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Tuesday, November 26, 2013

Merino wool

I have a friend who has been hearing incredible stories about the wonders of Merino wool and insists that if I can find out why it has such unusual properties, it might just be the impetus to get me posting blogs again after my long silence.  In the process of course, she expects to get some in-depth answers. 
The rise to fame of Merino ‘Icebreaker’ garments all started nearly 20 years ago when Sir Peter Blake, a New Zealander who circumnavigated the world and wore his merino shirt for a solid 40 days and nights.  At the end of the test he was amazed to report that it smelled as sweet as the day he put it on. There have been lots of tests since to see if those who normally sweat heavily and suffer from BO [Body Odour] had similar results. They did. In fact the reports say that the Merino wool garment did not ever appear to be wet!  To explain, you need to know that sweat is just water with some salts in it and it has no smell itself. However, if the sweat stays on your skin , bacteria that are always present are activated and multiply and they are the culprits that have the bad smell. So if there’s no moisture on the skin, there’s no smell from you! 
You would be right to jump to the conclusion that if you wear a Merino wool garment next to your skin the Merino wool must be able to absorb water quickly and hold onto it so that your skin stays dry. In fact, as the picture on the right shows, marino wool fibres are scaly and they have a very strong tendency to bind water in their structure - actually they can absorb over 1/3 their own weight in water - wicking it away from the skin and holding on to it until it evaporates. In the meantime the merino garment still feels dry to the touch and has the same insulating ability.  
I heard an even more amazing story recently about an acquaintance who was wearing merino wool socks while he was trekking up north. While crossing a frozen lake he broke through the ice and got one foot soaking wet. He had no alternative but to continue the trek and much to his surprise, he said his sock kept his foot warm all day - it appeared to act like thewetsuit’ a diver would wear in cold water - the Merino sock made a good insulator restricting loss of body heat whether it was wet or dry. 
The diameter of natural wool fibres can be anywhere between 10 to 55 µm (1000 µm = 1 mm) as the highly magnified picture on the left shows - a human hair is around 100 µm. The picture also shows that the surface of all wool fibres - no matter what their diameter - is made up of scales and it is the large scales on most traditional wools that act like barbs against your skin and for most people makes it feel uncomfortably itchy.  Merino wool on the other hand feels like silk.
I’ve saved the best for the last!  Although Merino wool garments never smell, you may want to wash them occasionally! It’s easy - Merino clothing is machine washable so just toss them in the machine with the rest of your clothes. 
Researching for this post has led me to find out far more about the ancient breed of Merino sheep.  If you want more, click on Merino 101.   Rie

Monday, April 8, 2013

Where’s George?

My lifelong partner, my husband for 64 years, and my best friend, died of heart failure on March 28. He was 89 and he was ready to go. 
That will explain why I have not been posting for the last month.

At the Visitation and Celebration of George’s life last week, people would have noticed that there was no body present nor was there an urn of ashes. Instead we framed the following statement beside his picture:

It was George’s request that his body be donated for the advancement of medical education and research.  On his death, arrangements were made through our local Provincial Department of Health with the Inspector of Anatomy Services, for his remains to be transported directly from the hospital to Dalhousie University Faculty of Medicine, the University Medical School where our daughter received her MD.  There his remains will be used to teach medical students and for research. 

This summer we will have a family Memorial and plant an oak tree in his memory at our summer house. George’s ashes will be returned to us in due course and be used to nourish the tree.

George was a museum man and writer and gave of himself throughout a long life in which he was privileged to play a role in seeing that the history of his Province and Canada were preserved for future generations.  With the donation of his remains, he continues to give of himself for the good of others.

George was the love of my life and as I mourn that he is gone, I am comforted by the realization that he lives on in my memories and in the memories of those of us who knew him well.  I like to think that  a person like George is never really gone.  I feel that, in a lovely way, he lives on in those he knew and influenced and, through them, to younger generations.  Rie

Wednesday, March 13, 2013

Speculations on life’s origins

In my last post I described what it was like on Earth some 3.8 billion years ago when evidence indicates that life first appeared on Earth. The atmosphere was made up of volcanic gases like carbon dioxide, methane, sulfur dioxide, ammonia etc. but no oxygen.  That meant there was no ozone layer in the upper atmosphere to absorb the ultraviolet rays of the sun that cause chemical bonds between atoms to break. That meant that for chemistry to become more advanced and life to originate, it had to have happened in an environment where there was a source of energy and that was away from the light of the sun.

