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Thursday, August 15, 2013

PPT On Software


Software Presentation Transcript: 
Software History & Significance
System Software
Application Software
Software Issues
Programming Languages
Enterprise Software

2.Software History & Significance
The first applications of computers in business were in the early 1950s.
Software was less important (and less costly) in computer systems then as opposed to now, because early hardware was literally hardwired by hand for each application.
Today, however software comprises a much larger percentage of the cost of the modern computer systems

3.Reasons of New Trends
The price of hardware is dramatically decreased, while performance of hardware is increased exponentially.
Software has become increasingly complex and its price has increased along with its complexity.
Software development is slow, increasingly complex, error prone and expensive. Finally, salaries of software developers are steadily increasing because there is an increased demand for their skills.

4.The Software Crisis
The software crisis is that organizations are not able to develop new software applications fast enough to keep up with rapidly changing business conditions and rapidly evolving technologies.
Computer hardware can be designed and manufactured on automated assembly lines and so can be turned out rather quickly, but software must be engineered by hand.

5.The Software Crisis
The result is that organizations are unable to make full use of hardware due to lack of software to effectively exploit the hardware.
Further, organizations not only must develop new applications quickly, but they must also maintain their existing software.
Often, more than 80% of IT personnel maintain existing software, leaving less than 20% to develop new applications.

6.Large applications today may contain millions of lines of computer code, written by hundreds of people over the course of several years.
Clearly, the potential for errors is huge, and testing and debugging software is expensive and time-consuming.

7.Software Fundamentals
Software consists of computer program, which are sequences of instructions for the computer.
The process of writing (or coding) programs is called programming.
The individuals who perform this task are called programmers.

8.Unlike the hardwired computers of the 1950s, modern software uses the stored program concept.
In this concept, stored programs are accessed and their instructions are executed (followed) in the CPU.
Once the program has finished executing, a new program is loaded into memory and the computer hardware addresses another task.

9.Computer programs include documentation, which is a written description of the functions of the program.
A software enables the user to instruct a computer system to perform specific functions that provide business value.

10.Types of Software
System Software
Application Software



RADAR COMMUNICATIONS Presentation Transcript:

2.RADAR – Radio Detection & Ranging
Radar is an Electromagnetic System for the detection and location of objects
Radar operates in microwave region
100MHz – 36 GHz, max up to 240GHz
3Operation    of Radar
Radar radiates energy into space and detect the echo signal reflected from an object/target.
Location and presence of the object both are detected by comparing the received echo signal with the signal that was transmitted.

3.It can operate in :
Its ability to measure distances with high accuracy and in all weather is one of the major attributes.

4.Basic Principle of Radar Communication
Transmitter generates Electromagnetic signal (such as short pulse sine wave) radiated into space by an antenna.
Portion of the transmitted energy is intercepted by the target and re-radiates in many directions
The re-radiated directed back towards the radar is collected back by the radio antenna, which delivers it to the receiver.

5.If the target is in motion, there is a shift in the frequency of the echo signal due to Doppler effect.
The frequency shift is proportional to the velocity of the target relative to the radar
Doppler Effect:
A change in the observed frequency of a wave, as of sound or light, occurring when the source and observer are in motion relative to each other.
The frequency increases when the source and observer approach each other and decreases when they move apart.

6.Radar Applications
Air Traffic Control
Ship Safety

PPT On Protein Purification and Analysis


Protein Purification and Analysis Presentation Transcript:
1.Protein Purification and Analysis

2.Protein Purification and Analysis
    Numbers of genes:
Humans    ~40,000 genes
Yeast        ~6000 genes
Bacteria    ~3000 genes
    Solubility of proteins important for purification:
60-80% soluble, 20-40% membrane
Some proteins expressed at high levels (collagen, hemoglobin)
Some proteins expressed at low levels (repressors, signaling)
Fibrous proteins - structural (collagen, elastin, keratin)
Globular proteins - structure and/or function (actin, enzymes)

3.Steps of purification and analysis
  (1)  Choose protein to purify
  (2)   Choose source (natural or expressed)
  (3)   Soluble in aqueous solution?? (problem     with       membrane proteins)
  (4)   Stability
  (5)   Purify
  (6)   Study (activity, structure, mechanism of        action, etc.)

