What is an Exciton?

• It is a bound state of an electron & hole which are attracted to each other by the electrostatic coulomb force.

Exciton Energy Levels

• An Exciton forms when a photon is absorbed by a Semiconductor (Semiconductor is a material that has a small band gap between the VB & CB).
• Exciton exists in insulators, semiconductors & some liquids.
• An Exciton pair is defined as an electron & hole that it leaves behind when it is excited up to the CB.
• An Exciton Bohr Radius is the distance in an electron - hole pair.

Difference between Aerogel & Xerogel

Aerogel

• Has very amorphous pattern.
• Clusters were randomly dispersed. 

Aerogel

 

Xerogel

• Some peaks in pattern were considerably enhanced.
• Very distorted by intercalation.

Xerogel

Review on Chemistry of Biomolecules

Definitions
 
Co-factor
Non-protein  chemical compound that is bound to a protein.

Con-enzyme
If the co-factor is organic,then it is co-enzyme. 

Apo Enzyme
Protein component of an enzyme to which the co-enzyme attaches to form an active enzyme.

Holo Enzyme
A complete catalytic activity of enzyme together with bound enzyme or metal ion.

Prosthetic Group
Is a kind of co-factor which is a organic molecule that is permanently attached to an enzyme.

Regulatory Enzyme (Adjustable Enzyme)
Control the rate of reaction by an enzyme by some effector (inhibitor or activator) or by alternation of some conditions such as pH.

Allosteric Enzyme
Function through reversible non-covalent binding of a regulatory metabolic at a site other than catalytic active site.

DNA Intercalation
It is an insertion by covalent linkage of  a molecule into the double-stranded Deoxyribonucleotide polymer between internal bone pairs stacked one on another perpendicular to the double helix axis.

Preservative

It is any substance that inhibiting, retarding or arresting the group of 
micro-organisms or any deterioration of food due to micro-organisms.

Exceptions for Preservatives

1. Sugar
2. Vinegar
3. Alcohol / Wine

Inflammable Organic Solvents in the Laboratory

Alcohol

More details

Acetone

More details

Phenol

More details

Benzene

More details

Ether

More details

Use of Laboratory Glasswares & Equipments

1. Conical Flask
   To collect filtrates to mix solutions.
2. Beaker
   To mix and put liquids.
   To measure solutions.
3. Test Tube
   To mix liquids & separate.
4. Boiling Tube
   Boil for certain amount of solution.
5. Ignition Tube
   To heat in high temperature.
6. Filter Funnel
   To filtrate liquids & solutions.
7. Measuring Cylinder
   Measure liquids.
8. Filter Paper
   Filter liquids regularly.
9. Tongs
   To hold ignition tube & boiling tube.
10. Test Tube Holder
    To hold the test tube & boiling tube.
11. Wire Gauze
    To place on conical flask or beaker on the tripod stand.
12. Tripod Stand
    To place flask or beaker which is to be heated.
13. Wash Bottle
    To store distilled water.
14. Spatula
    To take solid chemicals.
15. Watch Glass
    To take solid chemicals & measuring.
16. Glass Rod
    To filter & mix chemicals.
17. Stand
    To hold the filter funnel.

Degaldoruwa Temple Arts

Vessantara is shown the way to the big mountain by the kings.Detail of a narrative painting of Vessantara Jataka,Degaldoruwa Rajamaha Vihara, Gunnapana between 1771 & 1786.

Dembawa Temple Arts

Battle with Mara. Painting on cloth (Petikada). Dembawa Rajamaha Vihara.
Late 18th century.

Divine being fanning the Buddha. Detail of a painting on cloth (Petikada). Dembava Rajamaha Vihara. Late 18th century.