Just such an environment was provided in hydrothermal vents deep in the ocean.  On the map upper left, these vents are indicated by the red dots and are commonly found near places where the Earth’s tectonic plates are moving apart and sea water seeps into cracks in the Earth’s crust. This causes superheated seawater rich in dissolved inorganic compounds, to spew out of the vents and they supply the chemical energy to support up to 100,000 times as many more living organisms as ordinary seawater. These organisms depend on populations of microorganisms that ingest sulfur compounds for their energy to stay alive and reproduce . At first these strange microoranisms, that could withstand such tremendous heat and pressure in the dark depth of the oceans, were thought to be a special type of bacteria but, with the advent of the relatively new science of genetics, astonishingly, an entirely new form of life called Archaea were identified in the early 1970’s – see the ‘Tree of Life’ diagram below on the left.
At present, the most popularly held speculations about how life started on Earth center on thermal vents but, for lack of conclusive evidence, there are still at least 7 plausible theories and there have been lots of suggestions that life might have had a free ride on comets from other star systems. Actually, even if life came from outer space, the question of how life began there would still remain. 
Whatever theory prevails - eventually a loop of chemical reactions occurred in a closed environment that could reproduce itself. Self replication is the fundamental aspect of what we call life because it means there is a whole new set of rules that, once started, takes over  – Darwin’s law of natural selection. The replicas react to their immediate environment and if they possess some change from the original parent, then the offspring can survive normally only if the change is an improvement on the parental design.  Since there have been many
inevitable errors in replication and thus improvements, it is easy to imagine how step-by-step more complex and adaptable offspring proliferated. Evolution was unstoppable. 

Indeed all the evidence points to a single ancestor from which all other life forms on Earth evolved. As a case in point, all the DNA and RNA molecules found in every living cell have a structure such that the information on replication is in a particularly reliable arrangement as is the energy storage system using the Adenosine triphosphate [ATP] molecule. 

A number of scientific teams are using their impressive know-how and ingenuity to try to create life in an artificial environment but I must say I am concerned about their efforts!  They are tampering with the very basis of our existence and - as is illustrated by what has happened here on Earth – once started, life is amazingly persistent.  It also happens to be chiral and in a posting I did on right and left handedness in molecules shows, getting it wrong just in that one sense could be fatal.  Rie 

Thursday, February 21, 2013

Origin of life

Mostly for my own satisfaction, in my last couple of posts I have written of what is known about the beginnings of our Universe in the 'Big Bang'; how the elements were formed in Supernova explosions of huge early stars that ejected clouds of interstellar dust called nebulae; and finally the formation of our sun and its solar system in one such nebula. At the end of that last post I promised that in this one, I would summarize what is known about how life got started on Earth. I will keep that promise but it’s going to take a couple of postings to do so.

For those who may regularly visit my site, you will have noticed that, for the first time in 2 ½ years I have missed my self-imposed Sunday morning deadline this week. The main reason was that as I researched the topic of the origin of life on Earth, I was on a very steep learning curve and on Sunday, I still had a lot to understand before I was ready to write anything on such a momentous topic. It’s been a fascinating journey and I’ve enjoyed the experience so much I didn’t want to stop until I was satisfied I had a pretty good grasp of the subject.

So picking up the saga from the last posting where we left a molten Earth to cool and to form and reform the Earth’s continents, around 4 billion years ago, most molecules were probably moving slowly enough that when they collided, they interpenetrated and reacted chemically by exchanging or sharing their surface electrons. Constant volcanic eruptions would have released huge clouds that mostly contained water vapour, and carbon dioxide [CO2], with lesser amounts of methane [CH4], sulfur dioxide [SO2], nitrogen, carbon monoxide [CO], ammonia [NH3], hydrogen sulfide [H2S] and others; gases that contained all the main elements essential for life. 

