The document discusses lipids and fatty acids. It defines lipids as organic compounds that are relatively insoluble in water but soluble in organic solvents, related to fatty acids, and used by living cells. Lipids are composed of alcohols, fatty acids, and sometimes other components like phosphoric acid or nitrogenous bases. Fatty acids are carboxylic acids with hydrocarbon tails that can be saturated or unsaturated. They are classified based on factors like chain length and number of double bonds. Common saturated fatty acids include palmitic acid and stearic acid, while unsaturated examples include oleic acid, linoleic acid, and docosahexaenoic acid.
A complete review of carbohydrates. definition, source of carbohydrates. Importance, function of carbohydrates. translocation of carbohydrates in plants.
A complete review of carbohydrates. definition, source of carbohydrates. Importance, function of carbohydrates. translocation of carbohydrates in plants.
This presentation is made for F.Y.Bsc. Students.
The presentation includes the General Properties of Carbohydrate and the classification of carbohydrates.
Carbohydrates are generally classified into monosaccharides (simple sugars), oligosaccharides (containing few sugar units) and polysaccharides (containing many sugar units).
Monosaccharides are sugar molecules containing short chain of carbon atoms, one aldehydic or ketonic group and hydroxyl groups attached to remaining Carbon atoms.
Oligosaccharides are formed by polymerisation of monosaccharide molecules by elimination of water molecules.
Polysaccharides are high molecular weight substances composed of large number of moosaccharide units combined to form one large polymer molecule. They may be straight chain or branched chain polymers.
Carbohydrates: Monosaccharides- structure and functionDr. GURPREET SINGH
this presentation describes about the structure of carbohydrates in detail with specific reference to monosaccharides, their classification, structural component and functions
A Comprehensive Introduction to Lipids and its chemistry, classification, qualitative tests and disorders related to its metabolism. This will give readers a overall insight to this topic. All types of queries and suggestions are most welcome
Lipid Chemistry-Complete - Alex -Dr Ayman- 2015 - 2016 - More Detailed.pptAyman Abdo
This presentation shows the classification and occurrence of human lipids and their biological value. It also reveals the chemical formula of human lipids
This presentation is made for F.Y.Bsc. Students.
The presentation includes the General Properties of Carbohydrate and the classification of carbohydrates.
Carbohydrates are generally classified into monosaccharides (simple sugars), oligosaccharides (containing few sugar units) and polysaccharides (containing many sugar units).
Monosaccharides are sugar molecules containing short chain of carbon atoms, one aldehydic or ketonic group and hydroxyl groups attached to remaining Carbon atoms.
Oligosaccharides are formed by polymerisation of monosaccharide molecules by elimination of water molecules.
Polysaccharides are high molecular weight substances composed of large number of moosaccharide units combined to form one large polymer molecule. They may be straight chain or branched chain polymers.
Carbohydrates: Monosaccharides- structure and functionDr. GURPREET SINGH
this presentation describes about the structure of carbohydrates in detail with specific reference to monosaccharides, their classification, structural component and functions
A Comprehensive Introduction to Lipids and its chemistry, classification, qualitative tests and disorders related to its metabolism. This will give readers a overall insight to this topic. All types of queries and suggestions are most welcome
Lipid Chemistry-Complete - Alex -Dr Ayman- 2015 - 2016 - More Detailed.pptAyman Abdo
This presentation shows the classification and occurrence of human lipids and their biological value. It also reveals the chemical formula of human lipids
Lipids-Introduction, properties and functions.
Classification-Simple lipids, complex lipids and derived lipids.
Lipids contain fatty acid and alcohol.
Saturated and Unsaturated fatty acids. Nomenclature of fatty acids, Cis-trans isomerism, essential fatty acids
Simple lipids-Fats, waxes
Compound lipids-Structure, function with examples of Phospholipids, Glycolipids, sulpholipids and lipoproteins.
Derived lipids: Structure, types, and functions of steroids, terpenes and carotenoids.
