Condoms

• What is condoms actually?
• What does it for?
• How does it works?
• What is condoms made of?

There are many questions over many children's mind.

How Does It Work?

Condoms work by keeping semen (the fluid that contains sperm) from entering the vagina. The male condom is placed on a guy's penis when it becomes erect (and before any sexual contact). It is unrolled all the way to the base of the penis while holding the tip of the condom to leave some extra room at the end. This creates a space for semen after ejaculation and makes it less likely that the condom will break.

The two main function of condoms basically is:

• Prevent from pregnancy
• Stop spreading sexually transmitted diseases (i.e: HIV)

Mainly condoms are made from latex nowadays but there is also another type of materials such as sheep intestine, polyurethane.


Latex condoms 

• With oil-based lubricant. 
• likely to slip off due to loss of elasticity caused by the oils.
   
  

Latex(rubber) structure

Polyurethane condoms 

• Same width and thickness as latex condoms.
• 0.04 mm and 0.07 mm thick. 
• Material of many female condoms.

Lambskin condoms  

• Made from lamb intestines. 
• Greater ability to transmit body warmth and tactile sensatio. 
• Cause fewer allergenic reactions than latex.  
• Increased risk of transmitting STDs compared to latex because of pores in the material, are large enough to allow infectious agents to pass through. 

All condoms are more comfortable for both partners when use with additional or latex-safe lubricants. 
Lubricants reduce friction during sexual intercourse, which lessen the risks of breakage by keeping the barrier moist and in doing so, also help ensure that genitals remain moist enough to make barrier use more pleasurable.


Nonoxynol-9

• N-9.
• Non-ionic nonoxynol surfactantthat used to cleaning and cosmetic products.
• Widely used in contraceptives for its spermicidal properties.
• Active ingredient in most spermicidal creams, jellies, foams, gel, film, and suppositories.   

 Below are the examples of types of one of the famous brand for condoms (durex)

Regular condoms for a natural feeling

 

Narrower condom to provide a tighter fit for extra confidence.

 

Our thinnest latex condom for ultimate sensitivity

 

It’s the special lube that creates the gentle tingling.

 

Longer and wider for a better fit!

 

Three fun fruit flavours.

 

Ultra fine for enhanced sensitivity.

 

500 unique raised dots mean 100% enhanced pleasure.

 

It’s the one with uniquely positioned ribs and raised dots. In all the right places!

 

With a gentle lubricant for a natural feel during lovemaking.

 

Slightly thicker. With extra lubrication. For those who want the ultimate reassurance.

 

An exciting selection of condoms and lubes.

Non-latex condoms – suitable for sensitive users.

How does medicine actually work in our body?

Aww...sick again...have to take medicine again...


I'm pretty sure there are many people curious about how medicine has been deliver inside our body.
These are the question will be asked:

• How to get the drug molecule to the target site?
• How to get the drug to its target in one piece and avoid being broken down half way to the target site?

Now I will lead everyone to reveal these answer.
The scientist have make use of the liposomes or virosomes.


What are liposomes?

Liposome and phospholipid molecule

Liposomes basically are the microscopic vesicles particles composed of lipids.
It can filled with drugs and deliver to the target site safely.
The most common constituent of liposome is phospholipid that speontaneously form closed structures in aqueous because a phospholipid molecule has a hydrophilic head and a hydrophobic tail.
Hydrophilic means by "water-loving" while hydrophobic means by "water- fearing"
Since the head is hydrophilic, it will attracted to the water; however the tail is hydrophobic which will repeal from water molecules.


So, it will form a closed structures automatically.
This natural allignment creates two rows of tightly fitted phospholipid molecules which called as phospholipid bilayer.


Hydrophobic are intercalated within the membrane, on the other hand hydrophilic can be entrapped within the internal aqueous region.

action of liposome

Liposome filled with drug will reach the target site and the liposome will fused into the cell and release the drug into the cell.

What are the advantages of being using liposomes to deliver drugs?

• Liposomes are non-toxic and biodegradeble.
• Faster response.
• Allow a smaller dosage to used.
• To avoid drug to hydrolyse in stomach
• Patient do not have to be unconscious

Now, you should know how drugs being deliver safely to the target site.  Have a nice day ^^

Best friend forever – Pencil and Eraser

OH MY GOSH~!  I accidentally stuck half centimeter of a pencil lead on my finger-tip! Is there any possibility that I will get into lead poisoning?

Ladies and gentlemen, do not panic as pencil lead is not really the lead, it is a non-toxic mixture which is made of graphite and clay now. It is known as lead because of the graphite marked like lead and last time the pencil is made of lead, so until now there is still some of the people thought pencil is made of lead. Well, as I said the pencil lead is now made of graphite and clay, not the actual lead.

