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Root Canal

 DE ENGLISH

 

A bus stops and 2 men get on. They sit down and engage in an animated conversation

 

The lady sitting next to them ignores them at first, but her attention is galvanized when she hears one of them say the following

 

"Emma come first.

Den I come.

Den two asses come together

I come once-a-more

Two asses, they come together again

I come again and pee twice

Then I come one lasta time

 

The lady can't take this any more, "You foul-mouthed sex obsessed pig," she retorted indignantly. "In this country. we don't speak aloud in Public places about our sex lives.

 

"Hey, coola down lady," said the man. "Who talkin'abouta sex? I'm a justa tellin' my frienda how to spell 'Mississippi'.

 

$5.00 says you're gonna read this a

+ نوشته شده در  Fri 22 Sep 2006ساعت 13:12  توسط مسعود  | 

Sunday, Sep. 24
GAME TIME
Carolina at Tampa Bay 1:00 p.m.
Chicago at Minnesota 1:00 p.m.
Cincinnati at Pittsburgh 1:00 p.m.
Green Bay at Detroit 1:00 p.m.
Jacksonville at Indianapolis 1:00 p.m.
N.Y. Jets at Buffalo 1:00 p.m.
Tennessee at Miami 1:00 p.m.
Washington at Houston 1:00 p.m.
Baltimore at Cleveland 4:05 p.m.
N.Y. Giants at Seattle 4:15 p.m.
Philadelphia at San Francisco 4:15 p.m.
St. Louis at Arizona 4:15 p.m.
Denver at New England 8:15 p.m.
Monday, Sep. 25
GAME TIME
Atlanta at New Orleans 8:30 p.m.
Open date: Dallas, Kansas City, Oakland, San Diego

Return to top

WEEK 4
Sunday, Oct. 1
GAME TIME
Arizona at Atlanta 1:00 p.m.
Dallas at Tennessee 1:00 p.m.
Indianapolis at N.Y. Jets 1:00 p.m.
Miami at Houston 1:00 p.m.
Minnesota at Buffalo 1:00 p.m.
New Orleans at Carolina 1:00 p.m.
San Diego at Baltimore 1:00 p.m.
San Francisco at Kansas City 1:00 p.m.
Detroit at St. Louis 4:05 p.m.
Cleveland at Oakland 4:15 p.m.
Jacksonville at Washington 4:15 p.m.
New England at Cincinnati 4:15 p.m.
Seattle at Chicago 8:15 p.m.
Monday, Oct. 2
GAME TIME
Green Bay at Philadelphia 8:30 p.m.
Open date: Denver, N.Y. Giants, Pittsburgh, Tampa Bay

+ نوشته شده در  Fri 22 Sep 2006ساعت 13:10  توسط مسعود  | 

The 400 Richest Americans
09.21.06, 10:00 AM ET


Rank Name Net Worth ($bil) Age Residence Source
1 William Henry Gates III 53.0 50 Medina, WA Microsoft
2 Warren Edward Buffett 46.0 76 Omaha, NE Berkshire Hathaway
3 Sheldon Adelson 20.5 73 Las Vegas, NV casinos, hotels
4 Lawrence Joseph Ellison 19.5 62 Redwood City, CA Oracle
5 Paul Gardner Allen 16.0 53 Seattle, WA Microsoft, investments
6 Jim C Walton 15.7 58 Bentonville, AR Wal-Mart
7 Christy Walton & family 15.6 51 Jackson, WY Wal-Mart inheritance
7 S Robson Walton 15.6 62 Bentonville, AR Wal-Mart
9 Michael Dell 15.5 41 Austin, TX Dell
9 Alice L Walton 15.5 57 Fort Worth, TX Wal-Mart
11 Helen R Walton 15.3 86 Bentonville, AR Wal-Mart
12 Sergey Brin 14.1 33 Palo Alto, CA Google
13 Larry E Page 14.0 33 San Francisco, CA Google
14 Jack Crawford Taylor & family 13.9 84 St Louis, MO Enterprise Rent-A-Car
15 Steven Anthony Ballmer 13.6 50 Bellevue, WA Microsoft
16 Abigail Johnson 13.0 44 Boston, MA Fidelity
17 Barbara Cox Anthony 12.6 83 Honolulu, HI Cox Enterprises
17 Anne Cox Chambers 12.6 86 Atlanta, GA Cox Enterprises
19 Charles De Ganahl Koch 12.0 70 Wichita, KS oil, commodities
19 David Hamilton Koch 12.0 66 New York, NY oil, commodities
21 Forrest Edward Mars Jr 10.5 75 McLean, VA candy
21 Jacqueline Mars 10.5 67 Bedminster, NJ candy
21 John Franklyn Mars 10.5 70 Arlington, VA candy
24 Carl Icahn 9.7 70 New York, NY leveraged buyouts
25 John Werner Kluge 9.1 92 Palm Beach, FL Metromedia
+ نوشته شده در  Fri 22 Sep 2006ساعت 13:9  توسط مسعود  | 