4.Protein Purification and Analysis
(1) Choose protein to purify -
(2) Choose source (natural or expressed)
Source of protein for study
Early biochemistry (1970’s)
      utilized proteins that were abundant from natural sources
      (myoglobin, lysozyme, hexokinase)
 Middle biochemistry (1980’s to mid 1990’s)
      isolated small amounts of proteins, get gene, express and  
      purify from bacteria, yeast, insect cells, mammalian cells
Now (2000s)
     get gene from library based on homology
     choose gene and express and study it
Still problems with:
membrane proteins and solubility

5.Protein Purification and Analysis
 (2) Choose source (natural or expressed)
Break open cells by destroying membranes and releasing cytosolic protein mix - crude extract
If nuclear or membrane protein - more work!
(3) Soluble in aqueous solution?? (problem with membrane proteins)
(4) Stability (perform purification/analyses in cold)
(5) Purify
Separate proteins using fractionation based on physical characteristic:
1. solubility
2. electrical charge
3. size + shape 
4. affinity for other molecules 
5. polarity

        Important steps:
   1. Pack column - Column is packed with material (resin)
     that can absorb molecules based on
      some property (charge, size,  
      binding affinity, etc.)
   2. Wash column – Molecules washed
      through the column with buffer
   3. Collect fractions - Fractions are taken, at some point your molecule will elute

7.Ion exchange chromatography
Separate by charge
Elute protein
    Increase salt or pH to
    elute protein of interest

8.Protein Purification and Analysis

9.Protein Purification and Analysis
Additional Chromatography info
HPLC (high-performance liquid chromatography)
Column can be:
hydrophobic, (+) or (-) charged, stereospecific, etc.
Resin needs to have incompressible beads
high pressure pumps speed the movement of proteins down the column
HPLC limits protein band spreading - increase resolution

10.Gel Electrophoresis

Separation of proteins, nucleic acids, etc. by size, shape, charge
Proteins migrate based on their charge-to-mass ratio
Proteins visualized (radioactivity or staining)
Use gels made of crosslinked polymer (polyacrylamide) or solidified agarose

12.SDS Gel Electrophoresis
Used to estimate purity and molecular weight, separate proteins by size
Denature protein by adding SDS (then separate by size only)

13.Isoelectric focusing gel electrophoresis
determine the isoelectric point (pI) of a protein
separates proteins until they reach the pH that matches their pI (net charge is zero)

14.Separate proteins by size or density
Differential centrifugation - separates large from small particles
Isopycnic (sucrose-density) centrifugation - separates particles of different densities

15.Protein Sequencing
Function of protein depends on its amino acid sequence
Proteins with different functions always have different sequences
Changing just 1 amino acid can make a protein defective
Functionally similar proteins from different species have similar sequences

PPT On Intracellular and extra cellular industrial enzymes


Intracellular and extra cellular industrial enzymes Presentation Transcript: 
1.Intracellular and extra cellular industrial enzymes

2.Enzymes are being used more and more for industrial bioconversion i.e. making a chemical product using purified enzymes rather by pure chemical methods (e.g. citric acid production) or using whole cells (e.g. yeast in brewing).

3.Extracellular enzyme
The enzymes that function in our digestive systems are manufactured in cells - but work
   Spiders and flies are two examples of animals that have taken extracellular digestion.
They secrete an enzyme soup into or on their food. In spiders, this is injected into the prey's body. The enzyme soup digests the prey's body contents (specific enzymes breaking down proteins to AAs, lipids into FAs and glycerol and polysaccharides into monosaccharides) and the spider simply sucks up the resulting already digested food.
Saprophytic fungi also secrete enzymes through their hyphal tips in order to digest their food.

4.Intracellular enzyme
Enzymes that act inside cells are responsible for catalysing the millions of reactions that occur in metabolic pathways such as glycolysis in the mitochondria and in the photosynthetic pathway in the chloroplast.
The lysosome contains many enzymes that are mainly responsible for destroying old cells.

