Monthly Archives: June 2014

Cholesterol

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Cholesterol is a lipid molecule with the following structure: structure of cholesterol

Steroid hormones (estrogen, progesterone, aldosterone, testosterone, etc) are made of cholesterol.  It is a component of every cell wall in the body.  As such it is essential for normal body functioning.

HDL (high density lipoprotein) and LDL (low density lipoprotein) cholesterol are not actually cholesterol.  There is only one type of cholesterol (structure above), but the way cholesterol travels in the blood varies.  Cholesterol cannot easily float around in the blood since fat does not mix readily with water.  In order to move around the blood, fats come together as droplets and associate with proteins.  This is the general structure:

HDLThe protein is called a lipoprotein because it is a protein associated with lipids (lipo).  Lipoproteins in the “fat droplet” can have different structures.  The different structures are genetically determined and certain structures are associated with cardiovascular disease.

What is the difference between HDL and LDL?  The fat composition of the “fat droplet” varies.  This figure gives a summary:

Cholesterol table comparisonChylomicrons are the form that fats take when traveling from the intestines to the liver.  They move via the lymph initially.  VLDL is the fat droplet that the liver creates to send fats to the tissues – in particular to the adipose (fat cells) for storage.  If you eat extra sugar your liver turns that into fatty acids and uses VLDL to transport them out into the body.  HDL is a form that is sent out to pick up fat from the tissues.  High levels of HDL are considered beneficial since these droplets are scavengers of cholesterol and fat in the body.  LDL transports extra lipids to the body tissues as well.

From the above descriptions it would follow that HDL would become LDL once it has picked up extra cholesterol and fatty acids.  Higher HDL levels in the blood indicates less extra cholesterol and fatty acids.

Hot Water

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I moved to Phoenix on June 18th in 2011.  For the first week or two the temperatures were hot but it still was cooling down into the 70’s or 80’s at night.  Then it really heated up.  Night time lows were in the 90’s!  I was looking for ways to keep cool and conserve energy when my attention turned to the hot water heater.

The hot water heater was in a centrally located closet at the condo I was living in.  This would be a good thing in the winter, but in the summer the last thing I wanted was a “heater” running in the middle of the house.  Besides, in Phoenix, in the summer, it is impossible to get cold water out of the tap anyway.  That solidified my decision – I turned it off and it remained off until things cooled down in the fall.

That year I would occasionally turn it back on to wash the dishes or to take a bath.  I liked the water really hot for those activities. The “warm” tap water was fine for showers and the occasional hand washing.  And, in the summer, I’m more apt to shower to cool off than soak in a hot tub of water.

When I moved into my own place I continued the same routine.  As soon as it warmed up the hot water was turned off.  I found that I could take the water from my 100 foot black garden hose for dish washing.  In fact it was often too hot from that source and I’d have to dilute it with cooler water.  This simple solar hot water heater eliminated even more of my use of the standard unit.

Solar Hot Water Heater

My solar hot water heater at work in the sun.

When fall came, I decided to leave the hot water heater off most of the time.  The hose for hot water worked fine in the winter as well.  As for showers and baths it only took a half hour to bring the hot water tank up to temperature and so I would just flip the circuit when I was about to bath.

Occasionally I mention to people that I turn off the hot water in summer, but I have yet to find a like minded person.  It seems like such a logical thing to do.  I am quite surprised that no one else does it. I’d be curious to hear from you.  Do you turn off your hot water?  Do you have simple ideas for conserving energy around water heating?  If you don’t turn off your hot water – why not?

I was talking with one of my regular clients on Saturday night at the Hawaiian Experience Spa when I learned that he uses a traditional solar hot water system.  I was pleased to find a comrade in conservation.  The best news he shared was that he too turns his hot water heater off!

He’s much more sophisticated than I am.  He says for $40 you can get a 220 Volt timer for the system.  He figured the timer paid itself off in a matter of months.  His water heater goes on at 4:30 am for a half hour.  Just long enough to heat the water so he can take his morning shower.  Sweet! eh?

Perfect Timing

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Purslane

Purslane is a common weed and tasty snack

It went just like this last year.  Early spring brings malva (mallow) and mustard as the predominant weeds in my yard.  Then, I have a brief respite when I can look out at the quarter acre of mostly bare ground and breath easy.  Since I’m used to California and the dry season,  I think I am done weeding for the year.  I relax my guard down, but suddenly the purslane (Portulaca oleracea) appears.

I am curious. How does it know when to emerge?  But perhaps I have the answer.  I know, from college studies of horticulture and plant physiology, that seed germination is a response to a number of environmental cues.  Things like temperature, day length (photoperiodism), light exposure, and water exposure can activate germination and end the dormancy of the seed.

What is so surprising to me is that these same plants seemed to grow whenever and where ever I watered in California but here in Phoenix they seem locked into a biorhythm.   I don’t think their genetic code for germination has changed, so it must be that my awareness of their pattern is enhanced.

I think my awareness is increased do to greater contrast.  The weed life in my garden flourishes in the cool and warmer spring here in Phoenix.  Then there is a lull before the succession to the next species ensues.  The lull makes the second splash of life more dramatic.  Last year I thought our summer rains stimulated the second growth, but I can see this year that the second emergence is already beginning, ahead of the monsoon.

Mature Purslane

Young purslane – a good stage for eating.

I am also willing to entertain a second level of genetic code regulating the first layer. When conditions are not right for germination seeds remain dormant.  When the optimal light, heat, etc is present dormancy is unlocked and seeds begin the germination process. However, seeds that we purchase from the store often lack dormancy.  This means that they will germinate given a little warmth and water.  Wild seeds that have a more robust dormancy requires more stimulation than just water and heat.

What about purslane seeds I can purchase?  Yes, you can purchase purslane seeds.  And one would expect them to germinate with just water and warmth.  This suggests that something about dormancy has been changed.  This is the mystery.  The genetic code has not been modified, yet my wild purslane does behave differently than purslane I might plant intentionally.

We all contain a huge amount of DNA that we don’t express.  For instance, I have the genetic code to look like a frog, yet I only express the genetic code to look like a human.  Likewise, wild and domestic purslane have the same coding (I don’t think Monsanto has been tinkering with this one, yet).  However, there appears to be an intelligence in control., an intelligence that can foresee optimal germination conditions.