Lipoproteins-classified into chylomicrons, very low-density lipoproteins (VLDL), low density lipoproteins (LDL) and high-density lipoproteins (HDL) and their function.
Eicosanoids-prostanoids, leukotrienes (LTs), and lipoxins (LXs).
Functions of Eicosanoids
Lipids, micelles and liposomes.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
2. LIPIDS
The term ‘Lipids’ first coined by German Biochemist Bloor in 1943
Lipids are important heterogenous group of organic substances in plant and
animal tissue
Chief concentrated storage form of energy
These are related either actually or potentially to the fatty acids
Chemically these are esters of alcohol (commonly glycerol)with fatty acids
Insoluble in water and soluble in nonpolar organic solvents like ether,
chloroform, acetone, benzene etc( fat solvents)
Hydrophobic in nature
Oily or greasy substances
Unlike carbohydrates and proteins these are not polymers
Lipids are mostly small molecules
In addition to alcohol and fatty acids, some of the lipids may contain
phosphoric acid, nitrogenous base and carbohydrates.
“Lipids may be regarded as organic substances relatively insoluble in water, soluble in organic
solvents actually or potentially related to fatty acids and utilized by the living cells.”
3. Functions of lipids
Storage form of energy (triglycerides)
Structural components of biomembranes (phospholipids and cholesterol)
Metabolic regulators (steroid hormones and prostaglandins)
Act as surfactants, detergents and emulsifying agents (amphipathic lipids)
Act as electric insulators in neurons
Provide insulation against changes in external temperature (subcutaneous
fat)
Give shape and contour to the body
Protect internal organs by providing a cushioning effect (pads of fat)
Help in absorption of fat soluble vitamins (A, D, E and K)
Improve taste and palatability of food.
4. Composition of lipids1.ALCOHOL
The alcohol found in lipids are saturated
It include glycerol and higher alcohol such as cetyl alcohol, myricyl
alcohol etc
The unsaturated alcohol present in lipids are pigments like phytol
(constituent of chlorophyll), lycophyll (pigment in tomato)
Glycerol is the most common alcohol present in lipids
Glycerol is a 3C compound. The 1st and 3rd C atom are identical
Glycerol
Cetyl alcohol
CH3-(CH2)14-CH2OH
Myricyl alcohol
CH3-(CH2)28-CH2OH
5. Composition of lipids2.FATTYACID
Fatty acids (FA)are the carboxylic acids with hydrocarbon side chain
General formula, R—CO—OH, where COOH (carboxylic group) represents
the functional group
Depending on the R group (the hydrocarbon chain), the physical properties of
fatty acids may vary
These are long chain organic acids having usually 4- 30 carbon atoms
It contains only one carboxylic group (monocarboxylic)
The nonpolar hydrocarbon tail makes the lipids hydrophobic in nature and
oily or greasy
Contains even number of carbon atoms as these are synthesized from 2C
units.
These are usually straight chain derivatives. Still other possess ring structure
(cyclic FA)
Some contains hydroxyl groups (hydroxy or oxygenated fatty acids)
Do not occur in free state in tissues ,found in covalently bound form
If free, the carboxyl group of fatty acid will be ionized
7. Nomenclature of fatty acid
The systemic name is based on the hydrocarbon from which is derived
(Genevan system)
The saturated fatty acid end with a suffix –anoic (eg: octanoic acid) while the
unsatuated fatty acid end with suffix –enoic (eg: octadecenoic acid)
The position of C atom in the fatty acid chain is indicated either by numbering
(1,2,3 etc) or by use of Greek letters (α,β etc)
The numbering starts from the carboxyl carbon (from the –COOH carbon) –
carbon No.1. (C1)
The carbon adjacent to –COOH group - carbon number 2 (α-carbon), then
carbon atom 3 (β-carbon) and so on.
The end –CH3 carbon is known as the ω-carbon (‘Omega’ carbon).
starting from the methyl end, the carbon atoms may be numbered as omega
(ω)-1,2,3, etc.