5.Considerations when selecting a strain:
Does it do what is required?
Is it safe?
Is it cost effective?
Enzymes may be intracellular or extracellular. What is the advantage of extracellular production?
Already outside cell
Limited number secreted so easier to isolate
More robust so less likely to be broken down by heat of chemicals

6.Why are intracellular enzymes more difficult to isolate than extracellular ones?
Because they are inside the cell, first the cell has to be broken open then the enzyme separated from the mixture of all the cellular contents
Why is it more efficient to use isolated enzymes than whole cells?
Isolated enzymes are usually more efficient in biotechnology than whole cells because enzyme concentration is higher and no unwanted enzymes are present

7.Enzymes and Sources
Overproducing strains of Bacillus, Aspergillus, Rhizopus, and Mucor.
Aspergillus niger.
Yeast and Aspergillus.
Certain strains of yeast and fungi.
Glucose isomerase
Flavobecterium arborescens or Bacillus coagulans

8.Production of Enzymes
Cultivate the organisms producing the desired enzymes.
Production can be regulated
Fermentation conditions ca be optimized for overproduction.

9.Enzyme production
Surface and submerged techniques:
Surface = enzyme produced on the     surface of a solid medium
Submerged = the mould or bacterium producing the enzyme is grown throughout a liquid medium
Advantages and disadvantages?
Submerged – more yield as growth throughout but aeration necessary

10.The maximum enzyme production is usually in stationary phase of microbe growth, so a batch or fed-batch process are usually used.
The medium must be chosen to stimulate the microbe into synthesizing the correct enzyme.
For example to stimulate a microbe to synthesize amylase enzymes, a medium with starch but no sugars is used.

11.Production of Enzymes
What type of medium would you use to stimulate a microbe to synthesize a protease?
A medium with proteins but no amino acids is used.

12.Microbes are encouraged into the log phase initially with a medium with a lot of protein
This encourages rapid increase in the number of cells, but not much protease is produced.
Cells  are then introduced into the fermentation vessel and allowed to grow for a further 1-8 days.
The medium now has very little protein in it. Why?

13.The microbe must produce a lot of protease because as the enzyme leaves the cell it doesn’t immediately come into contact with protein that it can break down – more protease produced to maximise the amount of amino acids from the small amount of protein.

14.Down stream processing
   The remaining mixture contains enzymes, waste materials, nutrients and cells
   The enzyme is extracted by downstream processing

15.Down stream processing
Cell separated from the media usually by filtration or something by centrfugation.
Depending on intra/extracellular nature of the enzyme, the cell or fermentation broth is further processed.
Recovery of intracellular enzymes is more complicated and involves the disruption of cells and removal of debris and nucleic acids.
Increasing permeability of cell membrane (CaCl2 (salt) or dimethylsulfoxide (DMSO) or change in pH
Last resort is cell disruption. 

PPT On Production Of Enzymes By Fermentation Method


Production Of Enzymes By Fermentation Method Presentation Transcript: 
1.Production Of Enzymes By Fermentation Method

2.What is fermentation?
Pasteur’s definition: “life without air”, anaerobe
    redox reactions in organisms.
New definition: a form of metabolism in which the end products could be further oxidized.
   For example: a yeast cell obtains 2 molecules of
   ATP per molecule of glucose when it ferments it
   to ethanol.

3.What is fermentation?
   Microorganisms, typically grown on a large scale, to produce valuable commercial products or to carry out important chemical transformations. This process is commonly referred to as Fermentation.

4.Types of fermentation process
There are two methods of fermentation used to produce enzymes.
submerged fermentation
solid-state fermentation.

5.Submerged fermentation/ Solid-state fermentation
Submerged fermentation involves the production of enzymes by microorganisms (e.g. bacteria, yeast) in a liquid nutrient media (water content of the media: > 95%)
Solid-state fermentation is the cultivation of microorganisms on a solid substrate.
Carbon containing compounds in or on the substrate are broken down by the micro organisms, which produce the enzymes either intra-cellularly or extra-cellularly.

  6.The enzymes are recovered by methods such as centrifugation, for extra cellularly produced enzymes
    and lysing of cells for intracellular enzymes.
Many industries are dependent on enzymes for the production of their goods.
Industries that use enzymes generated by fermentation are the brewing, wine making, baking and cheese making.

