Sunday, January 29, 2006

Ganguly Ganguly everywhere...

You switch on a news channel, you will find people talking about the exclusion of dada (Saurav Ganguly) from the Indian cricket team. Do we really need to make this a big issue and circumcenter the whole issue around it?

I personally don't think so. We all very well know the theory of "Survival of the fittest". Every sports is about that only. When you perform you are part of the team and if you don't then you better be a part of numb spectators!!! And why it should not be like that. There is no place for emotions in sports. Either you show results or you are out of the squad.

We all know the emotions associated with the game of cricket in India. And we should concentrate more on the team performance, rather than cribbing about the exclusions of the bad perfomers. We all know worldwide exclusion of non-performers in every sport, then whats so special about "dada".

After the match fixing scandal i personally don't feel like watching two idots playing and millions watching them playing (as americans say about cricket)! Moreover is ganguly the only player who has been excluded till now from the Indian cricket team?

Friday, January 27, 2006

Can you 'Guess Who's Smiling?'

I have entered the Happydent ‘Guess Who's Smiling' Contest and has scored pretty well. Think you can do better? Well then click on the link given below to show us what you're made of!

Click Here

And what's in it for you, you ask? Well apart from being able to gloat that you beat your pal, you stand to win super prizes like Nokia N70s, Apple iPods, latest Audio CDs and loads more!

So what are you waiting for? Get started!


Thursday, January 26, 2006

Long live Republic of India!

Wednesday, January 18, 2006


During prime time, when the whole family is sitting together and watching with great concentration some stupid 'K......' family soap, you will find "Ab beti ki suraksha har maa ki zimewari" (Now it is the responsibility of the mother to look after her daughter during the mensuration cycle) or the stupid sarkari family planning advertisement popping up and you will try to change the topic and start talking about something else!!
Where is the media heading towards and it wants the society to grow up and adopt this kind of attitude.
Now when you try to change the channel and to your utmost embarrasment here comes Kohinoor luxury condom. Oho..! What is this doesn't they have anything else to show and advertise about. Yes! they do have a heap of surrogated advertisment from Set Wet hair styling gel to Hanes under garments and plenty of others following the surrogated advertisement trend from the liquor industry.
Is that how we want to sell the product, and generate awareness in the society?

Tuesday, January 17, 2006

Synthetic Milk: A health hazard to human lives

The synthetic milk technology was invented by milkmen of Kurukshetra (Haryana) about 15 years. The technology later spread to the other states like Rajasthan, Himachal Pradesh, Uttar Pradesh and the practice is feared to have been adopted in the deficit areas of Bihar, Madhya Pradesh, Karnataka and Orissa too. Synthetic milk is prepared by mixing urea, caustic soda, refined oil (cheap cooking oil) and common detergents. Detergents are added to emulsify and dissolve the oil in water giving the frothy solution, the characteristic white colour of milk. Refined oil is used as a substitute for milk fat. Caustic soda is added to the blended milk to neutralize the acidity, thereby preventing it from turning sour during transport. Urea/ sugar are added for solid-not-fat (SNF). The above prepared synthetic milk looks like natural milk, except in taste and nutritional qualities. The cost of preparing synthetic milk is less than Rs. 5 per liter and it is sold to consumers at a price arranging between Rs. 12 – 18 per liter after blending it with natural milk. The use of synthetic milk has been found to have “cancerous” effects on human beings. Urea and caustic soda are very harmful to heart, lever and kidneys. Urea is an additional burden for kidneys as they have to do more work to remove urea from the body. Caustic soda which contains sodium acts as slow poison for those suffering from hypertension and heart ailments. Caustic soda also deprives the body from utilizing lysine, an essential amino acid in milk, which is required by growing babies. Such artificial milk is harmful for all, but is more dangerous for pregnant women, fetus and persons who are already having heart and kidney problems.

Chemically to detect urea, caustic soda, starch/ glucose, sugar, pond water or nitrate etc. at home for the consumers particularly for house wives is very difficult. But before utilizing the milk at home, house wives, consumers may see the main characteristics of natural milk and synthetic milk mentioned below in the table:


Physical properties

Natural milk

Synthetic milk


No pronounced taste, but is slightly sweet to most persons (Palatable)





pH (Hydrogen-ion concentration)

6.8 (acidic), which indicates that it is really somewhat on the acid side of neutrality (Natural)

10 -– 11 (Alkaline)


No soapy feeling if rubbed between fingers

Gives you a soapy feeling

Effect of heating

No change, continues to remain white on boiling

Turns yellowish on boiling

Effect on storage

No change in colour

Turns yellowish after sometime

If urea present

Weakly positive (light yellow)

Highly positive (intense yellow)

About the author:

M. L. Garg

Ex. Chief Chemist-cum-Incharge,

Govt. Analytical Laboratory

Sangrur - 148001

Everything is there on Web!

You will find plenty of people running here and there to hide their income from the taxation department, but there are some investment firms which can make the life of these people even more miserable. One of the instance can be found here.

The complete investment potential and investment made is available on this link along with the contact number of the client.

So here comes "Income-Tax-Department"......

Monday, January 16, 2006

My Investment Portfolio!

You must have thought about investing your hard earned money, in some stock, or mutual fund. But what really matters is the return!!!

So based on the analysis on the performance of stock market from June 2004 to May 2005, i came out with an investment portfolio, based on "Portfolio Optimization Theory" which i studied during my MBA.

The below mentioned pie-chart shows you the percentage wise stock allocation.