Little Girl, 3 Million Years Old, Offers New Hints on Evolution

If the fossil Lucy, the most famous woman from out of the deep human past, had a child, it might have looked a lot like the bundle of skull and bones uncovered by scientists digging in the badlands of Ethiopia.

The paleontologists who are announcing the discovery in the journal Nature today said the 3.3-million-year-old fossils were of the earliest well-preserved child ever found in the human lineage. It was estimated to be about 3 years old at death, probably female and a member of the Australopithecus afarensis species, the same as Lucy’s.

An analysis of the skeleton revealed evidence of a species in transition, the scientists said in interviews yesterday.

+ نوشته شده در  Fri 22 Sep 2006ساعت 12:40  توسط مسعود  | 

Former Enron executive Jeffrey Skilling is shown in this 2006 file photo. Skilling was ticketed for public intoxication earlier this month in Dallas, according to a newspaper report. Skilling, convicted in May of 19 counts of fraud, conspiracy, insider trading and lying to auditors in the investigation following the company's 2001 collapse, was arrested about 1:45 a.m. Sept. 9, 2006 according to a report in Wednesday's online edition of the Houston Chronicle.  (AP Photo/Pat Sullivan)
The Enron crook guy that costed me so much money got arrested for public intoxication in Dallas Just last week .
He is planed to go and serve minimum of 30 years in jail ( drink cold water , sort of speaking )
+ نوشته شده در  Thu 21 Sep 2006ساعت 10:23  توسط مسعود  | 


Earth Biofuels, Inc. (EBI) is a vertically integrated energy company and the first of its kind in the biofuels industry. As a producer, distributor, and marketer of biodiesel fuel, the company operates at each level of the supply chain from raw materials to the retail level. Additionally, the company is rapidly expanding, through construction or acquisition, into the ethanol market.

Earth Biofuels, Inc. is a publicly traded company (OTCBB: EBOF) on the OTC Bulletin Board exchange. As a majority-owned subsidiary of Apollo Resources International, Inc. (OTCBB: AOOR), EBI’s stated mission is to reduce America’s dependence on foreign energy and improve environmental conditions through renewable domestic alternatives.
+ نوشته شده در  Thu 21 Sep 2006ساعت 7:37  توسط مسعود  | 

From a desperate investor ( Massoud S ) to his wife

 

Dear wife its true that we lost lots of money but don’t worry , this is the end. The ethanol stocks have bottomed up and there is no way but up. Its true that some companies have delayed the IPO,s but with the winter coming and the crises in Middle east something will happen and that will be the time to sell but for the time being I will hold on to VSE since there is no way but UPPPPPPPPPPPPP

+ نوشته شده در  Wed 20 Sep 2006ساعت 12:15  توسط مسعود  | 

AT THE CURRENT RATE OF PRODUCTION OF ETHANOL THERE WILL BE A 20 MILLION GALLON INCREASE FROM THE 2ND QUARTER. THE AVERAGE SPOT PRICE BEING 2.10 TO 2.45 THEY SHOULD BE BLOWING OUT EARNINGS ESIMATE SOMEWHERE AT .80 PER SHARE. EARNINGS IS WHAT PEOPLE ARE LOOKING FOR. AT 18.10 SHARE PRICE THIS IS AN ABSOLUTE BARGAIN. WHAT A GROWTH STORY WITH 3 ADDITIONAL 110 MILLION PLANTS COMING IN THE NEXT 14 MONTHS. SEE EVERYONE AT THE FINISH LINE.

+ نوشته شده در  Wed 20 Sep 2006ساعت 12:9  توسط مسعود  | 

As oil prices have dropped, some managers are putting more money into exchange traded funds focused on technology.

Why? Take a look at iShares S&P Global Technology Sector (AMEX:IXN - News). In the past month, it's up 6.9%.

The most popular tech ETF, Technology Select Sector SPDR (AMEX:XLK - News), has gained 6.7% in the past month.

At the same time, Energy Select Sector SPDR (AMEX:XLE - News) is down more than 9.61% in the past month. It's the most heavily traded energy ETF, averaging 17 million shares per day.

