2016年4月24日 星期日

Hydrogen and water

You may find it interesting that hydrogen and water use the same prefix. It is:

hydr(o)-

Actually it is related to how hydrogen was discovered.

Hydrogen was discovered by Henry Cavendish. He collected the air bubbles from metal-acid reaction and found this air to be inflammable. He named it "inflammable air", which later was given the name hydrogen by Antoine Lavoisier. Lavoisier name it hydrogen because he obtained water after burning hydrogen. The word "hydrogen" means "substance that produces water" (please refer to Lesson 16-5 for the suffix -gen).

 Cavendish's apparatus for making and collecting hydrogen. Source : Wikipedia
Henry Cavendish was a notoriously shy man, some even postulated that he suffered from autism. However, he achieved a lot.

Henry Cavendish. Source: Wikipedia

Although Cavendish was not the first person to discovered the air bubbles from metal-acid reaction, he was the first person who collected the air and characterized them. Therefore, he was recognized as the person who discovered hydrogen. He also discovered carbon dioxide by dissolving alkali in acids.

中文版

2016年4月19日 星期二

dendroprovenance and dendrochronology

Pueblo Bonito. Source: Wikipedia
Anasazi Indians, who mysteriously "vanish" from the present-day Four Corners region of the United States, comprising southeastern Utah, northeastern Arizona, northwestern New Mexico, and southwestern Colorado in 12 and 13th centuries, left many huge architectural structures in the desert. The biggest one, Pueblo Bonito, is a five-floored building with 500 rooms.

All of those buildings were made by wood. How did Anasazi Indians find so many logs in that region?

Actually, they gathered logs from mountains that are far away. In order to determine where they obtained their building materials, research team checked the strontium (Sr) content in those logs.

Strontium is a decayed product from rubidium (Rb). After rubidium is decayed and strontium is produced, because it is similar to calcium (Ca), it will be absorbed into plant just like calcium. The Rb content in the soil is different in different areas, so scientists can deduce the origin of plant from the Sr content.

From the Sr data, research team determined these logs were from Chuska and San Mateo Mountains. However, dendroprovenance results said otherwise.

Dendroprovenence is a new method developed from dendrochronology. The prefix dendr(o)-, meaning tree, is taught in Lesson 19-1. The middle part of the word, chron(o)-, meaning time, is taught in Lesson 24-2. The last part, the suffix -logy, meas study, science.

Putting them together, dendrochronology means to study the time of the tree.

Source: Ms. Lin
Dendrochronology is used by scientists to study the amount of precipitation in the past. When we chop down a tree (tree A), the outmost ring of tree A represent the amount of precipitation of this very year. Then we can count the rings of the tree. The number of rings tell us how old this tree is. If it has 100 rings, then this tree is 100 years old.

Say we find a log (tree B) also from the same area as tree A. Because precipitation varies year by year, the patterns of thick-and-thin rings in trees that grow in the same area around the same time will be similar because the climate is the same. So if we find one section of tree B is almost identical to one section of tree A, then we can take a good guess about how old tree B is. We can even figure out how long ago tree B was chopped down! This method is called dendrochronology.

As of dendroprovenance, it looks for much smaller details. We knew that precipitation varies year by year and the patterns of tree rings growing in the mountain ranges that surround the same area are similar because the climate is the same. However, each mountain range has its own microclimate. So, if we look more closely to these growth rings, we will find that growth patterns of trees from one mountain range are not identical to those of trees in nearby ranges.

The word provenance means origin or source. Because this method can help scientists find the where are those trees from, it is named dendroprovenance.

In this report, scientists found that some of the trees Anasazi Indians used were obtained from Zuni mountains. However, they switched to Chuska Mountains after 1020 A.D.

Dendroprovenance can be very useful for illegal logging. If we can establish the "fingerprints" of trees in every area, then we can catch those illegal loggers with indisputable evidences!

Reference:

Jared Diamond. 2006. Collapse.(大崩壞)。p.186-7(廖月娟譯)

2015/12/7. Unexpected wood source for Chaco Canyon great houses. Science Daily.

中文版

parthenogenesis: female reproduction without male

What is parthenogenesis?

This word can be split into two part.

The prefix partheno- is from Greek word parthenos, meaning virgin; and the suffix -genesis means production. Put them together, parthenogenesis means sexual reproduction with development of a gamete without fertilization.

Parthenogenesis can be found in some plants and invertebrates, especially arthropods. For vertebrates it was only observed under captivity.

However, in a study done by Stony Brook University, they found that about 3% of the smalltooth sawfish (Pristis pectinata) underwent parthenogenesis.

Smalltooth sawfish. Source: Science Daily
Smalltooth sawfish is one of the large fish living in Florida. It was listed as endangered in 2003 because the population decreased to 1-5% (about 200 individuals left) of 1900.