Miller-Urey experiment 
The water vapour condensed and rained down in torrential storms that created the oceans while frequent lightening flashes helped cause the evolution of Chemistry to create ever more complex organic molecules. The experiment performed in 1953 by Miller and Urey was the first to prove that molecules of life like amino acids were formed in this manner. This important discovery inspired a multitude of further experiments that in turn produced an amazing variety of the molecules of life - like the nucleotide base, adenine for instance, which is one of the most important organic molecules for life as we know it today. Adenine is an integral part of DNA, which is found in every cell and spells out the genetic code used for directing the chemistry of cellular life. Adenine and similar nucleotide bases are found also in RNA, a smaller molecule that actually reads the DNA code and is the catalyst that performs the chemistry that it dictates.

We have known for many years that life depends on chemical reactions to exist and that life itself is a special form of chemistry in which the reactions are self-contained and self-sustaining and that they lead to their own replication and therefore growth.  So when we think of the origin of life, we see that the organic molecules involved in the chemistry of life were present; there were the abundant sources of energy available to push chemistry between them toward ever more complex interactions, and it is in the evolutionary nature of phenomena of many natural emergent events that have occurred on Earth that some form of primitive life would have evolved. By its very nature however its origins could leave us no fossil record and so we are left to speculate until life can be started, with the right conditions and compounds, in the laboratory.
This week I’ve enjoyed not feeling the constraint – self imposed though it may have been – of having to meet a deadline on Sundays so have decided to just post when I have found something new and interesting that I feel compelled to write about.  I’ll be back soon with more on what is known about the beginnings of life on our planet.  Rie  

Sunday, February 10, 2013

Birth of Earth

The beautiful Eagle Nebula
In my last post I described the dying of a huge star in a spectacular supernova explosion that spewed out chemically enriched dust and gases that formed a nebula cloud out of which a solar system like ours emerge. It is because astronomers have studied new solar systems in various stages of evolution, that we now have well accepted theories about how our own developed.   

Apparently, under the force of its own gravity the portion of the nebula cloud from which we came into being, contracted over a period of around 10 million years or so and, as it shrank, material was drawn in from space around it. The increasing amount of matter resulted in a larger gravitational pull and made material speed inward ever faster. When this mass smashed into the center, its energy of motion was transformed into heat energy and the temperature increased until it reached around 15 million degrees. At that temperature, the nuclei of hydrogen atoms are moving so fast that when they collide, they fuse forming Helium nuclei and give off incredible amounts of heat and light energy. That is the story of how our sun was born in our corner of cold dark space. The marvelous process by which stars are created is more fully illustrated in a posting I did on the sun a couple of years ago.

In the process of its formation, the sun had pulled in 99.86% of the matter in its vicinity and the slight rotation of the nebula cloud had speeded up so that the remaining 0.14% of matter  formed into planets that had just enough speed that they didn’t fall into the sun but orbited around it. As the planets grew by sweeping up the all the dust and rocky debris in their orbits, the birth of the sun sent out a blast of solar wind that cleared out all the remaining dust and rubble. 

Click on picture to enlarge & read the
thickness of the layers of Earth's interior
It’s interesting to have a look at the video simulation of all of this happening.  The video also depicts the Earth  in its early years when it was a molten mass and the heavy liquefied iron-nickel alloy sank to the center. Not mentioned is that the Earth’s mantle is kept molten by radioactive elements like uranium that give off heat as they decay. The story of the cooling of our planet and how our continents formed is told in some detail in an earlier post about the ‘Earth’s Crust’

Earth turned out to be the only one of the eight planets in our solar system that was at just the right distance from the sun to have a temperature range suitable for life. It has been speculated for years that there are other planets like ours in the Universe but it is the recent detection of billions of new planets that sparked my interest in going back to the very beginning and writing about the spectacular events that eventually produced our planet Earth. 

It is obvious that it has been a natural process and now, with the confirmation of so many other planetary systems, the probability that other intelligent beings exist becomes more real.  The problem is, with what we know of the Laws of Physics, it would take us at least 75,000 years to just reach the closest star similar to our own. That means we’ve no place to go if we don’t smarten up and keep our beautiful planet Earth habitable. For me it also increases the importance of the SETI  [Search for Extra-Terrestrial Intelligence]   program that searches for non-natural radio signals from sections of space outside our Solar System.  

Next week, if I find enough time to research it, the subject of my post will be what we know about how life started on Earth.  Rie