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2021年5月29日星期六

Hypothesis of translocation

Phloem consists of living cells arranged end to end. Phloem vessels contain cytoplasm, and this goes through holes from one cell to the next.

Phloem transports sucrose up and down the plant. This is called translocation.

https://www.bbc.co.uk

Sugars produced in sources, such as leaves, need to be delivered to growing parts of the plant via the phloem in a process called translocation.

The sucrose from the source are usually translocated to the nearest sink (root) through the phloem sieve tube elements.

https://organismalbio.biosci.gatech.edu

The phloem tissue is the principal sugar conductive (傳導的) tissue in plants. Over 90 years ago, Ernest Münch (1930) proposed the now widely accepted mechanism for phloem transport. According to his theory, the mass flow in the phloem is driven by an osmotically generated pressure gradient. As the sieve pores interconnect the protoplasts (cells which have had their cell wall removed) of the sieve tubes, the transport in the sieve tube itself is a mass flow driven by a pressure gradient.



A dynamic version of Münch’s pressure flow model, the sugar (violet arrows) and water (blue arrows), and the relative proportion of sieve elements (SEs) and companion cells (CCs) in the respective phloem zones. Sugar is translocated via the phloem through essentially leaky instead of sealed pipes.

The solute concentration are controlled by release/retrieval mechanisms in the sieve element–companion cell complexes (SECCCs). Differential release/retrieval balances control the influx/efflux of sugars and water in the various phloem zones. In the collection phloem, the uptake or retrieval dominates; in the release phloem, the release dominates. In the transport phloem, having a dual task (nourishment of lateral and terminal sinks), the balance between release and retrieval varies with the requirements of the plant.

The gradual loss of solutes and corresponding amount of water towards the sink (root), where massive delivery of water and solutes takes place, has been attributed to the relative size reduction of CCs along the source to sink path, which may explain a decreasing retrieval capacity of the SECCCs in the direction of the sink.

https://academic.oup.com

The Forbidden Forest

forbidden: not permitted or allowed

alibis: an excuse usually intended to avert blame or punishment

avert: to turn away or aside

feeble: markedly lacking in strength

creep: to move along with the body prone and close to the ground

cock: rooster

blundering: characterized by or prone to foolish or careless errors

sob: to cry or weep with convulsive catching of the breath

dread: to fear greatly

hourglass: an instrument for measuring time consisting of a glass vessel having two compartments from the upper of which a quantity of usually sand runs in an hour into the lower one

miserable: being in a pitiable state of distress or unhappiness

swore: past tense of swear

meddle: to interest oneself in what is not one's concern

sneak: to go stealthily or furtively

goblin: an ugly or grotesque sprite that is usually mischievous and sometimes evil and malicious

stride: to move with or as if with long steps

peer: to look narrowly or curiously

ajar: slightly open

give in: surrender

kindling: easily combustible material for starting a fire

troll: a dwarf or giant in Scandinavian folklore inhabiting caves or hills

sack: dismiss

pock around: to look around or search through something

furore: an outburst of public excitement or indignation

deserve: to be worthy of

leer: to cast a sidelong glance

march: to make steady progress

sniff: to take air into the nose in short audible breaths

delighted: highly pleased

scud: to move or run swiftly especially as if driven forward

oaf: a stupid person

moan: a low prolonged sound of pain or of grief

werewolf: a person transformed into a wolf or capable of assuming a wolf's form

clutch: to grasp or hold with or as if with the hand or claws usually strongly, tightly, or suddenly

lookout: a matter of care or concern

glee: exultant high-spirited joy

after all: in spite of considerations or expectations to the contrary

frown: to contract the brow in displeasure or concentration

take over: to assume control or possession of or responsibility for

nasty: physically repugnant

fierce: violently hostile or aggressive in temperament

growl: to utter a growl

breeze: a light gentle wind

summat: somewhat

stagger: to move on unsteadily

coward: one who shows disgraceful fear or timidity

now and then: from time to time

stump: the basal portion of a bodily part remaining after the rest is removed

hoist: raise

slither: to slide on or as if on a loose gravelly surface

squint: to look or peer with eyes partly closed

grim: fierce in disposition or action

faint: weak

gleam: to shine with or as if with subdued steady light or moderate brightness

chestnut: a grayish to reddish brown

centaur: any of a race of creatures fabled to be half human and half horse and to live in the mountains of Thessaly

sorrow: deep distress, sadness, or regret especially for the loss of someone or something loved

pat: to strike lightly with a flat instrument

timid: lacking in courage or self-confidence

fling: to move in a brusque or headlong manner

grumpy: moodily cross

hoof: a curved covering of horn that protects the front of or encloses the ends of the digits of an ungulate mammal and that corresponds to a nail or claw

undergrowth: low growth on the floor of a forest including seedlings and saplings, shrubs, and herbs

rustle: a quick succession or confusion of small sounds

crunch: to chew or press with a crushing noise

fume: to utter while in a state of excited irritation or anger

racket: a fraudulent scheme, enterprise, or activity

idiot: a foolish or stupid person

splash: splashed liquid or semiliquid substance

thrashing: a severe beating or flogging

flog: to beat with or as if with a rod or whip

tangled: exceedingly complex

stick out: project

mane: long and heavy hair growing about the neck and head of some mammals (such as horses and lions)

