Friday, December 18, 2015

Comments on a research article on toxicity of TCM medincines

Nature Scientific Reports published an article "Combined DNA, toxicological and heavy metal analyses provides an auditing toolkit to improve pharmacovigilance of traditional Chinese medicine (TCM)". This research is valuable because it raises the concern over the unregulated TCM market and the safety of TCM medicines. The toxicity due to heavy metals is particularly alarming and warrants systematic investigation, because unlike biological toxicity, chemical toxicity cannot be reduced at an elevated temperature under which TCM medicines are typically prepared.

What is not obvious, however, in reading this article is that this type of research has one common idiosyncrasy: disproportionally picking somewhat poisonous and toxic TCM medicines, and non-plant-based medicines. In actual TCM practice, plant-based medicines (herbs) are used very much more frequently than animal- and mineral-based ones, and a professional TCM doctor is well aware of toxicity of commonly used medicines, such as Asarum, one of those researchers' favorite victims. Naturally, a "surprise" in finding toxicity in these medicines can only come from less-informed lay persons or non-practitioners.

In future studies, the researchers should select medicines based on their usage or prescription frequency. If there's no aggregate or frequency statistics on the prescribed medicine names, one way to create an approximate frequency list is mine, created about ten years ago based on herb name occurrence on the Internet. See with its result at

Saturday, August 22, 2015

Best Age to Have a Baby

Here's a short summary of Huffington Post's article, What's the Best Age to Have a Baby?.

  • In terms of the infant's health, the mother's best age for first-child birth is 26. In terms of the infant's mortality, the best age is 32.
  • In terms of the mother's long-term health, the best age is, on average, 31. In terms of the mother's life expectancy, it's 34 or 35.

The primary research article cited by this news report is University of Texas sociologist Dr. John Mirowsky's Parenthood and Health: The Pivotal and Optimal Age at First Birth published in 2002. One other interesting bit in the article is the "positive association between health and age at first birth that is linear for men and parabolic for women". According to the full article (see Fig. 1 on p.333 and confirm with Fig. 2 on p.337), the linearity for men simply means the older, the better. That is, the older the man is at the time his wife or sex partner gives birth to their first baby, the healthier he will be in the future. Note there's an age range for this investigation. Both figures show ages starting at 15 and ending at 45.

Tuesday, June 16, 2015

Easier to do push-ups in a high flying airplane

A few days ago, I was in an airplane flying at an altitude of over 32,000 feet or 10,000 meters. It was a 13-hour flight. To make this journey a little more comfortable, I did some stretching and, with flight attendants' approval, took a tiny corner to do push-ups. It seems to be easier to do push-ups in this high flying airplane. I did 66 without too much effort, almost tying my record set on ground 20+ years ago.

I'm curious to see how much easier to do this exercise at this altitude. So here's my calculation. If I simplify the calculation by assuming all the mass of the earth to be at the center of the earth (as opposed to integrating the mass along the 6371 km radius), Newtonian universal gravitation between me and the earth is reduced by about 3 thousandths at 10000 meters altitude:

F0 = G (mmemearth)/(6371000)^2

F10k = G (mmemearth)/(6371000+10000)^2

where F0 is the force between me and the earth when I'm at sea level, and F10k the force when I'm at 10,000 meters altitude. Calculation of the percent change can omit the constant G and both masses m's:

1/(6371000)^2 - 1/(6371000+10000)^2
----------------------------------- = .00313189770433034782 i.e. 0.313%

For a person weighing 70 kg or 154 pounds, that translates to 0.22 kg or about half a pound.

What's more, since the plane travels at the speed of 900 km (560 miles) per hour on this inter-continental flight, the centrifugal force [note] additionally reduces a 70 kg person by 686 newtons or 700 grams:

Fc10k = 70000 * (900000/3600)^2/(6371000+10000) = 685.62921172230057984641 newtons
 or 700 grams or 1.54 pounds

So in total, the body weight is effectively reduced by about 0.5 + 1.5 = 2 pounds in the plane traveling at 900 km/hour at 10000 meters altitude.

[note] Centrifugal force is imaginary in Newtonian mechanics and is used as a convenient expedient. A physicist may choose to do calculation in Lagrangian mechanics.

Wednesday, April 1, 2015

Reverseing Alzheimer's disease

Alzheimer's disease is generally believed to be non-curable. But a recent off-purpose finding shows that a cancer treatment drug, saracatinib, can reverse the symptoms of the disease, on rats for now. Read Repurposed experimental cancer drug restores brain function in mouse models of Alzheimer’s disease. Also interesting is that "Individuals interested in participating in the trial can find more information at".