7.   Advantages:
Measure of process parameters is easier than with solid-state fermentation.
Bacterial and yeast cells are evenly distributed throughout the medium.
There is a high water content which is ideal for bacteria.
High costs due to the expensive media.

8.Solid State Fermentation
Solid-state fermentation (SSF) is another method used for the production of enzymes.
In solid state,  water content is  40~ 80%.
Solid-state fermentation involves the cultivation of microorganisms on a solid substrate, such as rice husk, wheat bran, sugar beet pulp, wheat and corn flour.

9.SSF has many advantages over submerged fermentation. These include:
High volumetric productivity
Relatively high concentration of product
Less effluent generated
Simple fermentation equipment.


11.Aerobic fermentation
Adequate aeration.
Bioreactors- adequate supply of sterile air.
In addition, these fermentors may have a mechanism for stirring and mixing of the medium and cells .
  eg.  Antibiotics, enzymes, vitamins.

12.In anaerobic fermentation, a provision for aeration is usually not needed.
   e.g. Lactic acid, ethanol, wine
When referring to fermentation regarding food, there are no distinctions between
   anaerobic and aerobic metabolism.

13.Fermentation changes the characteristics of the food by the action of the enzymes produced by bacteria, mould and yeasts, which can occur in aerobic or anaerobic conditions

14.The process of fermentation requires a food source (e.g. glucose); enzymes form
   bacteria or yeast and (depending on the product) anaerobic or aerobic conditions.

15.Of all the microbial products manufactured commercially, antibiotics are the most important.
Antibiotics are chemical substances produced by microorganisms to kill other microorganisms.
They are used in the treatment of infectious diseases.

PPT On Chromatographic Techniques


Chromatographic Techniques Presentation Transcript:
1.Chromatographic Techniques

2.Paper Chromatography

3.Paper chromatography is a technique that involves placing a small dot of sample solution onto a strip of chromatography paper.
The compounds within the mixture travel are non-polar.
Adsorbent: More polar substances bond with the cellulose paper more quickly.

4.Paper Chromatography

5.Paper Chromatography-Procedure
The paper is placed in a jar containing a solvent such as ethanol or water then sealed.
A small concentrated spot of solution that contains the sample of the solute is applied to a strip of chromatography paper about 2 cm away from the base of the plate

6.4. As the solvent rises through the   paper, it meets the sample mixture  which starts to travel up the paper  with the solvent.

5. Paper chromatography takes from   several minutes to several hours.

7.Different compounds in the sample mixture travel at different rates due to
 differences in solubility in the solvent
 differences in their attraction to the  fibers in the paper.

8.In this method, the solvent moves upward against gravitational force.
The only force that cause the motion is capillary force. So the speed of the process is slow.

9.In this method, the solvent is kept in a trough at the top of the chamber and is allowed to flow down the paper.
The liquid moves down by capillary action as well as by the gravitational force.
In this case, the flow is more rapid as compared to the ascending method.

10.Because of this rapid speed, the chromatography is completed in a comparatively shorter time.
The developing solvent is placed in a trough at the top which is usually made up of an inert material.
The paper is then suspended in the solvent. Substances that cannot be separated by ascending method, can be separated by the above descending method.

11.    After development, the spots corresponding to different compounds may be located by:
 their color,
 ultraviolet light,
or by treatment with iodine vapors.
   The paper remaining after the experiment is known as the Chromatogram.

12.If Rƒ value of a solution is zero, the solute remains in the stationary phase and thus it is immobile.
If Rƒ value = 1 then the solute has no affinity for the stationary phase and travels with the solvent front.

13.  The final chromatogram can be compared with other known mixture chromatograms to identify sample mixes, using the Rf value in an experiment.