Concerning about inbreeding, the scientists started to do their DNA fingerprinting. Surprisingly, they found some of the females were reproducing without mating.

There were five of them that are extremely close to each other, according to the DNA fingerprinting result.

In the past, parthenogenesis only happened for sharks in captivity, not to mention those sharks weren't healthy at all.

Perhaps it is a way to preserve the population when the population size is so low. Although parthenogenesis does not help with genetic diversity, it will help to maintain the population size.

Reference:

Andrew T. Fields, Kevin A. Feldheim, Gregg R. Poulakis, Demian D. Chapman. 2015. Facultative parthenogenesis in a critically endangered wild vertebrate. Curr. Biol. 25(11):R446-R447

中文版

2016年4月17日 星期日

What is hypercapnia?

In November 22, 2015, a woman felt uncomfortable while she was driving through Highway No.3 in Nantou, Taiwan. Because her daughter was fainted in the same vehicle, she called the police.

When the police arrived, they found that she did not turn on the air-conditioning. She switched to circulation, which did not allow fresh air to come in.

I often found it curious why our car has a setting "circulation". Although it can prevent bad smell coming from outside to enter our car, but it also prevent fresh air from coming in. If we drive for a long time and leave the setting on "circulation" (like this woman did), you may suffer from hypercapnia.

What is hypercapnia?

The prefix hyper-, we is from Lesson 6-1, meaning above.

The prefix capn- is introduced in Lesson 17-1, meaning carbon dioxide. It can also be written as capno-, depending on what letter connecting to it.

The suffix -ia is introduced in Lesson 16-4, meaning condition.

Putting them together, hypercapnia is a condition of abnormally elevated carbon dioxide (CO2) levels in the blood.

According to Wikipedia, hypercapnia normally triggers a reflex which increases breathing and access to oxygen, such as arousal and turning the head during sleep. A failure of this reflex can be fatal, for example as a contributory factor in sudden infant death syndrome.

Symptoms and signs of early hypercapnia include flushed skin, full pulse, tachypnea (abnormally rapid breathing), dyspnea (difficult in breathing), extrasystoles (a heartbeat outside the normal rhythm), muscle twitches, hand flaps, reduced neural activity, and possibly a raised blood pressure. According to other sources, symptoms of mild hypercapnia might include headache, confusion and lethargy. Hypercapnia can induce increased cardiac output, an elevation in arterial blood pressure, and a propensity toward arrhythmias.

Recently, a research paper suggested if the carbon dioxide in the ocean keeps rising, the fish will also suffered from hypercapnia too!

Source: Wikipedia

Hypercapnia is also called carbon dioxide toxicity. It will happen within 30 minutes when the concentration of carbon dioxide reach 6%.

Next time when you are going for a long ride with your family, please remember to check the air-conditioner's setting!

Reference :

民視新聞。2015/11/22。國道驚魂!車內只開循環 女副駕缺氧昏厥

Wikipedia. Hypercapnia.

Ben I. McNeil & Tristan P. Sasse. 2016. Future ocean hypercapnia driven by anthropogenic amplification of the natural CO2 cycle. Nature. 529, 383–386

2016年4月13日 星期三

What is homeopathy?

From the news of BBC in 2015, the NHS of United Kingdom was going to move homeopathy to the blacklist, meaning NHS will no longer pay for it.

However, it was the first time I've heard of homeopathy. What is it?

According to Wikipedia, Homeopathy is a system of alternative medicine created in 1796 by Samuel Hahnemann, based on his doctrine of like cures like (similia similibus curentur), a claim that a substance that causes the symptoms of a disease in healthy people would cure similar symptoms in sick people.

Dr. Samuel Hahnemann. Source: Wikipedia
The explanation sounds kind of hard to comprehend. For example, if you are allergic to pollens, most of the doctors will prescribe antihistamine. However, the doctors who practice homeopathy, they will give you some solutions which is consisted of diluted pollen. The factor of dilution is usually 1012, some will even dilute to 1060!

Although homeopathy was created by Dr. Samuel Hahnemann, the concept -- like cure like -- was originated created by Hippocrates in 400 B.C. For treating mania, Hippocrates will prescribe a small dose of mandrake root. However, mandrake root will produce mania in much larger doses.

According to modern search, doctors found that the effect of homeopathy is not significant comparing to placebo. Because NHS of Great Britain had paid 4 million pounds to homeopathy, so the test results brought serious consideration for not including homeopathy anymore.

The word "homeopathy" clearly explained the concept of this treatment. When we take this word apart, it becomes homeo- and -pathy.

The prefix homeo- is the same as home-. It is originated from Greek homoios, meaning like, resembling. In addition to homeo-, there is another prefix hom(o)-, which we learned in Lesson 16-2. It is originated from Greek word homos, meaning common, same.

