DNA can be separated by agarose gel electrophoresis in which agarose is used as a matrix. DNA sample is added to the slot and current is applied to it. The smaller molecules move faster and the larger molecules are retarded. In this method, separation is based on charge and size of the DNA fragment. Isolation of DNA from agarose gels by electrophoresis can be done using the DEAE-cellulose membrane. It is done by transfer of all DNA fragments from an agarose slab gel onto DEAE-cellulose paper. Individual fragments of DNA are then eluted using 0.1 M NaCl.

The dielectric strength of a material is a measure of the electrical strength of an insulator. It is defined as the maximum voltage required to produce a dielectric breakdown through the material.

Its SI unit is Volts per unit thickness.

Van de graaff generator is used to generate high voltages of the order of a few million volts. This results in generation of large electric fields for experimental purposes.

Principle

• The inner sphere has a higher potential than outer if the charge q is positive.
• If the two spheres are connected through a wire, the charge will flow from high to low potential.
• Thus, providing smaller potentials at the inner sphere will keep building large amount of charge at the outer sphere, till the breakdown field of air (3 x 10⁶ V/m) is reached.
• This accumulates close to millions of volts.

(a)Polar Dielectric : Those substances in which the centre of positive and negative ions of molecules are not concentrated but are separated, are called polar dielectric substances. Each molecule of these substances have net permanent electric dipole moment and each molecule behaves like an electric dipole. For example, HCl molecule  

In absence of an external electric field, the molecules of a polar dielectric substance are arranged in irregular manner due to thermal energy. Due to this, any volume of a substance which has molecules in large amount has zero resultant dipole moment and thus, the resultant dipole moment of the substance is zero. On placing the substance in external electric field, each molecule applies torque on the dipole that tries to align the molecule along the direction of external electric field. On increasing the electric field intensity of the external electric field, more of the molecules get align themselves in the direction of the external electric field. Thus, there is net dipole moment in the substance.

(b)Non−polar Dielectrics : Those substances in which the centre of both passive and negative charges of the molecules are coincide, are called non-polar dielectric substances. For example, H2​, CO2​, N2​ and O2​ etc.  Each molecule of these substances has zero dipole moment. Thus, the net dipole moment of the whole substance is zero.

If a non-polar dielectric substance is kept in an external electric field, then the centre of the positive charge is along the electric field and the centre of the negative charge is displaced opposite to the direction of the electric field. this induces some dipole moment in each molecule.
"The induction of electric dipole moment in a dielectric substance in the presence of external electric field is called the polarization of dielectric substance.

Writing Informal Invitations:
Informal

• Written in a letter form, in an informal format. Such letters are very persuasive in nature.
• Written in the first person.
• Salutation is ‘dear + name’.
• Complimentary close ‘Yours sincerely’.
• Date of writing the invitation is given.
• Sender’s address appears on the left-hand side.
• Various tenses used to suit the sense.

Sample 1: Mr and Mrs G Joseph of 27, The Apple Tree Orchard, Kottayam, have decided to have a party on the occasion of the twenty-first birthday of their son, Vineet. Write the invitation giving details of the date, time and venue. Do not exceed 50 words.

A shuttle vector is defined as a plasmid capable of replicating in two different organisms.
Vectors are the DNA molecules that carry a foreign DNA segment and replicate within the host cell such as bacteriophages, cosmids, phagemid, BAC (bacterial artificial chromosomes), YAC (yeast artificial chromosome) animal and plant vectors, and shuttle vectors.
Plasmid DNA acts as a vector to transfer a piece of alien DNA attached to it.
Recombinant DNA = vector + insert
Mosquito is an insect vector that transfers the malarial parasite into the human body, similarly, the plasmid is used to transfer alien DNA into the host organism.
Shuttle vectors are those vectors that can be used for more than one organism like used for both prokaryotes and eukaryotes.

A shuttle vector is a vector  constructed so that it can propagate in two different host species.  Therefore, DNA inserted into a shuttle vector can be tested or manipulated in two different cell types. The main advantage of these vectors is they can be manipulated in E. coli, then used in a system which is more difficult or slower to use (e.g. yeast).
Shuttle vectors include plasmids that can propagate in eukaryotes and prokaryotes  or in different species of bacteria . There are also adenovirus shuttle vectors, which can propagate in E. coli and mammals.

Fowler's position facilitates the relaxing of tension of the abdominal muscles, allowing for improved breathing. In immobile patients and infants, the Fowler's position alleviates compression of the chest that occurs due to gravity. Fowler's position increases comfort during eating and other activities, is used in postpartum women to improve uterine drainage, and in infants when signs of respiratory distress are present. Fowler's position is also used when oral or nasal gastric feeding tubes have been implemented as it minimizes the risk of aspiration. Peristalsis and swallowing are aided by the effect of gravitational pull.

XeO₃ is isostructural with BrO₃- . (pyramidal structure)  

The economy of the Soviet Union was based on state ownership of the means of production, collective farming, and industrial manufacturing. The highly centralized Soviet-type economic planning was managed by the administrative-command system.

Iraq invaded Kuwait in August 1990. After attempts made by several countries to persuade Iraq to leave Kuwait failed, the UNO decided to liberate Kuwait from Iraqi occupation by using military force. A huge coalition force of 660,000 troops from 34 countries fought against Iraq and defeated it. This war came to be popularly known as the Gulf War.

Electric field of an electric dipole at a point in space depends upon the position of the point.

• The dipole field at a point is inversely proportional to the cube of distance from the center to the point.
• For a very small dipole, the 2a approaches zero. This is called point dipole.

electric field due to infinite thin wire

 1/R²