"We're seeing a rotation out of energy into tech," said Anthony Welch, a money manager at Sarasota Capital Strategies. "We really noticed it around mid-July. As a result, we've sold all of our energy positions."

Out Of Energy

Along with Ian Naismith, his co-manager at the Florida-based private asset management firm, he actually began moving out of energy several months ago.

Now the managers are eyeing tech. "We're approaching the time of year when tech is a seasonal favorite of ours," said Welch.

Much of the sector's revenue is produced between October and January.

That's especially true with software makers.

"We just learned today you can go online and beta test Microsoft's new Vista operating system," said Naismith. "That's sure to cause a lot of excitement in the marketplace."

The veteran ETF pickers like charts for SPDRs Technology and iShares S&P Global Technology.

"Both have been in an upward trend the last couple of months," said Welch. "They're both off their April highs, though. So technically they've only been looking better since mid-July."

Seasonal Trend

If seasonal trends kick in, that would give tech ETFs more momentum. "You don't want to buy these until you have a clear breakout," said Naismith. "So we're waiting for the market to tell us whether seasonal factors are indeed a head wind."

If they do jump in, the duo say they'll put a protective stop under the ETFs.

If prices go up, they'll adjust those stops. "Tech is more volatile, and it's still early in this rotation period," said Naismith.

The top holdings in both iShares S&P Global Technology and SPDRs Technology are nearly identical.

"Both funds correlate very strongly with one another," said Welch. "That's why most people would probably want to invest in SPDRs Technology. It has quite a bit more volume, has half the expense ratio and is U.S.-based."


+ نوشته شده در  Wed 20 Sep 2006ساعت 11:52  توسط مسعود  | 

GS CleanTech Corporation, through its subsidiaries, provides various environmental management services to industrial organizations in the United States. The company’s environmental services include transportation, distribution, recycling, and disposal services specific to the materials and processes of its clients for a range of industrial wastes; and field services, such as remedial, industrial cleaning, and other related services. It offers its services through four service centers located in Lowell, Sandwich, and Milford, Massachusetts; and Plainville, Connecticut. The company was formerly known as KBF Pollution Management, Inc. and changed its name to Veridium Corporation. Further, it changed its name to GS CleanTech Corporation in July 2006. The company was founded in 1984 and is headquartered in New York City. GS CleanTech Corporation is a subsidiary of GreenShift Corporation.
+ نوشته شده در  Wed 20 Sep 2006ساعت 11:17  توسط مسعود  | 

Year 2032
 

A father and his son are walking the Manhattan streets
when the father stops at a vacant lot, takes a deep
breath and tells his son: "To think that at one time
here on this very lot stood the Twin Towers."

The son looks at his father and asked: "Dad, what are
the Twin Towers?"

Father says: "My dear son, the Twin Towers were two
tremendously tall buildings with lots of offices that
were the heart of the United States, but approximately
31 years ago, several Arabs destroyed the buildings."

The boy then thought for a minute and then asked his
father: "Daddy, what are Arabs?"
+ نوشته شده در  Mon 18 Sep 2006ساعت 18:9  توسط مسعود  | 





+ نوشته شده در  Mon 18 Sep 2006ساعت 5:16  توسط مسعود  | 

As you know this stock is being clobbered and it hurts, man to say the least!

I like you are waiting for the energy stocks to take off again and they will, but I am afraid that is might be quite a while. Ben Stein says that gas prices based on futures will be $2/gal. If that is true were in for a lot more hurt.

So I started to examine that Dow and found that the beverage stocks are starting to move. I looked at Hans, LBIX, JSDA and out of the three, I believe the greatest gain as least short term is LBIX. I am told that they are going to announce their quarter results at the end of the month and the street says they only have to beat a .02 EPS to cause the stock to climb.

I did a little investegation and here is what I found out about the company:

1) 40% growth rate.
2) They own the rights to Hansen Naturals in Canada. (monster selling hot)
3) Just announced the opening of a distribution center in Chicago to service the southern part of the USA's market.
Ceasar's cockail drink sales ramping.
4) Stock expected to hit double digits in the near future.
5) Last quarter shelving costs 5x (from $220K to $1.2M)
6 Insider sales of stock ramping, most buying in mid $5's.
7) CEO bought 1M shares over the counter. Something I like to see, to say the least!
8) Just landed a contract with Loblaws (a 1000 store chain)
9) We have had one of the hottest summers and all beverage companies have experienced a ramp in sales!
10) Guru Boys rate the stock as an "outperform"
11) They are only 2.6% institutional owned and when the big boys rate it as a "BUY", it will rocket people!