The suffix -pathy is also having a Greek origin. It is written as pathos in Greek, meaning feeling, suffering, emotion, disorder or disease. We will learn that in Lesson 23-1.

When we put together these two words, then it become like cures like. Isn't it interesting?

References:

Wikipedia. HomeopathySamuel Hahnemann
Oneline Etymology Dictionary. Homeopathy
Dorland's Illustrated Medical Dictionary.
2015/11/13. James Gallagher. Homeopathy 'could be blacklisted'. BBC.
中文課程:順勢療法(Homeopathy)

Archaefructus : not the oldest angiosperm anymore

In 2015, an ancient plant fossil named Montsechia vidalii has claimed the throne of the oldest angiosperm. Before its discovery, Archaefructus liaoningensis was believed to be the oldest angiosperm in the world.

Archaefructus liaoningensis Source: wikipedia
The flowers for both of them do not have petal nor sepal. For Archaeofructus, the scientists found its fruit and female flowers. There was no male flower to be found. Both of them seem to produce unisexual flowers.

The word Archaefructus is also a combination of prefix and suffix. Try to figure it out before you see the rest of this article.

The prefix, archae(o)-, is the same as arche(o)-. We have learned it from Lesson 16-2. Both of them are originated from Greek word archaios, meaning ancient, old.

The other part of Archaefructus, -fructus, is also having a Greek origin. It is originated from fructus, meaning fruit.

Putting them together, Archaefructus, meaning "ancient fruit".

Archaeofructus was dated back 125 million years and Montsechia was dated back 130 million years. Therefore, Archaeofructus is no longer the oldest angiosperm anymore.

However, both of them are water-borne plants. The research team for Montsechia also suggested that its pollens are probably carried by water.

Although only 5% of angiosperm live in water, the discovery of Montsechia suggested a possibility that the primitive angiosperms could be all water-borne.

As a final note, the second part of Archaefructus' name, liaoningensis, is a memoir of the place it was discovered. It was found in the Province of Liaoning, China.

中文課程請點:Archaefructus 遼寧古果

2016年4月12日 星期二

Oophila : an interesting unicellular algae.

In Lesson 16-1, we introduced many suffixes related to attraction. They are :

-phil, -phile, -philia, -philic, -tropin, -tropism.

There's a unicellular algae named Oophila amblystomatis, which live symbiotically with spotted salamander (Amblystoma maculatum) and hence its name "amblystomatis".

spotted salamander. Source: wiki
How about its genus "Oophila"? Well, it is a combination of one prefix and one suffix.

The former part oo is originated from the prefix  oo- , which comes from Greek ōon, meaning egg.

The later part -phila is originated from the suffix -philia, which is written as philein in Greek. It means "like, loving".

Putting them together, Oophila meaning egg-loving.

Is this algae egg-loving? Apparently so. It is living with the embryo of spotted salamander symbiotically. As a result, the embryo of spotted salamander looks greenish. The special thing with this relationship is the algae is actually living INSIDE the cell. This is the first time scientists discovered such a thing. Usually, the adaptive immune system of vertebrates will attack the foreign tissues (in this case, the algae). However, it seems that the algae has made peace with the salamander's immune system.

Scientists discovered that the salamander cells have arranged their mitochondria alongside with the algae, so their mitochondria can use as much oxygen from the algae as possible; and the salamander algae (Oophila's nickname) can use the metabolic waste (CO2) from salamander's mitochondria.

Scientists also found that spotted salamander can pass the algae through generations. Isn't it cool?

References:

Anna Petherick. 2010/7/30. A solar salamander-Photosynthetic algae have been found inside the cells of a vertebrate for the first time. Nature News.

Ryan Kerney, Eunsoo Kim, Roger P. Hangarter, Aaron A. Heiss, Cory D. Bishop, and Brian K. Hall. 2011. Intracellular invasion of green algae in a salamander host. Proc. Natl. Acad. Sci. USA. 108(16):6497–6502, doi: 10.1073/pnas.1018259108

2016年4月10日 星期日

Achilles tendon

In Lesson 15-1 we learned the prefixes for tendon: tend(o)-, tendin(o)-, ten(o)- and tenont(o)-.

In this article I want to tell a story about Achilles tendon.

Achilles tendon. Source: wiki
Which one is Achilles tendon? Achilles tendon is the one that labelled as tendo calcaneus. It is the thickest tendon of human body.

Well, why is this tendon called Achilles tendon? In Homer's Iliad, it was told during the Trojan War, Achilles was struck on his unprotected heel (right on this tendon!) by a poisoned arrow shot by Paris, that killed him.

The story also told that in the same war, after killing Hector (the Prince of Troy), Achilles is said to have cut behind Hector's Achilles tendons, and threaded leather thongs through the incisions in order to drag him behind a chariot.