14.Thin layer chromatography (TLC)
TLC is widely used.
Stationary phase solid+ adsorbent
Adsorbent like silica gel (polar), alumina.
Traveling of solvent and elute via capillary action 

15.Plate preparation
TLC plates are made by mixing the adsorbent +  small amount of inert binder calcium sulfate (gypsum) + water.
This mixture is spread as a thick slurry on an unreactive carrier sheet, usually glass, thick aluminum foil, or plastic (support) 

PPT On Network Switch


Network Switch Presentation Transcript:
1.Lecture 4 Network Switch

2.Network switch
A network switch is a computer networking device that links network segments or network devices.
The term commonly refers to a multi-port network bridge that processes and routes data at the data link layer (layer 2) of the OSI model.
Switches that additionally process data at the network layer (layer 3) and above are often called layer-3 switches or multilayer switches.

 A router is a device that forwards data packets between computer network, creating an overlay internet work.
 A router is connected to two or more data lines from different networks.

4.When a data packet comes in one of the lines, the router reads the address information in the packet to determine its ultimate destination. Then, using information in its routing table or routing policy, it directs the packet to the next network on its journey. Routers perform the "traffic directing" functions on the Internet.
A data packet is typically forwarded from one router to another through the networks that constitute the internetwork until it gets to its destination node

5.Network interface controller
A network interface controller (also known as a network interface card, network adapter, LAN adapter and by similar terms) is a computer hardware component that connects a computer to a computer network.

6.Wireless network interface controller
A wireless network interface controller (WNIC) is a network interface controller which connects to a radio-based computer network rather than a wire-based network such as Token Ring or Ethernet.

7.A WNIC, just like other NICs, works on the Layer 1 and Layer 2 of the OSI Model.
A WNIC is an essential component for wireless desktop computer.
This card uses an antenna to communicate through microwaves.
A WNIC in a desktop computer usually is connected using the PCI bus. Other connectivity options are USB and PC card. Integrated WNICs are also available, (typically in Mini PCI/PCI Express Mini Card form).

8.A patch cable or patch cord is an electrical or optical cable used to connect ("patch-in") one electronic or optical device to another for signal routing.

9.Devices of different types (e.g., a switch connected to a computer, or a switch to a router) are connected with patch cords. Patch cords are usually produced in many different colors so as to be easily distinguishable, and are relatively short, perhaps no longer than two meters.

10.Network IO
The term I/O is used to describe any program, operation or device that transfers data to or from a computer and to or from a peripheral device.
 Every transfer is an output from one device and an input into another.
Devices such as keyboards and mouse are input-only devices while devices such as printers are output-only.
A writable CD-ROM is both an input and an output device.

11.Unshielded twisted pair (UTP)
UTP cables are found in many Ethernet networks and telephone systems. For indoor telephone applications, UTP is often grouped into sets of 25 pairs according to a standard 25-pair color code originally developed by AT&T Corporation. A typical subset of these colors (white/blue, blue/white, white/orange, orange/white) shows up in most UTP cables.

12.Unshielded twisted pair (UTP)
UTP cables are found in many Ethernet networks and telephone systems. For indoor telephone applications, UTP is often grouped into sets of 25 pairs according to a standard 25-pair color code originally developed by AT&T Corporation. A typical subset of these colors (white/blue, blue/white, white/orange, orange/white) shows up in most UTP cables.

13.UTP cable is also the most common cable used in computer networking. Modern Ethernet, the most common data networking standard, utilizes UTP cables. Twisted pair cabling is often used in data networks for short and medium length connections because of its relatively lower costs compared to optical fiber and coaxial cable.

14.RS Components stocks connectors for electrical and electronic applications, from heavy duty industrial/power connectors through to crimp terminals. You will also find tooling, accessories, IEC and mains leads as well as a wide variety of audio and video products

15.crimping tool
A crimping tool is a tool designed to crimp or connect a connector to the end of a cable. For example, network cables and phone cables are created using a crimping tool to connect the RJ-45 and RJ-11 connectors to the end of the cable. In the picture to the right, is an example of what a crimping tool looks like. This example shows a tool capable of crimping both RJ-11 and RJ-45 connectors 



MOSFET Presentation Transcript:
1.Metal Oxide Semiconductor Field Effect Transistor

It is a type of  transistor
Another name for the MOSFET is the insulated-gate FET or IGFET.
This name emphasizes the fact that the gate electrode is electrically insulated from the device body (by the oxide layer).
It is this insulation that causes the current in the gate terminal to be extremely small (of the order of (10 -15 A).