The return calculated on the following portfolio turned out to be 80.55% and the Beta of the portfolio is only .88

Though the history cannot predict the future, but still you will get an idea. I have also put up an excel sheet HERE

Your suggestions are most welcome. I want to mention one thing again that, this analysis has been made to the data that is approximately one and a half year old. But you will still get a decent idea about making your own portfolio from the attached excel sheet.

FIFA World Cup 2006 Schedule

Group A
DateMatchCity - Venue
09/06/2006Germany vs Costa RicaMunich - FIFA World Cup Stadium
09/06/2006Poland vs EcuadorGelsenkirchen - FIFA World Cup Stadium
14/06/2006 Germany vs PolandDortmund - Westfalenstadion
15/06/2006Ecuador vs Costa RicaHamburg - FIFA World Cup Stadium
20/06/2006Costa Rica vs Poland Hanover - FIFA World Cup Stadium
20/06/2006Ecuador vs GermanyBerlin - Olympiastadion

Group B
DateMatchCity - Venue
10/06/2006England vs ParaguayFrankfurt - Waldstadion
10/06/2006Trinidad and Tobago vs SwedenDortmund - Westfalenstadion
15/06/2006 England vs Trinidad and TobagoNuremberg - Frankenstadion
15/06/2006Sweden vs ParaguayBerlin - Olympiastadion
20/06/2006Paraguay vs Trinidad and TobagoKaiserslautern - Fritz-Walter-Stadion
20/06/2006Sweden vs EnglandCologne - FIFA World Cup Stadium

Group C
DateMatchCity - Venue
10/06/2006Argentina vs C�te d'IvoireHamburg - FIFA World Cup Stadium
11/06/2006Serbia and Montenegro vs NetherlandsLeipzig - Zentralstadion
16/06/2006Argentina vs Serbia and MontenegroGelsenkirchen - FIFA World Cup Stadium
16/06/2006Netherlands vs C�te d'IvoireStuttgart - Gottlieb-Daimler-Stadion
21/06/2006C�te d'Ivoire vs Serbia and MontenegroMunich - FIFA World Cup Stadium
21/06/2006Netherlands vs ArgentinaFrankfurt - Waldstadion

Group D
Date MatchCity - Venue
11/06/2006Mexico vs IranNuremberg - Frankenstadion
11/06/2006Angola vs PortugalCologne - FIFA World Cup Stadium
16/06/2006Mexico vs AngolaHanover - FIFA World Cup Stadium
17/06/2006Portugal vs IranFrankfurt - Waldstadion
21/06/2006Iran vs AngolaLeipzig - Zentralstadion
21/06/2006Portugal vs MexicoGelsenkirchen - FIFA World Cup Stadium

Group E
Date MatchCity - Venue
12/06/2006Italy vs GhanaHanover - FIFA World Cup Stadium
12/06/2006USA vs Czech RepublicGelsenkirchen - FIFA World Cup Stadium
17/06/2006Italy vs USAKaiserslautern - Fritz-Walter-Stadion
17/06/2006Czech Republic vs GhanaCologne - FIFA World Cup Stadium
22/06/2006Ghana vs USANuremberg - Frankenstadion
22/06/2006Czech Republic vs ItalyHamburg - FIFA World Cup Stadium

Group F
Date MatchCity - Venue
13/06/2006Brazil vs CroatiaBerlin - Olympiastadion
12/06/2006Australia vs JapanKaiserslautern - Fritz-Walter-Stadion
18/06/2006Brazil vs AustraliaMunich - FIFA World Cup Stadium
18/06/2006Japan vs CroatiaNuremberg - Frankenstadion
22/06/2006Croatia vs AustraliaStuttgart - Gottlieb-Daimler-Stadion
22/06/2006Japan vs BrazilDortmund - Westfalenstadion

Group G
Date MatchCity - Venue
13/06/2006France vs SwitzerlandStuttgart - Gottlieb-Daimler-Stadion
13/06/2006Korea Republic vs TogoFrankfurt - Waldstadion
18/06/2006France vs Korea RepublicLeipzig - Zentralstadion
19/06/2006Togo vs SwitzerlandDortmund - Westfalenstadion
23/06/2006Switzerland vs Korea RepublicHanover - FIFA World Cup Stadium
23/06/2006Togo vs FranceCologne - FIFA World Cup Stadium

Group H
Date MatchCity - Venue
14/06/2006Spain vs UkraineLeipzig - Zentralstadion
14/06/2006Tunisia vs Saudi ArabiaMunich - FIFA World Cup Stadium
19/06/2006Spain vs TunisiaStuttgart - Gottlieb-Daimler-Stadion
19/06/2006Saudi Arabia vs UkraineHamburg - FIFA World Cup Stadium
23/06/2006Ukraine vs TunisiaBerlin - Olympiastadion
23/06/2006Saudi Arabia vs SpainKaiserslautern - Fritz-Walter-Stadion

Rounds of Sixteen
Date MatchCity - Venue
24/06/2006RS1 - Winner Group A vs Runner Up Group BMunich - FIFA World Cup Stadium
24/06/2006RS2 - Winner Group C vs Runner Up Group D Leipzig - Zentralstadion
25/06/2006RS3 - Winner Group B vs Runner Up Group AStuttgart - Gottlieb-Daimler-Stadion
25/06/2006RS4 - Winner Group D vs Runner Up Group CNuremberg - Frankenstadion
26/06/2006RS5 - Winner Group E vs Runner Up Group FKaiserslautern - Fritz-Walter-Stadion
26/06/2006 RS6 - Winner Group G vs Runner Up Group HCologne - FIFA World Cup Stadium
27/06/2006RS7 - Winner Group F vs Runner Up Group EDortmund - Westfalenstadion
27/06/2006RS8 - Winner Group H vs Runner Up Group GHanover - FIFA World Cup Stadium

