass). The antineutrinos fly out of the experiment and are lost, but the energies of the remaining electrons are measured and added together. The energy ‘missing’ from the electrons is then used to infer the mass of the lost neutrinos.

“Energy is used to flip the molecules around”

Water molecules ‘flip’ before being split by electrolysis

Scientists at Northwestern University in the US were puzzled as to why splitting water seems to require more energy than expected. Electrolysis of water consists of two half-reactions, with one taking place at each electrode used in the process. The reaction should, in theory, need a voltage of 1.23 V to be applied across the electrodes to get started. However, in reality, a voltage of over 1.5 V is required. The leader of the study, Franz Geiger, said that this extra energy is one of the reasons why electrolysis of water has not been widely used at scale.

Geiger’s team shone an infrared laser onto the surface of the electrode and measured the intensity of reflected light at half the original wavelength. This technique revealed that the orientation of the water molecules at the electrode depended on the voltage: hence, energy is used to flip the molecules around. Water molecules have positively and negatively charged regions, similar to the north and south poles of a bar magnet. The researchers explained that since the surface of the electrode is negatively charged, the water molecules initially align with their positive end towards the surface. However, they must ‘flip’ to allow the oxygen atom in the more negative region to offload its electrons onto the electrode and progress the reaction. This study has spurred more research into alternative electrodes and catalysts that could ‘pre-align’ the molecules, reducing the energy needed to initiate the reaction.

“Another solution is to engineer the cells to ‘hide’ from the patient’s immune system”

Engineered brain cells could offer Parkinson’s cure

Neuroscientists at the Florey Institute of Neuroscience and Mental Health in Australia have produced promising research into the treatment of Parkinson’s disease. Parkinson’s is a neurodegenerative disease that causes tremors, problems with balance, and loss of muscle control. It can be treated by the transplantation of healthy nerve cells, but this is a difficult procedure, as the body’s immune system will target and destroy foreign cells. One solution is to provide the patient with immunosuppressant drugs, but these increase the risk of cancer and serious infections and can cause tissue damage. Another solution is to engineer the cells to ‘hide’ from the patient’s immune system – a technique known as ‘cloaking.’

To cloak the cells, the scientists altered eight genes in the brain cells, adding modifications found in placenta and cancer cells, which are naturally immune-evasive. They then added a ninth “suicide gene” to prevent the cells from multiplying uncontrollably; if they became cancerous, they could be destroyed with the drug ganciclovir. The transplanted cells successfully restored muscle control in rats with Parkinson’s disease, without the need for immunosuppressant drugs, opening a promising new avenue for a Parkinson’s cure.

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