3.Device Structure
The transistor is fabricated on a p-type substrate, which is a single-crystal silicon wafer that provides physical support for the device. Two heavily doped n-type regions, indicated in the figure as the n+ source and the n+ drain regions, are created in the substrate.
A thin layer of silicon dioxide (Si02) of thickness tox (typically 2-50nm)2, is grown on the surface of the substrate, covering the area between the source and drain regions.
Metal is deposited on top of the oxide layer to form the gate electrode of the device. Metal contacts are also made to the source region, the drain region, and the substrate, also known as the body.

4.Device Operation
The source and the drain have been grounded and a positive voltage is applied to the gate. Since the source is grounded, the gate voltage appears in effect between gate and source and thus is denoted vGS.
The positive voltage on the gate causes the free holes to be repelled from the region of the substrate under the gate (the channel region). These holes are pushed downward into the substrate, leaving behind a carrier-depletion region. The depletion region is populated by the bound negative charge associated with the acceptor atoms.

5.The positive gate voltage attracts electrons from the n+ source and drain regions into the channel region. When a sufficient number of electrons accumulate near the surface of the substrate under the gate, an n region is in effect created, connecting the source and drain regions.
Now if a voltage is applied between drain and source, current flows through this induced n region, carried by the mobile electrons. The induced n region thus forms a channel for current flow from drain to source.

6.This induced channel is also called an inversion layer.
The value of vGS at which a sufficient number of mobile electrons accumulate in the channel region to form a conducting channel is called the threshold voltage and is denoted Vt.

7.Now applying a positive voltage vDS   between drain and source. The voltage vDS causes a current iD to flow through the induced n channel. Current is carried by free electrons traveling from source to drain.
The magnitude of iD depends on the density of electrons in the channel, which in turn depends on the magnitude of vGS .
Specifically, for vGS = Vt the channel is just induced and the current conducted is still negligibly small. As vGS exceeds Vt more electrons are attracted into the channel. The result is a channel of increased conductance or, equivalently, reduced resistance.
The conductance of the channel is proportional to the excess gate voltage (vGS - Vt), also known as the effective voltage or the overdrive voltage.

8.Operation as vDS Is Increased
let vGS be held constant at a value greater than Vt and vDS appears as a voltage drop across the length of the channel. That is, as we travel along the channel from source to drain, the voltage increases from 0 to vDS. Thus the voltage between the gate and points along the channel decreases from vGS at the source end to vGS - vDS at the drain end. Since the channel depth depends on this voltage the channel is now no longer of uniform depth; rather, the channel will take the tapered form, being deepest at the source end and shallowest at the drain end.
As vDS is increased, the channel becomes more tapered and its resistance increases correspondingly. Eventually, when vDS is increased to the value that reduces the voltage between gate and channel at the drain end to Vt that is, vGD = Vt or vGS - vDS = Vt  or vDS = vGS - Vt the channel depth at the drain end decreases to almost zero, and the channel is said to be pinched off.

9.Increasing vDS beyond this value has little effect (theoretically, no effect) on the channel shape, and the current through the channel remains constant at the value reached for vDS - vGS - Vt .The drain current thus saturates at this value, and the MOSFET is said to have entered the saturation region of operation. The voltage vDS at which saturation occurs is denoted vDSsat
                VDSsat = VGS - Vt
The region of the iD-vDS characteristic obtained for vDS < vDSsat is called the triode region

10.Resistor Loaded NMOS Inverter
The input to the inverter is at the gate of the N-channel output transistor NO and VIN = VGS. The output is at the drain and VOUT = VDS = VDD – IRL RL. For VIN < Vt, transistor is in cut off mode and does not conduct drain current. Since the ID(OFF) = 0 and the output is VOUT = VDD. As the input is increased slightly above the threshold voltage transistor begins to conduct. At this point only a small current flows and the drain voltage is lightly less than VDD.
 As long as VDS >= VGS – Vt, transistor is operating in the saturation region. With further increase of the input, a larger drain current conducts and the output voltage continues to fall.
In summary, for a low input the output is high. Conversely for a high input the output is low.
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