What an opportunity to double your money!

And next quarter they will present the results of a huge ad campaign that they are launching in California. It was in that state that they JUST won two "BEST TASTING BEVERAGE" awards competing against every known beverage company including products that are being developed and will be on the market in the future!
+ نوشته شده در  Fri 15 Sep 2006ساعت 9:24  توسط مسعود  | 

Americans always overeact in the short-term, there is no long-term vision like in Japan or Brazil. Oil prices are down today, gas prices are down today so we forget the long-term objective of independence from foreign oil, improving the trade deficit by not sending hundreds of billions of dollars overseas, improving the rural economy and in doing so create jobs at John Deere, Catepillar, Ford, Monsanto, Pioneer, etc. etc. We will wait until gas prices are $5.00 a gallon or the countries that hate us shut us off and then look to the government for an immediate solution. It's just our way.
+ نوشته شده در  Fri 15 Sep 2006ساعت 9:8  توسط مسعود  | 

Source BBC News | CNN News | Forbes News | Google News | NY Times News | Reuters News | Yahoo News | Games | News Forum | E-Mail

Category Business | Entertainment | Health | Odd | Politics | Science | Sports | Technology | Top Stories
+ نوشته شده در  Fri 8 Sep 2006ساعت 6:23  توسط مسعود  | 

Becky ; I bought the stock at 21.15 and it already dropped 10 percent probably due to the
new fields in gulf of Mexico and the tension of sanctions that is cooling down for Iran ,
then you can tell easily that Ethanol is no longer the talk of town simply because it might cost a lot more than gas in coming month
+ نوشته شده در  Thu 7 Sep 2006ساعت 12:54  توسط مسعود  | 

E85

E85 (85% ethanol and 15% gasoline) is an approved motor fuel that can be used in Flexible Fuel Vehicles (FFV’s). Today there are approximately 6 million FFV’s on U.S. roads manufactured by domestic and foreign automakers. VeraSun launched its branded E85 product "VE85" in May of 2005. VE85 is now available at select retailers in SD, MN, IL, WI, PA IN, and IA.

E85

For more information, visit the VE85 Website.

+ نوشته شده در  Thu 7 Sep 2006ساعت 12:49  توسط مسعود  | 

Ethanol Production Process

The pethanol results in approximately 2.8rocess of converting corn into  gallons of denatured ethanol and 18 lbs. of Distillers Grains from every bushel of corn. This process is described below.

Production Process

+ نوشته شده در  Thu 7 Sep 2006ساعت 12:48  توسط مسعود  | 

Octane
Octane
Octane
+ نوشته شده در  Thu 7 Sep 2006ساعت 7:42  توسط مسعود  | 

+ نوشته شده در  Thu 7 Sep 2006ساعت 7:40  توسط مسعود  | 

Giacomo Girolamo Casanova (April 2, 1725 in VeniceJune 4, 1798, in Dux, Bohemia, now Duchcov, Czech Republic) was a famous Venetian adventurer, writer and womanizer. He is universally known for his ability to seduce and conquer many a woman's heart. According to his autobiography Histoire de ma vie (Story of My Life), regarded as one of the most authentic sources of the customs and norms of European social life during the 18th century, he slept with 122 women during his lifetime.

Although he is often associated with Don Juan because both of them seduced many women, Casanova is in fact very different from his fictitious counterpart. While Don Juan is a legend, Casanova is a historical character. Unlike Don Juan, Casanova genuinely loved the women he seduced, often remaining friends with them long after their affair ended. His numerous love affairs are only one aspect of Casanova's life.

+ نوشته شده در  Sun 3 Sep 2006ساعت 13:21  توسط مسعود  | 

Extended-Hours Trading
+ نوشته شده در  Thu 31 Aug 2006ساعت 4:31  توسط مسعود  | 

Advanced Order Types

Conditional Trades

Set order triggers for stocks and options based on price movement of other stocks or indices.

Contingent Orders

A contingent order triggers a stock or option order based on the price movement of any stock, or up to 40 selected indices.

  • The order can be for stock or single-leg options.
  • Contingent orders can be either day orders or good-'til-canceled (GTC) orders.
  • For day contingent orders, both the contingent criterion and order are good for the day only.
  • For GTC contingent orders, both the contingent criterion and order are good for 120 days.
  • If the contingency is met on day 60, the triggered order is live for 60 days.