pearly: resembling, containing, or adorned with pearls or mother-of-pearl

quiver: to shake or move with a slight trembling motion

hood: a flexible covering for the head and neck

crawl: to move on one's hands and knees

stalk: to go through (an area) in search of prey or quarry

transfix: to hold motionless by or as if by piercing

bolt: to move suddenly or nervously

swiftly: with speed

stagger: to move on unsteadily

galloping: progressing, developing, or increasing rapidly

blond: of a flaxen, golden, light auburn, or pale yellowish-brown color

palomino: a horse that is pale cream to gold in color and has a flaxen or white mane and tail

sapphire: a gem variety of corundum in transparent or translucent crystals of a color other than red, especially one of a transparent rich blue

linger: to remain existent although often waning in strength, importance, or influence

livid: black and blue

clamber: to climb awkwardly or with effort especially by using both the hands and the feet

awkward: lacking dexterity or skill (as in the use of hands)

flank: the fleshy part of the side between the ribs and the hip

heave: to rise and fall rhythmically

mule: a hybrid between a horse and a donkey

paw: to touch or strike at with a paw

paw: the foot of a quadruped (such as a lion or dog) that has claws

foretell: to tell beforehand

stray: a domestic animal that is wandering at large or is lost

rear: to cause (a horse) to rise up on the hind legs

bellow: to make the loud deep hollow sound characteristic of a bull

lurk: to lie in wait in a place of concealment especially for an evil purpose

alongside: at the side: close by

whisk: a quick light brushing or whipping motion

plunge: to cause to penetrate or enter quickly and forcibly into something

startle: to frighten or surprise suddenly and usually not seriously

monstrous: horrible

slay: to kill violently, wantonly, or in great numbers

slain: kill

curse: a prayer or invocation for harm or injury to come upon one

dapple: any of numerous usually cloudy and rounded spots or patches of a color or shade different from their background

desperate: having lost hope

cling: to hold or hold on tightly or tenaciously

clench: to hold fast

codswallop: words or ideas that are foolish or untrue

croak: to make a deep harsh sound

canter: lope

pace: to walk with often slow or measured tread

hiss: to make a sharp sibilant sound

sibilant: having, containing, or producing the sound of or a sound resembling that of the s or the sh in sash

feverish: marked by intense emotion, activity, or instability

fortune-teller: one that professes to foretell future events

neat: free from dirt and disorder


Online dictionary used: https://www.merriam-webster.com

2021年5月28日星期五

溶腩酵素

酵素可以減肥,無知婦孺才會受騙。首先要明白什麼是酵素 (Enzyme)︰

存於生物體內的蛋白質性觸媒,持有特定基質的作用。則是在生物體內,物理性條件(濃度、溫度與pH值等)之下,進行化學反應,有助於消化器官,或組織內營養素的分解,和進行各種代謝作用。

https://terms.naer.edu.tw

An enzyme is a substance that acts as a catalyst (催化劑) in living organisms, regulating the rate at which chemical reactions proceed without itself being altered in the process. The biological processes that occur within all living organisms are chemical reactions, and most are regulated by enzymes.

https://www.britannica.com

既然酵素能夠有助分解食物,便可以加速吸收,人會得到更多營養,理論上只會導致肥胖。

延伸閱讀︰

Key and lock hypothesis (假設) of enzyme

Enzymes are folded into complex 3D shapes that allow smaller molecules to fit into them. The place where these molecules fit is called the active site.

In the lock and key hypothesis, the shape of the active site matches the shape of its substrate (基質) molecules. This makes enzymes highly specific. Each type of enzyme can usually catalyst only one type of reaction.

Chitosan (甲殼素) 無效

This article aims to determine whether chitosan, a popular, over-the-counter, weight loss supplement, is an effective treatment for overweight and obesity.

Results obtained from high-quality trials indicate that the effect of chitosan on body weight is minimal and unlikely to be of clinical significance.

Mhurchu, C. N. (2005). Effect of chitosan on weight loss in overweight and obese individuals: a systematic review of randomized controlled trials. Obesity Reviews, 6(1), 35-42. https://doi.org/10.1111/j.1467-789X.2005.00158.x

White Kidney Bean (白腎豆) 有效

In summary, after analysis of the various effective parameters, our results clearly revealed that intake of dietary 2,400 mg Phaseolus vulgaris extract (PVE) capsules daily by obese human subjects is more effective at reducing body weight and body fat mass compared to daily intake of placebo in a short time period. In our experiments, no clinically significant changes and adverse events occurred or felt due to the active product during the trial period. PVE has the potential to induce weight loss and reduce fat mass caused by carbohydrates through its alpha‐amylase inhibiting activity. This work provides the detail information for the depth study and wide applications of PVE in the future work.

Wang, S. (2020). Regular intake of white kidney beans extract (Phaseolus vulgaris L.) induces weight loss compared to placebo in obese human subjects. Food Science and Nutrition, 8(3), 1315–1324. https://doi.org/10.1002/fsn3.1299

2021年5月25日星期二

賣書者言

如果一個賣書者只是將書籍視之為一件普通的貨物,工作對於他或她來說會是非常枯燥乏味。

2021年5月24日星期一

是非

「唯有沉默,才容得下更多。」

改自明川的文字

說話的規訓

「人的本性,本來就有某種野性,渴望說出不中聽的實話,傾向說出帶刺的和不馴的真話。」

改自《半蝕》

他人的痛苦

「明白他人的痛苦的人,自己大概也經歷過複雜、深層而龐大的痛苦,才能具備對痛苦的想像力。」

《半蝕》