Achilles drag Hector's body behind a chariot outside Troy after killing him.
Source: wiki
It was said that Hector predicted Achilles death while he was dying. In Greek mythology, Achilles' mother, the goddess Thetis, received a prophecy of her son's death. Hearing this, she dipped him into the River Styx to protect his body from harm. However, she kept hold of his heel, meaning that the water did not touch this part of his body and it was therefore vulnerable.

After Hector's death, his brother Paris shot Achilles right on the only vulnerable spot.

Because Achilles has only this only weak spot and hitting this spot cause his death, the phrase "Achilles heel" becoming a phrase referring to the vulnerable spot for anyone.

The oldest written record for Achilles tendon is in 1693, written by Philip Verheyen, the French/Dutch anatomist.

Reference:

Achilles tendon. Wikipedia.

2016年4月7日 星期四

New way of protein modification: stearoylation

We learned the prefixes for lipid in Lesson 14-3. They are:

adip(o)-, lip(o)-, pi(o)-, pimel(o)-, stear(o)-, steat(o)-

One of the prefixes, stear(o)- is used in stearic acid. There is a paper on Nature that is related to stearic acid in 2015.

In this paper, the research team discovered that the activity of human transferrin receptor 1 (TFR1) can be affected by stearoylation. The stearoylated TFR1 cannot activate JNK protein so mitochondria will not become fragmented.

Because fragmented mitochondria is poorly functional, stearoylation is actually a good thing in this aspect.

What is stearic acid? Stearic acid is a long-chain fatty acid, with 18 carbons with no double bond. We usually express fatty acid as "C18:0", meaning this fatty acid has 18 carbons with no double bond. The structure of stearic acid can be seen in the picture below:

Stearic acid. Source: wikipedia
Stearoylation is a whole new way of protein modification. We knew phosphorylation, ubiquitination and glycosylation can affect protein activity. But stearoylation is the first time.

To make this story more interesting, the whole discovery was started on a mistake. So making mistakes isn't so bad sometimes, huh?

Reference:

Teleman A.A. et. al., 2015. Regulation of mitochondrial morphology and function by stearoylation of TFR1. Nature. doi:10.1038/nature14601

2016年4月5日 星期二

小扁豆(lentils)與水晶體(lens)

第十四課(一)裡面我們學到水晶體(lens)。用來形容水晶體的字首是lent(i)-

不過,小扁豆的英文名稱是lentils。或許讀者會覺得,為什麼要提到小扁豆呢?

長在田裡的小扁豆。圖片來源:wiki
這就要看小扁豆的學名了。小扁豆的學名是:Lens culinaris。注意到屬名了嗎?跟水晶體一模一樣呢!為什麼小扁豆會使用水晶體作為學名呢?

原來是因為小扁豆的種子的形狀(如下圖)。

小扁豆的種子。圖片來源:wiki
看到了嗎?小扁豆的種子的形狀,跟水晶體以及透鏡都很像!所以就借了lens這個詞來給小扁豆啦!學到現在同學不知道有沒有發現,語言,不論是英文或中文,借詞借字是很常見的事情。只是因為英文不是我們的母語,我們認得的字沒有那麼多,所以就不那麼清楚了。

lentil and lens : are they related?

In Lesson 14-1 we learned a tissue in our eye called lens. The prefix for describing lens is lent(i)-.

However, there is also a plant, a legume which is named lentils. If we check the scientific name for lentil, you will find is very interesting. The scientific name for lentil is Lens culinaris.

How come a genus of a plant use the tissue of our eyes as its name?

Well, it's very simple. The seeds of lentils look very similar to the lens in our eye and also the lens we use for observing objects.
lentils. Source: wikipedia
Therefore, it is named lentils. It is very common to borrow words here and there to describe new things.

How come iris can be related to both eyes and plants?

We have learned iris in Lesson 14-1. The prefix for iris, irid(o)- is derived from rainbow (please referred to Lesson 5-3).

However, iris also meaning a plant.

Iris. Source: wikipedia
Iris plant is a monocot with beautiful flowers. The artist Van Gogh drew a famous painting for it. How come tissue in the eye become a plant?

Well, as we mention in this article first, the tissue in our eyes get the name iris because different people has different color of iris. Therefore, the Greek word for rainbow, iridos, is borrowed for describing the tissue in our eyes.

How about the plant iris? Isn't all iris blue?

Actually not. Because that famous painting from Van Gogh, we thought all iris are blue. Actually there are many different shades of colors for iris.

Different colors of iris. Source: wikipedia gallery
Source: Wikipedia Gallery
Source: wiki
Because iris has so many shades of colors, Greek named it iris. That's why the word iris can be used for the tissue in our eyes and also a plant!

Reference.

Wikipedia Iris (anatomy)_Etymology, Iris (plant)