Contact Us

  • Call a dedicated trading specialist at
    800-503-3407
  • Send an e-mail
  • Instant message a Fidelity representative

Illustration of hypothetical Contingent Order trade

For illustrative purposes only.

One-Triggers-the-Other (OTO)

A one-triggers-the-other order actually creates both a primary and a secondary order. If the primary order executes, the secondary order automatically triggers to release to the market.

An OTO order can help you save time: place a buy order as your primary order and a corresponding sell limit or sell stop at the same time. Or, if you trade options regularly, use a one-triggers-the-other order to leg into a buy-write or covered call position.

  • An OTO can be created for any combination of stock and/or single-leg options.
  • Time in force must be the same for both orders.
  • For OTO orders that are good 'til canceled (GTC), the whole order is good for 120 days (e.g., if the primary order executes on day 15, the secondary order is live for 105 days).
  • If the primary order is canceled, the secondary order is also canceled.
  • If the secondary order is canceled, the primary order remains open as a separate order.

Illustration of hypothetical One-Triggers-the-Other trade

For illustrative purposes only.

One-Cancels-the-Other (OCO)

With an OCO order, two orders are live in the market at the same time. If either order executes, the other automatically triggers to cancel. If either order is canceled, however, the other still remains open.

  • Orders can be for any combination of stocks or single-leg options.
  • When orders are placed for retirement accounts, a price reasonability-check helps prevent both OCO orders from executing in a fast market. This feature does not exist in non-retirement accounts.
  • Orders can be for the same shares of the same stock, but on opposite sides of the market (sell limit and sell stop).

Illustration of hypothetical One-Cancels-the-Other trade

For illustrative purposes only.


Trailing Stops

Automatically adjust your market or limit stop order for stocks when market conditions move in your favor.

  • Use for day orders or good-'til-canceled (GTC) orders, good for 120 days.
  • Set with a percentage (%) or dollar ($) trail value.

Illustration of hypothetical Trailing Stops trade

For illustrative purposes only.


Multileg Options

View and trade multileg option pairings at National Best Bid or Offer (NBBO) or better.

  • Choose your strategy: Buy Writes, Spreads (Vertical, Calendar, Diagonal, and Ratio), Straddles, Strangles, Collars, Combinations, Condors, or Butterfly Spreads.
  • Navigate through multileg strategies for every month and strike price for an underlying stock or index.
  • View streaming theoretical price combinations of pairs or individual leg prices.

Directed Trading or Intelligent Order Routing

Pick your market, exchange or ECN:

  • Integrates streaming time and sales with consolidated quotes from multiple market centers.
  • Customizable trading ticket speeds order entry to the market center of your choice.
  • No additional premiums.

Let Fidelity do it for you with intelligent order routing technology:

  • Scans market in real-time.
  • Dual algorithms act on visible and hidden liquidity to access routing technology.
  • Bases orders on current prices and sizes.

Order Destinations

  • Primary Markets — NYSE, NASDAQ SuperMontage and the Amex
  • Regional Exchanges — Boston, NSX (Cincinnati), Midwest, Pacific /ARCA.
  • ECNs — BRUT, INET and Bloomberg TradeBook (BTRD).

Basket Trading

  • Monitor, trade and manage a minimum of 2 to 50 stocks as a single entity — using cash or margin — any time during standard market sessions.
  • Automatically allocate your investment across multiple securities with an equal dollar amount or number of shares.
  • Assign specific share tax lots after your order has been entered.
  • Group your investments by stock characteristic, market sector, investment goal, or any other classification.
  • Create up to 20 watch baskets, track their performance, and buy them at a later date at the market price. Change the selection or number of stocks anytime.

   More about Basket Trading Disclosures and risks



Extended-Hours Trading

  • Trade at your convenience: Place trades online before and after standard daytime market hours.
  • Check the price before you order: Free real-time quotes are available during the extended-hours trading sessions. Quotes are best bid and ask and size across a number of linked ECNs, and the NASDAQ.
  • Automatically get the best prices: ECN systems electronically match buyers and sellers, ranked first by price, next by time or order places.
  • Enjoy low commissions: After-hours trades follow your regular commission schedule1.

Trading Hours: Pre-market trades can be placed 7:30 a.m. and 9:15 a.m. ET and are eligible for execution between 8:00 a.m. to 9:15 a.m. ET. After-hours trades may be placed and are executed between 4 p.m. and 8 p.m. ET, Monday to Friday. There is no trading on market holidays2.

Eligible Securities: All NASDAQ (National Market and Small Cap) and listed securities.


