SCIENCE:

ASTRONOMY


Our April meeting was held as usual at the Driftwood Spars Hotel St Agnes, the meeting was well attended.
The talk which included a number of short videos was on 'Black Holes', one of the strangest objects in our universe. We saw how building on the work of Newton Einstein's 1915 theory of general relativity led to a understanding of gravity in terms of the bending of 4 dimensional spacetime. Using Einstein's result physicists during the early 20th century were able to predict the possibility of black holes, neutron stars and white dwarf stars and the conditions needed for their formation. We looked at how astronomers have been able to detect black holes including recent experiments to measure gravitational waves caused by two black holes coalescing. The talk was followed by an interesting question and answer session.
Our next meeting will be a week later than usual on Monday the 20th May, 2pm at the Driftwood Spars.
The subject of the talk will be 'The Moon and where it came from'. After reminding ourselves about the formation of the solar system we will look at the various ideas put forward for the formation of the Moon, including the modern theory based on analysis of lunar material. We will then remind ourselves of the remarkable events of nearly 50 years ago, the first Moon landing.
The May meeting will be the last of this session, the Astronomy Group will resume after the summer break in October.


Bob Williams 01326 219334


 

SCIENCE MEETING.


Please note that the time and day of the meetings for 2018 has been changed to 10:30 on the second Thursday of month at the Victoria Inn, Threemilestone Coffee is available from 10.00 am.

The Vic are offering us a special morning snack deal. A croissant + coffee for £4:00 or bacon bap + coffee for £5:00. Also if you are planning to have lunch and/or attending the quiz later, then reserve a table in advance on 01872 278313 and mention that you are with the science or quiz group. 

 


In April Arthur Willis gave an interesting talk on ‘Radioactive Waste Management Decommissioning and Disposal in the UK’,an area in which he was involved with for most of his career in the nuclear industry.  

Click here for the slides of the presentation.  


On 9th May a well attended meeting heard an excellent and riveting talk by Steve Tarrant, Assistant Mine Manager, about the exciting new developments planned for South Crofty mine that will re-establish the fortunes of Cornish tin as a major world producer. Tin has been mined at South Crofty for over 400 years until the crash in the world tin price in 1985 that lead to closure of tin mines in Cornwall, South Crofty being the last one in 1998. U3a South Crofty Presentation

There is a strong community and government support to see South Crofty producing tin again with the creation of 275 jobs. Could now be a good time to buy shares in Cornish tin?  For a more detailed information on this project visit www.strongbowexploration.com/projects/uk/south-crofty/ .

In June we had a most interesting talk by Dr Paul Lucas on “How our Bodies Deal with Drugs and Toxins.”
The human body is exposed to a myriad of foreign compounds including drugs, toxins and pollutants globally known as xenobiotics. Fortunately humans have evolved metabolic mechanisms that in the main are able to detoxify and excrete these compounds to minimise their toxic effects.
Most polar small molecules are generally unable to penetrate a cell's semi-permeable membrane unless they have a specific transport protein.  Nonpolar molecules, however, can pass through this membrane into the cell. Xenobiotic metabolism protects the body from these substances with enzymes that will react with most nonpolar compounds. This specialization prevents them from attacking key compounds that are part of the organism's normal biochemistry.
Metabolism of these xenobiotics occurs through two phases, the first involving hydroxylation, which is carried out by a large family of haem enzymes, known as cytochrome P450s(CYPs). These are mainly located in cells in the liver and can be induced or inhibited. Their normal function is to metabolise steroid hormones, vitamins A and D and bilirubin. They have broad specificity and are able to process most xenobiotics, making them more hydrophilic and less toxic. Occasionally due to genetic differences toxicity may result e.g. 10% of Caucasians have absent CYP2D6 activity and are at risk of jaundice with certain drugs. CYP mediated reactions generate significant levels of reactive oxygen species and are key to the toxicity of many xenobiotics, particularly if they deplete the cells reserve of glutathione, the major intracellular antioxidant.
The second phase involves joining of the hydroxylated product with a variety of hydrophilic compounds such as glucuronic acid. The overall effect is to render lipophilic compounds into water soluble compounds that can be eliminated by the body via the kidney or gut.
One of my thoughts from this talk is that future genotyping of your CYPs status could be important for developing personalised medicines to reduced risk of toxicity.
On 11th July my colleague Phil Carson will talk on “Blood Coagulation”.
Blood Coagulation or haemostasis, is the process by which blood changes from a liquid to a gel, forming a blood clot. This process is the stopping of blood loss from a damaged vessel which is then followed by repair of cellular damage. Blood coagulation is a complicated physiological process with four systems working together to maintain the steady state in the body and enable the relatively stable equilibrium between interdependent elements. It functions with many close links to other mechanisms of the body being affected by deficiencies and triggered by diseases. 
The actual blood vessel linings themselves, or vascular endothelium, have an essential role in controlling the overall process. Then platelets, which are essentially cellular fragments, work primarily to stem any blood leakage. Subsequently a protein cascade results in the blood changing from a liquid to a gel to form a solid blockage to prevent blood flow. The final stage is the clot removal process or fibrinolysis, which occurs as wound healing occurs to reinstate the blood flow.  
These systems contain both pro-active factors to drive activation and inhibitors to result in control and switch mechanisms. Abnormalities in any of these four systems can therefore result in either haemostasis (bleeding) or thrombosis (inappropriate clotting and the formation of a clot in a blood vessel).
Phil will review Blood Coagulation and follow the four interdependent systems illustrating with some common and not so common disorders. He will also look at some other factors that can affect blood coagulation such as patient variables, effect of some snake venoms, drugs used in anticoagulant therapy and the tests used to monitor them.
Please note that there will be no science meeting in August.
 Roy Fisher    01872 270528      raf59@talktalk.net

Roy Fisher  01872 270528      raf59@talktalk.net


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For all activities, please check our Google Calendar to confirm dates, times and locations

Pat Harrod & Wendy MorrisGroups coordinator