Quarter Finals
DateMatchCity - Venue
30/06/2006QF1 - Winner RS1 vs Winner RS2Berlin - Olympiastadion
30/06/2006QF2 - Winner RS5 vs Winner RS6Hamburg - FIFA World Cup Stadium
01/07/2006QF3 - Winner RS3 vs Winner RS4Gelsenkirchen - FIFA World Cup Stadium
01/07/2006QF4- Winner RS7 vs Winner RS8Frankfurt - Waldstadion

Semi Finals
Date MatchCity - Venue
04/06/2006SF1 - Winner QF1 vs Winner QF2Dortmund - Westfalenstadion
05/06/2006SF2 - Winner QF3 vs Winner QF4Munich - FIFA World Cup Stadium

3rd Place
DateMatchCity - Venue
08/06/2006Loser SF1 vs Loser SF2Stuttgart - Gottlieb-Daimler-Stadion

Date MatchCity - Venue
09/06/2006Winner SF1 vs Winner SF2Berlin - Olympiastadion

If you further want detailed schedule kindly download or view Complete match schedule

Fortune 100 Best Companies to Work for in 2006

By treating employees well, these firms are thriving -- despite merciless cost pressures -- and blazing a trail for others to follow. Find the complete list on the following URL:

Saturday, January 14, 2006

How Turbochargers Work?

When people talk about race cars or high-performance sports cars, the topic of turbochargers usually comes up. Turbochargers also appear on large diesel engines. A turbo can significantly boost an engine's horsepower without significantly increasing its weight, which is the huge benefit that makes turbos so popular!

Photo courtesy Garrett

In this article, we'll learn how a turbocharger increases the power output of an engine while surviving extreme operating conditions. We'll also learn how wastegates, ceramic turbine blades and ball bearings help turbochargers do their job even better!

What Is a Turbocharger?
Turbochargers are a type of forced induction system. They compress the air flowing into the engine (see How Car Engines Work for a description of airflow in a normal engine). The advantage of compressing the air is that it lets the engine squeeze more air into a cylinder, and more air means that more fuel can be added. Therefore, you get more power from each explosion in each cylinder. A turbocharged engine produces more power overall than the same engine without the charging. This can significantly improve the power-to-weight ratio for the engine (see How Horsepower Works for details).

In order to achieve this boost, the turbocharger uses the exhaust flow from the engine to spin a turbine, which in turn spins an air pump. The turbine in the turbocharger spins at speeds of up to 150,000 rotations per minute (rpm) -- that's about 30 times faster than most car engines can go. And since it is hooked up to the exhaust, the temperatures in the turbine are also very high.

One of the surest ways to get more power out of an engine is to increase the amount of air and fuel that it can burn. One way to do this is to add cylinders or make the current cylinders bigger. Sometimes these changes may not be feasible -- a turbo can be a simpler, more compact way to add power, especially for an aftermarket accessory.

Where the turbocharger is located in the car

Turbochargers allow an engine to burn more fuel and air by packing more into the existing cylinders. The typical boost provided by a turbocharger is 6 to 8 pounds per square inch (psi). Since normal atmospheric pressure is 14.7 psi at sea level, you can see that you are getting about 50 percent more air into the engine. Therefore, you would expect to get 50 percent more power. It's not perfectly efficient, so you might get a 30- to 40-percent improvement instead.

One cause of the inefficiency comes from the fact that the power to spin the turbine is not free. Having a turbine in the exhaust flow increases the restriction in the exhaust. This means that on the exhaust stroke, the engine has to push against a higher back-pressure. This subtracts a little bit of power from the cylinders that are firing at the same time.

Turbos on High
A turbocharger helps at high altitudes, where the air is less dense. Normal engines will experience reduced power at high altitudes because for each stroke of the piston, the engine will get a smaller mass of air. A turbocharged engine may also have reduced power, but the reduction will be less dramatic because the thinner air is easier for the turbocharger to pump.

Older cars with carburetors automatically increase the fuel rate to match the increased airflow going into the cylinders. Modern cars with fuel injection will also do this to a point. The fuel-injection system relies on oxygen sensors in the exhaust to determine if the air-to-fuel ratio is correct, so these systems will automatically increase the fuel flow if a turbo is added.

If a turbocharger with too much boost is added to a fuel-injected car, the system may not provide enough fuel -- either the software programmed into the controller will not allow it, or the pump and injectors are not capable of supplying it. In this case, other modifications will have to be made to get the maximum benefit from the turbocharger.

How It Works
The turbocharger is bolted to the exhaust manifold of the engine. The exhaust from the cylinders spins the turbine, which works like a gas turbine engine. The turbine is connected by a shaft to the compressor, which is located between the air filter and the intake manifold. The compressor pressurizes the air going into the pistons.

Image courtesy Garrett
How a turbocharger is plumbed in a car

The exhaust from the cylinders passes through the turbine blades, causing the turbine to spin. The more exhaust that goes through the blades, the faster they spin.

Image courtesy Garrett
Inside a turbocharger

Photo courtesy Garrett
Turbo compressor blades

On the other end of the shaft that the turbine is attached to, the compressor pumps air into the cylinders. The compressor is a type of centrifugal pump -- it draws air in at the center of its blades and flings it outward as it spins.

In order to handle speeds of up to 150,000 rpm, the turbine shaft has to be supported very carefully. Most bearings would explode at speeds like this, so most turbochargers use a fluid bearing. This type of bearing supports the shaft on a thin layer of oil that is constantly pumped around the shaft. This serves two purposes: It cools the shaft and some of the other turbocharger parts, and it allows the shaft to spin without much friction.