  1. All orders are valid only for that particular Premarket or After Hour trading session.
  2. Extended Hours trading involves additional risks and may not be appropriate for all investors.

PDFs require Adobe® Reader®

Options trading entails significant risk and is not appropriate for all investors. Prior to trading options, you must receive from Fidelity Investments a copy of Characteristics and Risks of Standardized Options (PDF) by clicking on the hyperlink text, and call 1-800 FIDELITY to be approved for options trading.

NBBO price is determined with the best single leg prices on a single market from any of the six option exchanges (AMEX, CBOE, ISE, BOX, or PHLX) at the time the order was executed or within 30 seconds of the order being received by the CBOE's order routing system.

System availability and response time may be subject to market conditions.

Margin is extended by National Financial Services, Member NYSE, SIPC.

+ نوشته شده در  Thu 31 Aug 2006ساعت 4:30  توسط مسعود  | 

Common animal (including human) organs include the heart, lungs, brain, eye, stomach, spleen, pancreas, kidneys, liver, intestines, skin, uterus, and bladder. Animal organs inside the thorax or abdomen are often referred to as internal organs (this term is not used for organs inside the head or other parts of the body). The internal organs collectively are often called viscera, the plural of the rarely-used viscus.

Many organs can be transplanted from a healthy or recently deceased person to another with a diseased or damaged organ. Work is underway to allow some organs to be transplanted from other animals to humans (xenotransplantation).

Plant organs

Plant organs can be divided into vegetative and reproductive. Vegetative plant organs are root, stem and leaf, while reproductive are flower, seed and fruit.

The vegetative organs are essential for maintaining the life of a plant (they do the vegetative, vital functions, like photosynthesis), while the reproductive are essential in the reproduction. But, if there is asexual vegetative reproduction, the vegetative organs are those which create the new generation of plants, and therefore usually creating a clonal colony.

Organ systems

A group of related organs is an organ system. Organs within a system may be related in any number of ways, but relationships of function are most commonly used. For example the urinary system comprises organs that work together to produce, store, and carry urine.

The functions of organ systems often share significant overlap. For instance, the nervous and endocrine system both operate via a shared organ, the hypothalamus. For this reason, the two systems are combined and studied as the neuroendocrine system. The same is true for the musculoskeletal system, which involves the relationship between the muscular and skeletal systems.

See also

+ نوشته شده در  Wed 30 Aug 2006ساعت 9:7  توسط مسعود  | 

+ نوشته شده در  Wed 30 Aug 2006ساعت 8:55  توسط مسعود  | 

+ نوشته شده در  Wed 30 Aug 2006ساعت 8:51  توسط مسعود  | 

+ نوشته شده در  Wed 30 Aug 2006ساعت 8:50  توسط مسعود  | 

+ نوشته شده در  Wed 30 Aug 2006ساعت 8:48  توسط مسعود  | 

Description

In organisms that reproduce sexually, once a sperm fertilizes an egg cell, the result is a cell called the zygote that has all the DNA of two parents. In plants, animals, and some protists, the zygote will begin to divide by mitosis to produce a multicellular organism. The term embryo refers to the early stages of this development, after the zygote has divided at least once, but before the process has completed to produce the next stage of development.

In animals, the development of the zygote into an embryo proceeds through specific recognizable stages of morula, blastula, and gastrula. This process involves the creating of a hollow sphere of cells in which three tissue layers develop. In plants. the process is not so standard. The stages of embryo development in plants is more dependent upon the kind of plant being produced.

Information

  • Plants: In botany, a seed plant embryo is part of a seed, consisting of precursor tissues for the leaves, stem (see hypocotyl), and root (see radicle), as well as one or more cotyledons. Once the embryo begins to germinate — grow out from the seed — it is called a seedling. Plants that do not produce seeds, but do produce an embryo include the bryophytes and ferns. In these plants, the embryo is a young plant that grows attached to a parental gametophyte.
  • Animals: The embryo of a placental mammal is defined as the organism between the first division of the zygote (a fertilized ovum) until it becomes a fetus. In humans, the embryo is defined as the product of conception from implantation in the uterus through the eighth week of development. An embryo is called a fetus at a more advanced stage of development and up until birth or hatching. In humans, this is from the eighth week of gestation. In other vertebrate animals, the embryo develops inside an egg. Invertebrate animals also develop from an embryo.

