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2017年10月28日星期六

何謂生命

要知道胎兒是否有唐氏綜合症,可從母親抽血檢驗。 如果這種新技術的結果呈陽性,可以提取絨膜絨毛樣本來確認病情。 (:絨膜絨毛從絨毛膜長出,與母親的血液提供最大的接觸面積。)然而,如果胎兒有遺傳缺陷,人工流產是否有道德問題。 如何界定生命? 未成熟的胎兒是不是一個活的個體呢?讓他/她出生,會否苦了他/她?




In order to test if the fetus has Down Syndrome, blood is then taken from the mother. If the result of this new technique is positive, chorionic villus sampling is taken to confirm the illness. (Chorionic villi sprout from the chorion to provide maximum contact area with maternal blood.) However, is it moral to undergo abortion if the fetus has genetic deficiency. How to define life? Is it really possible to define that the young fetus is not a living individual?

Reference: http://www.obg.cuhk.edu.hk
Definition and image of chorionic villi: en.wikipedia.org
Translation helped by Google

2017年10月14日星期六

點解湖底不結冰


攝氏四度的水密度最高,會沉下去。

When the temperature of  water decreases, there is fewer kinetic energy and H2O molecules in liquid water takes up less space and density increases.

Below 4 degree of Celsius, however, the density decreases again.

Water and ice have the same network of bonds (hydrogen bond). Water at 25 degree of Celsius is so rapidly breaking bonds between H2O units and reforming them that extra water molecules get trapped inside the water lattice. That's why water is more dense than ice?

The bonds in water break more slowly as temperature decreases and the structure tend to trap fewer extra water molecules. At low temperature, more of the water has the same lattice (crystal) as ice.

(Text is modified from butane.chem.uiuc.edu / Image from wtamu.edu)

2017年10月8日星期日

justice

http://dictionary.cambridge.org/dictionary/english/justice

physiology about development of sperms

大家有沒有想過睪丸(testes)為何是在體外(陰囊內 inside scrotum)? 因為製造精子(spermatogenesis)的最佳溫度大概是攝氏 34-35 度。所以男仕們不要浸那麼多熱水浴,或者可以以淋浴取代,還能夠減少用水,更加環保。這樣亦可以解釋到 scrotum 夏天為散熱而鬆馳,冬天為保溫而收縮的現象。
Reference (temperature): blogs.scientificamerican.com

如果睪丸停留在腹股溝(groin)或者在腹腔(abdominal cavity)內而沒有降至陰囊,則稱為隱睪症(cryptorchidism),通常要在嬰孩時期靠手術解決。
Reference: healthcare.org.hk

2017年10月7日星期六