There are many tradeoffs involved in designing a turbocharger for an engine. In the next section, we'll look at some of these compromises and see how they affect performance.

Design Considerations
Before we talk about the design tradeoffs, we need to talk about some of the possible problems with turbochargers that the designers must take into account.

Too Much Boost
With air being pumped into the cylinders under pressure by the turbocharger, and then being further compressed by the piston (see How Car Engines Work for a demonstration), there is more danger of knock. Knocking happens because as you compress air, the temperature of the air increases. The temperature may increase enough to ignite the fuel before the spark plug fires. Cars with turbochargers often need to run on higher octane fuel to avoid knock. If the boost pressure is really high, the compression ratio of the engine may have to be reduced to avoid knocking.

Turbo Lag
One of the main problems with turbochargers is that they do not provide an immediate power boost when you step on the gas. It takes a second for the turbine to get up to speed before boost is produced. This results in a feeling of lag when you step on the gas, and then the car lunges ahead when the turbo gets moving.

One way to decrease turbo lag is to reduce the inertia of the rotating parts, mainly by reducing their weight. This allows the turbine and compressor to accelerate quickly, and start providing boost earlier.

Small vs. Large Turbocharger
One sure way to reduce the inertia of the turbine and compressor is to make the turbocharger smaller. A small turbocharger will provide boost more quickly and at lower engine speeds, but may not be able to provide much boost at higher engine speeds when a really large volume of air is going into the engine. It is also in danger of spinning too quickly at higher engine speeds, when lots of exhaust is passing through the turbine.

A large turbocharger can provide lots of boost at high engine speeds, but may have bad turbo lag because of how long it takes to accelerate its heavier turbine and compressor.

In the next section, we'll take a look at some of the tricks used to overcome these challenges.

Optional Turbo Features

The Wastegate
Most automotive turbochargers have a wastegate, which allows the use of a smaller turbocharger to reduce lag while preventing it from spinning too quickly at high engine speeds. The wastegate is a valve that allows the exhaust to bypass the turbine blades. The wastegate senses the boost pressure. If the pressure gets too high, it could be an indicator that the turbine is spinning too quickly, so the wastegate bypasses some of the exhaust around the turbine blades, allowing the blades to slow down.

Ball Bearings
Some turbochargers use ball bearings instead of fluid bearings to support the turbine shaft. But these are not your regular ball bearings -- they are super-precise bearings made of advanced materials to handle the speeds and temperatures of the turbocharger. They allow the turbine shaft to spin with less friction than the fluid bearings used in most turbochargers. They also allow a slightly smaller, lighter shaft to be used. This helps the turbocharger accelerate more quickly, further reducing turbo lag.

Ceramic Turbine Blades
Ceramic turbine blades are lighter than the steel blades used in most turbochargers. Again, this allows the turbine to spin up to speed faster, which reduces turbo lag.

Sequential Turbochargers
Some engines use two turbochargers of different sizes. The smaller one spins up to speed very quickly, reducing lag, while the bigger one takes over at higher engine speeds to provide more boost.

Another optional feature is the intercooler. We'll take a look at one on the next page.

When air is compressed, it heats up; and when air heats up, it expands. So some of the pressure increase from a turbocharger is the result of heating the air before it goes into the engine. In order to increase the power of the engine, the goal is to get more air molecules into the cylinder, not necessarily more air pressure.

Image courtesy Garrett
How a turbocharger is plumbed (including the charge air cooler)

An intercooler or charge air cooler is an additional component that looks something like a radiator, except air passes through the inside as well as the outside of the intercooler. The intake air passes through sealed passageways inside the cooler, while cooler air from outside is blown across fins by the engine cooling fan.

The intercooler further increases the power of the engine by cooling the pressurized air coming out of the compressor before it goes into the engine. This means that if the turbocharger is operating at a boost of 7 psi, the intercooled system will put in 7 psi of cooler air, which is denser and contains more air molecules than warmer air.


Wednesday, January 11, 2006

How Air Bags Work?

For years, the trusty seat belt provided the sole form of passive restraint in our cars. There were debates about their safety, especially relating to children, but over time, much of the country adopted mandatory seat-belt laws. Statistics have shown that the use of seat belts has saved thousands of lives that might have been lost in collisions.

Air bags have been under development for many years. The attraction of a soft pillow to land against in a crash must be very strong -- the first patent on an inflatable crash-landing device for airplanes was filed during World War II! In the 1980s, the first commercial air bags appeared in automobiles.

Since model year 1998, all new cars have been required to have air bags on both driver and passenger sides. (Light trucks came under the rule in 1999.) To date, statistics show that air bags reduce the risk of dying in a direct frontal crash by about 30 percent. Newer than steering-wheel-mounted or dashboard-mounted bags, but not so widely used, are seat-mounted and door-mounted side air bags. Some experts say that within the next few years, our cars will go from having dual air bags to having six or even eight air bags! Having evoked some of the same controversy that surrounded seat-belt use in its early years, air bags are the subject of serious government and industry research and tests.

In this article, you'll learn about the science behind the air bag, how the device works, what its problems are and where the technology goes from here.

The Basics

Before looking at specifics, let's review our knowledge of the laws of motion. First, we know that moving objects have momentum (the product of the mass and the velocity of an object). Unless an outside force acts on an object, the object will continue to move at its present speed and direction. Cars consist of several objects, including the vehicle itself, loose objects in the car and, of course, passengers. If these objects are not restrained, they will continue moving at whatever speed the car is traveling at, even if the car is stopped by a collision.

Stopping an object's momentum requires force acting over a period of time. When a car crashes, the force required to stop an object is very great because the car's momentum has changed instantly while the passengers' has not -- there is not much time to work with. The goal of any supplemental restraint system is to help stop the passenger while doing as little damage to him or her as possible.