Growth of the Human Embryo

Week 1-4 After conception, the embryo will begin to "search" for a place to attach to the wall of the uterus (endometrium). When it comes into contact with the endometrium and implants itself there, the connections between the mother and the embryo will begin to form, including the umbilical cord. The embryo's growth centers around an axis, which will become the spine and spinal cord.

Week 5-6 Chemicals produced by the embryo stop the woman's menstrual cycle. The brain begins to develop, showing brain wave activity at about the 6th week. The heart will begin to beat around the same time. Stubs begin to be visible where arms and legs will grow later. All of the main organs begin to grow. The head represents about one half of the embryo's axial length, and more than half of the embryo's mass.

Week 7-8 The embryo's blood type becomes apparent. Embryo is capable of motion, and the eyes begin to form. Most organs have developed or have begun developing. At the end of the 8th week, the embryonic stage is over, and the fetal stage begins.

See also

+ نوشته شده در  Wed 30 Aug 2006ساعت 8:47  توسط مسعود  | 

+ نوشته شده در  Wed 30 Aug 2006ساعت 8:46  توسط مسعود  | 

Stem cells in animals are primal undifferentiated cells that retain the ability to produce an identical copy of themselves when they divide (self-renew) and differentiate into other cell types. In higher plants this function is the defining property of the meristematic cells. Stem cells have the ability to act as a repair system for the body, because they can divide and differentiate, replenishing other cells as long as the host organism is alive.

Medical researchers believe stem cell research has the potential to change the face of human disease by being used to repair specific tissues or to grow organs. Yet there is general agreement that, "significant technical hurdles remain that will only be overcome through years of intensive research."[9]

The study of stem cells is attributed as beginning in the 1960s after research by Canadian scientists Ernest A. McCulloch and James E. Till.

Contents

[hide]

Stem cell types

Potency

The potency specifies the differentiation potential (the potential to differentiate into different cell types) of the stem cell.

  • Totipotent stem cells are produced from the fusion of an egg and sperm cell. Cells produced by the first few divisions of the fertilized egg cell are also totipotent. These cells can differentiate into embryonic and extraembryonic cell types.
  • Pluripotent stem cells are the descendants of totipotent cells and can differentiate into cells derived from the three germ layers.
  • Multipotent stem cells can produce only cells of a closely related family of cells (e.g. hematopoietic stem cells differentiate into red blood cells, white blood cells, platelets, etc.).
  • Unipotent cells can produce only one cell type, but have the property of self-renewal which distinguishes them from non-stem cells.

Sources

Stem cells are also often categorized according to their source, as either adult, embryonic, cancer or cord blood stem cells.

  • Adult stem cells are undifferentiated cells found among differentiated cells of a specific tissue and are mostly multipotent cells. They are more accurately called somatic (Greek σωμα sōma = body) stem cells, because they need not come from adults but can also come from children or umbilical cords. Particularly interesting are adult stem cells termed "spore-like cells". They are present in all tissues[10] and seem to survive long time periods and harsh conditions.
  • Embryonic stem cells are cultured pluripotent cells obtained from the undifferentiated inner mass cells of an early stage human embryo (sometimes called a blastocyst, which is an embryo that is between 50 to 150 cells). Embryonic stem cell research is "thought to have much greater developmental potential than adult stem cells," according to the National Institutes of Health.[11] Research using embryonic stem cells remains at the zenith of stem cell science because, unlike somatic cells, embryonic stem cells are pluripotent. However, research using stem cells derived from the human embryo is still in the basic research phase, as these stem cells were first isolated in 1998 (at least for humans), whereas adult stem cells have been studied since the 1960s.[12] Research with embryonic stem cells derived from humans is controversial because, in order to start a stem cell 'line' or lineage, the destruction of a human embryo is usually required. In an attempt to overcome these moral, political and ethical hurdles, medical researchers have been experimenting with alternative techniques of obtaining embryonic stem cells by extraction, which does not involve the cloning or destruction of a human embryo.
  • Cord blood stem cells (hematopoietic stem cells) are derived from the blood of the placenta and umbilical cord after birth. Since 1988 these cord blood stem cells have been used to treat Gunther's disease, Hunter syndrome, Hurler syndrome, Acute lymphocytic leukemia and other blood and immune disorders occurring mostly in children. Umbilical cord blood use has become so common that there are now umbilical cord blood banks that accept donations from parents. It is collected by removing the umbilical cord, cleansing it and withdrawing blood from the umbilical vein. This blood is then immediately analyzed for infectious agents and the tissue-type is determined. The cord blood is processed and depleted of red blood cells before being stored in liquid nitrogen for later use, at which point it is thawed, washed of the cryoprotectant, and injected through a vein of the patient. This kind of treatment, where the stem cells are collected from another donor, is called allogeneic treatment. When the cells are collected from the same patient on whom they will be used, it is called autologous and when collected from identical individuals (i.e. homozygous twin), it is referred to as syngeneic.