6 5 4 3 2 1
CH3 — CH2 — CH2 — CH2— CH2 — COOH
ω1 ω2 ω3 ω4 ω5
6 5 4 3 2 1
CH3 — CH2 — CH2 — CH2— CH2 — COOH
ω δ γ β α
8. Nomenclature of fatty acid (conts…)
Widely used convention to indicate the number and position of the double bond(s) in
the case of unsaturated fatty acids is to write the number of carbon atoms, the number
of double bond(s) and the position of the double bonds(s) below the name of the acid.
For example,
1. Oleic acid having 18 carbon atoms and a double bond between carbon atoms 9 and 10
is written as 18:1; 9.
2. Linoleic acid (18 carbon atoms and 2 double bonds at C 9 and C 12) is written as 18:2;
9, 12.
An alternative method to write the name of an unsaturated fatty acid is to write first
the position of double bond(s) in numerals and then the total number of carbon atoms
in Roman followed by the suffix -enoic acid.
Eg :
1. Oleic acid written as 9-octadecenoic acid and
2. Linoleic acid written as 9, 12-octadecadienoic acid.
Other representations
∆ represents double bonds-eg: ∆9 indicates double bond is between 9 and 10
ω – eg: ω6 series indicates double bond is between 6 and 7 from the ω end.
9. Classification of fatty acids
1.Based on the presence or absence of double bond
• Saturated FA (no =bond)
• Unsaturated FA (1 or more =bond)
2. Based on nature of chain
• Straight chain FA
• Branched chain FA
• Cyclic fatty acids
• Hydroxy or oxygenated fatty acids
3. Based on total number of carbon atoms
• Even chain FA
• Odd chain FA
4. Based non length of hydrocarbon chain
• Short chain FA (2 to 6 carbon atoms)
• Medium chain FA (8 to 14 carbon atoms)
• Long chain FA (16 to 22 carbon atoms)
• Very long chain FA (>24 carbon atoms)
10. 1.Based on the presence or absence of double bond
1. SATURATED FATTY ACIDS
>Contains only single bonds
>The general formula for these acids is CnH2n+1COOH.
>Eg: butanoic acid (C4) - C3H7COOH or CH3-CH2-COOH or
CH3-(CH2)2-COOH
>Saturated fatty acids may found in
a. Straight chain fatty acids
#Even numbered-eg:palmitic acid(16C), stearic acid (18C)
#Odd numbered- eg: propionic acid(3C), Valeric acid(5C)
b. Branched chain fatty acids
#Even numbered –eg: Isopalmitic acid(16C)
#Odd numbered- eg: Anteisopalmitic acid(17C),
Tuberculostearic acid (19C)
13. 1.Based on the presence or absence of double bond
2. UNSATURATED FATTY ACIDS
>Contains one ore more double bonds
>These may be classified, based on the degree of unsaturation.
A. Monoethenoid acids — Contains one double bond
CnH2n–1COOH;
eg: oleic acid.
B. Diethenoid acids —Contain Two double bonds;
CnH2n−3COOH;
eg: Linoleic acid.
C. Triethenoid acids — ContainThree double bonds;
CnH2n−5COOH;
eg:Linolenic acid.
D. Tetraethenoid acids — Contain Four double bonds;
CnH2n−7COOH;
eg: Arachidonic acid
>Monoethenoid acids are commonly called as monounsaturated fatty acids (MUFAs)
and the remaining ones as polyunsaturated fatty acids (PUFAs).
14. ISOMERISM
1. Exhibit geometric isomerism;
If the atoms or acyl groups on same side of double bond- cis configuration
If the groups on opposite side of double bond- trans configuration.
➢cis-isomers are less stable than trans-isomers.
➢Most of naturally occurring unsaturated fatty acids exist as cis isomer
➢Eg:
2. Positional Isomers: A variation in the location of the double bonds along the
unsaturated fatty acids chain produces isomer of that compound. Thus, oleic
acid could have 15 different positional isomers.