What an air bag wants to do is to slow the passenger's speed to zero with little or no damage. The constraints that it has to work within are huge. The air bag has the space between the passenger and the steering wheel or dash board and a fraction of a second to work with. Even that tiny amount of space and time is valuable, however, if the system can slow the passenger evenly rather than forcing an abrupt halt to his or her motion.

There are three parts to an air bag that help to accomplish this feat:

  • The bag itself is made of a thin, nylon fabric, which is folded into the steering wheel or dashboard or, more recently, the seat or door.

  • The sensor is the device that tells the bag to inflate. Inflation happens when there is a collision force equal to running into a brick wall at 10 to 15 miles per hour (16 to 24 km per hour). A mechanical switch is flipped when there is a mass shift that closes an electrical contact, telling the sensors that a crash has occurred. The sensors receive information from an accelerometer built into a microchip.

  • The air bag's inflation system reacts sodium azide (NaN3) with potassium nitrate (KNO3) to produce nitrogen gas. Hot blasts of the nitrogen inflate the air bag.
The inflation system is not unlike a solid rocket booster (see How Rocket Engines Work for details). The air bag system ignites a solid propellant, which burns extremely rapidly to create a large volume of gas to inflate the bag. The bag then literally bursts from its storage site at up to 200 mph (322 kph) -- faster than the blink of an eye! A second later, the gas quickly dissipates through tiny holes in the bag, thus deflating the bag so you can move.

The air bag and inflation system stored in the steering wheel

The inflation system uses a solid propellant and an igniter.

Even though the whole process happens in only one-twenty-fifth of a second, the additional time is enough to help prevent serious injury. The powdery substance released from the air bag, by the way, is regular cornstarch or talcum powder, which is used by the air bag manufacturers to keep the bags pliable and lubricated while they're in storage.


According to Scientific American:

    The idea of using a rapidly inflating cushion to prevent crash injuries had a long history before the U.S. Department of Transportation called for the equipment to be adapted for automobiles in the 1980s. The first patent on an inflatable crash-landing device for airplanes was filed during World War II.
Early efforts to adapt the air bag for use in cars bumped up against prohibitive prices and technical hurdles involving the storage and release of compressed gas. Researchers wondered:
  • If there was enough room in a car for a gas canister
  • Whether the gas would remain contained at high pressure for the life of the car
  • How the bag could be made to expand quickly and reliably at a variety of operating temperatures and without emitting an ear-splitting bang

They needed a way to set off a chemical reaction that would produce the nitogen that would inflate the bag. Small solid-propellant inflators came to the rescue in the 1970s.

In the early days of auto air bags, experts cautioned that the new device was to be used in tandem with the seat belt. Seat belts were still completely necessary because air bags worked only in front-end collisions occurring at more than 10 mph (6 kph). Only seat belts could help in side swipes and crashes (although side-mounted air bags are becoming more common now), rear-end collisions and secondary impacts. Even as the technology advances, air bags still are only effective when used with a lap/shoulder seat belt!


It didn't take long to learn that the force of an air bag can hurt those who are too close to it. Researchers have determined that the risk zone for driver air bags is the first 2 to 3 inches (5 to 8 cm) of inflation. So, placing yourself 10 inches (25 cm) from your driver air bag gives you a clear margin of safety. Measure this distance from the center of the steering wheel to your breastbone. If you currently sit less than 10 inches away, you can adjust your driving position in the following ways:

  • Move your seat to the rear as far as possible while still reaching the pedals comfortably.
  • Slightly recline the back of your seat. Although car designs vary, most drivers can achieve the 10-inch distance even with the driver seat all the way forward by slightly reclining the back of the seat. If reclining the seat makes it hard to see the road, you can raise yourself up by using your car's seat-raising system (not all cars have this!) or a firm, non-slippery cushion to achieve the same effect.
  • Point the air bag toward your chest, instead of your head and neck, by tilting your steering wheel downward (this only works if your steering wheel is adjustable).

The rules are different for children. An air bag can seriously injure or even kill an unbuckled child who is sitting too close it or is thrown toward the dash during emergency braking. Experts agree that the following safety points are important:

  • Children 12 and under should ride buckled up in a properly installed, age-appropriate rear car seat.
  • Infants in rear-facing child seats (under one year old and weighing less than 20 pounds / 9 kg) should never ride in the front seat of a car that has a passenger-side air bag.
  • If a child over one year old must ride in the front seat with a passenger-side air bag, he or she should be in a front-facing child safety seat, a booster seat or a properly fitting lap/shoulder belt, and the seat should be moved as far back as possible.


In response to concerns about children -- and others, especially smaller people -- being killed or seriously injured by malfunctioning or overly powerful air bags, the National Highway Traffic Safety Administration (NHTSA) in 1997 issued a final rule to allow auto manufacturers to use lower-powered air bags. This rule permits air bags to be depowered by 20 to 35 percent. In addition, starting in 1998, repair shops and dealers were allowed to install on/off switches that allow air bags to be deactivated. Vehicle owners could now be authorized (by the NHTSA) to get on/off switches installed for one or both air bags in their car if they (or other users of their car) fell into one or more of these specific risk groups:

  • For both driver and passenger sides - Individuals with medical conditions in which the risks of deploying the air bag exceed the risk of impact in the absence of an air bag
  • For the driver side (in addition to medical conditions) - Those who cannot position themselves to properly operate their cars at least 10 inches (25.4 cm) back from the center of the driver air bag cover
  • For the passenger side (in addition to medical conditions) - Individuals who need to transport a baby in a rear-facing child restraint in the front seat because the car has no rear seat, the rear seat is too small to accommodate a rear-facing child seat or because it's necessary to constantly monitor a child's medical condition
  • For the passenger side (in addition to medical conditions) - Individuals who need to carry children between one and 12 years old in the front seat because (a) the car has no rear seat, (b) the vehicle owner must carry more children than can fit into the back seat or (c) because it's necessary to constantly monitor a child's health

If you would like to get an on-off switch installed in your car, you need a copy of NHTSA's brochure, "Air Bags and On-Off Switches: Information for an Informed Decision," and the accompanying form, Request for Air Bag On-Off Switch. You can find these on the NHTSA Web site, as well as at AAA clubs, new-car dealers and state motor vehicle departments. The NHTSA will send you a letter of authorization that you can take to a repair shop. (Before you bother with all this, you should check with your auto dealer or repair shop to see if an on-off switch is available for your car.) Some retrofit on-off switches can be found and used if federal requirements are met -- switches must be operated by a key and equipped with warning lights to indicate whether the bags are turned off or on.

Obviously, even you have the option of turning it off, the air bag should be left on for drivers who can sit at least 10 inches back. For those who can't (even with the suggestions listed above), the bag can be turned off. A group of doctors at the National Conference on Medical Indications for Air Bag Deactivation considered the medical conditions commonly reported in letters to the NHTSA as possible justification for turning off air bags. They did not, however, recommend turning off air bags for relatively common conditions, such as pacemakers, eyeglasses, angina, emphysema, asthma, mastectomy, previous back or neck surgery, advanced age, osteoporosis, arthritis or pregnancy.

Generally speaking, you can't deactivate your air bag without installing a retrofit on-off switch. However, if a retrofit on-off switch is not yet available (from the vehicle manufacturer) for your car, the NHTSA will authorize air bag deactivation on a case-by-case basis under appropriate conditions. Never try to disable the bag yourself -- remember, this is no soft cushion! It packs a wallop and can hurt you when you don't know what you're doing.

As for factory-installed on-off switches, the NHTSA allows car manufacturers to install passenger air bag on-off switches in new vehicles under limited circumstances -- only if the vehicle has no rear seat or if the rear seat is too small to accommodate a rear-facing child safety seat. And manufacturers are not currently allowed to install on-off switches for the driver air bag in any new vehicle. Why these rules? The NHTSA decided against widespread factory-installed on-off switches for fear that they would become standard equipment in all new vehicles -- even those purchased by people not in at-risk groups. They also saw the integration of on-off switches into new cars (and the subsequent redesign of instrument panels) as something that would divert resources from the development of safer, more advanced air bag systems.

The Future of Air Bags

Activities aimed at maintaining and improving the lifesaving benefits of air bags are in full swing. New NHTSA-sponsored tests use improved "dummy" injury criteria based on new knowledge and research.

Until recently, most of the strides made in auto safety were in front and rear impacts, even though 40 percent of all serious injuries from accidents are the result of side impacts, and 30 percent of all accidents are side-impact collisions. Many carmakers have responded to these statistics (and the resulting new standards) by beefing up doors, door frames and floor and roof sections. But cars that currently offer side air bags represent the new wave of occupant protection. Engineers say that designing effective side air bags is much more difficult than designing front air bags. This is because much of the energy from a front-impact collision is absorbed by the bumper, hood and engine, and it takes almost 30 to 40 milliseconds before it reaches the car's occupant. In a side impact, only a relatively thin door and a few inches separate the occupant from another vehicle. This means that door-mounted side air bags must begin deploying in a mere five or six milliseconds!

Volvo engineers experimented with different ways of mounting side air bags and chose seat-back installation because that protects passengers of all sizes regardless of how the seat is positioned. This arrangement allows them to place a triggering mechanical sensor on the sides of the seat cushions under the driver and front passenger. This prevents the air bag on the undamaged side of the car from inflating. Installing the entire air bag package in the seat-back also offers the advantage of preventing unnecessary deployments that might be caused by collisions with pedestrians or bicycles. It takes a collision of about 12 mph (19 kph) to trigger side air bags.

BMW engineers have chosen door-mounted air bags. The door has more space, allowing for a bigger bag that provides more coverage.

The head air bag, or Inflatable Tubular Structure (ITS), was featured in all of BMW's 1999 models (except convertibles). The head bags look a little like big sausages and, unlike other air bags, are designed to stay inflated for about five seconds to offer protection against second or third impacts. Working with the side air bag, the ITS is supposed to offer better protection in some side collisions.

All of this makes it pretty clear that the science of air bags is still new and under rapid development. You can expect many advances in this field as designers come up with new ideas and learn from real-world crash data.


Tuesday, January 10, 2006

How Stem Cells Work?

Inside an embryo no bigger than the period at the end of this sentence are dozens of stem cells. Initially, these cells are blank slates, meaning that their fate is undecided. But they have great potential. Stem cells are pluripotent, which means that they can develop into every cell, every tissue and every organ in the human body.

Photo courtesy University of Wisconsin Board of Regents

Microscopic 10x view of a colony of embryonic stems cells

(The stem cell colonies are the rounded, dense masses of cells.)

Their almost limitless potential has made stem cells a significant focus of medical research. Imagine having the ability to return memory to an Alzheimer's patient, replace skin that was lost during a terrible accident or enable a wheelchair-bound person to walk again. But before scientists can use stem cells for medical purposes, they must first learn how to harness their power. They can't treat disease until they learn how to manipulate stem cells to get them to develop into specific tissues or organs.

In this article, we will look at stem cells, find out how they work, discover their potential to treat disease and get inside the fierce debate surrounding their research and use.