Treatments

Main article: Stem cell treatments

Medical researchers believe that stem cell research has the potential to change the face of human disease. A number of current treatments already exist, although the majority of them are not commonly used because they tend to be experimental and not very cost-effective. Medical researchers anticipate being able to use technologies derived from stem cell research to treat cancer, spinal cord injuries, and muscle damage, amongst a number of other diseases, impairments and conditions. However, there still exists a great deal of social and scientific uncertainty surrounding stem cell research, which could possibly be overcome by gaining the acceptance of the public and through years of intensive research.

Stem cells however are already used extensively in research, and some scientists do not see cell therapy as the first goal of the research, but see the stem cells as a tool worthy in itself. [1]

Controversy surrounding stem cell research

Main article: Stem cell controversy

There exists a widespread controversy over stem cell research that emanates from the techniques used in the creation and usage of stem cells. Embryonic stem cell research is particularly controversial because, with the present state of technology, starting a stem cell 'line' requires the destruction of a human embryo and/or therapeutic cloning. Opponents of the research argue that this practice is a slippery slope to reproductive cloning and tantamount to the instrumentalization of a potential human being. Contrarily, medical researchers in the field argue that it is necessary to pursue embryonic stem cell research because the resultant technologies are expected to have significant medical potential. The ensuing debate has prompted national and international authorities to seek suitable regulatory frameworks and highlighted the fact that stem cell research represents a social and ethical challenge.

Key events in stem cell research

See also

References

  1. ^ National Institutes of Health, "Stem Cell Basics," July 19, 2004.
  2. ^ Vacanti MP, Roy A, Cortiella J, Bonassar L, Vacanti CA (2001). "Identification and initial characterization of spore-like cells in adult mammals". J Cell Biochem 80 (3): 455-60. PMID 11135375.
  3. ^ National Institutes of Health, Stem Cell FAQ, April 13, 2005.
  4. ^ Graham, Judith and Schodolski, Vincent J., "Son of former President Reagan enters the fray with a speech at the Democratic convention." Chicago Tribune, July 27, 2004.
  5. ^ Wicha MS, Liu S, Dontu G (2006). "Cancer stem cells: an old idea--a paradigm shift.". Cancer Res 66: 1883-90. PMID 16488983.
  6. ^ Bonnet D, Dick JE (1997). "Human acute myeloid leukemia is organized as a hierarchy that originates from a primitive hematopoietic cell.". Nat Med 3: 730-7. PMID 9212098.
  7. ^ Shostak S (2006). "(Re)defining stem cells". Bioessays 28 (3): 301-8. PMID 16479584.
  8. ^ Shinin V, Gayraud-Morel B, Gomes D and Tajbakhsh S (2006). "Asymmetric division and cosegregation of template DNA strands in adult muscle satellite cells". Nat Cell Biol 8 (7). Entrez PubMed 16799552
  9. ^ National Institutes of Health, "Stem Cell Basics," July 19, 2004.
  10. ^ Vacanti MP, Roy A, Cortiella J, Bonassar L, Vacanti CA (2001). "Identification and initial characterization of spore-like cells in adult mammals". J Cell Biochem 80 (3): 455-60. PMID 11135375.
  11. ^ National Institutes of Health, Stem Cell FAQ, April 13, 2005.
  12. ^ Graham, Judith and Schodolski, Vincent J., "Son of former President Reagan enters the fray with a speech at the Democratic convention." Chicago Tribune, July 27, 2004.
  13. ^ Wicha MS, Liu S, Dontu G (2006). "Cancer stem cells: an old idea--a paradigm shift.". Cancer Res 66: 1883-90. PMID 16488983.
  14. ^ Bonnet D, Dick JE (1997). "Human acute myeloid leukemia is organized as a hierarchy that originates from a primitive hematopoietic cell.". Nat Med 3: 730-7. PMID 9212098.
  15. ^ Shostak S (2006). "(Re)defining stem cells". Bioessays 28 (3): 301-8. PMID 16479584.
  16. ^ Shinin V, Gayraud-Morel B, Gomes D and Tajbakhsh S (2006). "Asymmetric division and cosegregation of template DNA strands in adult muscle satellite cells". Nat Cell Biol 8 (7). Entrez PubMed 16799552

External links


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