15. ➢DOCOSAHEXAENOIC ACID: DHA (Ω3, 22:6)
➢Docosahexaenoic acid (DHA) is a polyunsaturated
fatty acid which is synthesized from α-linolenic or
obtained directly from dietary fish oil. This fatty acid is
present in high concentrations in retina, cerebral cortex,
and sperms.
➢DHA is particularly needed for development of the
brain and retina and is supplied via the placenta and
milk. In EFA deficiency, nonessential polyenoic acids of
the ω9 family replace the essential fatty acids in
phospholipids (PL), other complex lipids and
membranes.
18. Unusual unsaturated fatty acid
Nemotinic acid (16C)
It is excreted in the growth medium by a citrivorium
mould.
This fatty acid is unique in that it contains the single,
double and triple C—C linkages.
Nemotinic acid is one of the few naturally-occurring
compounds containing the allene group
19. 2. Based on nature of chain
1.STRAIGHT CHAIN FATTY ACIDS
Linear chain
Eg:
1.Palmitic acid (C16)
16CH3-15CH2-14CH2-13CH2-12CH2-11CH2-10CH2-9CH2-8CH2- 7CH2-
1COOH-2CH2- 3CH2-4CH2--5CH2-6CH2
2. Stearic acid (C18)
2.BRANCHED CHAIN FATTY ACIDS
Eg: Anteisopalmitic acid (C17)(Methyl hexadecanoic acid)
18CH3-17CH2-16CH215CH2-14CH2-13CH2-12CH2-11CH2-10CH2-9CH2-8CH2-7CH2-6CH2-
1COOH-2CH2--3CH2-4CH25CH2
20. 2. Based on nature of chain
3.HYDROXY OR OXYGENATED FATTY ACIDS
Ricinoleic acid (found in castor oil -87%). It is a C 18 acid with a double bond at C9 and an
OH group on C12.
Cerebronic acid, a C 24 acid obtained from animal lipid, is another important hydroxy acid
with an OH group on C2.
9, 10 dihydroxystearic acid(C18). A common oxygenated fatty acid, isolated from plants and
bacterial lipids.
9, 10-epoxystearic acid (C18) is isolated from rust spore lipids (20%).
21. 4. CYCLIC FATTY ACIDS
These are of rare occurrence.
Hydnocarpic acid and Chaulmoogric acid. Chaulmoogra oil, obtained from the plant
Hydnocarpus kurzil and used in the treatment of leprosy, contains 2 such acids. Chaulmoogric
acid has a cyclopentenyl ring in its 18-carbon structure..
Lactobacillic acid, Lipids from the lactobacilli contain a fatty acid, with a cyclopropyl group.
This fatty acid may result from the addition of a methylene group across the double bond
of vaccenic acid.
Sterculic acid from plant sources has a comparable structure, with a suggested relationship
to oleic acid. It may be derived from oleic acid by the addition of a methylene group
across the double bond in a manner that the unsaturated nature is not altered, unlike the
lactobacillic acid.
2. Based on nature of chain
22. 3. Based on total number of carbon atoms
1. EVEN CHAIN FATTY ACIDS
Eg: palmitic acid(16C)
Stearic acid (18C)
Isopalmitic acid(16C)
2. ODD CHAIN FATTY ACIDS
Eg: Valeric acid (5C)
Propionic acid (3C)
Tuberculostearic acid(19C)
23. 4. Based non length of hydrocarbon chain
• Short chain FA (2 to 6 carbon atoms)
• Acetic acid(2C), Caproic acid(6C)
• Medium chain FA (8 to 14 carbon atoms)
• Caprylic acid (8C), Myristic acid (14C)
• Long chain FA (16 to 22 carbon atoms)
• Palmitic acid(16C), Behenic acid(22C)
• Very long chain FA (>24 carbon atoms)
• Cerotic acid(26C)
24. ESSENTIAL FATTY ACIDS
The fatty acids that cannot be synthesized by
the body and therefore, should be supplied
through diet is known as essential fatty
acids(EFA)
Chemically they are polyunsaturated fatty acids(PUFA)
Eg: linoleic acid(ω6, 18C, Δ 9,12)
Linolenic acid(ω3, 18C, Δ 9,12,15)
Arachidonic acid(ω3, 20C, Δ 5,8,11,14)
Normal dietary allowance of PUFA is 2-3% of total
calories.