What is a Stem Cell?

A stem cell is essentially the building block of the human body. The stem cells inside an embryo will eventually give rise to every cell, organ and tissue in the fetus's body. Unlike a regular cell, which can only replicate to create more of its own kind of cell, a stem cell is pluripotent. When it divides, it can make any one of the 220 different cells in the human body. Stem cells also have the capability to self-renew -- they can reproduce themselves many times over.

There are two types of stem cells: embryonic stem cells and adult stem cells. Embryonic stem cells come from an embryo -- the mass of cells in the earliest stage of human development that, if implanted in a woman's womb, will eventually grow into a fetus. When the embryo is between three and five days old, it contains stem cells, which are busily working to create the various organs and tissues that will make up the fetus.

Adults also have stem cells in the heart, brain, bone marrow, lungs and other organs. They are our built-in repair kits, regenerating cells damaged by disease, injury and everyday wear and tear. Adult stem cells were once believed to be more limited than stem cells, only giving rise to the same type of tissue from which they originated. But new research suggests that adult stem cells may have the potential to generate other types of cells, as well. For example, liver cells may be coaxed to produce insulin, which is normally made by the pancreas. This capability is known as plasticity or transdifferentiation.

So where do scientists get the stem cells they use in their research?

Acquiring Stem Cells for Research

In the early 1980s, scientists learned how to pull embryonic stem cells from a mouse and grow them in a laboratory. In 1998, they first reproduced human embryonic stem cells in a lab.

Photo courtesy University of Wisconsin Board of Regents

Culture trays containing human embryonic stems cells being stored in heat-controlled storage and studied by developmental biologist James Thomson's research lab at the University of Wisconsin in Madison

Where do researchers get human embryos? Embryos can either be made via reproduction -- merging sperm and egg -- or by cloning. Researchers aren't likely to create an embryo with sperm and egg, but many use fertilized embryos from fertility clinics. Sometimes, couples who are trying to have a baby create several fertilized embryos and don't implant them all. They may donate the ones that are left over to science.

Another way to create an embryo is via a technique called therapeutic cloning. This technique merges a cell (from the patient who needs the stem cell therapy) with a donor egg. The nucleus is removed from the egg and replaced with the nucleus of the patient's cell. (See How Cloning Works for a detailed look at the process). This egg is stimulated to divide either chemically or with electricity, and the resulting embryo carries the patient's genetic material, which significantly reduces the risk that his or her body will reject the stem cells once they are implanted.

Both methods -- using existing fertilized embryos and creating new embryos specifically for research purposes -- are controversial. But before we get into the controversy, let's find out how scientists get stem cell to replicate in a laboratory setting in order to study them.

Replicating Stem Cells in a Lab

An embryo that has developed for three to five days is called a blastocyst. A blastocyst is a mass of about 100 or so cells.

Photo courtesy Michael Vernon, West Virginia University


The stem cells are the inner cells of the blastocyst. They will ultimately develop into every cell, tissue and organ in the body.

Scientists remove stem cells from the blastocyst and culture them (grow them in a nutrient-rich solution) in a Petri dish in the laboratory. After the cells have replicated several times and are becoming too numerous for the culture dish, they are removed and placed into several other dishes. In just a few months, several stem cells can become millions of stem cells. Embryonic stem cells that have been cultured for several months without differentiating are referred to as a stem cell line. Cell lines can be frozen and shared between laboratories.

Photo courtesy University of Wisconsin Board of Regents

Microscopic 5x view of a colony of undifferentiated human embryonic stems cells being studied in developmental biologist James Thomson's research lab at the University of Wisconsin in Madison: The embryonic stem cell colonies are the rounded, dense masses of cells. The flat, elongated cells are fibroblasts used as "feeder cells."

Adult stem cells are much harder for scientists to work with because they are more difficult to extract and culture than their embryonic counterparts. Stem cells not only are hard to find in adult tissue, but scientists also have difficulty getting them to replicate in the laboratory.

But even embryonic stem cells, which can be grown effectively in the lab, are not easy to control. Scientists are still struggling to get them to grow into specific tissue types.

The State of Stem Cell Research

Ideally, scientists would like to be able to grow a particular type of cell in the laboratory and then inject it into a patient, where it would replace diseased tissue. But stem cells are not yet being used to treat disease because scientists still haven't learned how to direct a stem cell to differentiate into a specific tissue or cell type (brain vs. liver, for example) and to control that differentiation once the cells are injected into a person.

Scientists have not yet reached the stage where they can get stem cells to differentiate reliably.

Take the example of diabetes. To treat diabetics, scientists must not only create insulin-producing cells, but they must be able to regulate how those cells produce insulin once they are in the body.

In nature, stem cells are triggered to differentiate by internal and external cues. The internal cues are genes inside each cell, which are like a series of instructions that dictate how it should function. The external cues are chemicals released by other cells or contact with other cells, either of which may change the way the stem cell functions.

Scientists do know that turning genes on and off is crucial to the process of differentiation, so they have been experimenting by inserting certain genes into the culture dish and then using those genes to try to coax stem cells to differentiate into specific types of cells. But some sort of signal is needed to actually trigger the stem cells to differentiate. Scientists are still searching for that signal.

Photo courtesy University of Wisconsin Board of Regents

Differentiation success: Derived from human embryonic stem cells, precursor neural cells grow in a lab dish and generate mature neurons (red) and glial cells (green), in the lab of University of Wisconsin at Madison stem-cell researcher and neurodevelopmental biologist Su-Chun Zhang.