Graphite is a giant covalent molecule which has many planes. The forces which hold between the planes are actually weak Van der Waals force. The planes may slip over each other and the C-C bonds are strong.

Friend of pencil – Eraser

Before the eraser being invented, the bread was used to erase the marked of pencil. Typical erasers are made from synthetic rubber. Eraser is make by which the tiny globes or spheres of rubber  are bunched together.

How the erasers work?

When we made a mistake with pencil, we rub it with the eraser. But why the mark vanished after rubbing with eraser? It is because the eraser can breaks the bond between the graphite and the bond between the planes. Eraser also picks up the graphite particles when breaking the bond between the C-C particles of the planes.

Hence, leaves a clean white paper. There will be a residue or dust after rubbing, it is because of the tiny globes or spheres of rubber from the rubber which bunched together loose. So with these properties, we may rub off the mistake made by pencil with the help of eraser easily.

Why the food can last for so long~Huh?

Well, after watching this video. There is a question come out in the mind, why is it the french-fries still in a good shape for almost 10 weeks but all the other burgers went rotten. As we know, it is because of the chemical substances that present in the french-fries that prevent it from rotten, which is the preservative. Preservative is a substance that have been synthesized and add into products like foods, paints or even cosmetics to avoid the decomposition of any microorganisms or avoid any unwanted chemical changes.

Although these preservatives help us a lot in storing food for long periods of time, but somehow it still cost us a lot health problem if we taken in more than the prescribed limits.  “In a study conducted by Southhampton University in 2008, researchers confirmed that children who regularly eat certain preservatives and additives are more at risk for attention disorders such as hyperactivity and lack of impulse control.”

Sources : http://www.ehow.com/list_7377545_sort-preservatives-mcdonalds-food_.html

Let’s see what are those common preservatives that can be
found around us :

BHA (butylated hydroxyanisole) - C₁₁H₁₆O₂

An antioxidant. This food preservative is used to preserve the fresh pork and pork sausages, potato chips, instant teas, cake mixes and many more. In the state of California, they have listed it as a carcinogens  and expected to cause the live diseases and cancer.

Benzoates – C₆H₅COO^-

This food preservative is used in fruit juices, tea, coffee etc. It have been banned in Russia due to its role in triggering allergies, asthma and skin rashes. It is considered to cause the brain damage too.

Sodium Nitrate / Sodium Nitrite – NaNO₃ / NaNO₂

This food preservative is used in meats and fish. It will cause a human carcinogen which includes gastric cancer, oesophageal cancer and colon cancer etc. It is known that the sodium nitrite, sodium nitrate will forms nitrosamines in cured meats which will cause DNA damage and increased cellular degeneration.

Sulfite -  (SO₃)^2-

It can be found from all the wines because it is used in winemaking. Sulfites are often used as preservatives in dried fruits, radish, and dried potato products. People who are sensitive to sulfite will have breathing problem after consuming the food that was containing it. Sulfites are also known to destroy vitamin B₁.

Yucks~ your clothes are dirty? What to do?

There are so many branded detergent in the store but how do we determine which brand are the most effective brand?

Chlorine is added to the detergent to act as bleaching agent.  Chlorine able to displace iodine as the chlorine is a stronger oxidising agent compare to iodine.  So, we can use iodine to titrate with known concentration of sodium thiosulphate to determine the concentration of the’ free chlorine’ in the detergent  in order to compare which work the most effective. The more the concentrate of ‘free chlorine’, the more effective the detergent works.

How detergent work?

We have to understand the structure of the detergent molecule in order to know how the detergent works. The detergent molecule consists of two parts hydrophilic head and hydrophobic tail. Hydrophilic head is made up of sulphonate group which will attract the water molecule to be bind with it as it is polar. While, the tail is made up of a long hydrophobic hydrogen carbon tail.

In water, the hydrophilic head which is negatively charge will dissolve in water, as the water is positively charge. The hydrophobic tail will dissolve on the dirt layer. So, when the water is stir the grease will lift off from the surface. The dirt is emulsify after being lift off from the surface by the surfactant. The dirt then will be breaks into small pieces and wash away with water. They will not clump back into large molecule because each of the small molecule are carrying the same charge, negative charge they will repeal each other. 

Do you know? 

There are two types of water soft and hard water. Hard water contain high amount of mineral with it especially with Mg²⁺and Ca²⁺ ions. While the soft water is free of any minerals. Detergent is effective in both soft and hard water as it do not form scum with Mg²⁺and Ca²⁺  ions.