26. ESSENTIAL FATTY ACIDS(conts..)
BIOCHEMICAL BASIS OF ESSENTIALITY
Humans lack the enzyme that can introduce double
bonds beyond carbons 9 to 10
Introduction of additional double bonds in unsaturated
fatty acid is limited to the area between – COOH
group and the existing double bond and that it is not
possible to introduce a double bond between the –
CH3 group at the opposite end of the molecule and the
first unsaturated linkage. This would explain body’s
inability to synthesise an EFA from oleic acid.
27. ESSENTIAL FATTY ACIDS(conts..)
Functions of EFA
Structural elements of tissues: Polyunsaturated fatty acids occur in higher concentration in lipids associated
with structural elements of tissues.
Structural element of gonads: Lipids of gonads also contain a high concentration of polyunsaturated fatty
acids, which suggests importance of these compounds in reproductive function.
Synthesis of prostaglandins and other compounds: Prostaglandins are synthesised from Arachidonic acid
by cyclooxygenase enzyme system. Leucotrienes are conjugated trienes formed from arachidonic acid in
leucocytes by the Lipoxygenase pathway.
Structural element of mitochondrial membrane: A deficiency of EFA causes swelling of mitochondrial
membrane and reduction in efficiency of oxidative phosphorylation. This may explain for increased heat
production noted in EFA deficient animals.
Serum level of cholesterol: Fats with high content of polyunsaturated fatty acids tends to lower serum level
of cholesterol.
Effect on clotting time: Prolongation of clotting time is noted in ingestion of fats rich in EFA.
Effect on fibrinolytic activity: An increase in fibrinolytic activity follows the ingestion of fats rich in EFA.
Role of EFA in fatty liver: Deficiency of EFA produces fatty liver.
Role in vision: Docosahexaenoic acid is the most abundant polyenoic fatty acids present in retinal
photoreceptor membranes. Docosahexaenoic acid is formed from dietary linolenic acid. It enhances the
electrical response of the photoreceptors to illumination. Hence linolenic acid is necessary in the diet for
optimal vision.
28. ESSENTIAL FATTY ACIDS(conts..)
DEFICIENCY MANIFESTATIONS:
A deficiency of EFA has notyet been unequivocally demonstrated in humans.
In weaning animals, symptoms of EFA deficiency are readily produced. They are:
Cessation of growth.
Skin lesions: Acanthosis (hypertrophy of prickle cells) and hyperkeratosis
(hypertrophy of stratum corneum). Skin becomes abnormally permeable to water.
Increased loss of water increases BMR.
Abnormalities of pregnancy and lactation in adult females.
Fatty liver accompanied by increased rates of fatty acids synthesis, lessened
resistance to stress.
Kidney damage.
FATE OF EFA
EFA undergoes β-oxidation after necessary isomerisation and
epimerisation, like other unsaturated fatty acids
29. REFERENCE
Dr. M.N. Chatterjea, and Rana Shinde; Extbook of Medical
Biochemistry; Eighth Edition ;Jaypee Brothers Medical
Publishers (P) Ltd
D.M .Vasudevan, Sreekumari S., and Kannan Vaidyanathan;
Textbook of Biochemistry, For Medical Students; Sixth
Edition; Jaypee Brothers Medical Publishers (P) Ltd
J.L. Jain, Sunjay Jain and Nitin Jain; Fundamentals of
Biochemistry for University and College Students in India
and Abroad; Sixth Edition; S. Chand & Company Ltd.; 2005
Dr. U. Satyanarayana and U. Chakrapani; Biochemistry;
Fourth Edition; Elsevier India Pvt. Ltd; 2013