Photo courtesy University of Wisconsin Board of Regents

After transplantation into the brains of young mice, the neural precursor cells give rise to functioning neurons (red in A) and astrocytes (red in B), a star-shaped cell of the brain and spinal cord.

And there are other obstacles standing in the way of stem cell use. One is the problem of rejection. If a patient is injected with stem cells taken from a donated embryo, his or her immune system may see the cells as foreign invaders and launch an attack against them. Using adult stem cells could overcome this problem somewhat, since stem cells taken from the patient would not be rejected by his or her immune system. But adult stem cells are less flexible than embryonic stem cells and are harder to manipulate in the lab.

Next, let's examine how stem cells could potentially treat diseases.

Using Stem Cells to Treat Disease

If scientists can ultimately learn how to direct stem cells to differentiate into one type of tissue or another, they can use them for two very important medical purposes.

Photo courtesy University of Wisconsin Board of Regents

Culture trays containing human embryonic stems cells being viewed under a microscope and studied by developmental biologist James Thomson's research lab at the University of Wisconsin in Madison

First, pluripotent stem cells can be used to test new medications for safety and effectiveness. A medication could be tried out on a specific type of cell to gauge its response far more quickly than it could be tested in clinical trials. For example, scientists could use a cancer stem cell line to investigate whether a new anti-tumor drug stopped the cancer from growing.

Stem cells could also be used to repair cells or tissues that have been damaged by disease or injury. This type of treatment is known as cell-based therapy. One potential application is to inject embryonic stem cells into the heart to repair cells that have been damaged by a heart attack. In one Mayo Clinic study, researchers induced a heart attack in rats, then injected rodent embryonic stem cells into the damaged hearts. Eventually, the stem cells regenerated the damaged muscle tissue, improving the rats' heart function.

Stem cells may also one day be used to repair brain cells in patients with Parkinson's disease. Parkinson's patients are lacking the cells that produce a chemical messenger called dopamine. Without dopamine, their movements become jerky and uncoordinated, and they suffer from uncontrollable tremors. In studies, researchers have injected rodent embryonic stem cells into the brain of rats with Parkinson's disease. The stem cells generated dopamine-producing nerve cells, improving the rats' condition. Scientists hope they can one day replicate their success in human patients.

Eventually, scientists might even be able to grow entire organs in a laboratory to replace ones that have been damaged by disease. The idea is this: They would create a sort of scaffold out of a biodegradable polymer to shape the organ, and then seed it with either embryonic or adult stem cells. Growth factors specific to the organ would be added to guide the organ's development. The tissue-covered scaffold would then be implanted into the patient. As the tissue grew from the stem cells, the scaffold would degrade, leaving a complete ear, liver or other organ.

Some of the diseases that may one day be treated with cell-based therapy are:

Famous Crusaders for Stem Cell Research
Since 1991, when he was diagnosed with Parkinson's disease (a degenerative brain disorder that affects movement), actor Michael J. Fox has been a vocal proponent for stem cell research. His foundation has donated more than $35 million to help fund Parkinson's research. Fox and his foundation are hoping that scientists will one day be able to coax stem cells into producing dopamine, a chemical in the body that is deficient in patients with Parkinson's disease.

Photo courtesy National Institutes of Health (left), U.S. house of Representatives (right)

Michael J. Fox and Nancy Reagan

Former First Lady Nancy Reagan also became an advocate for stem cell research when her husband, former President Ronald Reagan, was stricken with Alzheimer's, another degenerative brain disease. He died of Alzheimer's in the summer of 2004.

Controversy Surrounding Stem Cell Research

Stem cell research has become one of the biggest issues dividing the scientific and religious communities around the world. At the core of the issue is one central question: When does life begin?

Photo courtesy University of Wisconsin Board of Regents

Microscopic 20x view of a colony of undifferentiated human embryonic stems cells being studied in developmental biologist James Thomson's research lab at the University of Wisconsin in Madison

To get stem cells, scientists either have to use an embryo that has already been conceived or else clone an embryo using a cell from a patient's body and a donated egg. Either way, to harvest an embryo's stem cells, scientists must destroy it. Although that embryo may only contain four or five cells, some religious leaders say that destroying it is the equivalent of taking a human life.

Photo courtesy Roslin Institute

Dolly (left)

Also at issue is the idea of cloning. If scientists can create an embryo in the lab, wouldn't they be able to implant that embryo into a surrogate mother's womb and allow it to develop into a baby? The idea of human cloning brings to mind frightening scenarios of babies genetically engineered to be "super-humans" with top IQs and super-hero-like physical capabilities; or babies created solely for the purpose of harvesting their organs. Cloning fears grew more fervent in 1997, when a group of Scottish researchers announced that they had successfully cloned a sheep named Dolly.

Even as scientists move forward in their understanding of stem cells and their ability to manipulate them, the ethical and political debates rage on. Many governments have placed tight restrictions on stem cell research or have tightly limited funding for it.

To bridge the debate, scientists are exploring less controversial avenues of research, using adult stem cells that are trained to act like embryonic stem cells, instead of creating a new embryo. Although they are not as pluripotent as embryonic stem cells, new research suggests that adult stem cells might be more flexible than scientists once imagined. Even if the outcome of the debate favors the use of stem cells, it will likely be at least a few more decades until stem cell therapies come into widespread use.

Stem Cells and Election Politics
The stem cell debate became a hotbed issue in the 2004 presidential election. During the campaign, presidential candidate John Kerry said he wanted to lift the barriers standing in the way of stem cell research in order to treat or even cure the millions of Americans suffering from debilitating diseases. President George W. Bush said he would allow research using existing embryonic stem cell lines, but for ethical reasons he would not fund the creation of additional stem cell lines. President Bush won his second term in the White House.


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